Climate Model Suggests Near-Total Loss Of Tundra, Reef Destruction - NYT

[hatrack]

If emissions of heat-trapping gases continue to accumulate in the atmosphere at the current rate, there may be many centuries of warming and a near-total loss of Arctic tundra, according to a new climate study. Over all, the world would experience profound transformations, some potentially beneficial but many disruptive, and all at a pace rarely seen in nature, said the authors of the new study, which is being published on Tuesday in The Journal of Climate.

"The question is no longer whether we will need to address this problem, but when we will need to address the problem," said Kenneth Caldeira, an author of the study and a climate expert at the Carnegie Institution's Department of Global Ecology, based at Stanford University. "We can either address it now, before we severely and irreversibly damage our climate, or we can wait until irreversible damage manifests itself strongly," Dr. Caldeira said. "If all we do is try to adapt, things will get worse and worse."

The paper's lead author, Bala Govindasamy of the Energy Department's Lawrence Livermore National Laboratory, said it might take 20 or 30 years before the scope of the human-caused changes becomes evident, but from then on there is likely to be no debate. The researchers ran a computer model that simulates both the climate system and the flow of heat-trapping carbon into the air in the form of carbon dioxide, then back into soils and the ocean.

EDIT

In the simulation, at least one ecosystem, the scrubby Arctic tundra largely vanishes as climate zones shift hundreds of miles north. Tundra would decline from about 8 percent of the world’s land area to 1.8 percent. Alaska, in the model, loses almost all of its evergreen boreal forests and becomes a largely temperate state. But vast stretches of land that were once locked beneath permanent ice cover would open up. The area locked beneath ice would diminish from 13.3 percent of the planet’s total land area to 4.8 percent. Conditions that nurture tropical and temperate forests could expand substantially, so that the two forest types could grow on nearly 65 percent of land surfaces instead of 44 percent now. But the pH of the oceans would fall because of a buildup of carbonic acid from dissolving carbon dioxide, eroding coral reefs and the shells of plankton and other marine life, Dr. Caldeira said.

EDIT

http://www.nytimes.com/2005/10/31/science/earth/01warm_web.html

[Boomer]

1. This makes it sound pleasant

Aside from the ocean damage (granted, a very large aside...) the other changes do not sound "threatening":

>> Tundra would decline from about 8 percent of the world’s land area to 1.8 percent. Alaska, in the model, loses almost all of its evergreen boreal forests and becomes a largely temperate state. But vast stretches of land that were once locked beneath permanent ice cover would open up. The area locked beneath ice would diminish from 13.3 percent of the planet’s total land area to 4.8 percent. Conditions that nurture tropical and temperate forests could expand substantially, so that the two forest types could grow on nearly 65 percent of land surfaces instead of 44 percent now. <<

So why would someone (such as Bush) be moved to a sense of urgency by this scenario?

[HereSince1628]

2. They clip doesn't mention increase in deserts and rise in sea-level

Increased volitility of weather, etc.

But you know all that CO2, plants need that, it's just like fertilizer ask any wingnut.

[htuttle]

4. Speaking of desertification...

Has anyone seen any projections for desertification over the next 50 years? That's been one of the factors I haven't seen much on.

I'd assume that most deserts will grow, but since precipitation patterns will also change, they may not grow everywhere. For example, I'm pretty sure I've read that North West Africa might end up getting more rain, rather than less if our models hold up (though it's likely that our models are still wrong on the specifics like that).

[phantom power]

5. I've read generic predictions that desertification will increase.

I can't recall any specific model predictions.

Although I think we must continue doing as much modeling as possible, I would agree that our current climate modeling capabilities are really up to the job. There are too many unknown factors that will play significant roles. Like this recent hoo-ha about methane releases from thawing permafrost. That could be huge, and clearly nobody was including it in their models. What other big gotchas are we unaware of? Whatever they turn out to be, we can't model it if we aren't aware of it.

[NNadir]

3. I wonder if Judith Miller has taken a position as environmental

correspondent at the NYT, having dones such a bang up job on war.

How exactly are the forests going to walk to these new temperate zones to take their 65%? Maybe they can fly on the backs of malaria mosquitos.

[hatrack]

6. Seed-carrying malarial mosquitoes, I trust

:eyes:

What I think this report conveys is between the lines. If we're talking about the loss of 90-odd percent of existing tundra terrains, then let's talk about what that entails:

Meltdown of huge stretches of Siberia, Scandinavia, Canada, Alaska;

Loss or replacement of most of the existing infrastructure across these territories: roads, pipelines, housing, airstrips, hospitals, etc and the concomitant effects on any humans living in these areas;

Release to the atmosphere of whatever methane, CO2 and other GHGs trapped in permafrost soils, frozen peat bogs, and boreal forests as they collapse and die;

And, as you noted, NN, these forests will spread to the north . . . how? They may eventually, assuming that they're not whipsawed in the process of moving ever-so-slowly towards the Pole by collapsing climate patterns, but it won't be in our lifetimes or in the lifetimes of anyone now alive or their children.