[Texgreen] Global warning

[Roger Baker]

http://lacitybeat.com/article.php?id=5816&IssueNum=214

According to paleontologist and NASA astrobiologist Peter Ward, we  
are about to climate-change ourselves right back to the Stone Age.  
Ward studies prehistoric mass extinctions, and, in his latest book,  
Under a Green Sky: Global Warming, the Mass Extinctions of the Past  
and What They Can Tell Us About Our Future, the scientist explores  
new data showing why, in the heavily carbon-ated atmospheres of the  
very distant past, oppressive heat levels would have been the least  
of your worries.

More ominously, Ward argues, a universally sweltering climate kick  
started a feedback cycle, disrupting the delicate balance that keeps  
our planet breathing. To reach a carbon-saturation of 800 to 1,000  
parts per million ' a figure currently posited by climate modelers '  
could be to precipitate a level of destruction not seen for millions  
of years. And it won't take millions of years to get there. 'The  
first big mass mortalities of humans will likely start around 2050,'  
Ward says. 'And by 2100, this will just be an unrecognizable globe to  
us.'

Mindy Farabee

CityBeat: The global-warming scenarios you posit are some of the worst.

Peter Ward: I think there are two biggies, the first being sea-level  
rise. That's going to happen faster and be more subtly devastating  
that anyone knows.

The thing that scares me so much now is, so much of human food now is  
being produced in deltas. The problem with sea-level rise is that it  
injects salt water up into places where salt previously hadn't been.  
And in the next few years, just from the heating we've already done,  
we are going to have a one- to three-meter sea-level rise, from  
thermal expansion of the ocean. Well, it turns out if you go to  
Bangladesh, even a five-foot rise would cause 13 million people to be  
displaced.

At the same time, the really scary thing going on is the melting of  
the Greenland ice cap. The two great big stores of fresh water are  
the Greenland and Antarctic ice caps. Greenland melts and sea level  
rises; the measurements are imprecise, but it's between eight and 20  
feet. But if the Antarctic sheet is combined with Greenland, that  
causes a rise of 240 feet.

Now, what you need to do is go back to any map of the Cretaceous  
Period to see what that looks like. A 240-foot rise just utterly  
changes the whole shape of the world. We're looking at a world that's  
absolutely unfathomable. And yet the sea-level rise is not the worst  
thing that could happen. Because that's displacement and crop change,  
and you can work around that.

The worst of the possibilities coming from global warming comes from  
these mass extinctions of the past. If we hook into one of those, you  
have a toxic atmosphere that no one can breathe. You have every human  
on the planet with a respirator.

How does that happen?

For years, of course, we thought past extinctions were all Armageddon  
and Deep Impact ' just impact, impact, impact. It's only been the  
past few years we've found out about these nasty sulfur bacteria that  
filled up the oceans during these past extinctions. At first it was  
thought that's a coincidence ' we had a mass extinction, and then the  
oceans filled with this sludge of sulfur bacteria. Then the discovery  
was made what kind of sulfur bacteria they are. They're forms that  
can only thrive when the ocean is super-saturated in hydrogen  
sulfide. We have found bugs that can only exist if there's so much  
hydrosulfide in the oceans that it's going to leak into the  
atmosphere and poison things on land. So that was the major discovery  
of the past couple years that had people so horrified.

This is related to the so-called 'conveyer belt' that keeps our  
oceans circulating?

When the Arctic is warm and the Antarctic is warm, there are no ocean  
currents. What's driving currents now is a warm tropics and a cold  
high latitude ' that's why there's wind, that's why there's currents.  
In the past when we've had globally warmed worlds, we've had little  
wind, a largely stagnant world. What keeps our oceans oxygenated is  
the presence of these currents. Without warm and cold that stops. And  
many times in the past [that's caused] an anoxic ocean ' a no-oxygen  
ocean ' and when that happens you get these super bugs. It's happened  
over and over in the past, and it's in our future if we keep doing  
what we're going to do.

And that kills everything?

Some things do survive. It's not universal throughout in these mass  
extinctions. The closest it came was [during the] Permian [Period],  
when 90 percent of all species went extinct. But 90 percent of all  
species had to translate to 99.9999 percent of all individuals. You  
would see a case where, here and there, there'd be some eddies. Some  
pockets of oxygen existed, and not everybody died out. But the planet  
itself would have been a big biological desert. It's a major, mass  
wholesale mortality of the planet, and after the Permian it stayed  
that way for three to five million years: this empty planet where all  
that thrived were bacteria.

Why do you believe we've entered another mass extinction now?

If you ask me, it really started during the Ice Ages, when humans  
really started killing off the big Ice Age mammals. That was the  
opening shot. But we're really going to be increasing the tempo of it  
as we warm the world. If we warm it too fast, plants can't migrate  
out of the way, and we kill them off simply because their ranges get  
run over by climates they can't deal with. In the oceans, we're  
already seeing the coral reefs dying out because of two things: It's  
warmer than they can deal with, but also, so much carbon dioxide is  
being pumped into the ocean that it's acidifying them. For instance,  
in the Arctic we're seeing terapods with the shells being eaten off  
their backs, literally. It's crazy what's happening.

In your book, you say our climate has only been stable for 10,000  
years, and that stability is what human civilization is predicated on.

Absolutely, our crops are only predictable because we don't see much  
change in climate. Weather becomes unpredictable if we globally warm  
a little bit. On the way [to a globally warmed world] we go into  
these instabilities, as it jumps back and forth between two states  
before reaching an end state. Well, [as that happens] farms fail. And  
human civilization is based on food ' that we have this abundance of  
food. We quit being cave people and started being a civilization when  
there was an abundance of food. If we cut back on farm yields, we  
face catastrophe. And this is what a change climate will do.

For instance, the wheat belt turns into the dust belt. All the  
Republicans with all the farm subsidies in the world, I'm sorry, if  
you have 10 years of dust and then come back to being good, the  
farmers are all busted and gone away.