Global Trends by Martin Khor

Monday 16 March 2009

New grim findings on global warming

Last week’s gathering of 2,000 scientists found the climate change situation much worse than previously reported.  They called on politicians act quickly and decisively.


With the world in economic recession, there is a temptation to downgrade or sideline the climate change. That would be a great mistake. 

However serious is the recession, the effects of the climate change crisis will be even more devastating and long lasting.

Last week, 2,500 scientists met in Copenhagen and issued a grim warning that the climate situation is far worse than what had been depicted in 2007 by the United Nations’ inter-governmental panel on climate change (IPCC).

They said that global warming is increasing beyond the worst forecasts, threatening to trigger irreversible shifts on the Earth’s environment, and resulting in social conflict and war in much of the world.

In a statement addressed to politicians, scientists warned that:  "The worst-case IPCC scenario trajectories (or even worse) are being realized…There is a significant risk that many of the trends will accelerate, leading to an increasing risk of abrupt or irreversible climatic shifts."

One example is that the IPCC predicted the sea level would rise by 7 to 23 inches by the end of the century.  But recent research showed that the rise could be 20 to 39 inches.

The rising sea level is caused by the melting of glaciers and ice sheets, and the effect is to flood coastal areas, causing millions of people to move from their homes and lands.

Warning that “dangerous climate change” is imminent, the statement said there is “no excuse for inaction” and that weak and ineffective governments must stand up to big business and vested interests.

The British economist, Lord Nicholas Stern, who in 2006 wrote a famous book on the economics of climate change, said his report had under-estimated the risks of global warming.

“The reason is that emissions are growing faster than we thought, the absorption capacity of the planet is less than we thought, the probability of high temperatures is likely higher than we thought, and some of the effects are coming faster than we thought,” he said.

The effects will be devastating unless politicians grasped the gravity of the situation, added Stern.  The most talked about scenario is for the average global temperature to rise by 2 to 3 or 4 degrees Celsius by the end of this century (compared to pre-industrial levels).

But Stern warned that a 6 degree rise is an increasing possibility.  That could mean massive rises in sea levels, whole areas devastated by hurricanes and others turned into desert, forcing billions of people to leave their homes.

Much of southern Europe would look like the Sahara, many of the world’s major rivers would dry up in the dry season or re-route, Stern added.  Hundreds of millions or probably billions would have to move, and the implications of that is “extended conflict, social disruption, war essentially, over much of the world for many decades.”

The conference heard that much of the Amazon rainforest may already be doomed. A study by the Hadley Centre of Britain showed that even a rise of just 2 degrees Celsius (above pre-industrial levels) could cause 20-40% of the forest to die in the next hundred years.

But this horror story is from the best scenario, that global emissions will peak in 2015 and then decrease significantly from then, while in fact emissions are presently still rising.

A temperature rise of 3 degrees would see drought destroy 75% of the forest, and a 4 degree rise would kill 85%, according to a Guardian report of the paper.  The loss of the Amazon would in turn have a catastrophic effect on the climate.

Another study showed that global warming may be converting tropical forests from net carbon sinks (that absorb carbon) to net carbon emitters.  Rising levels of CO2 in the atmosphere increase the growth of trees but also cause trees to die younger, and this reduces the carbon storage capacity of the rainforests.

According to a Guardian report, Australian scientist David Hilbert estimated that each degree of temperature rise will result in 14 tonnes of carbon emissions per hectare of rainforest, equating to 24.5 gigatonnes of carbon worldwide, or two and a half times the world carbon emissions in 2007.

At a warming rate of 0.05 degree per year, forests will produce 1.2 gigatonne a year of carbon, more than they are currently absorbing as a sink (about 1 gigatonne a year).

The Copenhagen meeting also heard other scientific findings showing why the climate situation is worse than that depicted by the IPCC’s 2007 reports. The Guardian columnist George Monbiot reported the following: 

     •  Partly because the IPCC estimates took no account of meltwater from Greenland's glaciers, the rise in sea levels this century could be two or three times as great as it forecast, with grave implications for coastal cities, farmland and freshwater reserves.

    • Two degrees of warming in the Arctic could trigger a massive bacterial response in the soils there. As the permafrost melts, bacteria are able to start breaking down organic material that was previously locked up in ice, producing billions of tonnes of carbon dioxide and methane. This could catalyse one of the world's most powerful positive feedback loops, with warming causing more warming.

Perhaps the most bitter-sweet report from Copenhagen was the “good news” that the current world recession could cause the greenhouse gas emissions by 40 to 50 per cent, according to an estimate by Terry Barker, director of the Centre for Climate Change Mitigation Research at Cambridge University.

The world should cut emissions very steeply.  But this should be done in a planned way that minimises economic disruption.  Having the global recession to do the job of cutting emissions is the wrong way, and hopefully it does not prove to be the only way.