RIVER INPUTS TO OCEANS AND GLOBAL CHANGE

Michel Meybeck Sisyphe, CNRS/Université Paris 6Charles Vörösmarty, Water Analysis Group, Univ. New Hampshire

Why and How to establish river fluxes at global scales ?

Where are the highest fluxes ?

When fluxes reacted or will react to global change ?

Who is responsible for riverine changes ?

Future evolution evolutions and new track

ASLO-HAWAI 2004

WHY SET UP RIVER FLUXES AT GLOBAL SCALES ?

QUESTIONS PRECURSORS

Global river we thering rates Clarke 1924, Alekin 1950s, Livingstone 1963

Origins of Sedimentary rocks Garrels and Mackenzie, 1971

Biogeochemical cycles: carbon, Garrels, Mackenzie, Hunt, 1973

Nitrogen, Sulfur, silica

Global denudation Fourier 1960, Janssen and Painter, 1974

Coastal geomorphology/Sedimentology Milliman 70’s

Pollutants Inputs to oceans Goldberg 70’s

Earth System and Global change IGPB 80’s

ASLO-HAWAI 2004

HOW TO CONSTRUCT GLOBAL RIVER FLUXES ?HOW TO CONSTRUCT GLOBAL RIVER FLUXES ?

River Set Global present figures Global reconstructs

small & representative flux past

big (concentrations & yields)

mapping future

controls

Some problems encountered

How to deal with extreme variations of conc. & yields over 2 or 3 orders of magnitude (e.g. hot spots ?)

Amazon in or out ? (15% of water fluxes)

Are yields influenced by sized (e.g. Sediment Milliman & Syvitski)

How to filter human impacts for assessing past natural fluxes

How to take into account all human impacts for future evolution (e.g. sources vs sinks; scenarios)

How to identify key controls/drivers in both natural and present day conditions

Space resolution ? Gobal to local river input

Time resolution. Average fluxes vs seas onal

DEVELOPING TOOLSDEVELOPING TOOLS

River data sets Large rivers Livingstone, 63Meybeck, 1979, 1982GEMS-Water, 1978Milliman/Meade/Syvitski, 80’s, 90’s...Meybeck, ragu (GEMS-GLORI) 1995 small pristine rivers LTER 70’sMeybeck, 80’s

Global data sets on geosphere runoff vegetation relief soilLithologyGIS tool 90’s

Global human pressures 90’s populationUrbanisationLand useFertilizers(Industries)(minings)

Global scenarios 00’s Climate chnage economicDemographicLand se water use Water policy

PRISRI : GLOBAL DISTRIBUTION OF DIC MEDIUM-SIZED BASINS

3 500 - 200 000 km2, rheic basins (n = 480)

% HCO3- / - DIC CONCENTRATION DIC EXPORT

99,599

90

75

50

25

10

10,5

RARE

UNCOMMON

COMMON

VERY COMMON

COMMON

UNCOMMON

RARE

10 50 1000,5 1 10 100

DIC mg/L

0,1 1 10 50

g C.m-2.y-1

In 50% of basins HCO3

- exceed 80% of anions

DIC concentration ranges over 2 orders of magnitude

DIC export ranges over 3 orders of magnitude

%

PRISTINE RIVER CHEMISTRYPRISTINE RIVER CHEMISTRY

GLOBAL BUDGETS ARE REACHING THEIR LIMITS GLOBAL BUDGETS ARE REACHING THEIR LIMITS EXAMPLE : DISSOLVED SILICAEXAMPLE : DISSOLVED SILICA

Global average (mg/L) Approach

Clarke, 1924 8,3 Few, big temperate rivers

Livingstone, 1963 13,1 d.o.

Meybeck, 1979 10,4 Biomes typology, 60 rivers, Amazon included

Probst, 1992 8,9 Multiregression (Meybeck’s data)

Meybeck and Ragu, 1996 7,7 250 rivers no typology

Meybeck, 1999 (unpubl.) 9,2 d.o. + 9 morphotectonic tpes (lytho. Control)

Treguet et al., 1995 9,0 (Meybeck + Ragu data)

Meybeck (unpubl.) 8,75 43 pristine rivers and tribs (exorheic + endorheic)

Relief Typology (Meybeck et al., 2001)

Classification of 15 relief patterns at global scale combining a relief roughness indicator and mean altitude at 30’

resolution, re-aggregated into 7 relief super-classes

Global figures

Global river fluxes

Mean annual Surface runoff at the 0.5° resolution

Database : Fekete et al. 1999, 2001

The rheic-arheic limit is here set at 3 mm/y on the long term (typically 1 flood every 10 years) The dry belts may be found in cold (NE Siberia), temperate

(Central Asia, Patagonia, Australia) or warm regions (Sahara / Arabia ; Kalahari)

The heterogeneity of the runoff mosaic depends on the resolution

Organisation of the continental surfaces by water into major units

Exo(%) Endo(%) Σ

25,7 9,0 34,8 Arheic

60,1 5,2 65,2 Rheic

Σ 85,8 14,2 100%

River network

River network : Vörösmarty et al. 2000 a & b, modified and adapted

Global figures

- The arheic areas are below 3 mm/yr annual runoff

- Due to uncertainty on the water balance ‘arheic’ areas may occur in non-desertic

regions, as NE Siberia, Mackenzie basin, Missouri basin, Patagonia etc. ...

Total area 133 M km2

Relative Water towers of the World as defined for major Köppen climate zones

Global figures

Exorheic

Endorheic

Water towers = > 2 x mean runoff in the climate zone & mountains

- Polar 332 mm/yr - Cold 251 mm/yr

World average runoff in Köppen climate zone: - Temperate 415 mm/yr (exorheic parts) - Dry 18 mm/yr

- Tropical 708 mm/yr All climate zones combined: - Endorheic 54 mm/yr

H. Dürr 2003

Average runoff per segment (mm/y)

Coastal zone segmentation

The upper and lower deciles of coastal basins runoff are >1200 mm/yr and <25 mm/yr

(median <200 mm/yr) [endorheic basins not considered]

H. Dürr 2003

Most of the continents water is discharged through a limited number of coastal basins : South-East Asia,

Congo, Siberia and Amazon-Orenoco

COASTAL ZONE SEGMENTATION: TOTAL WATER DISCHARGE PER SEGMENT (km3/y)

GLOBAL MAPPING OF RIVER FLUXESGLOBAL MAPPING OF RIVER FLUXES

6,0 7,1 8,7 18,4 41,2 0,3418,2

Area in each class (% of global) per classes of river runoff

0.01 0.1 0.2 0.5 2 5 10 q / q 3.6 36 72 180 716 1790 q(mm/yr)

0,01 0,31 1,1 6,1 36,2 54,6 1,8

Discharge (% of global)per classes of river runoff

0.01 0.1 0.2 0.5 2 5 10 q / q 3.6 36 72 180 716 1790 q(mm/yr)

World distribution of runoff and water fluxes

in exorheic basins

Coastal zone segmentation

(115 M km2, n=160, global runoff 358 mm/yr)

- 54,6 % of the discharge to ocean (22 800 km3/yr) originates from 18,2 % of exorheic area where annual runoff is between 2 – 5 times the world average

- 1,4 % of the discharge (600 km3/yr) originate from 21,8 % of exorheic area where annual runoff is less than 1/5 of the world average

H. Dürr 2003

0,02 26,536,828,35,81,71,0

Population (% of global per classes of population density

0.01 0.1 0.2 0.5 2 5 10 d / d

0.5 4.5 9 22 90 225 450 d(p/km2)

4,211,731,017,311,517,66,7

Area in each class (% of global) per classes of population density

0.01 0.1 0.2 0.5 2 5 10 d / d0.5 4.5 9 22 90 225 450 d(p/km2)

World distribution of population in exorheic basins

- 26,5 % of the population linked to oceans (1 390 M people) live in 4,2 % of exorheic area where population density exceeds 5 times the

world average

- 2,8 % of the population (140 M people) live in 35,8 % of exorheic area

where population density is less than 1/5 of the world average

Coastal zone segmentation

(115 M km2, n=160, global average density 45 p/km2)

H. Dürr 2003

GLOBAL SYNDROMES OF RIVERINE CHANGES• Flow regulation

• River course fragmentation

• River bed silting

• Neoarheism

• Salinization

• Chemical contamination

asphixiation, inorganic contamination, xenobiotics occurence

• Acidification

• Eutrophication

• (Microbial contamination)

• (Aquatic species introduction & invasion)

GLOBAL SYNDROMES OF RIVERINE GLOBAL SYNDROMES OF RIVERINE CHANGESCHANGES

SOME GLOBAL CHANGES AFFECTING RIVER FLUXESSOME GLOBAL CHANGES AFFECTING RIVER FLUXES

2,54 Mkm2 of irrigated land (in dry and semi arid and arid regions)

More than 5 % of global river runoff decrease (> 2000 km3/y)

Hundred of thousands of small to giant reservoirs

Total reservoir area >0,5 M km2 (Great Lakes + Caspian).

RIVER FLUXES TRENDS AFTER DAMMING THE COLORADO EXAMPLE (1910-1960)

A : annual water flow

B : annual sediment flux

• Colorado changes are some of the most dramatic change documented in a river

system

• This evolution was triggered by the construction of the Hoover Dam in 1936

TE17

NEOARHEISMNEOARHEISM

• Coastal zone now gets 30% less sediment• 700% increase in water held in rivers• Tripling of river runoff travel times

UNH

Vörösmarty et al. 2003

Sediment starving is a growing issue in some coastal zone

GLOBAL MAPPINGGLOBAL MAPPING

GLOBAL IMPACT OF LARGE RESERVOIRS : SEDIMENT TRAPPING EFFICIENCY

Global nitrogen fluxes through rivers : preindustrial vs contemporary

UNHGreen et al. 2003

• The global N fluxes (tot N) have increased more than 3 times• Regionally the fluxes have increased more than 10 times• Agriculture and urbanization are the two major N sources

NUTRIENTS FLUXES HETEROGENEITYNUTRIENTS FLUXES HETEROGENEITY(From GEMS-GLORI analysis)(From GEMS-GLORI analysis)

AREA CLUSTERS

The impacted temperate zone (N. America, Europe, China...) corresponds to 27,5 % of lobal area but to 52 % of P-PO4

3- fluxes and to 6 % of DIN fluxes to oceans

The dry and non- impacted wet tropics plus subarctic regions corresponds to 50,7% of global area and only to 30% of P-PO4

3- and 21,3 % of DIN fluxes

FLUXES RANKING

The most polluted rivers that represent only 5 % of global water discharge would contribute to 32 % of NO3-48 % of NH4+54 % of PO4

3- fluxes

Regional Analysis : Europe

- Continents can be disaggregated into coastal segments and their basins for which the space

distribution of Human Pressures is established

Regional Analysis : Europe

- Coastal basins are very explicit for global fluxes comparisons

(database : Green et al. 2004 Biogeochemistry)

Regional Analysis : Europe

Relative weights of European Regional Seas basins (Meybeck and Dürr in preparation)

North Atlantic /

North Sea Baltic

Arctic

N. Black Sea N.

Mediterranean

Europe

Total

Area % 23.4 19.7 19.9 25.5 11.5 100

Water Volume

% 30.7 16.5 23.7 13.9 15.2 100

Population

% 40.7 12.7 1.7 26.4 18.3 100

Suspended

Sediment % 25.5 3.1 12.0 16.2 43.1 100

Total Nitrogen

% 48.0 11.2 8.3 15.8 16.7 100

A SUCCESS STORY : NUTRIENTS CONTROL IN THE RHINE R.

• The major effort of sewage collection was between 1960 and 1975 : it resulted in particulate P abatment and NH4

+ decrease

• P-PO43- control then decrease was only achieved after the 1985 ban of P detergents

and the dephosphatation in most treatment plants

Van Dijk & Marteijn, 1993

EUTROPHICATIONEUTROPHICATION

mg P /L

mg P /L

RIVER BED INCISION

SLOPES LAKESALLUVIAL PLAINS

DELTAIC SEDIMENT

COASTAL SEDIMENT

NATURAL SOIL WEATHERING

LEACHING/EROSIONGROUNDWATER

RIVER BED

ATMOSPHERIC FALLOUT

UPPER COURSE MIDDLE/LOWER COURSE

ESTUARY/DELTA

COAST

1

2

3 4 5 6 7 8 9 10 11 12

13

16

NATURAL SOURCES/SINKS IN RIVER COAST PATHWAYS

14

15 a 15 c15 b

ESTUARINE SCIENTIST

HYDROLOGIST/LIMNOLOGIST COASTAL SCIENTIST

HYDROLOGISTSOIL SCIENTISTGEOCHEMIST

LAKES

GROUNDWATER

CONTAMINATION

ORES BUILDINGSIMPORTED PRODUCTS

MINING

RESERVOIRS

CITIES & INDUSTRIES

DUMPS PARTICULATE MATERIAL DEPOSITORIES

SLOPESWETLANDS

ALLUVIAL PLAINS

AQUIFERS

DELTAIC SEDIMENT COASTAL

SEDIMENT

EXPORTEDPRODUCTS

RIVER BED

ATMOS. POLLUTION

ATMOSPHERIC FALLOUT

SURFICIAL FILTERS

RIVERINETRANSFERS

SINKS & EXCHANGES

UPPER COURSE

MIDDLE/LOWER COURSEESTUARY/DELTA COAST

A

B2

C D

E

H I NJ

K

M

P

1

3 4 5 6 7 8

H

9 10 11 12

13

Q

16

F2F1 G1

G2

L

O

15 a

ANTHROPOSPHERE FLUXES

T

15 b

U

14

TAILINGS

PRISTINE LAND SURFACE

IMPACTED

LANDSURFACE

W

V

R

B1

B3

URBAN / INDUS. SOILS

Z

B2J3

ECONOMY/POLICY

MATERIAL TRANSFER WITHIN THE GEOSPHERE/ANTHROPOSPHERE SYSTEM

Surveys of anthroposphere leaks

Surveys of economic material fluxes

EVOLUTION OF CONTINENTAL AQUATIC SYSTEMS FROM HOLOCENE TO ANTHROPOCENE

Possible scenariosA : stabilized level, major Earth System change, unmanageable for Human development (laissez-faire)B : stabilized level with maximal acceptable risk for Human development and marked Earth System change (suppression of most polluted sites)C : stabilized level : acceptable risk for Human development with minimal Earth System change (precaution principle)P : return to pre-anthropocene level

A

B

CP

100Ź000 10Ź000 1Ź000 1Ź800 1Ź950 2Ź000 2Ź050 TIME

100Ź000 10Ź000 1Ź000 1Ź800 1Ź950 2Ź000 2Ź050 TIME

STATE INDICATOR

STATE INDICATOR

MODELS SCENARIOSŹ/ŹPROJECTIONS

DIRECT SURVEYS

ARCHEOLOGICALŹ/ŹHISTORICALŹDATA

ENVIRONMENTAL ARCHIVES

RESPONSES OF CONTINENTAL AQUATIC SYSTEMS TO CLIMATEVARIABILITY, LAND COVER CHANGE & DIRECT HUMAN PRESSURES

RESPONSES OF C.A.S. TO WATER USES & LAND USE

QM

HM

Hm

Qm

BP BP AD

ANTHROPOCENE

HOLOCENE

MAN AND RIVER RELATIONSMAN AND RIVER RELATIONS

DEVELOPMENT OF GLOBAL APPROACHESDEVELOPMENT OF GLOBAL APPROACHES

Simple extrapolation (Clarke, Livingstone, Alekin, Martin- Meybeck)

conc Q or yields A

Typologies (e.g. biomes) then extrapolation (Meybeck, 79,82,93; Schlesinger & Melack, 1981)

Multiple regressions with basin natural control factros (runoff, litho, relief) (Fourier, Janssen & Painter, ??)

Mutiple regression then application at fine resolution with global GIS (Probst et al, 90’s)

Mutiple regression with natural and human factors + GIS (Seitzinger, Caraco, 90’s)

Mutiple regression + some processing and routing (e.g. linked to residence time) (Vörösmarty et al., 90’s)

Next generation of river inputs

processes sources and sinks GCM scenarios regional

economy & policy scenarios (e.g. Seine, Rhine...).

RECENT PUBLICATIONSRECENT PUBLICATIONS

IGPB BAHC Synthesis, Kabat P. et al (2004). Vegetation, Water, Humans and the climate, Springer.

Gobal Sediment fluxes (BAHC-LOICZ-IGPB): Global Planet. Change (2003), 39, 1-2, 1-200.

Global Change and Water (WCRP, IGPB IHDP): Aquatic sciences, 64, 4, 300-400, (2002)

Global change and water vulnerabillity. Phil. Trans. Royal. Soc. B., 58, 1917-2065