Hotter, Faster, Worser

[Guest guest]

Hotter, Faster, Worser

by John Atcheson

 

 

Over the past several months, the normally restrained voice of science

has taken on a distinct note of panic when it comes to global warming.

 

How did we go from debating the " uncertainty " behind climate science to

near hysterical warnings from normally sober scientists about

irrevocable and catastrophic consequences? Two reasons.

 

First, there hasn't been any real uncertainty in the scientific

community for more than a decade. An unholy alliance of key fossil fuel

corporations and conservative politicians have waged a sophisticated and

well-funded misinformation campaign to create doubt and controversy in

the face of nearly universal scientific consensus. In this, they were

aided and abetted by a press which loved controversy more than truth,

and by the Bush administration, which has systematically tried to

distort the science and silence and intimidate government scientists who

sought to speak out on global warming.

 

But the second reason is that the scientific community failed to

adequately anticipate and model several positive feedback loops that

profoundly amplify the rate and extent of human-induced climate change.

And in the case of global warming, positive feedback loops can have some

very negative consequences. The plain fact is, we are fast approaching –

and perhaps well past – several tipping points which would make global

warming irreversible.

 

In an editorial in the Baltimore Sun on December 15th, 2004 this author

outlined one such tipping point: a self-reinforcing feedback loop in

which higher temperatures caused methane – a powerful heat-trapping

greenhouse gas (GHG) – to escape from ice-like structures called

clathrates, which raised the temperature which caused more methane to be

released and so on. Even though there was strong evidence that this

mechanism had contributed to at least two extreme warming events in the

geologic past, the scientific community hadn't yet focused on methane

ices in 2004. Even among the few pessimists who had, we believed – or

hoped – that we had a decade or so before anything like it began

happening again.

 

We were wrong.

 

In August of 2005 a team of scientists from Oxford and Tomsk University

in Russia announced that a massive Siberian peat bog the size of Germany

and France combined was melting, releasing billions of tons of methane

as it did.

 

The last time it got warm enough to set off this feedback loop was 55

million years ago in a period known as the Paleocene-Eocene Thermal

Maximum or PETM, when increased volcanic activity released enough GHGs

to trigger a series of self-reinforcing methane burps. The resulting

warming caused massive die-offs and it took more than a 100,000 years

for the earth to recover.

 

It's looks like we're on the verge of triggering a far worse event. At a

recent meeting of the American Academy for the Advancement of Sciences

in St. Louis, James Zachos, foremost expert on the PETM reported that

greenhouse gasses are accumulating in the atmosphere at thirty times the

speed with which they did during the PETM.

 

We may have just witnessed the first salvo in what could prove to be an

irreversible trip to hell on earth.

 

There are other positive feedback loops we've failed to anticipate. For

example, the heat wave in Europe that killed 35,000 people in 2003 also

damaged European woodlands, causing them to release more carbon dioxide,

the main GHG, than they sequester – exactly the opposite of the

assumptions built into our models, which treat forests as sponges that

sop up excess carbon.

 

The same thing is happening to a number of other ecosystems that our

models and scientists have treated as carbon sinks. The Amazon

rainforest, the boreal forests (one of the largest terrestrial carbon

sinks in the planet), and soils in temperate areas are all releasing

more carbon than they are absorbing, due to global warming-induced

droughts, diseases, pest activity, and metabolic changes. In short, many

of the things we treat as carbon sponges in our models aren't sopping up

excess carbon; they're being wrung out and releasing extra carbon.

 

The polar ice cap is also melting far faster than models predict,

setting off another feedback loop. Less ice means more open water, which

absorbs more heat which means less ice, and so on.

 

Even worse, we've substantially underestimated the rate at which

continental glaciers are melting.

 

Climate change models predicted that it would take more than 1,000 years

for Greenland's ice sheet to melt. But at the AAAS meeting in St. Louis,

NASA's Eric Rignot outlined the results of a study that shows

Greenland's ice cover is breaking apart and flowing into the sea at

rates far in excess of anything scientists predicted, and it's

accelerating each year. If (or when) Greenland's ice cover melts, it

will raise sea levels by 21 feet – enough to inundate nearly every sea

port in America.

 

In the Antarctic seas, another potentially devastating feedback loop is

taking place. Populations of krill have plummeted by 80% in the last few

years due to loss of sea ice. Krill are the single most important

species in the marine foodchain, and they also extract massive amounts

of carbon out of the atmosphere. No one predicted their demise, but the

ramifications for both global warming and the health of marine

ecosystems are disastrous. This, too, will likely feed on itself, as

less krill means more carbon stays in the atmosphere, which means warmer

seas, which means less ice, which means less krill and so on in a

massive negative spiral.

 

One of our preeminent planetary scientists, James Lovelock, believes

that in the not too distant future humans will be restricted to a

relatively few breeding pairs in Antarctica. It would be comfortable to

dismiss Professor Lovelock as a doom and gloom crazy, but that would be

a mistake. A little over a year ago at the conclusion of a global

conference in Exeter England on Avoiding Dangerous Climate Change,

scientists warned that if we allowed atmospheric concentrations of GHG

to exceed 400 ppm, we could trigger serious and irreversible

consequences. We passed that milestone in 2005 with little notice and no

fanfare.

 

The scientific uncertainty in global warming isn't about whether it's

occurring or whether it's caused by human activity, or even if it will

" cost " us too much to deal with it now. That's all been settled.

Scientists are now debating whether it's too late to prevent planetary

devastation, or whether we have yet a small window to forestall the

worst effects of global warming.

 

Our children may forgive us the debts we're passing on to them, they may

forgive us if terrorism persists, they may forgive us for waging war

instead of pursuing peace, they may even forgive us for squandering the

opportunity to put the nuclear genie back in the bottle. But they will

spit on our bones and curse our names if we pass on a world that is

barely habitable when it was in our power to prevent it.

 

And they will be right to do so.

 

John Atcheson's writing has appeared in the Washington Post, the

Baltimore Sun, the San Jose Mercury News, the Memphis Commercial Appeal,

as well as in several wonk journals. Email to: atchman

 

 

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