CLIM 101 Weather Climate and Global Society Impact
CLIM 101: Weather, Climate and Global Society Impact of Climate Change 1 Emilia Jin Lecture 21: Nov 11, 2008
IPCC AR 4 Working Group II Report "Impacts, Adaptation and Vulnerability" • Chapter 3 - Impacts on Fresh Water Resources and their Management • Chapter 4 - Impacts on Ecosystems, their Properties, Goods and Services • Chapter 5 - Impacts on Food, Fibre, and Forest Products
Climate and Non-climate Drivers of Change coping range of climate: the capacity of systems to accommodate variations in climatic conditions
Climate and Non-climate Drivers of Change • Climate drivers: Temperature and precipitation, and their variability on all timescales from days to the seasonal cycle to interannual variations • Non-climate drivers such as urbanisation and pollution can influence systems directly and indirectly through their effects on climate variables such as albedo and soil-moisture regimes. Socio-economic processes, including land-use change (e. g. , forestry to agriculture; agriculture to urban area) and land-cover modification (e. g. , ecosystem degradation or restoration) also affect multiple systems.
The SRES global storylines and scenarios
The SRES global storylines and scenarios
Percentage change in cropland area by 2080
Fresh Water Resources and their Management • The impacts of climate change on freshwater systems and their management are mainly due to the observed and projected increases in temperature, sea level and precipitation variability. • Semi-arid and arid areas are particularly exposed to the impacts of climate change on freshwater. • Higher water temperatures, increased precipitation intensity, and longer periods of low flows exacerbate many forms of water pollution, with impacts on ecosystems, human health, water system reliability and operating costs. • Climate change affects the function and operation of existing water infrastructure as well as water management practices. • Adaptation procedures and risk management practices for the water sector are being developed in some countries and regions (e. g. , Caribbean, Canada, Australia, Netherlands, UK, USA, Germany) that have recognized projected hydrological changes with related uncertainties. • The negative impacts of climate change on freshwater systems outweigh its benefits.
How human activities affect freshwater resources (both quantity and quality) and their management? • Water is indispensable for all forms of life. • Climate and freshwater systems are interconnected in complex ways.
The state of knowledge of climate change impacts on hydrology and water resources was presented • There apparent trends in streamflow volume, both increases and decreases, in many regions. • The effect of climate change on streamflow and groundwater recharge varies regionally and between scenarios, largely following projected changes in precipitation. • Peak streamflow is likely to move from spring to winter in many areas due to early snowmelt, with lower flows in summer and autumn. • Glacier retreat is likely to continue, and many small glaciers may disappear. • Generally, water quality is likely to be degraded by higher water temperatures. • Flood magnitude and frequency are likely to increase in most regions, and volumes of low flows are likely to decrease in many regions.
The state of knowledge of climate change impacts on hydrology and water resources was presented • Globally, demand for water is increasing as a result of population growth and economic development, but is falling in some countries, due to greater wateruse efficiency. • The impact of climate change on water resources also depends on system characteristics, changing pressures on the system, how the management of the system evolves, and what adaptations to climate change are implemented. • Unmanaged systems are likely to be most vulnerable to climate change. • Climate change challenges existing water resource management practices by causing trends not previously experienced and adding new uncertainty. • Adaptive capacity is distributed very unevenly across the world.
Observed Climate-related Trends Current Sensitivity and Vulnerability
Current Vulnerabilities of Freshwater Resources and their Management
Key Future Impacts and Vulnerabilities • Surface waters • Groundwater • Floods and droughts • Water quality • Erosion and sediment transport
Changes in Average Annual Runoff: 2050 s A 2
Change in Annual Runoff: 2041 -60/1900 -70
Annual Diffuse Groundwater Recharge: 2041 -2070/1961 -90
Change in the Recurrence of 100 -year Droughts
Costs of climate change in Okanagan, Canada
Cross-Scale Issues in the Integrated Water Management of Colorado River Basin
Some adaptation options for water supply and demand
Limits to Adaptation and Adaptive Capacity • Physical limit • Economic constraints to what is affordable • Political or social limits to the implementation of adaptation measures • The capacity of water management agencies and the water management system as a whole may act as a limit on which adaptation measures (if any) can be implemented.
Implications for Sustainable Development Millennium Development Goals (MDGs)
Future Climate Change Impacts on Freshwater
Fresh Water Resources and their Management • The impacts of climate change on freshwater systems and their management are mainly due to the observed and projected increases in temperature, sea level and precipitation variability. • Semi-arid and arid areas are particularly exposed to the impacts of climate change on freshwater. • Higher water temperatures, increased precipitation intensity, and longer periods of low flows exacerbate many forms of water pollution, with impacts on ecosystems, human health, water system reliability and operating costs. • Climate change affects the function and operation of existing water infrastructure as well as water management practices. • Adaptation procedures and risk management practices for the water sector are being developed in some countries and regions (e. g. , Caribbean, Canada, Australia, Netherlands, UK, USA, Germany) that have recognized projected hydrological changes with related uncertainties. • The negative impacts of climate change on freshwater systems outweigh its benefits.
Ecosystems, their Properties, Goods and Services • During the course of this century the resilience of many ecosystems (their ability to adapt naturally) is likely to be exceeded by an unprecedented combination of change in climate, associated disturbances (e. g. , flooding, drought, wildfire, insects, ocean acidification) and in other global change drivers (especially land-use change, pollution and over-exploitation of resources), if greenhouse gas emissions and other changes continue at or above current rates. • Several major carbon stocks in terrestrial ecosystems are vulnerable to current climate change and/or land-use impacts and are at a high degree of risk from projected unmitigated climate and land-use changes. • Approximately 20 to 30% of plant and animal species assessed so far (in an unbiased sample) are likely to be at increasingly high risk of extinction as global mean temperatures exceed a warming of 2 to 3°C above preindustrial levels. • Substantial changes in structure and functioning of terrestrial ecosystems are very likely to occur with a global warming of more than 2 to 3°C above pre-industrial levels. • Substantial changes in structure and functioning of marine and other aquatic ecosystems are very likely to occur with a mean global warming of more than 2 to 3°C above preindustrial levels and the associated increased atmospheric CO 2 levels. • Ecosystems and species are very likely to show a wide range of vulnerabilities to climate change, depending on imminence of exposure to ecosystem-specific, critical thresholds
Major Ecosystems Addressed in this report
GEC is more acute than ever • Heat wave hits Europe • 30, 000 people die in Western Europe Temperature anomaly (wrt 1961 -90) °C • 2003 observations Had. CM 3 Medium-High (SRES A 2) 2003 2060 s 2040 s
Ecological impacts of the European heatwave 2003 • Heat stress • Drought stress • Wildfires Schär et al. 2004 Precipitation Rebetez et al. 2006 Max. temperature August 2003
Ecological impacts of the European heatwave 2003 Relationships between the percentage of species loss and anomalies of moisture availability and growing-degree days Thuiller W. et. al. PNAS 2005; 102: 8245 -8250
Key Future Impacts and Vulnerabilities • Biogeochemical cycles and biotic feedback • Deserts: Vegetation response to rainfall variability in the Sahel Grasslands and savannas • Mediterranean ecosystems • Forests and woodlands • Tundra and Arctic/Antarctic ecosystems: Polar bears - a species in peril? • Mountains • Freshwater wetlands, lakes and rivers • Oceans and shallow seas • Cross-biome impacts: Crossing biomes: impacts of climate change on migratory birds • Global synthesis including impacts on biodiversity
Simulated Net Carbon Exchange of All Terrestrial Ecosystem
Vegetation Response to Rainfall Variability in the Sahel
Polar Bears – a species in peril
Coral reefs: Endangered by Climate Change?
Projected Appreciable Changes in Terrestrial Ecosystems
Compendium of Projected Risks due to Critical Climate Change Impacts on Ecosystems
Projected Risks due to Critical Climate Change Impacts on Ecosystems and Population Systems
Projected Risks due to Critical Climate Change Impacts on Ecosystems and Population Systems
Projected Risks due to Critical Climate Change Impacts on Ecosystems and Population Systems
Food, Fibre, and Forest Products • In mid- to high-latitude regions, moderate warming benefits crop and pasture yields, but even slight warming decreases yields in seasonally dry and low-latitude regions. • The marginal increase in the number of people at risk of hunger due to climate change must be viewed within the overall large reductions due to socio-economic development. • Projected changes in the frequency and severity of extreme climate events have significant consequences for food and forestry production, and food insecurity, in addition to impacts of projected mean climate. • Simulations suggest rising relative benefits of adaptation with low to moderate warming (medium confidence), although adaptation stresses water and environmental resources as warming increases. • Smallholder and subsistence farmers, pastoralists and artisanal fisherfolk will suffer complex, localised impacts of climate change. • Globally, commercial forestry productivity rises modestly with climate change in the short and medium term, with large regional variability around the global trend. • Local extinctions of particular fish species are expected at edges of ranges. • Food and forestry trade is projected to increase in response to climate change, with increased dependence on food imports for most developing countries. • Experimental research on crop response to elevated CO 2 confirms Third Assessment Report (TAR) findings. New Free-Air Carbon Dioxide Enrichment (FACE) results suggest lower responses forests
Impact of Selected African Droughts
European Heatwave Impact on the Agricultural Sector
European Heatwave Impact on the Agricultural Sector
Climate change and the fisheries of the lower Mekong
Assumptions about future trends in climate, food, forestry and fisheries
Sensitivity of Cereal Yield to Climate Change
Impacts on Grasslands of Incremental Temperature Change
Examples of Simulated Climate Change Impacts on Forestry
Impact of Coral Mortality on Reef Fisheries Coral reefs and their fisheries are subject to many stresses in addition to climate change (see Chapter 4). So far, events such as the 1998 mass coral bleaching in the Indian Ocean have not provided evidence of negative short-term bio-economic impacts for coastal reef fisheries (Spalding and Jarvis, 2002; Grandcourt and Cesar, 2003). In the longer term, there may be serious consequences for fisheries production that result from loss of coral communities and reduced structural complexity, which result in reduced fish species richness, local extinctions and loss of species within key functional groups of reef fish (Sano, 2004; Graham et al. , 2006)
Observed Climate-related Trends
Impacts of Climate Change and Socio-Economic Develoment Paths : the number of people at risk of hunger in developing countries
Key Conclusions and Their Uncentainties, Confidence Levels and Research Gaps • Projected changes in the frequency and severity of extreme climate events will have more serious consequences for food and forestry production, and food insecurity, than will changes in projectedmeans of temperature and precipitation. • Climate change increases the number of people at risk of hunger (high confidence). The impact of chosen socioeconomic pathways (SRES scenario) on the numbers of people at risk of hunger is significantly greater than the impact of climate change. Climate change will further shift the focus of food insecurity to sub-Saharan Africa. • While moderate warming benefits crop and pasture yields in mid- to high-latitude regions, even slight warming decreases yields in seasonally dry and low-latitude regions. • Experimental research on crop response to elevated CO 2 confirms Third Assessment Report (TAR) findings). New Free-Air Carbon Dioxide Enrichment (FACE) results suggest lower responses forests (medium confidence). Cropmodels include CO 2 estimates close to the upper range of new research (high confidence), while forest models may overestimate CO 2 effects. • Globally, commercial timber productivity risesmodestly with climate change in the short and medium term, with large regional variability around the global trend. • Local extinctions of particular fish species are expected at edges of ranges. • Food and forestry trade is projected to increase in response to climate change, with increased dependence of most developing countries on food imports. • Simulations suggest rising relative benefits of adaptation with low to moderate warming, although adaptation may stress water and environmental resources as warming increases.
Selected Conclusions for Food, Fibre, Forestry, and Ffisheries, by Warming Increments
Major impacts of climate change on crop and livestock yields, and forestry production
Selected Findings for Food, Fibre, Forestry, and Ffisheries, by Time Increments
THANK YOU! ANY QUESTIONS?
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