This is just a summary of all the posts...
Ice core samples from Antarctica have been analysed by the CSIRO and the Australian Antarctic Divison. These provide a measure of atmospheric gases trapped in the ice over hundreds of years. these samples have shown:
-> increases in CO2 from 280 ppm before the Industrial Revolution to 360 ppm now.
-> methane content increase from 700 ppb to 1700 ppb
--> N2O increase by 10%
Another estimate of carbon concentration is obtained by studying carbon isotopes in fossils.
Some less quantitative evidence are observations / events in our history:
-> In 1952 in London, a smog containing sulfuric acid (from SO2) and coal soot contributed to the deaths of 4000 people. Also, according to ... (above), in north east of USA as well.
-> photochemical smog (which is: "O3 particles and oxides of hydrocarbons" formed from "NOx and hydrocarbons" on exposure to sunlight) in Los Angeles in 1930s (not 1960s, according to the article entitled "Pollution" in Encarta)
-> acid rain, obviously, with its effects such as increasing acidity of lakes in Scandinavia, damage to pine forests in Europe and North America, erosion of priceless statuary in Europe which in the past 50 years did more damage than the weathering of the previous 500 years.
To accurately determine the increase in concentration globally is quite hard as acid oxides are quickly washed out by rain. There's a lack of data before 1950, during which measurements technology was limited.
for a research assignment. anyone know of any sources and suggestions?
