LES FLUX PARTICULAIRES ET LES FLUX PARTICULAIRES ET DISSOUS DISSOUS
DES CONTINENTS AUX OCEANS, DES CONTINENTS AUX OCEANS, EVOLUTION RECENTE DUES AUX EVOLUTION RECENTE DUES AUX
EFFETS ANTHROPIQUES EFFETS ANTHROPIQUES
• Changement global du système terre • Global change context within Earth System
• Pressions sur les systèmes fluviaux • Man and rivers: growing pressures
• Distribution globale des changements fluviaux •Mapping global river changes
• Interactions homme - fleuve, passées, présentes, futures • Man / river interactions: past, present, future
Académie des Sciences, Septembre 2003
M. MEYBECKUMR Sisyphe, CNRS / Univ. Paris VI
ALASKA PRISTINE RIVER BASINALASKA PRISTINE RIVER BASIN
• True pristine basins, with very limited land use and minimum contaminated atmospheric fallout, are now uncommon in the temperate zone
• Such Alaska and Southern Chile sites are selected by scientists to study the natural N and P cycles, sediment transfers, natural river chemistry, etc...
BE1
PRISTINE RIVER CHEMISTRYPRISTINE RIVER CHEMISTRY
VARIABILITY OF NATURAL RIVER VARIABILITY OF NATURAL RIVER CHEMISTRY AND LITHOLOGYCHEMISTRY AND LITHOLOGY
Sum of cations (µeq/L) Dominant ions Example
50 Ca2+, Cl- Rio Negro * (Amazonia) quartz sands
70 Na+, HCO3- Rio Tefe * (Amazonia) quartz sands
500 Mg2+, Ca2+, HCO3- Basaltic basins
600 Mg2+, HCO3- Peridotite basins
4 000 Ca2+, HCO3- Carbonated basins
5 000 Mg2+, SO42- Coal schists
9 000 Na+, SO42- Semliki R. Rift Valley
20 000 Na+, SO42- Bituminous Shale (Montana)
50 000 Na+, Cl- Urubamba tributary (Amazonia)
* Rain and vegetation control
There is no mean river water that can be used as a global or even regional reference
PRISTINE RIVER CHEMISTRYPRISTINE RIVER CHEMISTRY
GLOBAL OCCURENCE (% of area) OF WATER TYPES GLOBAL OCCURENCE (% of area) OF WATER TYPES AND THEIR ORIGINS (Pristine rivers model)AND THEIR ORIGINS (Pristine rivers model)
• Ionic types in pristine rivers are more diverse than originally thought by Gibbs (1972)
• CaCo3 is dominating in 77% of rivers (area weighted)• Rain and vegetation recycling is dominating over 2.6% of the
continents area and the evaporation over 8.2% (rheic realm only, runoff > 3 mm)
• Rock weathering control extends over 89% of the continents area
• Evaporated waters may result in many chemical types
Origin Rock dominated
Type% Total
Raindominated Silicate Carbonate Pyrite Evaporites
Evaporated
Na2SO4 3,2
NaCl 6,8
Na2CO3 3,6
MgCO3 2,4
MgSO4 2,0
MgCl2 0,1
CaSO4 5,2
CaCO3 76,9
Total 100 2,6 35,4 45,1 5,2 3,6 8,2
PRISTINE RIVER CHEMISTRYPRISTINE RIVER CHEMISTRY
PRISRI : GLOBAL DISTRIBUTION OF DIC PRISRI : GLOBAL DISTRIBUTION OF DIC MEDIUM-SIZED BASINSMEDIUM-SIZED BASINS
3 500 - 200 000 km3 500 - 200 000 km22, rheic basins (n = 480) , 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
WHAT IS GLOBAL CHANGE?WHAT IS GLOBAL CHANGE?
• Global Change is more than Global Climate Change• It has natural PLUS human/social dimensions
• A constellation of changes, many global in domain For example, we see large changes in:
U.S
. Bu
rea
u o
f the
Ce
ns
us
NOAA Vitousek (1994)
Macken
zie et al (2002)
Ric
ha
rds
(19
91
), WR
I (1
99
0)R
eid &
Mille
r (1989)
GLOBAL CHANGEGLOBAL CHANGE
GLOBAL SYNDROMES OF RIVERINE GLOBAL SYNDROMES OF RIVERINE CHANGESCHANGES
(examples)(examples)
• Flow regulation (Nile)• River course fragmentation (Volga, Colorado)
• Neoarheism (Colorado, Amu Darya, Nile)• Salinization (Rhine, Don, Murray, Colorado,
Amu Darya)• River bed silting (Huang He)
• Chemical contaminationasphixiation (Thames, Seine, Rhine)
inorganic contamination (Tinto, Seine, St Lawrence)xenobiotics occurence
• Acidification (Scandinavia, SE Canada)• Eutrophication (Loire)
• (Microbial contamination) (Ganges)• (Aquatic species introduction & invasion)
TROPICAL FOREST CLEARINGTROPICAL FOREST CLEARING
• Forest clearing is one of the major land use change of the last 50 years
• Short term impacts on river fluxes include high supply of eroded material and loss of nutrients (although very limited compared to other human impacts)
• Long term impacts are likely to occur for aquatic biota diversity and for the water balance
PD9
PRESSURES ON HYDROSYSTEMSPRESSURES ON HYDROSYSTEMS
IMPERIAL ROME APPARTMENT BUILDING IN OSTIA IMPERIAL ROME APPARTMENT BUILDING IN OSTIA (200 AD)(200 AD)
• Such building had drinking water supply up to the first floor, common flush toilets, and collected sewage
• Roof runoff and street runoff were also collected in drains
FB2
MAN AND WATER INTERACTIONS : NOTHING NEWMAN AND WATER INTERACTIONS : NOTHING NEW
BLAST FURNACE AT COPCA MICAS BLAST FURNACE AT COPCA MICAS (RUMANIA, 1970 ’s)(RUMANIA, 1970 ’s)
Environmental regulations and surveys were
abundant in Former socialists countries
although barely enforced, thus resulting in pollution
hotspots
Nat. Geogr. Mag., June 1976PF1
PRESSURES ON HYDROSYSTEMSPRESSURES ON HYDROSYSTEMS
AGROCHEMICALS, FERTILIZERS AND OLIGO-AGROCHEMICALS, FERTILIZERS AND OLIGO-ELEMENTS (Zn, Cu, Mo, B, …)ELEMENTS (Zn, Cu, Mo, B, …)
Agrochemicals may increase soil metal contentsFertilizers leaks provide nitrate and total phosphorous
PF34
EMC
PRESSURES ON HYDROSYSTEMSPRESSURES ON HYDROSYSTEMS
Global impacts of reservoirs on land to Global impacts of reservoirs on land to oceans fluxesoceans fluxes
• Most major rivers are impounded (neocastorization, Vörösmarty et al., 1997)
- North Am : Columbia, Churchill, Colorado, Rio Grande, Missouri, James Bay- South Am : Caroni, Parana, Tocantis- Africa : Volta, Nile, Zambezi, Orange, Niger- Europe : Volga, Danube, Don, Dniept, Dniestr, Spain- Asia : Yang Tse, Yellow, Indus, Tigris, Euphrate- Australia : Murray
• Global reservoirs area : 500 000 km2
• Global impacts- biodiveristy : loss of connectivity, regulated rive regimes- biogeochemistry : retention of DOC, POC, N, P and silica- hydrology : river aging (up to 2 y), hydrograph distortion- geomorphology : river bed changes downstream dam, sediment starving in coastal zone and related erosion
COLORADO HOOVER DAM (1935)COLORADO HOOVER DAM (1935)
• The first giant dam ever built• South California and Arizona economies have greatly
depended on Hoover dam
FA50
US Geol. Survey (Nat. Water Summary, 1984)
PRESSURES ON HYDROSYSTEMSPRESSURES ON HYDROSYSTEMS
A VANISHED RIVER : THE COLORADO RIVER A VANISHED RIVER : THE COLORADO RIVER MOUTHMOUTH
• All river water is used in the basin including the water left at the US/Mexico border
and desalinized at Yuma according to the bilateral
treaty
• Local indian culture in the Colorado delta does not
longer exist
QB2
Nat. Geogr. Mag., 1979
NEOARHEISMNEOARHEISM
RIVER FLUXES TRENDS AFTER DAMMING RIVER FLUXES TRENDS AFTER DAMMING THE COLORADO EXAMPLE (1910-1960)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
HIGHLY TURBID RIVER IN HIGHLY TURBID RIVER IN HIMALAYAHIMALAYA
• Due to very active tectonic uplift and glacial abrasion Himalayan rivers are naturally very turbid (1 < TSS < 10 g/L)
• Such rivers would be qualified as unsuitable for most water uses in most water quality scales
PD34
SEDIMENT TRANSFERSEDIMENT TRANSFER
YELLOW RIVER COURSE CHANGES OVER YELLOW RIVER COURSE CHANGES OVER THE LAST 2000 YTHE LAST 2000 Y
Due to the high sediment load (natural, then enhanced) the Huang He has changed its river mouth location over 975 km, thus
flooding several times its enormous flood plainThe last dike outbreak in the 1930’s, due to war action, has
caused one million casualties, mostly due to famine
AE33
RIVER BED SILTINGRIVER BED SILTING
Yang Tse Kiang
Yellow Sea
Pohai Sea
SOURCES, SINKS AND TRANSFERS OR RIVER SOURCES, SINKS AND TRANSFERS OR RIVER PARTICULATESPARTICULATES
NATURAL VS ANTHROPOCENE CONDITIONSNATURAL VS ANTHROPOCENE CONDITIONS
• Sediment transfer in fluvial systems is a complex set of erosion/sedimentation/remobilization processes• Human activities may completely modify and control sediment transfer quantity and quality (e.g. reservoirs,
pollution)
Ocean
Head waters
SEDIMENT TRANSFERSEDIMENT TRANSFER
Sediment transfer : solving contradictionsSediment transfer : solving contradictions
• There is world wide evidence of increased erosion and transport in headwaters as a result of land use change
- forest clearing- agriculture- urbanisation
• The Huang He sediment flux has increased 10 times between 1000 AD and 1950• Yet most long term records of suspended sediment fluxes in large river do not present significant increase (Walling et al., 2002)• Most of the generated sediment is stored within basins from slopes to floodplains and in lakes. This retention is also accelerated by reservoir construction• The natural retention is minimal in small and steep basins as those encountered in SE Asia. The world sediment budget to oceans is now taking it into account (Milliman & Syvitski, 1992)• Sediment sources and pathways and their associated carbon, nutrients and pollutants loads are now more and more generated and controlled by human activitites
SEDIMENT TRANSFER AND RIVER BED SILTINGSEDIMENT TRANSFER AND RIVER BED SILTING
GLOBAL SALINITY HAZARDGLOBAL SALINITY HAZARD
PC26
• Salinity hazard, linked to the water balance, is wide spread on all continents
• Unadequate irrigation may result in salt-build up in soils, long-term salinization of ground waters, and of rivers, thus limiting downstream
water uses• Endorheic regions (e.g. Central Asia) are particularly concerned
• Climate change may augment this risk
WD Williams (Ambio)
SALINIZATIONSALINIZATION
CHLORIDE POLLUTION OF THE RHINE RIVER CHLORIDE POLLUTION OF THE RHINE RIVER BY POTASH MINES (1945-2000)BY POTASH MINES (1945-2000)
During this period the daily release of NaCl has been regulated so that Cl- did not exceed 200 mg/L
UG53
GLOBAL SYNDROMES OF RIVERINE GLOBAL SYNDROMES OF RIVERINE CHANGESCHANGES
Du
mp
ing
in
to t
he
Rh
ine
(kg
/sec
)
IMPERIAL ROMA BIGGEST SEWAGE IMPERIAL ROMA BIGGEST SEWAGE COLLECTOR : THE CLOAQUA MAXIMACOLLECTOR : THE CLOAQUA MAXIMA
• Urban water supply and sanitation was at its best in
Imperial Roma• It has been probably
unequalled until modern sanitation (e.g. London) in
the late 1800 ’s
GG9 XIXth cent. drawing
ASPHIXIATION AND FAECAL CONTAMINATIONASPHIXIATION AND FAECAL CONTAMINATION
RHINE RIVER ASPHIXIATION (1960-1995)RHINE RIVER ASPHIXIATION (1960-1995)
The O2 minimum period lasted 15 years until sewage collection and Oxygen Demand treatment
was implemented (1960-1975)
OG17
R. Breukel
ASPHIXIATIONASPHIXIATION
River Rhine near Lobith, oxygen saturationp
erc
en
tag
e
1950 70 9560 80 90
average
minimum
SCHEMATIC TRENDS OF SEDIMENT SCHEMATIC TRENDS OF SEDIMENT CONTAMINATION IN ESTUARINE CORESCONTAMINATION IN ESTUARINE CORES
• Heavy metals (A) have peaked in the 1960 ’s (USA) to the 1980 ’s (some W. Europe rivers), their trends are barely documented on other continents• Carcinogenic polyaromatic carbons may still increase in some regions
• Polychlorinated biphenyls do not exist in nature (xenobiotics) : they trace the modern human pressure
• Both PAHs and PCBs are inadequately surveyed in rivers
TE3
CONTAMINATIONCONTAMINATION
ATRAZINE HERBICIDE USE MAP IN THE USAATRAZINE HERBICIDE USE MAP IN THE USA
The Corn Belt is the essential user of herbicides which are carried some 2000 km downstream to the Gulf of Mexico
through the Mississippi system
SC22
XENOBIOTICS OCCURENCEXENOBIOTICS OCCURENCE
RIVER EUTROPHICATION : DAILY pH CYCLES RIVER EUTROPHICATION : DAILY pH CYCLES IN THE LOIRE RIVER(AT DAMPIERRE)IN THE LOIRE RIVER(AT DAMPIERRE)
• During spring and summer algal blooms (chloro A > 100 µg/L) the daily pH cycles may reach 1.2 pH units
• Such events can only be noted during stable low flows : they are destroyed by floods
PA68
F. Moatar (1999, Univ. Tours)
EUTROPHICATIONEUTROPHICATION
∆pH
Dis
char
ge
A SUCCESS STORY : NUTRIENTS CONTROL IN THE A SUCCESS STORY : NUTRIENTS CONTROL IN THE RHINE R.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
NITRATE TRENDS IN WORLD RIVERSNITRATE TRENDS IN WORLD RIVERS
From 1960 to 1990 nitrate has increased in most
large riversMaximum rates are observed in smaller
catchments exposed to intensive fertilizer use
SD11
Seine
Rhine
Danube
Mississippi
Thames
EUTROPHICATIONEUTROPHICATION
IRRIGATION, RESERVOIRS & IRRIGATION, RESERVOIRS & EUTROPHICATION : EUTROPHICATION :
THE SILICA RETENTIONTHE SILICA RETENTION
• Already 4 000 km3/y (= 5% world runoff) loss through irrigation (Shiklomanov, 1998)
• The retention of nutrients by reservoir eutrophication, as for silica, combined with increased N and P loads in the last 50 y has generated major changes of N:P:Si ratio in some riverine fluxes to
coastal zone, hence causing dystrophy as for the Danube and Mississippi coastal zone
Si:N (g/g) trend in Mississippi
EUTROPHICATIONEUTROPHICATION
1900 2000
48 0,9
TOWARDS GLOBAL PICTURES OF TOWARDS GLOBAL PICTURES OF RIVERINE CHANGESRIVERINE CHANGES
• Geographic Information systems provide a new tool permitting the combination of multiple informations layers
• Information layers are now available at fine resolutions (1 to 50 km) for most Earth system components (runoff, river network,
relief, lithology...) to map past natural river state
• Socio-economic layers (water uses, environmental pressures, water needs) are still being developed or available at coarser
resolutions
• First global maps of present river state are coming out
COASTAL ZONE SEGMENTATIONCOASTAL ZONE SEGMENTATIONTHE NATURAL CONNEXION BETWEEN CONTINENTS AND THE NATURAL CONNEXION BETWEEN CONTINENTS AND
OCEANS THROUGH RIVERS IS COMPLEXOCEANS THROUGH RIVERS IS COMPLEX
• Some river basins are presently not active as in Sahara (arheism)• Some rivers are flowing to internal water bodies as Caspian Sea, Aral Sea, Chad Lake
(endorheism)• Some rivers can still be somewhat connected to oceans (Okawango-Zambezi,
Kerulem-Amur)• Some endorheic basins are mostly dry (Tarim, Lake Eyre)
• Coastal basins morphology is highly variable from narrow
strips (Peru-Chile) to very deep basins (Mississippi-
Amazon)
• Mean runoff in coastal basins range over
3 orders of magnitude as for other river fluxes (sediments, carbon,
nutrients)
• Mediterranean seas as Hudson/Foxe/Ungawa
and Golf of Mexico/Caribean may
intercept a major portion of riverine fluxes to
oceans
COASTAL ZONE SEGMENTATION : AVERAGE RUNOFF PER COASTAL ZONE SEGMENTATION : AVERAGE RUNOFF PER SEGMENT (mm/y)SEGMENT (mm/y)
GLOBAL MAPPINGGLOBAL MAPPING
Population pressure within coastal basins varies over more than 2 orders of magnitude from 0.3 inhab/km2 for the Laptev Sea or the
Gulf of Carpentaria to more than 300 inhab/km2 in South and East Asia
COASTAL ZONE SEGMENTATION:COASTAL ZONE SEGMENTATION: AVERAGE POPULATION DENSITY PER SEGMENT (p/km AVERAGE POPULATION DENSITY PER SEGMENT (p/km22))
GLOBAL MAPPINGGLOBAL MAPPING
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
POSSIBLE FUTURE OF RIVER POSSIBLE FUTURE OF RIVER SYSTEMSSYSTEMS
• Understanding the Past Man and River interactions is a clue to future scenarios
• Interactions are complex depending on local natural condition, water needs, water literacy, heritages (pressures, mental,...), econmic factors
• Interactions should consider far-reaching impacts (teleconnections) and long-term impacts, particularly on Earth system (climate,
biogeochemical cycles, coastal zone, aquatic biodiversity)
WORKING HYPOTHESES ON THE EVOLUTION WORKING HYPOTHESES ON THE EVOLUTION OF WATER QUALITY ISSUES IN WESTERN OF WATER QUALITY ISSUES IN WESTERN
EUROPEEUROPE(accelerated scale)(accelerated scale)
• There is no simultaneity of water quality issues• New issues have occured in the last 50 years
• Some issues have no been handled (e.g. faecal and organic pollutions)
WESTERN EUROPE
CL
CR
CN
PRISTINE
SEVERE IMPACT
MODERATE IMPACT
NEGLIGIBLE IMPACT
- 2000 0 1000 1492 1900 1950 1970 2000
MetalsFaecal
Nitrate
Xenobiotics
Radionucl.
LOCAL IMPACTS REGIONAL GLOBAL ANTHROPOCENE
MAN AND RIVER RELATIONSMAN AND RIVER RELATIONS
Meybeck, 2003, Philosophical transaction
Anthropogenic climate variability
ENVIR. REGUL.
ATM. POLL. CONTROL
RENATUR. / RESTOR.SEWAGE COLL. /TREAT.
REGULATION/RESTORATIONRESPONSES
HUMAN PRESSURES AGROCHEMICALSATM. POLLUTIONMINING IMPACTSURBAN POP. IMPACTS
LAND USERIVER ENGINEERING
TIME0 18001000 1900 1950 2000
ART. GW RECHARGEECOL. FARMING
< 0,1% global area affected
0,1 to 1%Natural climate variability
1 to 10 %
10 to 50 % > 50 %
Figure M6 : Working hypotheses on the occurrence of some major pressures on terrestrialaquatic systems at the global scale and related environmental remediation responses (notethe time acceleration)(adapted from Meybeck, 2001)
CLIMATE VARIABILITY
Anthropogenic climate variability
ENVIR. REGUL.
ATM. POLL. CONTROL
RENATUR. / RESTOR.SEWAGE COLL. /TREAT.
REGULATION/RESTORATIONRESPONSES
HUMAN PRESSURES AGROCHEMICALSATM. POLLUTIONMINING IMPACTSURBAN POP. IMPACTS
LAND USERIVER ENGINEERING
TIME0 18001000 1900 1950 2000
ART. GW RECHARGEECOL. FARMING
< 0,1% global area affected
0,1 to 1%Natural climate variability
1 to 10 %
10 to 50 % > 50 %
Figure M6 : Working hypotheses on the occurrence of some major pressures on terrestrialaquatic systems at the global scale and related environmental remediation responses (notethe time acceleration)(adapted from Meybeck, 2001)
CLIMATE VARIABILITY
Anthropogenic climate variability
ENVIR. REGUL.
ATM. POLL. CONTROL
RENATUR. / RESTOR.SEWAGE COLL. /TREAT.
REGULATION/RESTORATIONRESPONSES
HUMAN PRESSURES AGROCHEMICALSATM. POLLUTIONMINING IMPACTSURBAN POP. IMPACTS
LAND USERIVER ENGINEERING
TIME0 18001000 1900 1950 2000
ART. GW RECHARGEECOL. FARMING
< 0,1% global area affected
0,1 to 1%Natural climate variability
1 to 10 %
10 to 50 % > 50 %
Figure M6 : Working hypotheses on the occurrence of some major pressures on terrestrialaquatic systems at the global scale and related environmental remediation responses (notethe time acceleration)(adapted from Meybeck, 2001)
CLIMATE VARIABILITY
ENVIR. REGUL.ATM. POLL. CONTROLRENATUR. / RESTOR.SEWAGE COLL. /TREAT.
REGULATION/RESTORATIONRESPONSES
AGROCHEMICALS
MINING IMPACTSURBAN POP. IMPACTS
LAND USE
ART. GW RECHARGEECOL. FARMING
Figure M6 : Working hypotheses on the occurrence of some major pressures on terrestrial aquatic systems at the globalscale and related environmental remediation responses (note the time acceleration)(adapted from Meybeck, 2001)
0,1 to 1%
10 to 50 % ANTHROPOGENICCLIMATE VARIABILITY
< 0,1% GLOBAL AREA AFFECTED
NATURAL CLIMATE VARIABILITY1 to 10 %
> 50 %
HUMAN PRESSURESATM. POLLUTION
RIVER ENGINEERING
TIME0 18001000 1900 1950 2000
CLIMATE VARIABILITY
Human responses to environmental impacts are usually delayed
Anthropocene evolutionAnthropocene evolution
PRESSURES ON AQUATIC SYSTEMS AND PRESSURES ON AQUATIC SYSTEMS AND ENVIRONMENTAL RESPONSESENVIRONMENTAL RESPONSES
Meybeck, 2001
SCHEMATIC POSITIONS OF CONTINENTAL AQUATIC SYSTEMS SCHEMATIC POSITIONS OF CONTINENTAL AQUATIC SYSTEMS SHARED BY SOCIO-SYSTEMS AND EARTH SYSTEMSHARED BY SOCIO-SYSTEMS AND EARTH SYSTEM
• The Driver-Pressure-State-Impact-Response cycle in socio-systems is generally observed at short to medium periods (10-50 y)
• The parallel Environmental impacts-Earth System response- Regional to Global Change is a long term reaction (100-1000 y) still poorly known
EARTH SYSTEM
COMPONENTS
GLOBAL CHANGE DRIVERS
HUMAN DRIVERS
RESOURCESERVICES
RIVERINE SYNDROMES
EARTH SYSTEM
RESPONSE
EARTH SYSTEMS CHANGES
SOCIO-SYSTEMS EARTH SYSTEM
SHORT TERM REACTION
LONG TERM REACTION
SOCIETAL RESPONSES
SOCIAL AND ECONOMIC IMPACTS
CONTINENTAL AQUATIC SYSTEMS
CONTROL
FUNCTIONS
PRESSURE
USE
MAN AND RIVER RELATIONSMAN AND RIVER RELATIONS
EVOLUTION OF CONTINENTAL AQUATIC EVOLUTION OF CONTINENTAL AQUATIC SYSTEMS FROM HOLOCENE TO SYSTEMS FROM HOLOCENE TO
ANTHROPOCENEANTHROPOCENE
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
CONCLUSIONSCONCLUSIONS
• Only 30% of continents is actively exposed to river transfer
(92% of fluxes) •Regional and local references must be looked for
• Present-day natural chemistry and fluxes are variing over 2 to 3 orders of magnitude
• Locally Humans may have modified some ionic and nutrient fluxes by one order of magnitude
• Half of the world rivers are not any more in pristine state• Such global scale evolution confirms the occurrence of a new era where Human controls on Earth System match the
natural ones : the Anthropocene (Vernadski, Crutzen)