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It's getting hot in here

Johann Hari

Published 02 April 2007

Six Degrees: our future on a hotter planet
Mark Lynas Fourth Estate, 358pp, £12.99
ISBN 0007209045

During the cold war, every person on earth knew what the worst endgame would look like: the three-minute warning, the futile scrambling under desks, and universal incineration. With the just-as-real, just-as-dangerous threat of global warming, there is a vague sense of doom, but no clear mental picture of what meltdown would look like - until now.

Mark Lynas is, along with George Monbiot and Bill McKibben, the best writer about global warming working today. In Six Degrees, he does something so obvious and so necessary it is hard to believe nobody has done it before. He pores through the peer-reviewed scientific literature and describes, calmly and plainly, what scientists say will happen on earth as each degree of global warming occurs.

One of the last jeers of the dwindling band of climate change "sceptics" is that a world that is six degrees warmer sounds rather nice, thank you very much. John Redwood, a leading figure in David Cameron's fake-green New Tories, wheeled this canard out only last month. At first glance, they're right: a warming of 1°C to 6°C - which is what the authoritative Intergovernmental Panel on Climate Change (IPCC) predicts - doesn't sound like much.

It is. Lynas talks us through the six degrees of separation between us and a planet we do not recognise and cannot survive on. Some 18,000 years ago, the world was six degrees cooler. It was an ice age. Most of England was a freezing polar desert where winter temperatures went as low as -40°C. There were almost no animals, and the only plants to be found were a few species of lichens and mosses. It was possible to walk to France across the channel. No agriculture was possible, because the climate fluctuated too wildly. So what happens as we move in the opposite direction, up to six degrees warmer?

With just one degree of warming, here's what happens: the Great Barrier Reef bleaches and dies, the Greenland ice sheet melts, the Maldives and many islands in the South Pacific disappear beneath the waves, rockfalls from the Alps multiply as the mountains melt, the seasonal rainfalls in sub-Saharan Africa change leaving millions at risk of drought and famine, and hurricanes start to hit Brazil for the first time in millennia. One degree.

At three degrees, the Amazon rainforest - the planet's lungs - will die. Lynas explains: "The trees in the Amazon are used to constant humidity, and have no resistance to fire." Once the humidity dries out, so does the forest. They will burn and turn to ash.

And at six degrees - the IPCC's higher-end predictions for this century - humanity enters its endgame. "An entirely new planet comes into being - one unrecognisable from the Earth we know today," Lynas writes. The rainforests are gone, the world's ice supplies are only a memory, the seas are encroaching, and inland cities see temperatures ten degrees higher than today. In the world's major crop-growing areas - India, Australia, the inland United States - most crops are dying, and mass starvation is a perennial risk.

It becomes likely that the vast stores of methane lodged on sub-ocean shelves will bubble to the surface. Since methane is highly flammable, these could quickly be sparked - by lightning, or through human action - into vast fireballs tearing across the sky. The chemical engineer Gregory Ryskin calculates that this methane "could destroy terrestrial life almost entirely", with a major oceanic methane eruption having a force 10,000 times greater than the world's stockpiles of nuclear weapons.

The planet has been here before. Geologists have discovered that at the end of the Permian period, 251 million years ago, the world warmed rapidly by six degrees. It was the worst crisis ever endured by life on earth, "the closest this planet has come to losing its wonderful living biosphere entirely and ending up a dead and desolate rock in space". The earth was racked by "hypercanes" - hurricanes so strong they even left their mark on the ocean floor. Oxygen levels in the atmosphere plunged to 15 per cent - low enough to leave any fast-moving animal gasping for breath.

The only survivors were a few shelled creatures in the oceans, and a pig-like creature that had the land to itself for millions of years. (Whoever thought geological findings could give you nightmares?)

Six Degrees will make some readers want to sink into survivalism, but Lynas wisely warns: "Getting depressed about the situation now is like sitting inert in your living room and watching the kitchen catch fire, and then getting more and more miserable as the fire spreads throughout the house - rather than grabbing an extinguisher and dousing the flames."

Buy this book for everyone you know: if it makes them join the fight to stop the seemingly inexorable six degrees of warming and mass death, it might just save their lives.

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8 comments from readers

penny
13 April 2007 at 00:12

It is NOT the small change in average yearly temperature worldwide that would matter, but the large change in variance

of temperature both over time and geography. That is predicted by the same models that predict a rising temperature.

Higher average temp implies greater oscillation of the complex system, and thus of the temperature.

But, not to worry, Climate is a classic example of a chaotic system ( proved as a theorem) and this means that :

1) all these computer models are WORTHLESS as predictors.

2) Even if it got hotter and hotter, that doesn't mean it would cool down--perhaps violently--that can't be ruled out by ANY COMPUTATIONAL MODEL. In fact, it actually happened in the middle of the 11th century.

Finally, science is not about " What the majority of climate scientists believe". It is about TRUTH.

penny
13 April 2007 at 00:13

Mistype, I meant to type " Ththat doesn't mean it WOULD NOT cool down."

Penny

penny
13 April 2007 at 00:25

To make the concept of variance a bit clearer to a non-expert consider two students who have a test score average of 50 out of 100.

The first has 100 exam grades clustering within 10 points of 50. But, the second has

( large variance) 100 exam grades---many with a score of over 90 and many with a score of under 10. But, both are assumed to have the same average score of 50.

Thus, in a warmer world, some places may have much higher temps if others have much lower temps--and the average can be only six degrees higher, if the average is over the whole world.

Moreover, at some locations, the yearly temperatures at the location might vary greatly over a year.

This is---in fact-- what is predicted.

Penny

mrossmassler
18 April 2007 at 17:03

Re: penny's comments on an effective article - I am interested by all the additional details and comparisons, but in the end, I am completely confused by the last three comments. Do we abandon the "worthless" models and wait to find out what we should have done at some later time? In a chaotic system, is human safety increased by abandoning attempts at prediction? Are the permutations of temperature possibilities less dangerous than the simple rise in average temperature? Should we drop the subject because the TRUTH hasn't yet shown up? I think the article is about risk and wisdom, not only about science.

penny
19 April 2007 at 14:27

In response: Yes, ALL models are useless by the theorem. We cannot predict. We cannot determine what the best actions would be. Choices that seem sensible could lead to the worst outcomes.

Not everything can be predicted by mathematical models--NO MATTER HOW MUCH ONE WANTS THAT, OR NEEDS IT.

We should stop wasting resources on these climate models. We should INSTEAD focus our resources on preparing for the possibility of BAD climate and developing the technology to meet it.

Penny

penny
19 April 2007 at 14:30

In response to the question: Yes, the perturbations in temperature over geography are MUCH more dangerous than a mere six degree rise in temperature.

If the temperature at every point on the earth's surface rose six degrees, it would hardly effect anything.

But, that is not what tends to happen.

Penny

penny
19 April 2007 at 14:36

In a chaotic system, proved chaotic, attempts at numerical prediction are absolutely worthless. The resources used are just wasted.

Penny

And so is the "Historical measurement of data". It could be getting warmer and warmer and then by chaos one day it could just suddenly go into ice age mode.

In fact, this is what happened in the 11th century and it lasted for four hundred years.

What we did was change our heating technology, our crops, and our living modes to cope--as we did in the worse ice ages of the paleolithic period.

Penny

That is what the math says.

We may not like it, but we have no Choice.

Penny

Mark Sinclair-McGarvie
01 May 2007 at 23:34

Great article Johann.

I've read the book and I'm doing exactly what you suggest: buying the book for everyone I know.

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