nuevas evidencias sobre el cambio climático y eventuales...
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Gino Casassa
Conferencias sobre Cambio Climático, 21 agosto 2009Hotel Dreams, Temuco
Nuevas evidencias sobre el cambio climático y eventuales consecuencias para Chile
Gino Casassa
Centro de Estudios Científicos Valdivia, Chile
EFECTO INVERNADERO
VENUS: T = 462°C CO2 level = 96.5% P = 92 EarthMARS: T = -20 to -140°C CO2 level = 95.7% P = 0.007 Earth
IPCC, 2007
Rates of change for the three greenhouse gases, N2O, CH4, CO2 and their combined radiative forcing for the last 22 ka
Joos F., Spahni R. PNAS 2008;105:1425-1430
©2008 by National Academy of Sciences
IPCC, 2007
2005 relative to 1750
IPCC; 2007
GCMs
IPCC
IPCC AR4
IPCC AR4
DGF UCh – CONAMA, 2007PRECIS (Providing Regional Climates for Impact Studies),UK Met Office 25 km resolution
MESOSCALE MODELS
IPCC AR4
Clausius-Clapeyron
Water content in a warmer atmosphere
IPCC AR4
IPCC Technical Paper “Climate Change and Water”, 2008
FIG. 8. Linear trends from 1948 to 2004 in annual (water year) (a) discharge from each 48 lat 3 58 lon coastal box estimated from available gauge records and reconstructed river flow, (b) the runoff trend inferred from the discharge trend shown in (a), (c) observed surface air temperature and (d) precipitation (from Qian et al. 2006), and (e) CLM3- simulated snow cover and soil ice water. DAI et al., 2009, J.Climate.
“World’s major rivers drying up”
IPCC Technical Paper “Climate Change and Water”, 2008
Values represent the median of 12 climate models using the SRES A1B scenario.
Milly et al., Policy Forum, Science, 2008
Policy Forum, Science, 319, 573-574, 2008
COLAPSO DEL PRINCIPIO ESTATICO ¡DEBEMOS CONSIDERAR CAMBIO CLIMATICO!
EVENTOS CLIMATICOS EXTREMOS
IPCC AR4 WGI
Extreme weather events
IPCC AR4 WGII
2008/2009: verano más cálido desde 1915
La temperatura máxima alcanzó este verano pasado 30.6°C, como promedio de la estación de verano. El valor medio histórico es de 28.9°C, es decir, representa un calentamiento del aire 1.7°C mayor que el valor medio histórico. La zona centro-sur, entre Curicó y Temuco, también se caracterizó por presentar unos de los veranos más cálidos en los últimas 5 décadas. Los promedios de la temperatura máxima fueron 30.7°C en Curicó, 29.7°C en Chillán y 26.1°C en Temuco, representado así una anomalía térmica que superó en casi 2°C el promedio histórico. DMC, 2009
2003 SUMMER HEAT WAVE IN EUROPE
IPCC, 2007
IPCC AR4
IPCC AR4
IMPACTOS FISICOS
Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases.
Global assessment of data since 1970 has shown it is likely that anthropogenic warming has had a discernible influence on many physical and biological systems.
CRIOSFERA
Temperate ice (T=@ melting point)
vs.
Cold ice
(T< melting point)
IPCC, 2001
GLIMSWGMSNSIDC
Antarctica: 13,586,400 km2; Greenland 1,736,095 km2; Canadian Arctic islands: 151,057 km2; Central Asia: 114,800 km2; North America 76,880 km2; South America 29,347 km2 (Chile 75%) ; Europe: 5,759 km2; Africa: 10 km2
30 AÑOS
10 METERS
NATIONAL GEOGRAPHYC
O’Higgins Glacier, Patagonia
(Casassa, 2008)
Muir Glacier, Alaska
(NSIDC/WDC, 2006)
1945
2005
1941
2004
Lake Cachet 2, NPIApril 2008October 2008December 2008March 2009
Lake Témpanos, SPIApril-May 2007
GLACIAL LAKE OUTBURST FLOODS (GLOFs)= JÖKULHLAUPS
GLACIAR CHACALTAYA, BOLIVIA
Pouyaud et al., 2005, HSJ
WATER RESOURCESJob 6:15 … las corrientes impetuosasJob 6:16 que bajan turbias por el deshielo y mezcladas con la nieve,Job 6:17 que al tiempo del calor se secan, y al calentarse desaparecen en su cauce
EOS, Vergara et al., 2007
Warming 'opens Northwest Passage' The most direct shipping route from Europe to Asia is fully clear of ice for the first time since records began.14 Sep 2007
Meier et al., 2008
Greenland: 7.3 m SLE
Steffen et al.
Univ. Colorado
Greenland moulin
Jakobshavn Glacier
Dietrich et al., 2007
Retreat: 30 km in 150 yThinning: 60 m/yIce flow: 45 m/y
13.5 million km2 (10% of the Earth) - 98% covered by ice70% of the Earth´s fresh water - 91% of the ice on EarthStores 55 m of sea level - 2000 m average ice thickness>4500 m ice at some places - Ice velocities 10-2500 m/a
Antarctica,the seventh continent...
NASA/SVS
The Antarctic Ice Sheet
• 56.6 m sea level equivalent (SLE)• Temperatures well below freezing• West Antarctic ice sheet (5 m SLE) rests on a soft bed that is
below sea level• Inherently unstable?
Antarctica without ice
“The Weak Underbelly”
EastWest
Source: R. Bindschadler, NASA/GSFC
NASA – Waleed Abdalati
Warming on the Antarctic PeninsulaFaraday/Vernadsky
ICE SHELF COLLAPSES,
31 January 2002
LANSAT
NSIDC
ICE SHELF COLLAPSES,
17 February 2002
http://nsidc.org/iceshelves/
LANSAT
ICE SHELF COLLAPSES,
23 February 2002
http://nsidc.org/iceshelves/
LANSAT
ICE SHELF COLLAPSES,
05 March 2002
http://nsidc.org/iceshelves/
LANSAT
Larsen B Break-up 2002
10,000 years of ice gone in one month!
Ted Scambos, NSIDCMODIS Image
March 17
Global Warming Art by Robert A. Rohde
IPCC, 2007
SLR1961-2003: 1.8 mm/y
1993-2003: 3.1 mm/y
IPCC, 2007
IPCC AR4
Salomon et al., 2009, PNAS
Cayo Pelón, Venezuela
SEA LEVEL RISE by 21001 m or moreCopenhagen, March 2009
Bob Thomas, Chincoteague Island, Va, USA
Thawing of frozen ground
Thawing of frozen soil and rock in high-mountain areas can produce slope instability and rock falls. A reported case linked to warming is the exceptional rock fall activity in the Alps during the 2003 summer heat wave, when the active layer in the Alps deepened significantly, by 30% to 100% of the depth measured before the heat wave (Gruber, 2004, permafrost; Schär, 2004, role; Noetzli, 2003, permafrost).
The number of travel days for oil exploration on Alaskan tundra has been decreasing over recent decades as the opening dates come later and the closing dates come earlier (ACIA 2003)
Air temp. N of 65ºN
NH sea ice
NH frozen ground
NF snow cover
Global glacier mass balance
SH sea ice
Air temp. S of 65ºSIPCC. 2007
Artic Drainage Warming LakesEarlier Stream flow
Hydrology and Water Resources
Historical and recent measurements from Lake Tanganyika, East Africa
Upper mixed layer (surface water temperatures
Deep-water (600 m) temperatures
Depth of the upper mixed layer
Error bars represent standard deviations
O’Reilly et al., 2003
Warming Lakes In East Africa
IMPACTOS BIOLOGICOS
IPCC AR4 2007 WGII Approximately 20-30% of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5-2.5°C.
http://farm1.static.flickr.com/64/207836370_501760ba77.jpg
http://www.mbari.org/highCO2/
CORAL BLEACHING
Greening of the Arctic IPCC, 2007
Spring Events are Advancing
Spring phenological changes in birds and plants and their triggering by spring temperature are often similar as described by some cross-system studies;
The NAO influence is lower than the temperature trigger and is restricted to certain time periods (Walther et al. 2002)
Anomalies of spring phenological phases of birds
and trees in Germany
Species are Moving Poleward and Upward
Significant range shifts of more than 1,700 species averaging 6.1 km per decade toward the poles (or meters per decade upward), and significant mean advancement of spring events by 2.3 days per decade.
Temporal and spatial ‘sign-switching’ was found for 279 species. While the community and temporal sign-switching pattern was shown in diverse taxa studies, the species showing spatial sign switching pattern were northern hemisphere butterflies, such as Clossiana dia of France.
Simon Coombes
Parmesan and Yohe (2003)
Estimated changes in net primary productivity (NPP) (1982-1999) derived from independent NDVI data sets from the Global Inventory Monitoring and Modelling Studies (GIMMS) and Pathfinder Advanced Very High Resolution Radiometer (AVHRR) Land (PAL) (Nemani et al.,2003). An overall increase in NPP is observed, which is consistent with rising atmospheric CO2 and warming.
Trend in Many Regions towards
Earlier ‘Greening’ of Vegetation in the Spring
and Increased Net Primary Production
Global Terrestrial Changes
We examined 23 years of migration timing data collected at two capture locations in the Connecticut River drainage. We found that both dates of first capture and median capture dates have shifted significantly earlier by about 0.5 days/year.
We also quantified changes… of more northerly stocks in Maine and Canada. We found that the changes in migration timing were not unique to the Connecticut River stock and instead observed coherent patterns in the shift toward earlier peak migration dates across systems.
These consistent shifts are correlated with long-term changes in temperature and flow and may represent a response to global climate change
Juanes 2004
Return timing by day vs. year for Salmo salar collected at the Millbank trap in the Miramichi River, New Brunwick.
North America Salmon Migration
Marine
Global annual ocean primary production decreased from the CZCS era (1979-1986) to the present (1997-2002) by 6.3% (P<0.05). High latitude losses were 2.0 Pg C y -1, which accounted for 70% of the global decline in photosynthetic carbon uptake.
Gregg et al., 2003
In addition …
Long-term changes in the mean number of marine plankton species per association in the North Atlantic from 1960 to 1999 (Beaugrand et al. 2002)
Shifts to Temperate Species in North Atlantic Marine Ecosystems
All biological variables in the North Atlantic exhibited a pronounced change which started after circa 1982 for krill (decline), 1984 for the total abundance of copepods (increase), and 1988 for salmon (decrease).
The regional temperature increase therefore seems to be an important parameter that is at present governing the dynamic equilibrium of northeast Atlantic pelagic ecosystems.
North Atlantic Plankton and Fish
Krill
Copepods
Salmon
Beaugrand 2003
SST
Krill–ice relationships. Annual mean density of krill across the SW Atlantic versus a, sea-ice duration27 and b, the mean September latitude of 15% ice cover along a transect10 across the western Scotia Sea.
Krill density in the SW Atlantic sector from post-1976 krill data from scientific trawls. Green spots denote cells usable in thespatio-temporal model.
Southern Ocean and Plankton
Black line = total area burned anomalies over Canada for each 5 yr period 1920- 1999, in units of 105 km2.
Red line = 5 yr mean observed May- August temperature anomalies weighted by area burned, in K.
Green line = ensemble-mean 5 yr mean May-August area burned-weighted temp. anomalies CGCM2 model forced with anthropogenic GHGs and sulfate aerosols.
Gray lines = 5-95% range of internal variability in area burned, estimated from interannual variability.
Anomalies are calculated relative to the 1920-1999 mean.
Gillet et al. 2004
Forest Fires
1. Human emissions of greenhouse gases and sulfate aerosols have had a detectable warming effect during the fire season in Canada
2. Human-induced climate change has had a significant effect on the area burned by forest fires in Canada.
IMPACTOS HUMANOS
Arctic RegionHuman Systems
•Warming is disrupting indigenous hunting and food sharing as reduced sea ice causes the animals on which they depend to decline.
•Roads are sinking into melting permafrost, or being inundated by rising seas
•Reduced sea ice is a causing increases in coastal erosion.
ACIA 2004
Risks to Unique and Threatened Systems
NARA, 2005
Spread was observed into higher :• latitudes (Sweden: milder winters, early arrival of springs)• altitudes (the Czech Republic: shift from 700 to 1,100 m).
Lyme borreliosis and tick-borne encephalitis (Ixodes ricinus) have become more frequent in many places
Key measures include:• TBE vaccination• protective measures
– wearing suitable clothing– self-inspection after
outdoor activities to remove ticks early
Picture from Lindgren et al, Env. Health Perspect, 2000
Experience Infectious disease vectors in some areas
Heat-related Mortality in France
IPCC, 2007 WGII Latin America
CONCLUSIONES
IPCC AR4
Smith et al., PNAS, 2008