"Humankind is releasing CO2 at a rate of about 7* Gton C per year from fossil fuel combustion, with a further 2 Gton C per year from deforestation. Because the atmospheric CO2 concentration is higher than normal, the natural world is absorbing CO2 at a rate of about 2 or 2.5 Gton C per year into the land biosphere and into the oceans, for a total of about 5 Gton C per year. The CO2 concentration of the atmosphere is rising because of the 4 Gton C imbalance."
* Newest figures, 7.9 GT.http://www.realclimate.org/index.php/archives/2006/11/how-much-co2-emission-is-too-much/
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1960, the concentration of CO2 in the atmosphere was 315 ppm. Since the mid-1900s, CO2 levels have increased at an average annual rate in excess of 1 ppm, due to a combination of natural processes and increased combustion of fossil fuels. The average CO2 concentration in the atmosphere is now above 380 ppm and the rate of increase has been above 2% annually over the past five years. (More on our "Air" page).
uigi.com
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"Merely believing it all stays in the atmosphere for 100 years doesn't make it so".
You're so right. That's why it's called science. There is research to back it up.
MYTH: Carbon dioxide is removed from the atmosphere fairly quickly, so if global warming turns out to be a problem, we can wait to take action to reduce greenhouse gas emissions until after we start to see the impacts of warming.
FACT: Carbon dioxide, a gas created by the burning of fossil fuels (like gasoline and coal), is the most important human-made greenhouse gas. Carbon dioxide from fossil fuel use is produced in huge quantities and can persist in our atmosphere for as long as 200 years. This means that if emissions of carbon dioxide were halted today, it would take centuries for the amount of carbon dioxide now in the atmosphere to come down to what it was in pre-industrial times. Thus we need to act now if we want to avoid the increasingly dangerous consequences of climate change in the future.
[IPCC, 2001. Climate Change 2001: The Scientific Basis, p. 38.]
grida.no
from
environmentaldefense.org
and
How long does it take to reduce the buildup of greenhouse gases and other emissions that contribute to climate change? Do different greenhouse gases and other emissions have different draw down periods?
Table 1: Removal times and climate forcing values for specified atmospheric gases and aerosols.
Forcing Agent Approximate Removal Times3 Climate Forcing (W/m2) Up to the year 2000
Greenhouse Gases
Carbon Dioxide >100 years 1.3 to 1.5
Methane 10 years 0.5 to 0.7
Tropospheric Ozone 10-100 days 0.25 to 0.75
Nitrous Oxide 100 years 0.1 to 0.2
Perfluorocarbon Compounds (Including SF6) >1000 years 0.01
Fine Aerosols
Sulfate 10 days -0.3 to -1.0
Black Carbon 10 days 0.1 to 0.8
newton.nap.edu |
