CLIMATE CHANGE AND ENVIRONMENTAL DRIVERS
Mark Mulligan, King’s College London
KEY POINTS:1.Environmental drivers (ED’s) are fundamental, don’t forget them2.Some cannot be managed by us (e.g. rainfall inputs) so we are at their mercy3.We do not know it all – still a lot to understand about ED’s4.We cannot even measure the most fundamental ones at policy relevant scales (e.g. rainfall inputs)5.ED’s are spatially variable within as well as between basins – need for careful spatial targeting of interventions rather than ‘broad-brush’6.ED’s are highly dynamic in time7.Capacity of natural systems to buffer ED changes diminishing as ecosystems are degraded – impact on ecosystem service delivery
8.Climate change will be an increasingly important ED• must be seen within the context of current climate variability• rainfall change (not temperature) is the key for most of the
basins but is highly localised - rainfall may increase or decrease locally (global average is increase)
• catchments may wet up for 2040s then dry or vice versa thus continuous adaptation required
Ganges Volta
Limpopo
1. RS productivity and rainfall compared for 1000 points in and around each basin
2. Rainfall is not the only driver of plant productivity
3. There are other environmental (and socio-economic) drivers
4. Relationships with rainfall much stronger at low rainfall (e.g. Limpopo)
5. Form of relationship varies between and within basins
There is already significant inter-annual climate variability in some of the basins and this needs to be
incorporated in any intervention or planning
These are entire basin averages, parts of the basins may have different responses
Recent historic climate trends are not significant in the basins
Most 20th C warming occurs post 1950, so not seen here
Climate change is basins to 2050 Temperature change within and between CPWF phase I basins (mean of 17 GCM ensemble)
All warming
Significant differences within as well as between basins.
Change much more uniform in some basins than others.
South American basins
Asian basins
African basins
Precipitation change within and between CPWF phase I basins (mean of 17 GCM ensemble)
African basins
South American basins
Asian basins
Some wetting, some drying
Significant differences within as well as between basins.
Parts of a basin may dry while other parts wet
Change much more uniform in some basins than others.
Impacts of climate change on water availability for Andes basin. (mean of 17 GCM ensemble)
Combines effect of precipitation, temperature and thus evapo-transpiration changes
But environmental drivers are just one of many. Need to consider them within context of other drivers such as:
Population, economics and others in an integrated way
ar4-a2-ci-mean-2041-2060Ganges basin water balanceMean of 17 GCMs
2050 sees possible increases in rainfall over most of lowlands.
Some decreases in rainfall in Himalaya
% change
Some sharp increases in water balance because of additional snowmelt inputs
Very high % changes relative to current baseline in some areas
ar4-a2-ci-mean-2081-2100
40 years later spatial pattern changes a little
Still dominantly wetting in most of lowlands but now drying in the western high plateau
Stronger wetting in Himalaya
% change
% change
ar4-a2-ci-mean-2041-2060
Seen by administrative region, it is clear that some regions will have to deal with less water (eg Uttar Pradesh) and some with more water (Tibet).
National adaptation plans of action (NAPAs) then not so relevant as regional ones (possibly even local ones).
% change
ar4-a2-ci-mean-2081-2100
40 years later admin areas that had dried relative to baseline are now wetter than baseline (e.g. UP)
Some undergo further wetting (e.g. Tibet)
Interventions would need to be highly adaptable to cope with such water resource flip-flops even with the buffering of groundwater
ar4-a2-ci-mean-2041-2060Water supply to urban populations
The implications for water supply to urban areas indicates mostly increases (because of increased rainfall) and snowmelt.
% change
Increases in % terms especially high in foothills where extra snowmelt also contributes and in areas with lower baseline flows to start with
% change
ar4-a2-ci-mean-2081-2100Water supply to urban populations
Impacts on runoff through urban areas change in magnitude and pattern over the subsequent 40 years.Again adaptive capacity is important.
There is no flatlining in nature (most EDs vary over time) – water and food systems therefore need to
be responsive and adaptable to environmental drivers (as they often used to be)
Concluding
Win-wins and adaptation
Water is a common pool resource (CPR, use degrades the resource available to others) : so there may be no win-win solutions to managing change in ED’s. Someone’s gain is someone else’s loss. Role for BSM here.
Responding to changing Eds (esp. CV/CC) requires adaptive capacity perhaps focused as:
Less focus on?: More focus on?:
International capacity Local capacity
Hard(er) interventions Soft(er) interventions
Centralization Decentralization
Resource exploitation Efficiency of use
Livelihood homogenization.. Diversification
Built capital Social capital
1. Can we define the best intervention(s) to make under current environmental driver states?
1. System understanding (do we understand the system?)
2. Data quality (do we have the data?)
3. Politics (are the technical solutions politically feasible?)
4. Funding (is there investment potential?)
2. How will this intervention also work through the full cycle of climate variability?
3. How will the intervention work for 2040-4060 hydro-climatic conditions in the area?
4. How will it also work for 2080-2100 hydro-climatic conditions in the area?
Discussion: relevance of ED’s to CPWF related interventions