IPCC AR 4 I Climate Change Effects Climate

IPCC AR 4

I. Climate Change – Effects • • Climate change may have positive and negative effects for humans and ecosystems Media typically portrays climate change as negative

I. Climate Change – Effects A. Negative 1. • 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_fig 1. html

I. Climate Change – Effects A. Negative 1. • Sea Level Since 1880, sea level has been rising at a rate of ~15 cm century-1 • • • Accelerating since 1940 s 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

I. Climate Change – Effects A. Negative 1. • 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

www. panoramio. com/photo/31807235

I. Climate Change – Effects A. Negative 1. • Sea Level Caveats • • Sea level not rising in all areas Sea level rise began before Industrial Revolution

http: //www. epa. gov/climatechange/science/recentslc. html

http: //sealevel. colorado. edu/files/current/sl. pdf

I. Climate Change – Effects A. Negative 2. • 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

Source: U. S. Global Change Research Program

I. Climate Change – Effects A. Negative 1. 2. 3. • 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)

www. ncdc. noaa. gov/oa/climate/research/cei. html

Climate Change – Appropriate Scales • • Caveat: It’s important to consider climate change at appropriate scales (e. g. global vs. ( local) Link

I. Climate Change – Effects A. Negative 4. • Species Extinction & Ecosystem Changes Shifting climatic zones could expand ranges of warmth-tolerant species and contract ranges of warmth-intolerant species • • 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 • • • 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) Species composition of ecosystems almost certainly will change Changes in CO 2 concentrations p. H of ocean

Chen et al. 2011

I. Climate Change – Effects A. Negative 4. • Species Extinction & Ecosystem Changes Shifting climatic zones could expand ranges of warmth-tolerant species and contract ranges of warmth-intolerant species • • 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 • • • 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) Species composition of ecosystems almost certainly will change Changes in CO 2 concentrations p. H of ocean