Adapting Water Management A primer on coping with climate change

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March 2009

John H. Matthews, Tom Le Quesne

WWF Water Security Series 3 Adapting Water Management A primer on coping with climate change


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WWFs Water Security Series sets out key conceptsin water management in the context of the need forenvironmental sustainability. The series builds on lessonsfrom WWFs work around the globe, and on state-of-the-art thinking from external experts. Each primer inthe Water Security Series will address specic aspects

of water management, with an initial focus on theinter-related issues of water scarcity, climate change,infrastructure and risk.

Understanding Water Security

As an international network, WWF addresses globalthreats to people and nature such as climate change,the peril to endangered species and habitats, andthe unsustainable consumption of the worlds naturalresources. We do this by inuencing how governments,businesses and people think, learn and act in relationto the world around us, and by working with localcommunities to improve their livelihoods and theenvironment upon which we all depend.

Alongside climate change, the existing and projectedscarcity of clean water is likely to be one of the keychallenges facing the world in the 21st Century. Thisis not just WWFs view: many world leaders, includingsuccessive UN Secretaries General, have said as muchin recent years. Inuential voices in the global economyare increasingly talking about water-related risk as anemerging threat to businesses.

If we manage water badly, nature also suffers froma lack of water security. Indeed, the evidence is thatfreshwater biodiversity is already suffering acutelyfrom over-abstraction of water, from pollution of rivers,lakes and groundwater and from poorly-planned waterinfrastructure. WWFs Living Planet Report shows thatdeclines in freshwater biodiversity are probably thesteepest amongst all habitat types.

As the global population grows and demand for food andenergy increases, the pressure on freshwater ecosystemswill intensify. To add to this, the main effects of climatechange are likely to be felt through changes to thehydrological cycle.

WWF has been working for many years in many parts of the world to improve water management. Ensuring watersecurity remains one of our key priorities.

Acknowledgements

The authors would like to thank Joerg Hartmann, GuyPegram of Pegasys Systems, Jamie Pittock, and BartWickel for their thoughtful editorial and intellectualcontributions during the early stages of our musings.

Additional comments from Glyn Davies, Phillip Leonard,Li Lifeng, Stuart Orr, Dave Tickner, and Kit Vaughan

were immensely useful during the revision process.External reviewers included David Braun and Allison

Aldous of The Nature Conservancy and PeterMcCornick of the Nicholas School at Duke University,as well as a review of an early version of these musingsby the International Water Associations journal Water21 .

We would also like to express our appreciation to thefreshwater participants in the 2008 WWF San FranciscoClimate Camp and to the freshwater and climatechange staff at WWF-India, WWF-China, WWF-UK,and WWF-Brazil in shaping our ideas and imagesof what climate adaptation can and should be forfreshwater ecosystems.

The authors would like to acknowledge the serieseditors: Dave Tickner, Tom Le Quesne, and Mica Ruiz.


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04 SUMMARY

06 INTRODUCTION

07 PART AWhat does climate change feel like infreshwater?10 Freshwater climate change and precipitation13 How can we describe freshwater impacts

from climate change?16 Relative vulnerabilities: Developing contrasts

18 PART BPrinciples and priorities19 How can you think about what you can do?21 What is climate adaptation?24 What isnt climate adaptation?26 Identifying vulnerability and

embracing uncertainty

28 PART CWhat can you do in response to climatechange?

35 Further reading

CONTENTS

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Summary:

Withdrawals of water, the construction of dams and otherhard infrastructure, pollution, land-use shifts, invasivespecies, and habitat modication and destruction havedegraded many rivers, lakes and wetlands. In recentdecades anthropogenic climate change has also begun toalter freshwater ecosystems, and this force will continueto strengthen for the foreseeable future. For freshwaterecosystems, shifts in precipitation and evaporation

patterns will be a far more important aspect of climatechange than air temperature alone. Climate change maybe manifested in different ways, all of which have beenobserved in recent decades in different parts of the world:

Gradually, through a slow shift in the mean of someclimate variable;

Through increases in the frequency or intensity of extreme weather events such as oods or droughts an increase in climate variability;

Through sudden state-level changes, where a periodof climate stability is followed by a period of rapidchange before leading to some new stable period.

Climate change impacts on lakes, wetlands and riversdiffer fundamentally from effects on other biomes suchas forests or coral reefs because: (a) most bodies of freshwater are being used by humans and have not existedin a wild state for long periods of time; (b) managementof freshwater ecosystems must include their connectedterrestrial, estuarine, and marine biomes, since theycontribute substantially to freshwater health; and (c) theelements of climate that are most relevant to freshwaterare subject to high temporal and spatial uncertainty.

The impacts of climate change on freshwater ecosystemscan be characterised by shifts in water quality (e.g.,

pollutants, temperature, dissolved oxygen), water quantity,and water timing (normal ood and dry periods). Globally,water timing is likely to be the most important impact forboth humans and other species since it directly affectsboth water quantity and quality and because humansand other species often exhibit behavior that dependson predictable changes in ow. Unfortunately, it may alsobe the most difcult variable for models to predict with

high condence. As a result, water policy should focus onchanges at sub-annual resolution, such as seasonally ormonthly. Moreover, uncertainty should not be an excusefor inaction. Indeed, the process of reducing uncertaintymust become a guide for action.

The assessment of vulnerability to negative effects fromclimate change should distinguish between impactsassessment, which attempts to project future biophysicaland ecological changes in a deterministic manner, andvulnerability assessment, which attempts to combine an

assessment of future suites of change with an assessmentof the resilience of ecosystems and managementinstitutions. Due to the high levels of uncertainty in modelsof future hydrology, assessing vulnerability must focus asmuch on adaptive capacity as climate-model downscaling.It may be useful to think about future vulnerability in termsof potential stories about emerging climates rather thandenitive scenarios.

Freshwater ecosystems differ in their relative vulnerability toclimate change. For instance, large rivers will respond less

rapidly than small streams exposed to the same extent,type, and rate of climate change. Similarly, some societiesand institutions will be better adapted to change, andtherefore less vulnerable to negative impacts.

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unviable because of climate change. Equally,economic activities may need to shift.

5. Think carefully about water infrastructuredevelopment and management: Short-term gainsfrom building new irrigation, hydropower, or oodcontrol measures that are based on recent climatehistory may actually limit future options for climateadaptation, resulting in maladaptation. Assumptions

of hydrological stationarity in planning andmanagement decisions should be questioned.

6. Institute sustainable ood management policies: There is an increasing risk that ood defences basedon historic precipitation patterns will be overwhelmed.Sustainable ood management looks to reduce oodrisk by understanding how oods move throughcatchments and developing climate-appropriate riskreduction strategies, such as accommodation ratherthan defense.

7. Support climate-aware government anddevelopment planning: Many government economicand social planning decisions include assumptionsabout the future availability of water and freshwater-derived ecosystem services, and these decisionsmust take into account potential climate shifts if signicant social, and economic risks are to beavoided.

8. Improve monitoring and responsivenesscapacity: Finding our way through the uncertaintiesin predictions of climate impacts means that we

must become more attuned to shifts in ecological,hydrologic and social aspects in our systems asthey occur. We must make sure that the results of monitoring processes are embedded within ourmanagement, planning, and design processes.

Developing a strategy to help social and ecologicalsystems adapt to climate change that encompasses allof these concerns for freshwater resources is difcult butshould include two components: Firstly, a commitmentto lower greenhouse gas emissions to slow the rateof climate change in the future. Secondly, an activeapproach to institutional learning and exibility in the faceof climate and impact uncertainty. We propose eight

elements to an adaptive water strategy:1. Develop institutional capacity: The development

of strong institutional capacity, adaptive and effectivegovernance, and the ability to successfully implementsound adaptation policies should be regarded as thesingle most important task in facilitating successfuladaptation to climate change in freshwater. In thewater sector, these institutions are typically weakand seldom well-placed to cope with climate-drivenimpacts

2. Create exible allocation systems andagreements: Systems of water allocation and waterrights are required that are sufciently exible toprotect social, environment, and essential economicinterests under conditions of varying water availability.

3. Reduce external non-climate pressures: Theimpacts of climate change will be signicantlyexacerbated in systems that already experiencestress from other factors, such as over-abstraction,poorly planned infrastructure, or exotic speciesinvasions. Reducing these pressures is key to

facilitating adaptation.4. Help species, human communities and

economies move their ranges: Species may needto move both between and within ecosystems asconditions in headwaters or lower reaches become

Summary

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Introduction:

Climate change has profound implications for managingfreshwater resources and the people and speciesdependent on those resources, but water managementlong predates any awareness of anthropogenic climatechange. Indeed, large-scale water management has beenone of the great themes of the nineteenth and twentiethcenturies worldwide. Many of the largest constructionprojects in human history have been attempts to

consume, control, allocate, and regulate water, perhapsmost notably the construction of tens of thousands of dams and irrigation infrastructure. Moreover, extensiveindustrial and domestic consumption and discharge,pollution and the conversion of perhaps half of allwetlands globally to productive uses have had direimpacts on the many aquatic and terrestrial species thatrely on freshwater resources. 1

One study of 344 freshwater temperate and tropicalspecies suggested population declines of about 30%

between 1970 and 2003 alone. Freshwater ecosystemsnow experience rates of species extinction as high as orhigher than in any other biome. 2

Climate adaptation is the process of adjusting to andanticipating emerging climate regimes avoiding riskand facilitating change. Examples include reducing waterconsumption to compensate for lower precipitationrates, shifting the location of an industry away from anincreasingly drought-prone area to a wetter region, oraltering urban stream morphology to compensate for

larger and more frequent oods. Perhaps the greatestthreat to freshwater ecosystems from climate change isthe interaction between relatively traditional problems

such as over-abstraction or habitat fragmentation withclimate-driven shifts, such as more frequent droughts.

WWF is committed to the concept of exibility as aresponse in itself to climate change: while there maybe a range of predictions for future climate conditions,the uncertainties around those predictions are typicallyhigh and may require some time to nalise plans andapproaches. In some cases, we may not have the optionto move people, species, and industries, so we mustencourage and develop resilience to negative climateimpacts such as extreme weather events. In other cases,there may even be limits to adaptation, resilience, andsustainability that force very difcult choices upon us.

This primer is intended as a guide to some of the basicissues surrounding water management from a climatechange perspective.

6

Anthropogenic climate change, popularly known as global warming, is already alteringfreshwater ecosystems almost everywhere on earth: where water is found, how much wateris there, and in what form it exists liquid, frozen, or vapour. Before our eyes, climatechange is creating freshwater winners and losers among individuals, economies, wholesocieties and nations, and of course among species and ecosystems.

1 WWF, 2008. Living Planet Report 2008. WWF international, Gland, Switzerland, 8 pp

2 Ricciardi A., and Rasmussen J.B. 1999. (Extinction rates of North American freshwater fauna. Conservation Biology 13: 122022)


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PART A: What does climatechange feel like infreshwater?

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Much of the journalism covering anthropogenic climatechange describes impacts that are difcult to imagine:projected increases in mean air temperature by up to 6Cby 2100 do not easily register with human experienceand are not useful as the basis for sound policy.

People do not perceive climate per se. Like most species,we experience weather, and we experience weather asboth a local and a daily or seasonal phenomenon. We areoften most conscious of climate itself through weatherextremes that contrast with our sense of normal climate:very hard rains, long and severe droughts, and extremelyhot or cold days.

PART A:

What does climate changefeel like in freshwater?

8

Moreover, the term global warming suggests that airtemperature is the most important or most altered aspectof climate. But anthropogenic climate change is altering allaspects of climate, and air temperature alone is probablynot even the most important aspect of climate for livingthings on the planet. Indeed, precipitation is often a farmore restrictive part of local climate than air temperature,historically limiting where people can engage in many

industrial or agricultural activities and where you ndparticular wild species even non-aquatic species. Andprecipitation is the source of almost all surface freshwateron earth.


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3 Hayhoe, K., et al. 2004. Emissions pathways, climate change, and impacts on California. Proceedings of the National Academy of Sciences. 101(34). 12422-27

9

In the USA, the state of California has seen signicant

changes in mean winter temperatures and theaccumulation of snowfall in the mountains of the SierraNevada. Precipitation is very seasonal across most of the region, with long dry summers and cold wet winters.Much of the surface water in rivers and lakes in Californiaderives from the slow melt of the mountain snowpack,which acts like a frozen reservoir keeping ows relativelyeven and reliable throughout the year.

The economic development of California has assumedthat these conditions would remain the same into theforeseeable future. But these conditions are changing.

The combination of a rapidly growing economy andpopulation (greater demands) with a declining snowpack(diminishing supplies) means this assumption no longer

holds. Californians may not experience the shifts in

climate that are occurring at high elevations in winter,but they are experiencing the ecological effects of thoseshifts: pressure from local governments to change yardand garden plants from thirsty grasses to plants thatcan survive long periods without watering, a world-famous wine industry that seems likely to shift north intothe states of Oregon and Washington to survive; morefrequent and more serious wildres; and even seriousdiscussion about building desalinisation plants forsouthern parts of the state.

All of these impacts are a result of trends in Californiasclimate that are likely to continue and strengthenin coming decades, even with major reductions ingreenhouse gas emissions. 3

Freshwater climate change impacts are not always identied as being related to either anthropogenic climate change or tofreshwater.The western U.S. state of California is famous for its wine industry, but trends in the snowpack of the Sierra Nevada are r educingsummer and fall water availability for agriculture and cities. Some obser vers suggest that reduced water supplies and increasedclimate variability are likely to result in the California wine industry ef fectively shifting northwards to the U.S. st ates of Oregon andWashington and the Canadian province of British Columbia. Most consumers are likely to experience this shift as a change in t heindustrys priorities rather than as a product of the changes in regional precipitation regime.

I S T O C K

The end of the Californian wine industry?

G E T T Y I M A G E S


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PART A:

Freshwater climatechange and precipitation

10

Most surface freshwater is derived from precipitation. Across the planet, numerous aspects of precipitationare changing, such as the amount of annual or seasonalprecipitation; the seasonal timing of precipitation; thenormal form of precipitation (such as snow versus rain);the intensity of precipitation events (how much per unit of time); the frequency and severity of extreme events likedroughts and oods; and the net accumulation or loss of

water in places like glaciers and the poles. Moreover, allof these aspects of precipitation are expected to continueto shift over the coming century. In some regions, theseshifts will lead to dramatic impacts on regionally normalaspects of life, such as economic activities; the presenceof disease vectors; local livelihoods; characteristic qualitiesof ecosystems (re regime, onset of spring); and themixture of typical species.

Why should we think about precipitation and climatechange? After all, most humans consume water that is

derived from reservoirs, lakes, rivers, and (in the caseof boreholes and wells) groundwater. Almost invariably,however, such water derives from precipitation. Lakes andrivers, for instance, catch recent precipitation in the formof surface runoff, and most groundwater is recharged bysurface precipitation that percolates through rock and soil.

Frozen precipitation in high altitude areas and middle tohigh latitude regions can in effect become reservoirs of old, even ancient precipitation that helps feed lakes andrivers during droughts. But like steadily draining bank

accounts, lakes, rivers, groundwater and snowpacks andglaciers can become overdrawn beyond their capacityto renew their reserves (outows) or to balance their rate

of deposits (inows). In other words, climate shifts inprecipitation matter to humans because we depend uponprecipitation, whether we are aware of this dependence ornot. And these shifts also matter to freshwater ecosystems to the wild species that rely on freshwater, to agriculture,and to many other elements of human economies.

As individuals, we may nd it difcult or impossibleto directly perceive climate shifts in freshwater andprecipitation. Climate is a statistically dened normdened over some increment of time. 4 Even hard-to-perceive impacts from climate change can be quitesignicant, however, in altering key hydrological qualitiesand affecting species and economies.

Shifts in climate that alter freshwater ecosystems haveprofound socio-cultural, economic, and ecosystemimplications. Globally, many lakes, rivers, and wetlandsalready feel the impact of climate change in terms of whenthey contain water, how much water they hold, and thequalities of that water, including its temperature. Theseimpacts are likely to grow in strength in coming decadesand will have important implications for the living thingsdependent on that water and for the economic activitiesthat rely on freshwater resources.

Will climate shifts occur gradually or suddenly? The rateof climate change locally can be characterised by threepatterns that vary by region and temporal scale, thoughin many places all three types of change are occurringsimultaneously. First, gradual and persistent change

has been observed widely. Slow increases in mean airtemperature or a gradual advance in the arrival date of

4 Climate scientists are particularly loathe to attribute any specic weather event like a tropical cyclone or a very hot summer to climate change, since such individual eventscould theoretically occur in the absence of climate change. This is why they are more interested in how often such events occur, how severe they are, and how they altermean weather conditions (i.e., climate).


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11

PART A:Freshwater climate change and precipitation

summer monsoons are typical of this type of change.Statistically, such shifts involve a gradual movement inthe long-term average (mean) of some climate variable of interest. Many climate models characterise most aspectsof climate change as a slow shift in mean.

The second pattern is an increase in climate variability agreater frequency in the extremes of weather that oscillatearound some relatively stationary mean. For precipitation,some regions are seeing more frequent and more severeooding as well as more droughts. Weather extremessuch as very hot days, large tropical storms, or extremelyintense precipitation events appear to play importantecological roles in shaping where species are found (i.e.,range shifts).

For humans, they often drive reactive changes in policy,as when two so-called 500-year oods occur within adecade. Many analyses of recent historic climate showsignicant shifts in climate variability and the occurrence of weather extremes.

The third pattern occurs when a period of stable or slow-changing climate (state 1) is followed by a period of rapidclimate shift, which leads into another climate plateau(state 2). Such sudden state-level changes are difcult tomodel, but the long-term climate record suggests that theydo happen, with sudden change occurring once someclimate threshold or tipping point has been exceeded.In recent decades, only a few events might qualify forthis pattern, such as the sudden movement of a major

ocean current or atmospheric jet stream. For humansand already stressed natural systems, major state-levelchanges will probably feel like ecological catastrophes.

Alterations in freshwater systems from climate changeare not globally uniform. Some regions, for instance, haveseen increases in the quantity of freshwater over recentdecades, while others have seen precipitous declinesin rain or in the frequency of severe droughts. Makingworldwide generalisations about how economies and wildspecies will experience freshwater shifts is therefore noteasy. But beginning to understand how climate change

impacts lakes, rivers, and wetlands really means exploringthe relationship between climate change and precipitationand how together these alter local hydrology.

J H M A T T H E W S / W W F - U S A

The discussion of climate impacts on humans is normallydominated by economic effects, but freshwater ecosystemsalso perform cultural ecosystem services that may beperceived as just as signicant as industrial or livelihoodimpacts. Here, the drought-stricken Gambiri riverbed innorthern India, part of the Ganges basin, holds the mounds ofrecent cremations awaiting the return of the river to wash theashes downstream to the sacred mother Ganges. Disruptionof this service by the Gambiri from the synergies of climate

change and poor water management represent a profoundreligious crisis to Hindus in this basin.


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12

Although the impacts of climate shifts on freshwater

ecosystems can be dramatic, in many cases theyare not recognised as freshwater problems per se.For instance, parts of Australia have recently seensignicantly more climate variability, particularly in theform of frequent and severe droughts. The Australiangovernments new Department of Climate Changereports that in some regions (especially eastern andsouthern Australia) rainfall has decreased graduallysince the 1960s about 1020%. Even small changesin precipitation can lead to very large shifts in runoff,with river ows dropping up to 4060% in response.

Projections show additional large decreases in meanannual precipitation by 2050. Perhaps most important,

droughts are expected to become up to 20% more

frequent by 20305

. Existing economic institutions are notdesigned to cope with common and severe droughts;the 20022003 drought alone is estimated to have costabout US$7.6 billion (in 2006 US$). The effects are notlimited to Australia alone, of course. The resulting declinein Australias grain production is widely thought to haveexacerbated the global food crisis of 2008.

For residents of this area, the severity has led to majorchanges in water consumption and management,increases in wildre severity (US$261 million in theCanberra re of 2003, 2006 US$), and synergisticimpacts, such as the loading of three of Canberras fourdams by sediment-lled runoff following the 2003 re.

Australia has recently faced a series of severe droughts that have had serious economic impacts at regional, national, and globalscales. These droughts may signal a shift for some parts of the continent to a new precipitation regime.

A O s w e l

l / W W F - C a n o n

Australia: A long series of droughts or a new climate regime?

5 Pittock, B. 2003. Climate Change: An Australian Guide to the Science and Potential Impacts, Australian Greenhouse Ofce . http://www.greenhouse.gov.au/science/ guide/ index.html.


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13

Freshwater impacts can be described in terms of threedifferent but inter-related components: water quality,water quantity or volume, and water timing (sometimescalled water seasonality, ow regime, hydroperiod, orhydropattern). A change in one of these three elementsoften leads to shifts in the others as well. Water qualityrefers to how appropriate a particular ecosystems wateris for some use, whether biological or economic. Many

sh species, for instance, have narrow habitat qualitypreferences for dissolved oxygen, water temperature,dissolved sediment, and pH. Humans generally avoidfreshwater for drinking or cooking if it has excessive levelsof dissolved minerals or has a very high or low pH.

Water quantity refers to the water volume of a givenecosystem, which is controlled through the balance of inows (precipitation, runoff, groundwater seepage) andoutows (water abstractions, evapotranspiration, naturaloutows). At a global scale, precipitation is tending to fall

in fewer but more intense events, resulting in generallymore precipitation. At local scales, there is wide variation.

The most striking changes in water quantity often occurwith precipitation extremes like oods and droughts; lakeand wetland levels can also change radically as a result of even slight changes in the balance between precipitationand evaporation. The occurrence of precipitation extremesis expected to increase globally, as well as the severity of extreme events themselves.

Water timing or seasonality is the expected or average

variation in water quantity over some period of time,usually reported as a single year. Most water bodies havea normal seasonal variation that in wetlands and lakes iscalled the hydroperiod and in rivers and streams is called

ow regime; together, these terms are sometimes lumpedtogether as hydropattern.

Many terrestrial and aquatic species are extremelysensitive to water timing. Natural selection has adapted(in an evolutionary sense) the behaviour, physiology anddevelopmental processes of many aquatic organisms toparticular water timing regimes, such as spawning duringspring oods or accelerated metamorphosis from tadpoleto adult frog in a rapidly drying wetland. Shifts in watertiming mean that there may be detrimental mismatchesbetween behaviour and the aquatic habitat. In turn, theseshifts can affect sheries stocks and industries thatdepend on seasonal water ows.

Controlling water timing has long been a priority of humanwater management. A ooded rice eld is an attemptto change an ephemeral wetland or oodplain into aregulated ecosystem to optimise growth and yield. Thetens of thousands of dams and irrigation canals acrossthe planet today demonstrate the human desire tocontrol variations in water levels that occur on a naturalbut irregular basis, to provide more reliable irrigationor hydropower. Dams and other types of infrastructuredesigned for ood control reect a desire to reduce owvariability and extremes.

Unfortunately, many large-scale studies of freshwaterclimate impacts provide information only on total oraverage annual ow or runoff patterns. Such reportingignores sub-annual seasonal variation in climate trends as

well as how much variability exists between years. A smallshift in evapotranspiration or precipitation, for instance,can change a historically low-water period into a seasonwith frequent droughts, though at an annual resolution thenet shift in inows and outows may seem insignicant.

PART A:

How can we describefreshwater impacts fromclimate change?


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Source: IPCC The Intergovernmental Panel on Climate Change (IPCC) is the United Nations scientic panel

tasked with analysing climate change impacts on human and natural systems. The Fourth

Assessment Report was published in 2007 (see Further Readings). Here, the IPCC showsagreement across 15 climate models for several freshwater variables. To indicate consistency

of sign of change, regions are stippled where at least 80% of models agree on the sign of the

mean change. Changes are annual means for one future climate-development scenario (SRES

A1B) for the period 2080 2099 relative to 19801999. Soil moisture and runoff ch anges are

shown at land points with valid data from at le ast ten models. [Bas ed on WGI Figure 10.12]. 7

A preferable way of investigating the potential for seasonalimpacts is through the use of annual hydrographs.Worldwide, shifts in water timing are likely to be the mostwidespread and important type of climate impact onfreshwater systems.

Until now, efforts to manage water have typically assumedstationarity in the role of climate in hydropattern. Thatis, they have assumed that the historic record of seasonalvariation is a good guide to the future. This assumptionis probably much less valid today in the majority of freshwater ecosystems globally. Climate change isaltering the seasonality of many water bodies even whenthe water quantity at an annual scale remains relativelyunchanged. The timing of precipitation, for instance, isaltering in many regions, shifting the timing of seasons of high and low precipitation as much as several weeks. Andhigher air temperatures in winter and spring mean thatin many temperate regions there is more winter rain than

snow (leading to greater frequencies of winter ooding), asmaller snowpack, an earlier spring melt, more summerevapotranspiration and less reliable summer ows.Higher air temperatures also cause increases in the rateof evaporation from lakes and reservoirs and, in higherlatitudes and altitudes, decreases in the frequency andduration of lake ice cover.

The interaction between these elements is complex, andthe ecosystem impacts are difcult to model and predict.For instance, in the Pacic Northwest of the USA, summer

precipitation rates are dropping while summer watertemperatures are increasing at a rapid rate, impacting

PART A:How can we describe freshwater impacts from climate change?

14

salmonid population sizes and migration patterns, withseveral species likely to become locally or regionallyextinct within decades. 6 According to a US Forest Servicestatement,

Although the intensity of the effects will vary spatially,climate change will alter virtually all streams and rivers inthe [Columbia] river basin. Current predictions suggestthat temperature increases alone will render 27% of

headwater trout habitat in the Pacic Northwest unsuitableby 2030, 520% by 2060, and 833% by 2090 Salmon

6 Independent Scientic Advisory Board. 2007. Climate change impacts on Columbia River Basin sh and wildlife. Northwest Power and Conservation Council. http://www.nwcouncil.org/library/isab/ISAB%202007-2%20Climate%20Change.pdf.

7 IPCC. 2007. Climate Change 2007: Impacts, Adaptation, and Vulnerability. M. Parry, O. Canziani, J. Palutikoff, P. van der Linden, C. Hanson (eds.). Cambridge UniversityPress, Cambridge, UK.


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PART A:How can we describe freshwater impacts from climate change?

15

habitat loss would be most severe in Oregon and Idahowith potential losses exceeding 40% by 2090. 8

The interaction between warmer winter temperatures,increasing levels of nutrient pollution, and growing urbanpressures among the large, shallow lakes of the central

Yangtze basin of China is leading to near-permanenteutrophic conditions, even in the coldest months of theyear.

In many arid and semi-arid regions, annual precipitationlevels are decreasing, threatening the livelihoods of farmers and pastoralists and cities in regions likenortheastern Brazil, southern Africa, and major populationcentres in northern Mexico and the southwestern USA.

In temperate and boreal regions, annual precipitation levelsare generally increasing. Northern and western Europe inparticular are projected to see signicant increases in oodrisk, with mean annual runoff rates increasing between

515% by the 2020s and 922% by the 2070s, with muchof the change in precipitation coming during fall, winter,and spring and through more intense precipitation events.Paradoxically, the result will be both more oods and moredroughts.

Developing appropriate responses to emerging anduncertain threats is a serious challenge for policymakers.

As a UK government committee ruefully reported: Underclimate change, there will be both more water, and less.Even at a regional level, good policy that is future-oriented,exible, pro-active, and sustainable will be difcultto develop and will depend on clear conceptions of vulnerability and the uncertainty in forecasts from climatemodels.

Water quality/quantity/timing All freshwater climate impacts can be described in terms of their effects on water quality(oligotrophic vs. eutrophic, pH, and so on), water quantity or volume, and water timing (the

seasonality of normal water variation, such as a spring ood following high-altitude snowpack

melt). These three types of impacts are deeply interconnected. A shift in water timing, for

instance, could reduce or increase the intensity of normal dry-season low ows.

Water

Timing

Water

Quality

Water

Quantity

Wind

Evaporation

In ltration

Ground WaterDischarge

Sea

Lakes

Trees

Snow Rain

River

Ground WaterStorage

The water cycle The water cycle is complex and multifaceted. Most of the freshwater accessible to humans and

ecosystems is ultimately derived from precipitation, including surface water (lakes, wetlands,and rivers), frozen water sources (snowpacks, glaciers), and groundwater.8 http://www.fs.fed.us/ccrc/topics/salmon-trout.shtml.


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PART A:

Relative vulnerabilities:Developing contrasts

The three types of impacts can be used to describe howclimate will alter freshwater systems, but they do notdescribe how sensitive a particular system may be to anygiven shift in climate. Thus, assessing the vulnerability of afreshwater ecosystem or one of its components (such asthe headwaters versus the oodplain) is often a key objectof interest for resource managers. Here, vulnerability ismeant to describe the sensitivity and resilience of an eco-

hydrological system to shifts in its climate envelope. Oneuseful means of expressing relative vulnerability is throughcontrasts between types of freshwater ecosystems orthe uses of those ecosystems. The following list is byno means comprehensive. But these and other typesof contrasts should serve to illustrate how we can beginto identify what kinds of freshwater systems are mostvulnerable to changes in the local climate regime. Thisis likely to be particularly important in the context of theuncertainty associated with modeling future hydrologicalchanges.

Scale: Large versus small. Generally speaking, largesystems are buffered simply on the basis of having agreater base volume from climate impacts, particularlyextreme weather events such as droughts or oods. Smallsystems will respond more rapidly and often in moreserious ways (hypoxia, shifts from fresh to brackish orsaline conditions, high sediment loads).

Variability: Permanent versus temporary. Species andeconomic behaviour dependent on freshwater resources

that are normally temporary or ephemeral are more likelyto be acclimatised to weather variability. Thus, species andlivelihoods dependent on such systems such as manyaquatic macroinvertebrates, large migratory terrestrialvertebrates in eastern Africa, cattle ranchers are likely

to have higher inherent adaptive capacity. Species andpeople that depend primarily on permanent waterresources, however, may be very vulnerable to unexpecteddeviations in water quantity, quality, and timing. They areless likely to have experienced or be adapted for extremeweather events.

Nov Dec Jan Feb Mar April May June July Aug Sept Oct

500

400

300

200

100

0

p r e c

i p i t a t i o n

( m m

) , w a

t e r

l e v e

l ( c m

)

wet-season high flows advance

new mean old mean

water level

precipitation

dry season low flows fall

new mean

old mean

precipitation water levelbefore anthropogenic climate changeafter anthropogenic climate change

Moving hydropatterns Most precipitation climate data are reported at an annual scale, butan annual resolution ignores important elements of water timing and ow seasonality. Thus,

annual hydrographs that show normal variation in ow regime, hydroperiod, or hydropattern

are far more informative when trying to understand how changes in the timing or form of

precipitation will alter a given freshwater ecosystem. This sample hydrograph shows that evensmall shifts in precipitation timing can lead to very signicant shifts in ow regime.

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PART A:Relative vulnerabilities: Developing contrasts

17

Residence time: Old water versus new water. Mostfreshwater ultimately derives from precipitation, butsystems vary substantially in the residence time of theirwaters. The Pantanal in South America and the Okavangodelta in southern Africa, for instance, are both massivewetlands that receive pulses of water from direct, local/ regional and highly seasonal precipitation (new water),but they are sustained through their respective dry

seasons by the large reservoirs of groundwater that buildup during the wet season (old water, which fell weeks ormonths earlier). Indeed, groundwater is a critical sourceof water for humans in many regions globally, though theresidence time the effective age of the groundwaterreecting its recharge rate is not well understood inmost regions. This gap in knowledge could become anacute problem in groundwater-dependent areas withrelatively short residence times or increasing large waterdemand.

In any case, systems fed by snowpack and groundwatershould be fairly stable even if there are shifts in the timingof spring melts or monsoon seasonality compared tosystems that depend primarily on new water, particularlyin arid and semi-arid regions. Climate-sensitive systemswill respond very rapidly to even small shifts in the timing,amount, intensity, and form of precipitation. Large lakesmay also experience changes in water levels as a resultof even slight shifts in the relative timing and balancebetween precipitation and evaporation.


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PART B:Principlesand priorities


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PART B:

How can you think about what you can do?

The freshwater impacts of anthropogenic climate change will not be globally uniform or evenuniversally negative; there will be winners and losers. Even when focusing on adverse effects,differences in vulnerability and the ability to respond to negative shifts require careful thoughtabout how to plan and prioritise action. In this section, we discuss the special issues that applyto climate shifts on freshwater ecosystems and suggest the best means to start adapting toclimate shifts.

Are there qualities about climate change impacts onfreshwater that are special or unique relative to other typesof ecosystems? Do the impacts on freshwater ecosystemsrequire us to think in a way that is different than we mightfor marine or terrestrial ecosystems? We believe there arethree aspects about freshwater climate change that arecritical to keep in mind.

1. The aspects of climate change that most impactfreshwater are associated with high uncertainty. Thecondence surrounding predictions for air temperaturehas proven to be relatively high compared to manyother climate variables. The historic precipitationrecord has large gaps, but has slowly come intobetter focus. On the other hand, the precipitationcomponents of the circulation models that climate

scientists use to predict future climate show muchlower levels of condence. Often, the strongeststatements we can make about future climate relate tosimple consistencies among the models themselves,such as, Over the coming two decades, more thanhalf of the models suggest we can expect more winterprecipitation than currently. Worse, many circulationmodels do not have ne temporal or spatial resolution.

There may be very little certainty about mid-Marchclimate in a particular place in 10, 25, or 50 years.

Finally, the extent and renewal processes of manynatural reservoirs of water such as groundwaterand snowpack present very large uncertainties.Groundwater recharge rates and capacities are oftenunknown and demands on them are poorly regulated;the temperature uncertainties that determine whetherwinter precipitation falls as snow or as rain are quitehigh; and there are immense difculties in assessingwhether accumulated snowpack or glaciers willdissipate through melting (as liquid water) or sublimateor evaporate directly into the air as water vapour.Some improvement can be expected in modellingcapacity in coming years, but we are likely to alwayshave lower condence around the variables mostimportant to freshwater. Managing under uncertaintyis a dening characteristic of adaptation in freshwater.


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2. Freshwater rarely exists in a human-free vacuum:Human settlements have often been located nearfreshwater resources, and people have beenmodifying, developing, and exploiting those resourcesfor a very long time. There are regions (the Nile in

Africa, the Tigris-Euphrates in greater Mesopotamia, Yemen, Asia Minor, and the Tibetan plateau riverssuch as the Ganges, Mekong, and Yangtze) that

have been embedded in a matrix of intense humanuse for millennia. Recent evidence suggests thatsome wetlands in eastern China were rst alteredfor agriculture some 8,000 years ago. Denitionsof use vary widely as well: an ecologists aquaticmacroinvertebrate community is a ranchers cattletank. Thus, few bodies of water can be consideredpristine or wild, and efforts to assist theseecosystems with the process of climate adaptationneed to consider human and ecological communitiestogether.

PART B:Principles and priorities

3. Freshwater ecosystems do not end at the watersedge: Many of the basic nutrients that determine theecological health of freshwater ecosystems comefrom outside of freshwater systems migratorysalmon bring nitrogen from the open oceans torivers and forests far inland, watershed runoff andgroundwater discharges to rivers and lakes sustaintheir natural budgets of dissolved minerals, and the

steady rain of leaves and branches from riparianvegetation provide much of the organic carbon inlakes and rivers. Even in relatively wet regions, surfacewater is a rich conuence between terrestrial andaquatic organisms. So changes that happen beyondthe boundaries of the aquatic zone can have profoundeffects on freshwater ecosystems and vice versa.


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PART B:

What is climate adaptation?

There is a widespread concern among conservationand development professionals that climate adaptationrepresents such a fundamentally new way of envisioningour work that a complete shift in worldview is necessary.Is our toolkit for managing water infrastructure and aquaticspecies irrelevant? We believe that the overwhelmingmajority of the current theory and practice of conservationand development remains both relevant and usefuland that the past is a helpful but not unerring guide tothe future. We must maintain a mindfulness of climate

uncertainty. The Roman god Janus had a single head with two faces:one face saw the past and another looked to the future.Like Janus, we believe that water resource managers

must be mindful and aware of climate history, but we mustalso look forward into the future to a new, uncertain, andshifting climate. We must accept that our knowledge of water resources captures only a particular moment inclimate history. As a result, we must be humble aboutour ability to predict the future and thus become cautiousin our management of resources for coming decades.Indeed, some of the most signicant catastrophes

surrounding water may derive from making importantdecisions reactively or under pressure, without time toreect on the adaptive and maladaptive implications of those decisions for future resource managers.

Climate change by itself is nothing new; the earths climatehas passed through major shifts many thousands of times in the past. This period of climate change is noteven the rst climate shift humans have gone through,much less the majority of extant species. The most recentglacial period, for instance, ended only 12,000 years

ago, and there have been signicant global episodes of warming and cooling since then as well, long before theindustrial age of human society. Under historically normalcircumstances, species can adapt to shifts in climate,given sufcient time. The two most widely observedresponses in wild species are range shifts (where yound a species and in what abundance) and phenologicalshifts (when or how fast a behaviour occurs, like migration,breeding, the rate of development, and so on). Thesetwo responses parallel human responses to climate andweather as well a warmer climate might mean a longergrowing season, with a farmer changing the selection of crops to varieties that are associated with a warmer, drier,or wetter climate (a range shift) or altering the agriculturalcalendar (phenological shifts).

The Roman god Janus with his future- and past-oriented facesis a good analogy for how we should begin to incorporateclimate trends into water resource management: aware of pastimpacts and ecosystem health, but not using the past as adeterministic guide for the future and the new climate regimesit contains.

p h o t o l

i b r a r y . c

o m


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Many observers have argued that our current shift inclimate is a threat to livelihoods, economies, and speciesbecause the rate of change in the climate is so rapid. Bythe standards of signicant shifts in climate regime overthe past few million years, however, this view is incorrect.Some glacial-interglacial transitions occurred over onlya few decades. Instead, our current period of climatechange is notably different from previous periods for three

important reasons.First, human-source greenhouse gas emissions are theprimary forcing agents of global shifts. Second, humanshave altered the landscape substantially by moving otherspecies around (facilitating species invasions), fragmentinghabitats, reducing environmental quality through pollution,overharvesting wild species, and so on. Very signicantly,weve built a lot of hard infrastructure for watermanagement, such as dams, wells, wastewater treatmentplants, and irrigation systems. This infrastructure has often

profoundly altered the aquatic landscape includingposing barriers that may prevent species from shiftingtheir ranges and it was typically built (and is managed)with many tacit assumptions about climate stability andstationarity. Third, the current level of warming has notbeen seen for many hundreds of thousands of yearsand, most likely, several million years. Thus, many extantspecies have no ecological or genetic experience withemerging climatic conditions.

The cumulative effect of these three factors is that natural

and automatic climate adaptation is now more difcultthan during previous climate shifts. We have reducedthe ability of most organisms to easily respond to

climate change. In many cases, we have instead createdconditions that will result in less successful adaptationor even maladaptive and detrimental impacts on us andother species. The implications of exposing species tocompletely novel climate regimes cannot be determined.Of course, human societies are far more complex than12,000 years ago, but this complexity may itself lead toboth difculties and opportunities in adapting to major

climate shifts.Given the high levels of uncertainty around freshwaterresources and the amount of physical infrastructure builtaround certain ways of organising ourselves, we mustbe both socially and ecologically adaptive. That is, wemust become capable of reorganising ourselves to meetnew challenges and opportunities. Low-lying areas andestuaries, for instance, are likely to see signicant sea-levelrise, potentially inundating large cities and other settledareas. Many people will be on the move a human range

shift, in effect. And we must be able to re-absorb thesepeople in new capacities and roles even when they crossecological and national boundaries.

Moreover, when human populations remain physically inplace, changes in behaviour are likely to be necessary. Forinstance, if precipitation trends show a decline, farmersshould plant crops that are less water intensive or that canbe irrigated more efciently. Urban and industrial waterconsumption may need to be reduced.

Climate change, especially the impacts on freshwater

ecosystems, is associated with medium to high levels of uncertainty. Projections and modelling may only justifylow condence in predicted impacts, so institutions thatgovern water usage and management should focus on

PART B: What is climate adaptation?


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PART B: What is climate adaptation?

the process of decision making as an adaptation processin itself. For instance, the southwestern USA and northernMexico are projected to become much drier than therecent past, while the northeastern USA and southeasternCanada are projected to become much wetter. Thereare no high-condence projections on where the linebetween reduced and increased precipitation will fall, soinstitutions that manage water across a broad swath of

the central USA should manage their water resourcesas if they expect both more and less water, as well asinstitute a process of updating their institutions with thelatest regional climate science. To view the situation froma slightly different perspective, their climate adaptationstrategy should be to not rule out a range of adaptationscenarios until climate trends become clearer and morecertain. This exibility and ability to respond is at the core

of climate adaptation.

Climate impacts on freshwater species are complex, multifaceted, and difcult to predict. Salmonids in western North Americaappear to be shifting their ranges between basins (moving from one r iver system to another) and within basins (from warmerdownstream regions to cooler high-elevation tributaries). These responses may be direct physiological shifts (individual shavoiding higher temperatures), indirect responses (sh are tr acking range shifts in competing, predatory, and prey species), orsome combination of these factors. In migratory organisms such as salmon, the timing of migration itself may also be changing,representing a phenological response to climate change.

K S C H A F E R / W W F - C a n o n


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PART B:

What isnt climateadaptation?

There are two risky aspects of not adapting effectively.First is the risk of simple ignorance of not asking if our policies and actions will continue to be relevant andeffective given what is happening and what is likely tohappen.

We are now living in a period in which (for most regionsof the world) the realised impacts of climate change arerelatively small compared to the potential and predictedimpacts for the rest of the century and beyond. Thus, wehave hints of the shape of things to come as well as somemodelling that provides estimates of upper and lowerbounds for a series of new climates we will be passingthrough. Even given the levels of uncertainty associatedwith an assessment of future impacts, we often havesome means of sorting relative likelihoods. Thus, weshould enable an ongoing process of considering theclimate relevance of our behaviour and plans.

The second risk of not adapting well is potentially moreserious: the threat that our actions will be maladaptiveand will signicantly constrain our options in the future.Because the climate will be changing for decades evenunder our best attempts to control greenhouse gasemissions, some of our actions now may actually limitour ability to adapt to future climate conditions. Forexample, some communities or nations may respond tomore frequent oods by building dykes that channeliserivers or by designing high-capacity stormwater systemsto reduce threats in urban areas. Without careful

consideration, these responses may only transfer theproblem of extreme precipitation events downstream andreduce water quality for people and species. Investing inincreased water storage volume may encourage societiesto become proigate in water use exactly at the time that

they need to adapt to greater variability in water supply. And investments in large hard infrastructure projects toaddress changes in ooding patterns or water supply maybe far less cost-effective than nding ways to work withnatural systems (soft infrastructure) or demand reductionto achieve the same benets.


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The Colorado River of the arid southwestern USA hasbeen a major source of water across a vast region.

The rst river Compact was negotiated in 1922 andallocated water resources based on only a few decadesof ow and precipitation data. It also reected an era of planning that assumed that water that actually reachedthe estuary and ocean had been wasted, lost from thegrowing cities of the region and the rapid growth of highlyprotable agriculture irrigating a desert.

Although there were many inequities in the originalCompact, and the climate history determining acceptableows was based on awed and limited data, theCompact served more or less intact until the negotiationof a new interim agreement in December 2007 intendedto serve until 2026. The negotiators of this Compact

faced a very different set of needs and demands acrossthe region from the previous century, but climate modelsof changing water availability and timing were notincluded, presumably because they were associated withhigh uncertainty and presented difcult choices. Instead,they focused their efforts only on updating the recentclimate history and ow record for the Colorado.

The most up to date climate models show that thisregion is very likely to enter a period of severe droughtnot seen for many centuries (nor reected in existinghydrological data). The new Compact may already beirrelevant and maladaptive, endangered by the threats of serious drought leading to stakeholder lawsuits, interstateconict, and the need to develop a third climate-awarecompact soon.

I S T O C K

The Colorado River Compact: Long-term planning gone awry?

The Colorado River has been a source of contentious regional an international water management for over a century, but to date thearrangements assembled to allocate water within the USA and between the USA and Mexico have largely ignored the climate-drivenshifts in the eco-hydrology of the Colorado River basin.


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PART B:

Identifying vulnerability andembracing uncertainty

Many efforts to develop a climate adaptation strategyfocus on assessing the eco-hydrological and economicsensitivity and vulnerability of a given system to shifts inclimate. Much technical attention focuses on identifyingecosystem-level responses to specic climate elements,such as a drop in late-summer precipitation or a risein minimum winter temperatures. As a result, mostvulnerability assessments are categorized as identifying

specic climate shifts and developing system responses. There is something to be said for the usefulness of this approach. Given sufcient nancial and scienticresources, a formal vulnerability assessment of potentialand realised impacts on a system of interest thatsummarises the state of knowledge at a given time.Formal assessments have the advantage that they canfocus on specic issues, can quantify (or least bound) thelevels of climate uncertainty and condence, and can beupdated and re-evaluated as more knowledge becomes

available. They should become an important instrument of planning and encapsulate the best available data. Ideally,they should also identify climate opportunities as well asrisks, distinguish between potential and realised impacts,and identify where climate adaptation is already occurringfor ecosystems, species, societies, and economies.

However, an approach that emphasizes the deterministicapplication of physical and ecological modeling alonemay limit the problem of anthropogenic climate changeto simply developing a list of impacts and responses

what may be called impacts thinking. We advocate acontrasting process-oriented approach vulnerabilitythinking that promotes exibility, long-term planning andmonitoring, and adaptive management.

Climate shifts already have been or will soon be signicantenough to warrant a reconsideration of how most humaninstitutions function in relation to the ecosystems in whichthey are embedded. The ability of these institutions torespond successfully will determine the extent to whichclimate change does or does not have damaging socialand ecological impacts. Many current vulnerabilityassessments do not focus on this. Given that the

condence in specic shifts occurring in a particular placeby a particular time period is generally low, the physicaland ecological modeling approach may lead to a falsecondence in the set of potential impacts and responses.In truth, a comprehensive impacts assessment may beable to reduce the uncertainty around evapotranspirationrates or the frequency of extreme weather events, butit will not often be able to provide a single clear set of management recommendations. This is the uncertaintygap.

We believe that a freshwater vulnerability assessmentneeds to embrace two related elements at its corethat supplement physical and ecological modeling.Firstly, it must embrace uncertainty in moving towardsrecommended responses. This may require an approachthat considers future uncertainty through the developmentof emerging climate stories with contrasting qualitativequalities rather than quantitative, deterministic, andassiduously downscaled scenarios. Secondly, it mustassess the resilience of both ecological and institutionalsystems. It is this resilience that will ultimately determinehow well systems are able to respond, and where impactswill occur: in other words, where there is vulnerability.


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Vulnerability assessment should become a continuous,normal process rather than a single episodic event. Thus,one of the outcomes of assessing vulnerability shouldbe an emphasis on developing institutional processesand methods to (a) reduce the areas of uncertaintiesuncovered by a vulnerability assessment, and (b)identifying gaps within the institution itself that inhibitclimate-aware exibility. By embracing uncertainty in

climate projections, we can alter our water managementinstitutions in order to resolve those uncertainties. Thesetwo tasks are the core of adaptation thinking as anextension of impacts thinking.

PART B:Identifying vulnerability and embracing uncertainty

How should we prioritize impactsby relative certainty?

Concepts of vulnerability should be informally incorporatedinto all aspects of water resource planning even in theabsence of a formal vulnerability assessment. An effectiveschema for capturing the state of knowledge and degreeof uncertainty is through a series of focus questions:

What do we know is happening to the system inquestion already? For instance, a historic trend analysisover recent decades may reveal that peak river ows aredeclining in height and occurring earlier in spring. This isa known, veriable impact. At the same time, we mightalso know that infrastructure development has had asignicant impact on the connectivity of wild species anda concomitant reduction in livelihood activities orientedtowards shing.

What do we know will happen to the system? Risingtemperatures will accelerate and further alter spring owregime. Higher temperatures will also increase the waterdemands of existing crops and, coupled with further urbandevelopment, increase demands on freshwater systems.

What do we think with reasonable condence isgoing to happen? Precipitation patterns are likely to shift;lower low ows may lead to hyper-eutrophic conditions,signicantly increasing water treatment costs. Developingscenarios of potential suites of impacts, even unlikely butcatastrophic ones, can be useful for this set of issues. Forinstance, most climate models project gradual, persistentshifts in climate, but the climate record suggests thatmany large regime changes occur in a stepwise matter

periods of relative stability separated by a rapid transition.Sudden state-level change occurring over a period of oneor two decades would present quite a different type of change from gradual, slow shifts.


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PART C: What can you do inresponse to climatechange?

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We have two very general suggestions for supportingclimate adaptation initiatives. The rst should apply even if no other action is taken: support climate mitigation effortsto reduce the rate of emissions of greenhouse gases. Thissuggestion simply reects the need to reduce the rateof climate change to give species and human societiesmore time to adapt. However, the earth is now committedto changes in the climate for decades to come even if all

greenhouse gas emissions were to cease immediately.Ideally, then, we must consider more specic climateadaptation policies.

The second general climate adaptation suggestion is tomaintain exibility in order to avoid prematurely limitingfuture actions. In practice, this is a difcult rule to follow;sometimes decisions are forced and time-sensitive, orother priorities supersede adaptive strategies. In truth,rarely are decisions in development and conservationmade with high condence and perfect knowledge

under any circumstances. However, exibility implies thatwater management systems contain redundancies; thatinstitutions are capable of monitoring important ecosystemand social indicator variables; that institutions can learnand adjust their policies in response to new information;and that decision-making is both decentralised (occurringat scales that are relevant to microclimate conditions) andcoordinated (so that one region of a basin is not workingagainst another).

This second suggestion underlies many of the eight

elements of freshwater climate adaptation that follow. Thislist of recommendations is certainly not comprehensive,and not all elements will apply in every case. There arealso important interactions between the different elements.But they should serve to describe in a general way how

freshwater climate adaptation is both similar to and differsfrom both current water management approaches andadaptation in other biomes.

1. Develop institutional capacity

The development of strong institutional capacity should beregarded as the single most important task in facilitatingsuccessful adaptation to climate change in freshwater.

The actions required to successfully adapt to climateimpacts on freshwater systems depend on the existenceof adequate institutional capacity. The functions that willbe required of water management institutions includethe control and monitoring of legal and illegal water use,the monitoring and assessment of ongoing physicaland biophysical changes in freshwater systems, thecontrol and enforcement of pollution prevention, andthe regulation of water infrastructure development andoperation.

None of these tasks is straightforward, and each requiressignicant technical, nancial, and social capacities atdifferent scales, from strong and well-governed nationalwater ministries, through regional departments andbasin councils, to local river basin ofces and water userassociations. In all of these cases, these institutionsneed to discharge their functions independently and inthe absence of undue interference, corruption, or localcapture. Clearly, effective governance is an underlyingtheme in developing capacity.

The contemporary reality is very far from this. In the vastmajority of the world, water management institutionsare weak, under-resourced, and subject to inuence bypowerful vested interests. Unless and until signicantlymore resources are devoted to the development and

PART C: What can you do in response to climate change?


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support of strong water management institutions,considered and controlled adaptation to climate changewill be difcult at best.

2. Create exible allocation systems andagreements

The most profound impacts of climate change onfreshwater will be through changes in precipitation. Inmany cases, this will reduce the amount of water available,either in total across the year or at particular criticalperiods. If ecosystems and important social and economicwater uses are to be protected, it is necessary for patternsof water use to adapt to any such annual or seasonalchanges in water availability.

In all but the rarest circumstances, water use globally isgoverned by allocation or water rights systems that governwho is allowed to take water from a system, when, andin what quantities. An allocation system therefore either

explicitly or implicitly determines how much water is oris not retained for ecosystems. Allocation systems cantake many forms, including formal systems based onnational water laws, informal and traditional systems, or acombination of these types. 9 The type of allocation system,and in particular whether it is exible enough to be able torespond to changes in water availability, will be central toexpressing societal responses to climate change.

Many allocation systems already have mechanisms forcoping with existing levels of variability in water availability.

For example, differing water users and water uses canbe recognised as holding distinct priorities: when wateravailability is reduced, then water use by lower priority

9 Le Quesne T., et al. 2007. Allocating scarce water: A primer on water allocation, water rights and water markets. WWF-UK, Godalming, UK.


users is curtailed to protect higher priority uses. In anideal situation, basic social and environmental needs forwater will be of the highest priority, followed by essentialeconomic activities (for example, cooling water for powerstations). Mechanisms should also be in place to allowthe remaining water to be allocated or reallocated forappropriate economic activities. The presence of a waterallocation system that protects essential environmental

ows and social needs while permitting exibility ineconomic use of water helps to respond to climate-driven changes in water availability. In many cases, theexpectations for water availability must themselves beexible, whether on a seasonal (dry season versus wetseason) or on an episodic basis (mean conditions versusdroughts).

In reality, exible systems exist in few places at themoment. More often, under conditions of water scarcity,water is allocated not to social and environmental priorities

but rather to a par ticular sub-set of water users who may,for example, hold the longest standing water rights, as isthe case in parts of the USA. In many contexts, water issimply allocated legally or illegally to the most politicallypowerful groups, or appropriated by upstream overdownstream users.

Similar issues apply to water treaties between provinces,states, or nations. Typically, such treaties allocate waterbetween basins based on assumptions of water availabilitydrawn from historical precipitation patterns. If the amount

of water available changes while the provisions of treatiesremain xed, this may lead to over-withdrawals of waterimpacting on ecosystems or social water needs. In somecases, political unrest and conict may even result.


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3. Reduce external non-climate pressures

Freshwater ecosystems and species have long facedserious threats that are unrelated to anthropogenic climatechange, such as water pollution, exotic invasive species,overshing, and negative impacts from land-use shiftssuch as clearcutting riparian forests. The presence of so many nonclimate pressures is one of the most novelcomponents of this era of climate change. Past climateshifts did not coincide with such threats (and certainly not

all of them at once), and these external pressures reducethe natural adaptive capacity of wild and human systems.In many cases, we believe that reducing non-climatepressures means doing what we already know we mustand should be doing, but with more urgency and efcacy.

For instance, nutrient pollution is a problem worldwide.Many freshwater ecosystems have historically beenlimited in their productivity (the abundance and massof organisms living in these systems) by scarce nutrients.For algae and plants, nutrients such as phosphorous

and nitrogen have limited their relative biomass. Theseoligotrophic systems typically have clear water incontrast to eutrophic systems that tend to have ahigh abundance of plants and algae, which can evenchoke out other types of organisms and alter the wholebiogeochemistry of the water body.

For most human purposes, eutrophic conditions areassociated with low water quality. With the advent of cheap chemical fertilisers and the large concentration of humans (and their sewage) near freshwater ecosystems,

however, many oligotrophic systems enter eutrophicconditions more frequently and longer than in the past.Warmer air and water temperatures exacerbate the

problem. Damage to ecosystems occurs preciselybecause of the combined effects of pollution andchanging water temperatures. Management of agriculturalrunoff and effective sewage treatment can help reduceconcentrated nutrient inows and improve water qualitysubstantially, increasing climate-adaptive capacity forthese ecosystems.


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5. Think carefully about water infrastructuredevelopment and management

New irrigation, hydropower, or ood control measures thatare designed on the basis of recent climate history and theassumption that a given hydrological system is stationarymay not deliver the expected services over their lifetime.Uncertainty about future hydrology, a key parameter of infrastructure feasibility, is emerging as a great challengein infrastructure planning and engineering. Current owsin a river may be much larger than the future average,

for example, as extreme precipitation events increase infrequency, threatening the very safety of the structure. Orthey may decline and collapse as snowpack and glaciersin a headwaters region sublimate to the atmosphereinstead of melting into the basin. A hydropower stationbased on the past centurys record of ows may soon beover or under-designed.

By building the wrong structures now or by notmodifying existing structures, we may actually limit ourfuture options for climate adaptation. Planners need

to think both about how climate change will shape thesupply of water in terms of future river ows (and shiftsin their mean and variability) as well as the demand forwater services. Can energy demands be reduced throughincreased efciency rather than increased generation? Cancrop selection be shifted to less thirsty varieties? Someclimate impacts may not be direct or intuitive. For instance,upstream agricultural areas may need to abstract morewater to cope with increased evapotranspiration, whichmeans that this water is not available for downstreamdams. Indeed, evaporation from reservoir surfaces alreadyconsumes some 1020% of total runoff in many aridbasins such as the Nile, Colorado and Zambezi, and will


4. Help species, human communities, andeconomies move their ranges

For most species, exploiting landscape connectivity viarange shifts is a critical strategy in responding to climatechange. For instance, a particular species may breedin very specic areas that may be unpolluted and retaingood habitat quality. With changing temperature andprecipitation regimes, however, that species may beforced to move to higher, cooler altitudes, or downstreamif headwaters become more ephemeral. Thinking of

connectivity in climate-aware terms requires ensuring thatwhole components of a system are relatively unpollutedand do not have signicant physical barriers to movement.

These movements may be made by individuals (within-generation movements), for example moving to coolerportions of the same water body such as deeper water, ormoving upstream towards headwaters. Or they may occurover the lifetime of several individuals (trans-generationalmovements), such as through the process of colonisingnew aquatic habitats.

Humans too responded to past climate shifts by alteringwhere activities occurred such as shers shifting tolarger, more permanent bodies of water with increasinglyreliable sh stocks. In some cases, policymakersand resource managers may need to work with localcommunities or livelihood groups to extend their adaptivecapacity by assisting with the process of altering theranges or timings of their behaviours.


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almost certainly increase further. By creating an apparentincrease in security of supply, increased infrastructure mayresult in increased water-consuming activities, makingsocieties more vulnerable to future hydrological variabillity,not less.

Ideally, water infrastructure should become a tool infacilitating adaptation for both wild species and humancommunities. Water infrastructure and its managementmust be considered strategically, over climate-relevanttemporal and whole-basin spatial scales. Consideringthe size of the nancial investments embodied in largeinfrastructure development, the negative impacts onecosystems and local communities often associatedwith that development, and the climate uncertainties thatchallenge designers, planners would do well to makeconservative estimates of supply and aggressive estimatesof demands.


6. Institute sustainable ood management policies

Climate change is likely to result in an increase in extremeweather events. In many parts of the world, this is likelyto result in an increase in ood risk. In the context of changing precipitation patterns, the construction of hardengineering defences alone is likely to be insufcient,and may on occasion exacerbate the problem: thereis an increasing risk that defences based on historicprecipitation patterns will be overwhelmed, leading to very

signicant damage.Sustainable ood management takes an integratedapproach. It looks to reduce ood risk by understandinghow oods move through catchments, developing riskreduction strategies that include schemes to retainwater on uplands, and using oodplains and washlandsto alleviate ood peaks. Alongside these measures,sustainable ood management looks to ensure that humancommunities are as resilient as possible to ood risk, suchas avoiding the location of new development in high ood

risk areas and ensuring that any vulnerable communitiesare able to recover from ooding events.


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7. Support climate-aware government anddevelopment planning

Many government economic and social planning decisionsinclude assumptions about future availability of water.Most signicantly, agricultural development strategiespresuppose particularly water availability or climaticconditions. Similarly, the development of industriallocations and plans for future growth in urban centresdepend on assumptions about the availability of water,whether in an absolute annual-scale level of availability,

the availability of water during certain seasons, or thefrequency of ooding and droughts as climate variabilityincreases. If assessments of changing water availabilityare not taken into account in this planning, there are veryserious risks of signicant adverse social and economicconsequences if insufcient water is available to supportthe intended social or economic activity.


8. Improve monitoring and responsivenesscapacity

Vulnerability assessments ideally capture the mostaccurate state of knowledge of realized and potentialclimate change impacts on a human or natural systemof interest. Ideally, these assessments also state thelimits of that knowledge and point out where uncertaintyremains. A key implication behind such boundeduncertainty is developing institutional processes todetect trends, encompass areas of limited knowledge,

and determine appropriate institutional responses. Ideally,these mechanisms mean that assessing vulnerability andrapidly distributing that knowledge becomes embodiedwithin planning and management institutions as a normal,everyday process.

In practical terms, improving monitoring means identifyinghydrological, ecological, and/or social variables that canserve as early-warning indicators of shifts in importanttraits in system of interest. These changes may be short-term impacts such as droughts, or they may be more

complex, such as a shift in the mean number of heat-stress days for an endangered coldwater sh species.Certain ow rates or key species densities may be triggersthat lead to direct intervention or changes in planningor design policies, such as the need to revisit a basin-wide environmental ows assessment process. Scenarioplanning for responses to high-stress situations such assudden ood events before they occur is also critical, sothat sound reactions can be developed and negotiatedwith minimal conict.


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Hansen, L.J., J.L. Biringer, and J.R. Hoffman. 2003. Buying Time: A Users Manual for Building Resistance and Resilience to ClimateChange in Natural Systems. Island Press: Washington, DC.

Buying Time was the rst book-length treatment to move beyondclimate impacts to develop strategies for assessing vulnerabilityand implementing a climate adaptation plan. It remains animportant core reading.http://assets.panda.org/downloads/buyingtime_unfe.pdf

The Cooperative Program on Water and Climate has an excellentset of water-related resources, including its own publications aswell as links to those produced by other organisations. The lattersection is annotated and updated regularly.http://www.waterandclimate.org/index.php

Intergovernmental Panel on Climate Change. 2007. ClimateChange 2007: Impacts, Adaptation and Vulnerability. Contributionof Working Group II to the Fourth Assessment Report of theIntergovernmental Panel on Climate Change, M.L. Parry, O.F.Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds.,Cambridge University Press, Cambridge, UK, 976pp.

This volume represents the state of IPCC ndings on climateimpacts as of 2007 and is quite comprehensive in its discussionof cross-cutting and regional issues regarding climate impacts.

Adaptation strategy is less well covered. While one chapterfocuses on freshwater resources (updated below), many sectionsare directly relevant to freshwater ecosystems and resourcemanagement. This volume is far superior to the Summary for Policymakers that is more generally referenced.http://www.ipcc.ch/ipccreports/ar4-wg2.htm)

Intergovernmental Panel on Climate Change. 2008. ClimateChange and Water. Bates, B.C., Z.W. Kundzewicz, S. Wu and J.P.Palutikof, Eds. Technical Paper IV of the Intergovernmental Panel

on Climate Change, IPCC Secretariat, Geneva, 210pp. This document, published in mid 2008, is a signicantly updatedand more detailed version of the 2007 freshwater resourceschapter from Working Group 2.http://www.ipcc.ch/pdf/technical-papers/climate-change-water-en.pdf

Stern, N.H. 2007. The Economics of Climate Change: The SternReview. 2007. Cambridge University Press, Cambridge, UK.692pp.

The Stern Review represents one of the most creditable andwidely respected attempts to date to quantify economic impacts of current and projected climate change impacts.http://www.dcc.gov.uk/activities/stern.htm

Further reading


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Formed in 2007, the HSBC Climate Partnership brings together HSBC, TheClimate Group, Earthwatch Institute, Smithsonian Tropical Research Instituteand WWF to tackle the urgent threat of climate change on people, water, forestsand cities. For more information visit www.hsbc.com

text 2009 WWF-UK.

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The mission of WWF is to stop the degradation of the planetsnatural environment and to build a future in which humans livein harmony with nature, by: conserving the worlds biological diversity ensuring that the use of renewable resources is sustainable reducing pollution and wasteful consumption

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Adapting Water Management A primer on coping with climate change

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