PORTRAIT OF VENUS

Later in this article I'll describe terraforming problems (Venus's heat, dryness, toxic atmosphere, spin), but frankly, all such talk is premature. We're still technological savages--we know what needs doing, but not how to do it! So why try? Let's treat the early, industrial phases of terraforming as a black box, and just assume we'll clean up Venus--somehow. My real interest is what comes next: Venus as a biosphere--as a place, a very big, beautiful place. This is a theme of this website in general; Dubia, the Earth with doubled C02, ignores the time of catastrophe to focus on what Earth'd be like once it settles down as a global hothouse. Same focus here: what Venus looks like as a world--not as an engineering problem!

As I've studied the radar scans and sculpted Venus's landforms, it's struck me how Earthlike they are--more than I anticipated from the comments of researchers, who I think are reacting to the current climate, not the landforms. Not just Venus's climate--the cultural climate here on Earth. Mars-mania is rampant, largely spurred by a historical accident: for centuries, when crude scopes and visible light were all we had, Mars made for fascinating viewing and Venus was a blank. But Venus is more Earthlike than Mars! It's closer in distance, size, mass, gravity, atmospheric density, tectonic activity. Yes, it's hot, and there are alien structures, and the absence of water-erosion has led to a pitted surface that'll abound in lakes and be short on river drainages, at least at first... but overall, Venus is beautiful--a complex geography that'll generate (in any terraforming model) fascinating continents with complex shorelines, islands, mountains, rifts, and lakes. In comparison, poor Mars is chunky, battered, lunar and brutal, with regions that'll never be viable under any terraforming scenario. But if any of Venus becomes livable, most of it will be. You'll never be far from water on Venus--or life.

But that doesn't explain the skein of arcs and ridges. My insticts tell me something rubbery is happening on Venus. I see elasticity everywhere--stretching, warping, squeezing till it corrugates. I'm a sculptor, used to flexible clays and acrylics, not a geologist--raised on plate tectonics, they tend to hunt for Terran-style plates or to reject plate tectonics utterly, some going so far as to deny large-scale crustal movements at all--just local spreading along rifts, and bubbling-up via coronas and volcanoes. I see wider movements! But not in plates--more like skin. Rubber tectonics... string cheese tectonics. (Io's not the only pizza!) The stuff's not just bubbling up under pressure. Sure, on the local scale (coronas, shield volcanoes, farras), vulcanism dominates, but some kind of large-scale stretching, bending or sliding is going on too. I just don't know what--or why.

Without fossil shores to guide us, sea levels are arbitrary. Mine are a few hundred meters higher than some terraforming proposals I've seen, but rather than try and re-create Earth with its sprawling continental interiors, I wanted to reveal as much of Venus's native topographic complexity as possible. The resulting coast is positively fractal--nearly every place on Venus is near water, and that's good for life.

My maritime Venus has a bit less dry land than Earth, but much more biologically usable land--fewer deserts or harsh continental interiors. And the seas will have wide, warm shallows--coral reefs? This Venus could sustain quite a lush biosphere--and it's a true sphere, unlike Mars's patchwork, pierced by stratospheric volcanoes and frayed by cold high deserts. Unlike Earth's, too! Pierced by polar caps, by Tibet, by the Old World desert belt, Earth's bio-"sphere" is more Martian these days than we think. It's been fifty million years since we had an unbroken biosphere. Swathed in thick air, Venus can be paradise--with enough water.

Besides, the impact of all those extra Jovian or Saturnian ice mountains will impart extra spin to Venus, which needs it. Even a modest rise in sea level allows a lot more ice-bombardment, since the surface area of the new sea increases as it rises. I think it's worth it. Still, if you like, you can build a Venus with a sea level half a kilometer lower (the basins are shallow, so that's about as low as you can go without getting mere chains of salt lakes, like Central Asia--desert country, please notice!) At this lower setting, you gain millions of square kilometers of land, at the risk of a harsher, drier climate. I've gone for quality, not quantity. Why settle for a hot Mars--or just another Earth?

CLIMATE ZONES

While I discuss the many terraforming options in detail below, it's likely Venus will have either a parasol or a swarm of shade-rings that cool the equatorial zone to something like our own subtropical temperatures. Why the equator? Just as the sun heats best at high noon, you get the most for your construction dollar by shading the high-noon part of the planet first. You can build a bigger parasol and shade the whole world if you want, but I've assumed a partial shade will do the job. So... a mild equatorial zone. Thirty or forty degrees north and south will actually be hotter, for the less shielded sun heats the surface to Earth-equatorial temperatures or more. The poles are cooler, drier zones, though not nearly as cold as Earth's. These warm and cool zones create two convection belts (Hadley cells) in each hemisphere, instead of the three on Earth (and terraformed Mars). Slowly spinning worlds tend to have larger cells anyway (Venus now has essentially one or no cells, while fast-spinning Jupiter has many tight belts) so I doubt that even a Venus with an Earthlike thermal gradient would have a three-cell system.

Venus has next to no axial tilt now, unlike Earth and Mars. If we can set Venus spinning at all, I suppose we could impart any tilted spin we want; but for the sake of this experiment let's honor Venus's axis, and see what happens. No tilt doesn't mean no seasons--on Venus, my best guess is that night and day, each about a week long, will be the primary seasons--evening will be fall-like, late night rainy and wintery, morning springlike, afternoon summery. The week-long nights, under most terraforming scenarios, will be many times brighter than full-moon nights on Earth--more like daylight around Jupiter or Saturn. (See NIGHT AND DAY below.)

Summary: my climate model has a mild equatorial zone under the shade of mirror-rings, torrid zones in the mid-latitudes where the shade-rings thin out, and dry, cool but not icy poles. The air is dense, and will transport a lot of vapor, but surface winds are weaker than Earth's, since rotation is slow and thermal gradients between zones are milder. Spin is retrograde, so currents, prevailing winds and Coriolis effects all run backward. Deserts will cluster on equatorial east coasts where dry air descends, while mid-latitude west coasts will be the rainiest places on Venus. (It all gives me an odd sense of deja vu, as I spin my Earth globe, looking at Oregon and England. Plus ca change, plus c'est la meme...)

Oh, well! Let's change subjects, now... AND tone. For the megalomaniac portion of our show, we now switch you to that engineer's delight, "Terraforming Fantasies." Hang on to your skepticism--you'll need it.

WHAT VENUS NEEDS

Terraforming Mars involves only one truly big project: adding a decent atmosphere. This isn't simple--free oxygen's needed, and Mars is nitrogen-poor, and you need enough greenhouse gases to warm the planet yet not poison animal life--like us. But except for nitrogen, the ingredients are there on Mars already. Even extra water may not be needed--certainly much of it is there already. The Martian orbit, axial tilt, rotation, geography, and level of tectonic activity are all acceptable right now.

But Venus has multiple problems which must be solved simultaneously -- at least by the standards of geologic time.