Well, it is rather stupid to ignore. You may not believe that it is yet totally proven but there is more than just compelling evidence to suggest Global Warming. And anyway, it's stupid to think that a 100 years of major 24/7 pollution has not harmed this planets atmosphere, we're doing damage, wasting away the Earth and it is a finite resource.
The observed decrease is driven by a large and rapid decline in
methyl bromide, a brominated gas that is regulated internationally by the
Montreal Protocol. It is larger than that expected from model calculations as given in the WMO/UNEP 2002 Scientific Assessment to Ozone Depletion
Greenhouse gas emissions
Coal-burning power plants, automobile exhausts, factory smokestacks, and other waste vents of the human environment contribute about
22 billion tons of carbon dioxide and other
greenhouse gases into the earth's atmosphere each year. Animal agriculture, manure, natural gas, rice paddies, landfills, coal, and other sources contribute about 250 million tons of methane each year. About half of human emissions have remained in the atmosphere. The atmospheric concentrations of CO2 and CH4 have increased by 31% and 149% respectively above pre-industrial levels since 1750. This is considerably higher than at any time during the last 650,000 years, the period for which reliable data has been extracted from
ice cores. From less direct geological evidence it is believed that CO2 values this high were last attained 40 million years ago. About three-quarters of the anthropogenic emissions of CO2 to the atmosphere during the past 20 years is due to
fossil fuel burning. The rest is predominantly due to land-use change, especially
deforestation [7].
The longest continuous instrumental measurement of CO2 mixing ratios began in 1958 at
Mauna Loa. Since then, the annually averaged value has increased
monotonically from 315
ppmv (see the
Keeling Curve). The concentration reached 376 ppmv in 2003. South Pole records show similar growth
[8]. The monthly measurements display small seasonal oscillations.
Note that anthropogenic emissions of other pollutants - notably sulphate aerosol - can exert a cooling effect; this accounts for the plateau/cooling seen in the temperature record in the middle of the century
