Desert world

Following hard on the heels of yesterday's post, about whether we'd be able to tell if there'd been a technological civilization on Earth tens or hundreds of millions of years ago, today we have a new study in Nature projecting the configuration of the continents 250 million years in the future -- and what that might portend for life.

We've known about the movement of the continents since geologists Harry Hess, Frederick Vine, and Drummond Matthews conclusively demonstrated in the early 1960s that convection currents in the mantle were dragging the tectonic plates along and shifting the positions of pieces of the Earth's crust relative to each other.  Of course, we might have figured all that out thirty years earlier if we'd just listened to poor Alfred Wegener, who proposed what he called "continental drift" to explain such observations as the near perfect fit between the eastern coastline of the Americas and the western coastline of Europe and Africa.  But because such an idea ran counter to accepted geological model of the time, Wegener was laughed out of academia -- literally.  He ended up taking off to Greenland to do paleoclimatological studies of the ice cap, and froze to death in November of 1930, never finding out that he'd actually landed on the truth.

In any case, what all this means is that the current configuration of continents and oceans is only the latest in a continuously shifting tableau, and it won't be the last.  Because we now have a pretty good idea of the motions within the known fault lines, we can run the clock forward and find out where things are likely to be in the future.

And the picture, unfortunately, doesn't look all that great.

The Atlantic Ocean, currently widening, will begin to close up, and by 250 million years in the future all that will be left of it will be two shallow landlocked seas.  Almost all the Earth's land surface area will have coalesced into a single supercontinent, which geologists have nicknamed "Pangaea Ultima" -- a misnomer, as "ultima" means "last" and this isn't the first time this has happened, and it won't be the last.  The thing is, the projection is that this gigantic land mass will be aligned along the equator, one of three factors that are projected to make this a hot time for land-dwelling organisms on planet Earth -- the other two are the carbon dioxide released because of the widespread volcanism predicted to take place as everything smashes together, and the fact that by then, the astronomers are telling us the Sun is going to be 2.5% brighter than it is now.

The geologists are making dire predictions about what this will do to terrestrial life on Earth -- mass extinction being the gist of it.  

"It does seem like life is going to have a bit more of a hard time in the future," said Hannah Davies, a geologist at the GFZ German Research Centre for Geosciences in Potsdam, who co-authored the study.  "It’s a bit depressing...  There have been extinction events in the past, and will be extinction events in the future.  I think life will make it through this one.  It’s just kind of a grim period."

Well, okay, it'd be grim if you took the species around today (humans included) and teleported them into Pangaea Ultima.  None of us would last very long.  But I'm not quite as pessimistic as Davies is about life in general.  This change to a planet dominated by deserts -- something more like Arrakis or Tatooine than the lush and verdant planet we now have -- won't happen overnight, and it's sudden change that usually triggers mass dieoffs.  Sure, it's likely that there will be a whole different suite of species than there is now, but hell, we're talking about 250 million years, so that was going to happen anyhow.

Give species time to adapt, and they do.  As Ian Malcolm put it, "Life... uh... finds a way."

Now, whether we (or more accurately, our descendants) are amongst those species that make it that far remains to be seen.  Very few species survive for 100 million years, much less 250.  But honestly, right now I'm more concerned with whether we'll get our comeuppance for our rampant pollution, out-of-control resource use, and burning of fossil fuels in a hundred years; let the hundreds of millions of years take care of themselves.

So that's our latest look at a future that really isn't as depressing as the scientists are claiming it is.  Although it's a little sobering to think that our descendants could be the Jawas and Tusken Raiders of the future Earth.  Those things are freakin' creepy.

And don't even get me started about Sandworms.

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