1995 IPCC Update

• United Nations sponsored committee, which carries the authority of over 2,000 investigator, has concluded that humankind is now altering the climate in an identifiable way.
• The reports issued in November 1995 says that human-induced changes in the climate has been detected.
• Previously, researchers combined temperature records to look solely for warming effect brought about by emissions of carbon dioxide and other greenhouse gases.
• Recent studies have proved more sucessful because they have taken into account the cooling influence of sulfates derived from sulfur pollution.
• Computer simulations that include both greenhouse warming and sulfate cooling match more closely the pattern of observed warming over the last century.
• Including the effects of sulfate pollution has caused the IPCC to scale back its assesment of global warming.
  • Current porjection of 1 to 3.5 degrees C of warming by the year 2100, with the best estimate of 2 degrees C.
  • In the 1990 report, the IPCC estimated a warming of 4 degrees C over the same period.

• Revised projections of sea level change.
  • 15 to 90 cm by the year 2100, with a best estimate of 48 cm (1.57 feet).
  • In 1990, the IPCC forecast a 65 cm (2.13 feet) rise in sea level by 2100.

Impacts on the human population

• Temperuare increase
  • Decrease # degree heating days in northern US
  • Increases # degree coolsing days in southern US
  • Increase length of the growing season, but will also impact precipitation patterns
  • Increased magnitude of climatic extremes (eg., hurricanes)
• Agriculture
  • Global warming will result in changes in rainfall and soil moisture, which may disrupt agriculture in some areas. Winners and loosers
• Sea Level Rise
  • 92 million people at risk of flooding each year, a doubling of the current number.
  • In Florida, 1 foot rise in sea level = 200 feet of land lost along the shore
• Ecosystem Shifts
  • Warming will cause one-third of all ecosystems to shift to another type, such as from forest to grasslands.
  • Ecotones will shift to higher latitudes due to warming.
    • reduction of Earth's biological diversity???
• Global Warming and the Increased Threat of Disease
  • The recent resurgence and reemergence of infectious diseases around the world have been the main reasons for the relatively new recognition of the connection between global climate change and disease.
  • Warmer temperatures and changes in rainfall have created ideal conditions for vectors (animal host such as mosquitoes, ticks, and rodents, which transmit disease) and pathogens (bateria, viruses, and multicellular organisms) to survive in areas that were previously inhospitable to them.
  • Diseases that have emerged or reemerged in the 1990s - World Map
    • the outbreak of cholrea in Latin America in 1991
    • the outbreak of pneumonic plague in India in 1994
    • the hantavirus epidemic in the southwestern U.S. in 1994

Conclusion

• The IPCC found that the expected benifits of climate change will not balance the anticipated damage.
• The IPCC panel advocates pursuing a porfolio of actions aimed a mitigation, adaptation, and improving knowledge.
  • Promoting energy effciency.