Can Earth be compared to Venus?

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.

Figure 1

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