Many leading environmentalists, including Bill McKibben have indicated that the safe upper limit is 350 PPM others suggest the limit could be as high as 450 PPM. At the current rate it appears likely we will surpass 450 PPM of carbon dioxide (CO2) which will result in catastrophic global temperature increases of around 5 degrees.
Levels of GHGs have been rising steadily. In 1958 Carbon dioxide levels were at 317 PPM, in slightly more than 50 years we have seen this number rise by 83 PPM.
To understand the implications of this rise in CO2 we need only look at the state of the world 3 million years ago. During the Pliocene era levels of CO2 were around 400 PPM; temperatures were around 4 degrees hotter than they are today and sea levels were between five and 40 metres higher than today.
The rise in greenhouse gases (GHGs) like CO2 is a function of human activity such as burning fossil fuels and cutting down forests. One of the most troubling aspects of the rise in CO2 is the fact that it appears to be accelerating.
© 2013, Richard Matthews. All rights reserved.
The Dangerous Trajectory of CO2 Growth Since the 1880’s
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Debunking CO2 Myths and The Science of Climate Change
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Action on Climate Change
The Effects of Global Warming
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