4 Ecosystems, their properties, goods and services Coordinating Lead Authors: Andreas Fischlin (Switzerland), Guy F. Midgley (South Africa) Lead Authors: Jeff Price (USA), Rik Leemans (The Netherlands), Brij Gopal (India), Carol Turley (UK), Mark Rounsevell (Belgium), Pauline Dube (Botswana), Juan Tarazona (Peru), Andrei Velichko (Russia) Contributing Authors: Julius Atlhopheng (Botswana), Martin Beniston (Switzerland), William J. Bond (South Africa), Keith Brander (ICES/Denmark/UK), Harald Bugmann (Switzerland), Terry V. Callaghan (UK), Jacqueline de Chazal (Belgium), Oagile Dikinya (Australia), Antoine Guisan (Switzerland), Dimitrios Gyalistras (Switzerland), Lesley Hughes (Australia), Barney S. Kgope (South Africa), Christian Körner (Switzerland), Wolfgang Lucht (Germany), Nick J. Lunn (Canada), Ronald P. Neilson (USA), Martin Pêcheux (France), Wilfried Thuiller (France), Rachel Warren (UK) Review Editors: Wolfgang Cramer (Germany), Sandra Myrna Diaz (Argentina) This chapter should be cited as: Fischlin, A., G.F. Midgley, J.T. Price, R. Leemans, B. Gopal, C. Turley, M.D.A. Rounsevell, O.P. Dube, J. Tarazona, A.A. Velichko, 2007: Ecosystems, their properties, goods, and services. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 211-272. Ecosystems, their properties, goods and services Chapter 4 Table of Contents .....................................................213 Box 4.4 Coral reefs: endangered by climate change?......235 Executive summary 4.4.10 Cross-biome impacts.............................................237 ........................................................214 4.1 Introduction Box 4.5 Crossing biomes: impacts of climate change 4.1.1 Ecosystem goods and services .............................215 on migratory birds ..................................................239 4.1.2 Key issues ..............................................................215 4.4.11 Global synthesis including impacts on biodiversity .............................................................239 ..........................................215 4.2 Current sensitivities 4.2.1 Climatic variability and extremes ...........................215 4.5 Costs and valuation of ecosystem goods .........................................................245 4.2.2 Other ecosystem change drivers ...........................216 and services Box 4.1 Ecological impacts of the European heatwave 4.6 Acclimation and adaptation: practices, 2003 .......................................................................217 ....................................246 options and constraints 4.6.1 Adaptation options................................................246 ..................218 4.3 Assumptions about future trends 4.6.2 Assessing the effectiveness and costs of .......219 adaptation options ................................................247 4.4 Key future impacts and vulnerabilities 4.4.1 Biogeochemical cycles and biotic feedback .........219 4.6.3 Implications for biodiversity ..................................247 4.4.2 Deserts ...................................................................222 4.6.4 Interactions with other policies and policy implications ...........................................................248 Box 4.2 Vegetation response to rainfall variability in the Sahel ................................................................224 ...248 4.7 Implications for sustainable development 4.4.3 Grasslands and savannas ......................................224 4.7.1 Ecosystems services and sustainable 4.4.4 Mediterranean ecosystems....................................226 development..........................................................248 4.4.5 Forests and woodlands..........................................227 4.7.2 Subsistence livelihoods and indigenous peoples...248 4.4.6 Tundra and Arctic/Antarctic ecosystems ...............230 ...249 Box 4.3 Polar bears - a species in peril? ..........................231 4.8 Key uncertainties and research priorities .................................................................250 4.4.7 Mountains...............................................................232 Appendix 4.1 4.4.8 Freshwater wetlands, lakes and rivers...................233 ......................................................................252 References 4.4.9 Oceans and shallow seas ......................................234 212 Chapter 4 Ecosystems, their properties, goods and services Executive summary increasingly high risk of extinction as global mean temperatures exceed a warming of 2 to 3°C above pre- industrial levels (medium confidence) [4.4.10, 4.4.11, Figure During the course of this century the resilience of many 4.4, Table 4.1]. ecosystems (their ability to adapt naturally) is likely to be Projected impacts on biodiversity are significant and of key exceeded by an unprecedented combination of change in relevance, since global losses in biodiversity are irreversible climate, associated disturbances (e.g., flooding, drought, (very high confidence) [4.4.10, 4.4.11, Figure 4.4, Table 4.1]. wildfire, insects, ocean acidification) and in other global Endemic species richness is highest where regional change drivers (especially land-use change, pollution and palaeoclimatic changes have been muted, providing over-exploitation of resources), if greenhouse gas emissions circumstantial evidence of their vulnerability to projected and other changes continue at or above current rates (high climate change (medium confidence) [4.2.1]. With global confidence). average temperature changes of 2°C above pre-industrial levels, By 2100, ecosystems will be exposed to atmospheric CO2 levels many terrestrial, freshwater and marine species (particularly substantially higher than in the past 650,000 years, and global endemics across the globe) are at a far greater risk of extinction temperatures at least among the highest of those experienced in than in the recent geological past (medium confidence) [4.4.5, the past 740,000 years (very high confidence) [4.2, 4.4.10, 4.4.11, Figure 4.4, Table 4.1]. Globally about 20% to 30% of 4.4.11; Jansen et al., 2007]. This will alter the structure, reduce species (global uncertainty range from 10% to 40%, but varying biodiversity and perturb functioning of most ecosystems, and among regional biota from as low as 1% to as high as 80%) will compromise the services they currently provide (high be at increasingly high risk of extinction, possibly by 2100, as confidence) [4.2, 4.4.1, 4.4.2-4.4.9, 4.4.10, 4.4.11, Figure 4.4, global mean temperatures exceed 2 to 3°C above pre-industrial Table 4.1]. Present and future land-use change and associated levels [4.2, 4.4.10, 4.4.11, Figure 4.4, Table 4.1]. Current landscape fragmentation are very likely to impede species’ conservation practices are generally poorly prepared to adapt to migration and thus impair natural adaptation via geographical this level of change, and effective adaptation responses are likely range shifts (very high confidence) [4.1.2, 4.2.2, 4.4.5, 4.4.10]. to be costly to implement (high confidence) [4.4.11, Table 4.1, 4.6.1]. Several major carbon stocks in terrestrial ecosystems are vulnerable to current climate change and/or land-use Substantial changes in structure and functioning of impacts and are at a high degree of risk from projected terrestrial ecosystems are very likely to occur with a global unmitigated climate and land-use changes (high warming of more than 2 to 3°C above pre-industrial levels confidence). (high confidence). Several terrestrial ecosystems individually sequester as much Between about 25% (IPCC SRES B1 emissions scenario; 3.2°C carbon as is currently in the atmosphere (very high confidence) warming) and about 40% (SRES A2 scenario; 4.4°C warming) [4.4.1, 4.4.6, 4.4.8, 4.4.10, 4.4.11]. The terrestrial biosphere is of extant ecosystems will reveal appreciable changes by 2100, likely to become a net source of carbon during the course of this with some positive impacts especially in Africa and the Southern century (medium confidence), possibly earlier than projected by Hemisphere arid regions, but extensive forest and woodland the IPCC Third Assessment Report (TAR) (low confidence) [4.1, decline in mid- to high latitudes and in the tropics, associated Figure 4.2]. Methane emissions from tundra frozen loess particularly with changing disturbance regimes (especially (‘yedoma’, comprising about 500 Pg C) and permafrost through wildfire and insects) [4.4.2, 4.4.3, 4.4.5, 4.4.10, 4.4.11, (comprising about 400 Pg C) have accelerated in the past two Figure 4.3]. decades, and are likely to accelerate further (high confidence) Substantial changes in structure and functioning of marine [4.4.6]. At current anthropogenic emission rates, the ongoing and other aquatic ecosystems are very likely to occur with positive trends in the terrestrial carbon sink will peak before a mean global warming of more than 2 to 3°C above pre- mid-century, then begin diminishing, even without accounting industrial levels and the associated increased atmospheric for tropical deforestation trends and biosphere feedback, tending CO levels (high confidence). strongly towards a net carbon source before 2100, assuming 2 continued greenhouse gas emissions and land-use change trends Climate change (very high confidence)