This is really drawing straws. I can easily say, "all else being equal = the temperature of a planet is not primarily dependent upon its distance = from its star or the composition of its atmosphere but rather the size = of the star around which it revolves, or even the stage of the star!" = Of course these things are all important but they have little to do with = climate change beyond the aspect that it was noticed that atmospheres of = the terrestrial planets contributed to temperature differences. = Furthermore, Mars does have water, there is a ton of it frozen on its = polar caps. Las =20 =20 =20 VISIT HERPETOLOGICAL CONSERVATION AND BIOLOGY www.herpconbio.org = <http://www.herpconbio.org>=20 A New Journal Published in Partnership with Partners in Amphibian and = Reptile Conservation and the World Congress of Herpetology. =20 Malcolm L. McCallum Assistant Professor Department of Biological Sciences Texas A&M University Texarkana 2600 Robison Rd. Texarkana, TX 75501 O: 1-903-223-3134 H: 1-903-791-3843 Homepage: https://www.eagle.tamut.edu/faculty/mmccallum/index.html =20
________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Thu 6/29/2006 3:08 PM To: Malcolm McCallum; ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Wall Street Journal op-ed on "An Inconvenient = Truth" Malcolm quotes: > From: http://www.craigmont.org/grenhous.htm >=20 > The Connection to the Planets > The temperature of a planet, for the most part, reflects a balance = between > the amount of energy coming in to the planet from the Sun and the = amount of > energy that is radiated back out into space. The temperatures of terrestrial > planets are a measure of the amount of IR that has been absorbed. A = planet > with a high proportion of greenhouse gases in its atmosphere will be = able to > hold a lot more energy than an atmosphere that is deficient in = greenhouse > gases. [much snipped] As I wrote earlier, everything that is said here is true, but it's also substantially misleading if it is read only in this context. All other = things being equal, the primary determinants of a planet's temperature are its = distance to its host star and its internal heat, which is governed principally by = its size. By great chance, we have experimental proof that this contention is true = in our own solar system. Venus and Earth are virtual twins. They're the = same size, they were formed at the same time, and were almost certainly initially composed of the same relative abundances. But they could not be more = different now. Venus is cloud-covered, hot as hell (indeed, so hot that carbon = biochemistries cannot operate on the surface of the planet), and suffocated by 90 atmospheres of pressure at its surface. But much worse, Venus has not only lost its oceans due to its increased = solar flux, its current water inventory has now evolved to be only 1/100,000th = of Earth's. As a consequence, the rocks have become so dry that tectonic = activity stopped about a billion years ago, creating a "one-plate planet," = thereby capturing its internal heat within its lithosphere, the result being = that ca. 700 million years ago, about the time of the Cambrian Explosion on Earth, = the planet's surface melted in one giant episodic event. That has to be considered a bad day in anybody's book. This entire history of Venus can be attributed to nothing more than the chance placement of Venus just a little closer to the Sun than Earth is. Let me again recommend David Grinspoon's talk on the geological & = atmospheric history of Venus: http://aics-research.com/lotw/lotw20060619.html If you're not familiar with the story, it is jaw-dropping science. Wirt Atmar
