Moon Miners' Manifesto

#93 March 1996

The Shifting Climate of Mars

  Those brave optimists who essay to put together various schemes to bring about major climactic and environmental changes on Mars in order to render the planet much more appealing a destination for would-be Earth-forsaking homesteaders, can, at present, do little more than B.O.E. ("back of envelope") calculations of the material and energy inputs and relocations needed to bring about such changes.

  Whether the goal is "terraforming" (making the planet another "Earth") or "Lowellification" (making the planet at least as friendly as we thought it was fifty years ago), or "rejuvenescence" ("restoring" Mars to its wettest and warmest former state of about three billion years ago), the equations are hard to work without good data about the present.

  In point of fact, despite all the revelations of the Mariner and Viking missions, we know much less about the Mars of today, than most writers will admit.

1. We don't know within two or even three orders of magnitude how much water remains on Mars, locked up in the polar caps, in subterranean aquifers and lakes, or chemically bound up in hydrates, or frozen in the interstices of soil particles as permafrost. Nor is such vital information the target of instruments aboard presently budgeted missions to Mars.

2. We don't know how much carbon dioxide is locked up in clathrate frosts at the poles, nor how much may be chemically bound up in sedimentary carbonate rocks or limestone layers.

3. We have only a very crude idea of the relative altitudes of Martian surface features, and thus only a very imperfect idea of potential drainage basins and watersheds. Fortunately, this ignorance is being addressed by the Mars Global Surveyor ready for launch later this year.

4. Hubble has shown that what we thought we "knew" of Martian temperature ranges, was pegged to a transitory condition.

  Apparently, mean temperatures on Mars have dropped an astonishing 20° in the two decades since Vikings I and 2 established weather stations on the planet. By comparison, a mere 2° rise in terrestrial temperatures worldwide, would cause environmentalists and meteorologists and climatologists to reach for the panic button.

  At the moment,we have no idea how long-lasting this cooling will be, nor even if the downward swing has bottomed out, nor on what time frame such meta-seasonal changes take place. Given that, brainstorming pathways to a friendly future are interesting fantasies and no more. As they say, "garbage in, garbage out." Yet carefully designed future missions could tackle each of these points of our ignorance quite well.

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