Hotspots for GEC research: a primary focus of IGBP research

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1 Gradual Climate Change or Tipping Points in the System? Carlos A Nobre Chair, International Geosphere-Biosphere Programme (IGBP) and National Institute for Space Research (INPE) of Brazil Hotspots for GEC research: a primary focus of IGBP research 1

The global conveyor belt Surface Melt on Greenland happening much faster than expected Source:

a substantially larger rise in sea level Surface melting For sustained warmings above 4.5±0.

8 C in global average), it is likely that the ice sheet would eventually be eliminated.

2 The global conveyor belt Surface Melt on Greenland happening much faster than expected Source: Roger Braithwaite, University of Manchester (UK) Increasing concern about ice-sheet stability and a substantially larger rise in sea level Surface melting For sustained warmings above 4.5±0.9 C in Greenland (3.1±0.8 C in global average), it is likely that the ice sheet would eventually be eliminated. [Gregory and Huybrechts, accepted] Dynamic instability 70 meters thinning in 5 years Satellite-era record melt of 2002 was exceeded in Source: Waleed Abdalati, Goddard Space Flight Center 2

3 Focus on Amazonia Environmental Changes in Amazonia and the Hypothesis of Savannization Carlos A Nobre, Marcos Oyama, Manoel Cardoso, Gilvan Sampaio, Luis Salazar, David Lapola, and Marcos Costa Climate Change and the Fate of the Amazon Oxford University, UK March 2007 Slide courtesy: IPAM 3

4 Does vegetation matter for the Earth System? Is vegetation distribution a fingerprint of climate? or Does vegetation distribution influence and participate to climate (state and changes)? Does vegetation matter for the Earth System? The impacts of human activity on the Amazon rainforest could result in the collapse of large portions of the rainforest and significant loss of biodiversity within 30 to 50 years. A comparison is made with similar events in the Saharan ecosystem, which was once a region of richer vegetation, before its abrupt collapse about 6000 years ago 4

Remove vegetation from the continents large changes will happen in the water cycle Land=desert Land=forest ATMOSPHERE 421 000 km 3 464 000 km 3 71 000 km 3 31 000 km 3 410 000 km3 443 000 km 3 137

5 Remove vegetation from the continents large changes will happen in the water cycle Land=desert Land=forest ATMOSPHERE km km km km km km km km 3 OCEANS km km 3 CONTINENTS Kleidon et al. (2000) Vegetation partitions net radiation into more latent and less sensible heat (figure taken from Kabat et al.: Vegetation, Water, Humans, and the Climate, IGBP BAHC) 5

6 The ecosystems of Amazonia are subjected to a suite of environmental drivers of change LUCC Fire Climate Change Climate Extremes The Hypothesis of Savannization Nobre et al. (1991) proposed that a post-deforestation climate in Southern Amazonia would be warmer, drier and with longer dry season, typical of the climate envelope of the tropical savanna (Cerrado) domain of Central South America. Savannization in this context is a statement on regional climate change and not intended to describe complex ecological processes of vegetation replacement. 6

Biomes of tropical south America and precipitation

Forest-Savanna Boundary Number of consecutive

Forest Savanna Shrubland Annual Rainfall The

season) for maintaining tropical forests all over

seasonality in the Amazon tropical forest and

7 Biomes of tropical south America and precipitation seasonality Biomes of Brazil Tropical Forest-Savanna Boundary Number of consecutive months with less than 50 mm rainfall Tropical Forest Savanna Shrubland Annual Rainfall The importance of rainfall seasonality (short dry season) for maintaining tropical forests all over Amazonia Sombroek 2001, Ambio Evapotranspiration seasonality in the Amazon tropical forest and savanna Source: Rocha (2004) Latent Heat flux (W m -2 ) Forest Savanna mm day -1 Cerrado s.s. SP Floresta trop RO Floresta trop Manaus Floresta trop Santarém Net Radiation (W m -2 ) Forest Savanna 7

8 Is the current Climate-Biome equilibrium in Amazonia the only possible one? Two Biome-Climate Equilibrium States found for South America! -- current state (a) -- second state (b) Soil Moisture Rainfall anomalies Oyama and Nobre,

9 Precipitation mechanism in the Amazon Unconditional probability of a wet day. The daily data spans 1979 to mm < P < 5 mm 03 UTC 18 UTC Annual Precipitation 5 mm < P < 25 mm Instability lines SACZ Sea Breezes Source: Obregon, 2001 Ecological adaptation I: Deep rooting Fraction of water extracted by roots Dry season Wet season 68% Depth (m) 84% Water extraction at least up to 10 m Source: Bruno et al., 2005 Tropical forest data in Santarem km83 9

After rain +: water flow to the plant -: water flow away from the

10 Ecological adaptation II: Hydraulic redistribution a b c Source: R. Oliveira Sap-flow velocity Before rain a a Daytime b rain b b c c After rain +: water flow to the plant -: water flow away from the plant Source: Oliveira et al., 2005 Externally driven equilibrium change 10

In 2006, total deforested area (clear-cutting)

Resilience Stochastic Perturbations Gradual

, deforestation, fire, Fragmentation, global

) Does climate variability (severe droughts)

change, edaphic factors, and human use factors?

CHANGE DEFORESTATION AND BURNING AROUND THE

11 In 2006, total deforested area (clear-cutting) is 650,000 km 2 in Brazilian Amazonia (17%) Resilience Stochastic Perturbations Gradual Perturbations affect Resilience (e.g., deforestation, fire, Fragmentation, global warming, etc.) Does climate variability (severe droughts) play the key role linking together climate change, edaphic factors, and human use factors? Source: Greenpeace/Daniel Beltra I - LAND COVER CHANGE DEFORESTATION AND BURNING AROUND THE XINGU INDIGENOUS PARK, MATO GROSSO STATE, BRAZIL, Source: Tropical deforestation and climate change / edited by Paulo Moutinho and Stephan Schwartzman. -- IPAM - Instituto de Pesquisa Ambiental da Amazônia,

PROJECTED SCENARIOS Control 20% 40% 50% 60% 80% 100% or Soybean Source: Soares-Filho et al., 2006 - Amazon Scenarios Project, LBA Sampaio et al., 2007 PASTURE Precipitation SOYBEAN 1.

1 1.0 0.9 0.8 0.7 DJF MAM JJA SON 0.6 0% 20% 40% 60% 80% 100% Deforestation Area (%) 0.

12 PROJECTED SCENARIOS Control 20% 40% 50% 60% 80% 100% or Soybean Source: Soares-Filho et al., Amazon Scenarios Project, LBA Sampaio et al., 2007 PASTURE Precipitation SOYBEAN 1.2 Amazonia - PASTURE Area: East/Northeast 1.2 Amazonia - SOYBEAN Area: East/Northeast Relative Precipitation (p/p 0) DJF MAM JJA SON Relative Precipitation (p/p 0) DJF MAM JJA SON 0.6 0% 20% 40% 60% 80% 100% Deforestation Area (%) 0.6 0% 20% 40% 60% 80% 100% Deforestation Area (%) Precipitation Anomaly (%) Season JJA SON All Pasture -27.5% -28.1% All Soybean -39.8% -39.9% The reduction in precipitation is larger during the dry season, and is more evident when the deforested area is larger than 40%! Sampaio et al.,

II - FIRE At long term, fires have also important effects on biomes distribution: Fires less trees more grasses favor savannas in place of forests To account for fires when

13 II - FIRE At long term, fires have also important effects on biomes distribution: Fires less trees more grasses favor savannas in place of forests To account for fires when estimating the distribution of the natural biomes, we developed a new long-term fire parameterization based on the potential for lightning during dry-wet season transitions 13

The new long-term natural fires parameterization is based on major circulation patterns: Average Long-term characteristics of the zonal wind Intra-annual variance The

5 m 3 /s 3 (in grey): light./fire pot. light./fire pot. Cardoso et al.

broadleaf-evergreen trees (tropical forest), (2) broadleaf-deciduous trees (temperate forest) (3) broadleaf and needleleaf trees (mixed forest) (4) needleleaf-evergreen

with perennial groundcover (caatinga) (9) broadleaf shrubs with bare soil (semi-desert) (10) dwarf trees and shrubs with groundcover (tundra) (11) bare soil (desert) (13)

14 The new long-term natural fires parameterization is based on major circulation patterns: Average Long-term characteristics of the zonal wind Intra-annual variance The potential for lightning/fires in the tropics is higher were combined long-term average and intra-annual variance of the zonal wind is lower than 3.5 m 3 /s 3 (in grey): light./fire pot. light./fire pot. Cardoso et al. (2007), in review Impact of using the new fire parameterization in the biome estimates of the CPTEC Potential Vegetation Model: Major vegetation types: (1) broadleaf-evergreen trees (tropical forest), (2) broadleaf-deciduous trees (temperate forest) (3) broadleaf and needleleaf trees (mixed forest) (4) needleleaf-evergreen trees (boreal forest) (5) needleleaf-deciduous trees (larch), (6) broadleaf trees with groundcover (savanna) (7) groundcover only (prairie, steppes) (8) broadleaf shrubs with perennial groundcover (caatinga) (9) broadleaf shrubs with bare soil (semi-desert) (10) dwarf trees and shrubs with groundcover (tundra) (11) bare soil (desert) (13) ice. Accounting for fires corrected important differences between previous model estimates and reference data for the position of natural savannas in the tropics. In specific, large areas in India and SE Asia that were initially estimated as savannas are now corrected to dry forests. Cardoso et al. (2007), in review 14

majority of fires in Amazonia occur during the dry season as a

new statistical relations between precipitation and distance

fire activity in the region: Satellite fire data Prob.

15 Carvalho et al. (2001) Land use Dry season At year-decade time scales, the majority of fires in Amazonia occur during the dry season as a result of land use Using remote-sensing fire data, we found new statistical relations between precipitation and distance to main roads, which are the major drivers for yearlydecade fire activity in the region: Satellite fire data Prob. fire Model Data Precipitation observations Road maps Total prec. index Dist. main roads index Cardoso et al. (2003, 2007) 15

III - CLIMATE EXTREMES The impact of droughts Vegetation vulnerability to droughts Percent attainment of the Nix criteria

month < 18 C P(3 driest months) < 50 mm P(6 wettest months) > 600 mm 1000 mm < P annual < 1500 mm (A) Observed drought

Land area (1000 km2) of vegetation types for pixels with given drought frequency (%), forest land area is multiplied by 0.

16 III - CLIMATE EXTREMES The impact of droughts Vegetation vulnerability to droughts Percent attainment of the Nix criteria [1983] for savanna in the last 100 years Climate conditions for tropical savannas (Nix 1983) T mean > 24 C 13 C < T coldest month < 18 C P(3 driest months) < 50 mm P(6 wettest months) > 600 mm 1000 mm < P annual < 1500 mm (A) Observed drought frequency (% years); (B) distribution of savanna, transitional vegetation, and forest across the legal Brazilian Amazon; (C) Land area (1000 km2) of vegetation types for pixels with given drought frequency (%), forest land area is multiplied by 0.1 for scaling; (D) percent attainment of the Nix [1983] criteria for savanna vegetation in the last 100 years. Source: Hutyara et al,

17 The Drought of Amazonia in 2005 Source: Dr. Virgílio Viana Marengo et al

18 IV GLOBAL WARMING What are the likely biome changes in Tropical South America due to Global Warming scenarios of climate change? 18

The impact of global climate change on tropical forest biodiversity in Amazonia.

become non-viable by 2095! Source: Miles et al. 2004.

emissions scenarios, prepared for the IPCC/AR4. Models: BCCR-BCM2.0, CCSM3, CGCM3.

19 The impact of global climate change on tropical forest biodiversity in Amazonia. Climate Model: HADCM2GSa1 1% CO 2 increase/yr = SI/2 43% of 69 species of Angiosperms become non-viable by 2095! Source: Miles et al Climate Change Scenarios for Amazonia Results from 15 AOGCMs for the SRES A2 and B1 emissions scenarios, prepared for the IPCC/AR4. Models: BCCR-BCM2.0, CCSM3, CGCM3.1(T47), CNRM-CM3, CSIRO-MK3, ECHAM5, GFDL-CM2, GFDL-CM2.1, GISS-ER, INM-CM3, IPSL-CM4, MIROC3.2 (MEDRES), MRI-CGCM2.3.2, UKMO-HADCM3, ECHO-G 19

20 Climate Change Consequences on the Biome distribution in tropical South America Projected distribution of natural biomes in South America for from 15 AOGCMs for the A2 emissions scenarios, calculated by using CPTEC-INPE PVM. Salazar et al., 2007 Climate Change Consequences on the Biome distribution in tropical South America SRES B1 SRES B1 SRES B1 SRES A2 SRES A2 SRES A2 Grid points where more than 75% of the models used (> 11 models) coincide as projecting the future condition of the tropical forest and the savanna in relation with the current potential vegetation. The figure also shows the grid points where a consensus amongst the models of the future condition of the tropical forest was not found. for the periods (a) , (b) and (c) for B1 GHG emissions scenario and (d), (e) and (f) similarly for A2 GHG emissions scenario. Salazar et al., 2007 GRL (accepted) 20

21 Climate Change Consequences on the Biome distribution in tropical South America Percentage of the area where more than 75% of the experiments for the A2 GHG scenarios, coincide as projecting the permanence or disappearance of the current potential tropical forest, and where there is not a conclusive consensus amongst models Salazar et al., 2007 GRL (accepted) CPTEC-INPE PVM 2 Current pot veg Vegetation distribution under different CO 2 concentration scenarios 250 ppmv 180 ppmv 140 ppmv 450 ppmv 600 ppmv 850 ppmv Lapola, 2007 MSc Thesis at INPE 21

Projected distribution of natural biomes in South America for 2090-2099 from 14 AOGCMs for the A2 emissions scenarios, calculated by the CPTEC-INPE PVM with Carbon Cycle Lapola, 2007, MSc Thesis at

22 Projected distribution of natural biomes in South America for from 14 AOGCMs for the A2 emissions scenarios, calculated by the CPTEC-INPE PVM with Carbon Cycle Lapola, 2007, MSc Thesis at INPE Conclusions The future of biome distribution in Amazonia in face of land cover and climate changes Natural ecosystems in Amazonia have been under increasing land use change pressure. Tropical deforestation, global warming, increased forest fires and intense/more frequent droughts all act to reduce the resilience of the tropical forest. The synergistic combination of regional climate changes caused by both global warming and land cover change over the next several decades, exacerbated by increased drought and forest fire frequency, could tip the biome-climate state to a new stable equilibrium with savannization of parts of Amazonia and catastrophic species losses. 22

The ethical dimensions of Global Environmental Change There is an issue of ethics and justice: the people [and other forms of life] most likely to bear the brunt of

23 The ethical dimensions of Global Environmental Change There is an issue of ethics and justice: the people [and other forms of life] most likely to bear the brunt of Global Environmental Change are those who have contributed least to it Historical contributions to CO 2 emissions: Europe 30% USA 28% China 8% Amazonia 1% - 1.5% THANK YOU! 23

, 2007 mean precipitation scenarios (mm/day) -0.2-1.0-3.0 +0.2 +1.0 +3.

24 CPTEC PVM 2 Current pot veg Vegetation distribution under different annual mean temperature scenarios -2 C -4 C -6 C +2 C +4 C +6 C Lapola et al., 2007 CPTEC PVM 2 Current pot veg Vegetation distribution under different annual mean precipitation scenarios (mm/day) Lapola et al.,

Two Biome-Climate Equilibrium States found for South America Current potential vegetation Forest Savanna -- current state (a) -- second state (b) Soil Moisture Second State Results of CPTEC-DBM

25 Two Biome-Climate Equilibrium States found for South America Current potential vegetation Forest Savanna -- current state (a) -- second state (b) Soil Moisture Second State Results of CPTEC-DBM Initial Conditions : desert Rainfall anomalies Source: Oyama and Nobre, 2003 Precipitation all Amazonia 1.2 Amazonia - PASTURE 1.2 Amazonia - SOYBEAN Relative Precipitation DJF MAM JJA SON Relative Precipitation DJF MAM JJA SON % 20.0% 40.0% 50.0% 60.0% 80.0% 100.0% % 20.00% 40.00% 60.00% 80.00% % Deforestation Area (%) Deforestation Area (%) Precipitation Anomaly (%) Season All Pasture All Soybean JJA -15.7% -24.0% JJAS -13.7% -22.0% Sampaio et al.,

Is an equitable and sustainable ecological footprint achievable? 6.0 metric tons of carbon per capita 5.0 4.0 3.0 2.0 1.0 0.

26 Is an equitable and sustainable ecological footprint achievable? 6.0 metric tons of carbon per capita Per Capita Carbon Dioxide Emissions ( ) Brazil China France Germany India Indonesia Japan Russian Federation United Kingdom United States Average per capita Global CO 2 emissions: t C t C CDIAC, Amazonia - PASTURE Amazonia - Pasture Area: East/Northeast Relative precipitation (p/p0) y = x x R 2 = member 1 member 2 member 3 member 4 member 5 average Polynom (average) % 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Deforested Area (%) Sampaio et al.,

27 1.05 Amazonia - SOYBEAN Amazonia - SOYBEAN Area: East/Northeast Relative Precipitation (p/p0) y = x x R 2 = member 1 member 2 member 3 member 4 member 5 average Polynom (average) % 20% 40% 60% 80% 100% Deforested Area (%) Sampaio et al.,

Amazonia. Manoel Cardoso, Gilvan Sampaio and Carlos Nobre

Amazonia. Manoel Cardoso, Gilvan Sampaio and Carlos Nobre Combined deforestation and fire occurrence in long-term models of forests and savannas in the Brazilian Amazonia Manoel Cardoso, Gilvan Sampaio and Carlos Nobre Instituto Nacional de Pesquisas Espaciais