I. Climate Change – Effects

A. Sea Level Rise• Warming Ice Melt Sea Level Rise

• Increased conversion of ice to water• Thermal expansion

• Since 1880, sea level rising ~15 cm century-1

• Accelerated since 1940s

• Melting of all ice should lead to sea level rise of ~70 m

• Lomborg – More affluent world should lead to more protection against effects of sea level rise

http://www.grida.no/climate/vital/19.htm

I. Climate Change – Effects

B. Reduced Ice/Snow Cover• Temperate/Tropical glaciers• Polar ice caps

Holgate Glacier, AK Muir Glacier, AK1909 vs. 2004 1941 vs. 2004

After Dyurgerov and Meier (2005)

SAHFOS

European Space Agency

III. Climate Change – Effects

C. Extreme Weather• More and more severe

• Tropical storms• Tornadoes• Increasing economic losses

• Lomborg – Changing population patterns, demography, economic prosperity

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

www.hprcc.unl.edu/nebraska/US-tornadoes-1953to-present-bar.html

I. Climate Change – Effects

D. Precipitation Patterns• Warming should lead to

• Reduced precipitation at low latitudes• Increased precipitation at high latitudes

• Examples• Drought in many parts of the world• Reduced snowpack in Sierra Nevada Mountains

due to rainfall instead of snow• Increased agricultural production in some areas

• Combined with higher temperatures and [CO2]

Source: U.S. Global Change Research Program

20th Century

Source: U.S. Global Change Research Program

I. Climate Change – Effects

E. Ozone Holes• Global warming of the atmosphere

translates to stratospheric cooling• Stratospheric cooling may enhance ozone

destruction in Antarctic and make phenomenon more common in Arctic (Waibel et al. 1999)

I. Climate Change – Effects

F. Ecosystem Effects• 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

• Within an ecosystem, some species more sensitive to climate change than others

• Species composition of communities almost certainly will change

• Ex: Intertidal (Pacific Grove – Central CA)• Significant abundance changes in 32/45 species

between 1931 and 1994• 8/9 southern species increased significantly• 5/8 northern species decreased significantly

• Changes in CO2 concentration lower pH of ocean• Behavioral changes (Ex: Sockeye salmon)

I. Climate Change – Effects

G. Health• Consistently elevated temperatures can lead

to immunosuppression• Exacerbated by elevated levels of UV-B

• Allergies could worsen due to increased pollen production (heat), dust (drought), mold (humidity)

• Additional human mortality from severe summer heat

U.S. Global Change Research Program

I. Climate Change – Effects

H. Tropical Pests and Diseases• Many tropical diseases transmitted by

animal vectors – insects, rodents• Concern that global warming could increase

geographic ranges of vectorsa. Dengue fever• Ex: 1995 – Rising temperatures allowed a coastal

mosquito species to cross mountains and spread across Costa Rica, carrying dengue fever

• Reached as far north as Texas border• 140,000+ people infected; 4000+ died

I. Climate Change – Effects

H. Tropical Pests and Diseasesb. Malaria• Most prevalent vector-borne disease (1-2 million

cases/year)• Transmitted by Anopheles mosquitoes• Warming could lead to

• Broader geographic range (estimate that +2oC could expand range from 42 to 60% of land area)

• Higher metabolic rate More food• Faster maturation More rapid reproduction• Faster parasite life cycle

• Potential spread into large urban areas (Nairobi, Kenya; Harare, Zimbabwe) with immunologically naïve pop’ns

• Projections are controversial and highly variable

Climate Change – Effects