Remember When People Made Fun of Vice President Quayle's Remarks About Mars?

He said something about the potential for living on Mars that I suspect was what he remembered from a science class in the 1950s--when we didn't really know very much yet about Mars and its potential for human habitation.

So why isn't anyone making fun of this other, former Vice President's ignorance? From the July 1, 2007 New York Times:

We — all of us — now face a universal threat. Though it is not from outside this world, it is nevertheless cosmic in scale.

Consider this tale of two planets. Earth and Venus are almost exactly the same size, and have almost exactly the same amount of carbon. The difference is that most of the carbon on Earth is in the ground — having been deposited there by various forms of life over the last 600 million years — and most of the carbon on Venus is in the atmosphere.

As a result, while the average temperature on Earth is a pleasant 59 degrees, the average temperature on Venus is 867 degrees. True, Venus is closer to the Sun than we are, but the fault is not in our star; Venus is three times hotter on average than Mercury, which is right next to the Sun. It’s the carbon dioxide.

Parts of this statement are simply false. Mercury's sunlit side is 872 degrees Fahrenheit.

The statement about Venus's atmosphere is true, but misleading; Venus is remarkably hot because of the amount of carbon dioxide in the atmosphere. But guess what? All planets start out with a methane, ammonia, water vapor atmosphere, and evolve to a carbon dioxide, nitrogen, water vapor atmosphere. Mars has a comparably carbon dioxide rich atmosphere--and yet it isn't terribly warm. Why?

There are two major differences between the Earth and Venus that makes this comparison absurd.

1. Venus is 72% of the distance from the Sun as the Earth. That means that it gets 1.93 times the solar input. That's a big difference. Even if we had comparable atmospheres, Venus would be a lot warmer.

2. The presence of large bodies of liquid water on the early Earth--because we were getting about half the sunlight--provided both a basis for life--which converts quite a bit of atmospheric and oceanic carbon dioxide into glucose--and a geochemical process for converting carbon dioxide into carbonates. There is about 40x as much carbon dioxide locked up in carbonate minerals as there is in the atmosphere. The mechanisms are not spectacularly well understood.

This is just scaremongering by Al Gore--a person who clearly doesn't know much about the chemistry behind planetary atmospheres.