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IPCC AR4. Climate Change – Effects Climate change may have positive and negative effects for humans and ecosystems Media typically portrays climate change as negative. Climate Change – Effects Negative Sea Level Warming melting of glaciers and ice caps sea level rise
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Climate Change – Effects • Climate change may have positive and negative effects for humans and ecosystems • Media typically portrays climate change as negative
Climate Change – Effects • Negative • Sea Level • Warming melting of glaciers and ice caps sea level rise • Warming thermal expansion of water additional sea level rise • Melting of all ice sea level rise of ~70 m
http://www.epa.gov/climatechange/science/futureslc_fig1.html
Climate Change – Effects • Negative • Sea Level • Since 1880, sea level has been rising at a rate of ~15 cm century-1 • Accelerating since 1940s • Rates at ends of glacial periods ~40 cm century-1 • Sizes of polar ice sheets fairly constant over last century (some shrinkage in Antarctica) • Temperate glaciers have shrunk visibly • Warming should lead to increased atmospheric moisture and precipitation, which should cause a net growth of polar ice caps
Climate Change – Effects • Negative • Sea Level • Examples • Estimated that measures to protect low lying land in US from damage would cost > $100 billion • Bangladesh – More than 17 million people live less than 1 m above sea level • 38% of food production tied to flood plains • AOSIS (Alliance of Small Island States) – Strong concerns about sea level rise • Maldives – Highest elevation 24 m • Japan – Fishing rights around pinnacle • Social justice issue (Global Humanitarian Forum)
US East Coast –Sea Level Rise 1 m 3 m http://vrstudio.buffalo.edu/~depape/warming/east.html
Climate Change – Effects • Negative • Sea Level • Caveats • Sea level not rising in all areas • Sea level rise began before Industrial Revolution
Climate Change – Effects • Negative • Rainfall Patterns • Warming should lead to • Reduced precipitation at low latitudes • Increased precipitation at high latitudes • Examples • Reduced snowpack in Sierra Nevada Mountains due in part to rainfall instead of snow • Drought in many parts of the world
Annual Trends 1901-2005 http://www.epa.gov/climatechange/science/recentpsc_precipanom.html
Climate Change – Effects • Negative • Sea Level • Rainfall Patterns • Storms • Warming should lead to • More severe storms • Greater storm frequency • May not occur if temperature differential between poles and equator weakened, not strengthened (Lindzen)
Climate Change – Appropriate Scales • Caveat: It’s important to consider climate change at appropriate scales (e.g. global vs. local) • Link
Climate Change – Effects • Negative • Species Extinction & Ecosystem Changes • Shifting climatic zones could expand ranges of warmth-tolerant species and contract ranges of warmth-intolerant species • Colder-living species might be displaced poleward as well as upward in elevation • Species unable to adapt or move would go extinct • Predicted rates of 16.9 km/decade and 11.0 m/decade (Chen et al. 2011) • Populations of various species might be isolated, leading (eventually) to speciation (Good?) • Within an ecosystem, some species will be more sensitive to climate change than others • Species composition of ecosystems almost certainly will change • Changes in CO2 concentrations pH of ocean
Climate Change – Effects • Negative • Species Extinction & Ecosystem Changes • Shifting climatic zones could expand ranges of warmth-tolerant species and contract ranges of warmth-intolerant species • Colder-living species might be displaced poleward as well as upward in elevation • Species unable to adapt or move would go extinct • Predicted rates of 16.9 km/decade and 11.0 m/decade (Chen et al. 2011) • Populations of various species might be isolated, leading (eventually) to speciation (Good?) • Within an ecosystem, some species will be more sensitive to climate change than others • Species composition of ecosystems almost certainly will change • Changes in CO2 concentrations pH of ocean