By Andy May
We are often confronted with the idea that if the carbon dioxide level in the Earth’s atmosphere gets too high we will suffer from a “runaway greenhouse effect” and the Earth will become like Venus. This would be catastrophic. The temperature on the surface of Venus is roughly 737K (464°C or 867°F). It is hotter on the surface of Venus than on the daytime side of Mercury! In addition, Venus has very thick clouds of sulfuric acid. It is not a hospitable place. Could the Earth “go runaway” and become like Venus with the addition of more carbon dioxide to our atmosphere? James Hansen famously wrote in 2009, page 236:
“. .. if we burn all reserves of oil, gas, and coal, there’s a substantial chance that we will initiate the runaway greenhouse. If we also burn the tar sands and tar shale, I believe the Venus syndrome [the runaway greenhouse] is a dead certainty”
Could this be true? He got the idea by studying Venus. Is Venus “runaway?” Figure 1 is a profile of the Venusian atmosphere.