Letter: Let’s move on
I suppose we should be heartened by climate deniers, like Jim Bates, who at least use arguments that are not, on their face, utterly ridiculous. Unfortunately, his more valid points were last topics of lively debate among scientists in the 19th century, and have not been taken seriously by them for 100 years.
In summary, it was realized early in the early 1800s that some component of the atmosphere must be trapping the Sun’s heat, or Earth’s oceans would freeze. In the middle 1800s, CO2 was identified as that component. Probably 10 minutes after that, since the oceans had not long ago boiled away, it was reasoned that some mechanism must keep CO2 levels from increasing too high. This led to finding the regulating effects of chemical weathering.
Before one answers the question of how to describe the end of the last “ice age,” we must define our terms. There have been half a dozen periods, each lasting tens of millions of years, during which ice sheets advanced and retreated in response to the orbital changes known as Milankovitch cycles. It is interesting that Mr. Bates, in describing the last such retreat as the end of the last ice age, is referencing the changes, brought on by man, ending the late Cenozoic ice age, which showed no signs of ending otherwise.
He seems to suggest that vulcanism is responsible for any change in climate. Starting in 1954, Mr. Charles Keeling made daily measurements of CO2 concentration and this unbroken record continues. It shows a steady increase in CO2 utterly in line with anthropogenic sources and not at all perturbed with any volcanoes, fires or other such sources.
Mr. Bates asks us to keep things in prospective, so let’s consider one additional fact (a real fact this time): every ton of CO2 we release commits the planet and its inhabitants to its effects for several hundred thousand years, the time it takes for natural processes to remove CO2 from the atmosphere. We might want to think more carefully about just what those effects will be before we continue with business as usual.