Quote:
Originally Posted by Arctic Fox
Indeed, the Earth did cause it. And if you go back 500 million years you might find CO2 levels at ten times today's concentration, but you wouldn't want to live in that climate.
For virtually the whole time that Homo Sapiens has been in existence, CO2 has varied between 200 and 300 ppm.
In the mid-18th century (the start of the Industrial Revolution) the level was 280 ppm, and in the past 260 years it has increased to 400 ppm. In the past fifty years alone it has increased 25% (from 320 to 400 ppm).
Apart from cataclysmic events (which tend to cause mass extinctions) the Earth has never before witnessed such a rapid increase. So, while no-one is denying that Earth contributes to the CO2 cycle, it seems more than likely that Man is now playing a significant role.
Even if he is not, and the Earth has suddenly decided to ramp up CO2 concentrations by itself, it is in Man's interest to try to keep the increase as small as possible. Aside from the damage from more violent storms and rising sea levels, plants cannot adapt to rapid changes in their environment. Think crop failure and the death of native forests.
It may take decades for such problems to truly manifest themselves (although the evidence is already out there) but it will take many more decades to slow the increase and, hopefully, get the concentration back below the desired maximum of 350 ppm.
That is if we don't pass a tipping point beyond which Earth just cannot cope. It is comforting to think of Gaia - Earth taking care of itself and compensating for anything Man throws at it - but the reality is proving otherwise. Earth really doesn't care whether Mankind is here or not.
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The percentage of CO2 in the atmosphere is 0.039%.
The predominate element in the atmosphere is Nitrogen at 78.09% followed by Oxygen at 20.95%.
Does the change in CO2 from 300ppm to 400ppm still seem that significant when you consider what a small percentage CO2 is in our atmosphere?