PS336, Global Environmental Politics
Fall Semester 2005
Week 10 Outlines
Monday, October 17 - Preserving the Ozone Layer
Health Effects of UV radiation
I. Stages in Scientific Knowledge of Ozone Depletion Problem
Discovery and measurement of ozone layer
1830 - Initial Discovery
1930 - Dobson Spectrophotometer (for measuring ozone in the statosphere)
1956 - WMO Ozone Network
Theory of threat to ozone layer
1974 - Molina/Rowland (theory that CFCs deplete ozone layer) (other ozone depleting chemicals)
Evidence of stratospheric ozone loss
1985 - Antarctic ozone hole announced by British Antarctic Survey (ozone hole 2004)
1980s - lesser loss in temperate regions
1990s - Arctic ozone hole discovered
Early 1990s - Evidence of increased UV radiation
1990s - Evidence of health and environmental impacts
II. International Agreements to Protect the Ozone Layer
1985 Vienna (Framework) Convention on Protecting the Ozone Layer
1987 Montreal Protocol on Substances that Deplete the Ozone Layer (171 countries have ratified as of 2005)
CFCs
20% reduction by 1993
50% reduction by 1998
Halons
Freeze at 1986 levels by 1992
1990 London Amendments
CFCs - 100% reduction by 2000
Halons - 100% reduction by 2000
Carbon tetrachloride phased out by 2000
Methyl chloroform phased out by 2010
1992 Copenhagen Amendments
CFCs - 100% reduction by 1996
Halons - 100% phaseout by 1994
HCFCs
Freeze at 1989 levels by 1996
35% reduction by 2004
65% reduction by 2010
100% phaseout by 2020
Methyl Bromide
Developing Countries limit production at 1991 levels by 1995
1995 Vienna Adjustments
Methyl Bromide
Industrialized countries will
reduce by 50% by 2005
completely phase out , with exceptions for "critical agricultural uses" by 2010
HCFCs - developed countries move up phase-out date from 2030 to 2020,
1997 Montreal Amendment and Adjustments
1999 Beijing Adjustments
Summary of Phase-out Schedules
III. Impacts of the Montreal Protocol and Amendments
Reductions in the production and use of ozone depleting substances
Prognosis for recovery of the ozone layer
Wednesday, October 19 - The Science of Climate Change
I. Two Types of Scientific Errors
Type I: to conclude that there is a significant human imprint on the global climate when there is none
Type II: to fail to detect a significant human imprint on the global climate when one actually exists
Intergovernmental Panel on Climate Change
II. Knowledge of Climate Change
Theoretical understanding of the greenhouse effect
diagram of the greenhouse effect
comparisons of the atmospheres of Venus, Earth and Mars
CO2 Monitoring Records (increase in 2004 up to 3 ppm, compared to 1.8 annual average over last decade)
Paleoclimatological Research
temperature and CO2 concentrations over past 400,000 years
Contemporary Weather Records (see below in section III)
Potential Harbingers of Global Climate Change (see below in section IV)
Projections of Global Circulation Models (see below in section V)
Impact Studies
III. Recent Anomalies in Global Average Mean Temperature
Trends in global annual mean temperatures
"In light of new evidence and taking into account the remaining uncertainties, most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations," IPCC 2001 Report.
-1998 - the warmest single year since 1860; followed by 2002, 2003, and 2004 (2005 on track to be 1st or 2nd warmest)
Global average temperatures tend to be higher during El Nino cycles (map of Pacific Ocean)
-10 warmest years since 1860 occurred since1990; all of 1990s years were among among top 15
-for 23 consecutive years the average temperature has been above the 1960-1990 annual average
-16 consecutive months in 1997-98 broke temperature records
-increase of 0.5 degrees Celsius since 1975 (based on five year mean temperatures) --
or a rate of 2 degrees Celsius per century
IV. Possible Harbingers of Global Climate Change
-a decrease of approximately 10% in the extent of snow cover since the late 1960
-a 14% reduction in the amount of perennial Arctic Sea ice between 1978-1998 and a 40% reduction in ice thickness over the last 20-40 years
-an increase of .31 C in the temperatures of the top 300 meters of the Atlantic, Pacific, and Indian Oceans over the past 50 years
-an advance of 9.8 days in freshwater spring thaw dates at 38 sites in the northern hemisphere sites between 1846 and 1996, and an 8.7 day delay in fall freeze-up dates
-a rise in average winter termperatures as much as 7 degrees F in Alaska, Western Canada, and eastern Russia
-a shrinking of of 212 of 242 Antarctic glaciers by an average of 600 meters over last 50 years (also rapid melting of Arctic glaciers)
-a retreat of mountain glaciers in non-polar regions during the 20 century
-an increase of 2-4% in the frequency of heavy precipitations events during the latter half of the 20th century
-a rise in sea levels of .1 to .2 meters during the 20th century
-a substantial drop in the amount of long-wave radiation escaping from the earth between 1970 and 1997
V. Projections of Future Climate Change (global average mean temperatures)
(from reports of the IPCC)
1995 Report
1.8 to 6.3°F
2001 Report
2.5 to 10.4°F (upward estimate to lower anticipated levels of SO²)
VI. Potential for Abrupt Climate Change
Film - Scientific American, Hot Climate - Cold Comfort
Abrupt Climate Change and US National Security (Pentagon Report-2004)-see .pdf in margin
National Academy of Sciences Report on Abrupt Climate Change--2002