by Val Germann
The looming arrival of the 2007 IPCC report on Climage Change has focused this writer’s attention again on a very worrisome issue: How high can atmospheric CO2 concentrations go? To get a handle on this, take a look at the chart below, from the Scripps Institute:
By inspection this thing looks a little concave which implies that the rate might be increasing. A simple calculation confirms this impression. That is, from 1958 to 1981, 23 years, the parts-per-miliion of atmospheric CO2 increased from 315 to 340, or about 1.10 ppm per year. From 1981 to 2004, another 23 years, the CO2 concentration went up from 340 to 377 ppm, or about [37/23] 1.60 ppm year!
Why is this a big deal? It’s big because the rate looks like it’s currently doubling in about 45 years (and increasing) and would only have to do that twice more to get to a 6+ ppm/year increase, which would add 100 ppm to the atmosphere every 15 years. This would easily add 1,000 ppm of CO2 to the atmosphere between 2100 and 2200 AD, with the rate still increasing. Here’s another look at the problem, showing the long view and demonstrating the shocking rate of increase, and the increase of even that rate.
This graph, based on ice cores from the Antarctic, is a very disturbing thing. It shows without any doubt that CO2 in the atmosphere is rocketing upwards, following the human burning of fossil fuels. And it’s only going to get worse because as of today we’ve only burned about one-half of the world’s recoverable “conventional oil” and perhaps one-fourth of the recoverable natural gas. We probably have about 60 percent of recoverable coal left and there remain oceans (or pits) of low-grade tar sands. It’s likely a conservative estimate that the human race has yet to burn at least four or five times the amount of carbon it has burned so far, meaning that the launching pad look of the graph above has a long way to go, up, before it levels off.
Way back in the year 1750, the atmosphere had about 275 ppm of CO2 in it, likely even less if we go back to the days of the Caesars. In about one tenth of that time, from now to say the year 2200, we could well raise the CO2 level to more than five times its pre-industrial level, perhaps as high as 1,500, or even 2,000 ppm. This is so because we will burn over the next 200 years all the carbon mentioned above, and the biological world will be releasing massive amounts of carbon as the world warms.
It is not alarmist, but merely realistic, to say that a CO2 level of even 1,500 ppm would be cataclysmic both for us humans and most mammalian life on Earth, which would in effect be suffocated. Will the IPCC mention this angle in its upcoming report? This writer will be looking hard in all the footnotes because the idea could, just possibly, appear.