May 9th, 2011

Lovelock: 'We are past the point of no return'

The world has already passed the point of no return for climate change, and civilisation as we know it is now unlikely to survive, according to James Lovelock, the scientist and green guru who conceived the idea of Gaia - the Earth which keeps itself fit for life.

In a profoundly pessimistic new assessment, published in today's Independent, Professor Lovelock suggests that efforts to counter global warming cannot succeed, and that, in effect, it is already too late.

The world and human society face disaster to a worse extent, and on a faster timescale, than almost anybody realises.

He writes: " Before this century is over, billions of us will die, and the few breeding pairs of people that survive will be in the Arctic where the climate remains tolerable."

http://www.energybulletin.net/node/12126

The Venus Syndrome

Earth is Goldilock’s choice among the planets, the one that is just right for life to exist. Not too hot. Not too cold.

How does the Earth manage to stay in this habitable range? Is there a Gaia phenomenon keeping the climate in bounds? A nice idea, but it doesn’t work.

The Earth’s climate becomes more sensitive as it becomes very cold, when an amplifying feedback, the surface albedo, can cause a runaway snowball Earth, with ice and snow forming all the way to the equator.

If the planet gets too warm, the water vapor feedback can cause a runaway greenhouse effect. The ocean boils into the atmosphere and life is extinguished.

The Earth has fell off the wagon several times in the cold direction, ice and snow reaching all the way to the equator. Earth can escape from snowball conditions because weathering slows down, and CO2 accumulates in the air until there is enough to melt the ice and snow rapidly, as the feedbacks work in the opposite direction. The last snowball Earth occurred about 640 million years ago.

Now the danger that we face is the Venus syndrome. There is no escape from the Venus Syndrome. Venus will never have oceans again.

Given the solar constant that we have today, how large a forcing must be maintained to cause runaway global warming? Our model blows up before the oceans boil, but it suggests that perhaps runaway conditions could occur with added forcing as small as 10-20 W/m2.

There may have been times in the Earth’s history when CO2 was as high as 4000 ppm without causing a runaway greenhouse effect. But the solar irradiance was less at that time.

What is different about the human-made forcing is the rapidity at which we are increasing it, on the time scale of a century or a few centuries. It does not provide enough time for negative feedbacks, such as changes in the weathering rate, to be a major factor.

There is also a danger that humans could cause the release of methane hydrates, perhaps more rapidly than in some of the cases in the geologic record.

In my opinion, if we burn all the coal, there is a good chance that we will initiate the runaway greenhouse effect. If we also burn the tar sands and tar shale (a.k.a. oil shale), I think it is a dead certainty.
That would be the ultimate Faustian bargain. Mephistopheles would carry off shrieking not only the robber barons, but, unfortunately and permanently, all life on the planet.

http://www.columbia.edu/~jeh1/2008/AGUBjerknes_20081217.pdf

Too Late

At a high-level academic conference on global warming at Exeter University this summer, climate scientist Kevin Anderson stood before his expert audience and contemplated a strange feeling. He wanted to be wrong. Many of those in the room who knew what he was about to say felt the same. His conclusions had already caused a stir in scientific and political circles. Even committed green campaigners said the implications left them terrified.

The battle against dangerous climate change had been lost, and the world needed to prepare for things to get very, very bad.

"As an academic I wanted to be told that it was a very good piece of work and that the conclusions were sound," Anderson said. "But as a human being I desperately wanted someone to point out a mistake, and to tell me we had got it completely wrong."

Nobody did. The cream of the UK climate science community sat in stunned silence as Anderson pointed out that carbon emissions since 2000 have risen much faster than anyone thought possible, driven mainly by the coal-fuelled economic boom in the developing world.

The escalating scale of human emissions could not have come at a worst time, as scientists have discovered that the Earth's forests and oceans could be losing their ability to soak up carbon pollution.

The Southern Ocean's ability to absorb carbon dioxide has weakened by about 15% a decade since 1981, while in the North Atlantic, scientists at the University of East Anglia also found a dramatic decline in the CO2 sink between the mid-1990s and mid-2000s.

A separate study published this year showed the ability of forests to soak up anthropogenic carbon dioxide - that caused by human activity - was weakening, because the changing length of the seasons alters the time when trees switch from being a sink of carbon to a source.

Soils could also be giving up their carbon stores: evidence emerged in 2005 that a vast expanse of western Siberia was undergoing an unprecedented thaw.

The region, the largest frozen peat bog in the world, had begun to melt for the first time since it formed 11,000 years ago. Scientists believe the bog could begin to release billions of tonnes of methane locked up in the soils, a greenhouse gas 20 times more potent than carbon dioxide.

Bob Watson, chief scientist at the Environment Department and a former head of the IPCC, warned this year that the world needed to prepare for a 4C rise, which would wipe out hundreds of species, bring extreme food and water shortages in vulnerable countries and cause floods that would displace hundreds of millions of people. Warming would be much more severe towards the poles, which could accelerate melting of the Greenland and West Antarctic ice sheets.

Watson said: "We must alert everybody that at the moment we're at the very top end of the worst case scenario."

http://www.guardian.co.uk/environment/2008/dec/09/poznan-copenhagen-global-warming-targets-climate-change