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Thursday, Nov 25, 2004

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Need to act on climate change

By David King

Steps must be taken fast if climate change is to be tackled.

NEW EVIDENCE is emerging on almost a weekly basis to link rises in man-made carbon dioxide in the atmosphere with the real and immediate threat that global climate change presents to our environment, people and communities.

Earlier this year, scientists published a study in the journal Nature that indicated that many plant and animal species are unlikely to survive climate change. Their analyses suggest that 15-37 per cent of a sample of 1,103 land plants and animals would eventually become extinct as a result of climate changes expected by 2050.

And earlier this month, 300 scientists contributing to the Arctic climate impacts assessment warned that Arctic temperatures have risen by almost twice the global average over the past 50 years. This increase looks set to continue, with a further rise of between 4C and 7C possible by 2100.

The rise in Arctic temperatures is already impacting heavily on people and wildlife. Buildings from Russia to Canada have collapsed because of subsidence linked to thawing permafrost, and mammals such as polar bears and seals have been affected.

We know that the global temperature has now risen by between 0.6C and 0.7C over the past century. Globally, the 1990s were the hottest decade, and 1998 was the hottest year since our records began in 1861. Moreover, the seven hottest years since 1861 all fell in the 1990s.

Around the world, glaciers are thinning and in retreat and sea levels are rising. During the 20th century, the sea level rose by 10cm to 20cm, and global snow cover has diminished by 10 per cent since the 1960s.

Carbon dioxide levels are at their highest ever and set to increase. Natural effects alone, such as El Nino, could not have caused that increase. It is a result of man's action in burning up reserves of carbon at a rate that has never been exceeded before. The atmospheric concentration of carbon dioxide has risen by almost 30 per cent since the Industrial Revolution. Both the current concentration of about 379 parts per million (ppm) — compared with 280ppm in the pre-industrial era — and the current rate of increase of approximately 2ppm annually, are the highest since the last ice age. The planet has not experienced comparable concentrations for at least 740,000 years — and probably for many millions of years.

The Greenland ice sheet was retreating at a rate of around one metre a year in 2001, according to a NASA study. The latest study indicates it is moving back at about 10 metres a year. If the Greenland ice sheet were to melt, the sea level would rise by between six and seven metres. That would create a major problem for coastal cities.

More intense rainfall events are expected to be a feature of climate change. In 2002, severe floods in Europe caused 37 deaths and had an estimated direct cost of $16billion. According to the Association of British Insurers, 2000 was the wettest U.K. autumn for almost 300 years, with heavy rainfall leading to damage to 10,000 properties and nearly £1 billion in insurance claims.

During the heat wave of 2003, 14,000 people died in France, while the death toll across Europe reached 30,000. This was the worst natural disaster in Europe in 50 years. Statistical analyses show, with 90 per cent certainty, that roughly half of the severity of this hot summer can be attributed to global warming.

It is essential that we act now to mitigate these effects. However, further climate change over the next two to three decades is inevitable, due to past and present carbon dioxide emissions. We must also, therefore, adapt to ensure that we can manage the additional risks associated with these impacts.

The good news is that we now understand what is happening and therefore what we must do to address this. Global action to reduce carbon emissions is the key. Put simply, we must radically reduce the amount of greenhouse gases we produce (mainly carbon dioxide generated through mankind's use of fossil fuels) an dexplore other possible alternatives such as renewables, hydrogen and fusion.

There is as yet no consensus on what constitutes dangerous climate change, or at what level greenhouse gas concentrations should be stabilised to avoid it. In 1997, the European Union supported the case for limiting temperature rise to no more than 2C above pre-industrial levels, and a target level of lower than 550ppm of CO2 in the atmosphere, which is about twice the pre-industrial concentration. More recent research, however, has suggested that a level as low as 450ppm to 500ppm of CO2 may be needed to meet a 2C limit.

The recent approval of the Kyoto protocol by Russia will do much to re-invigorate the international climate change process. Ratification of Kyoto presents a raft of business opportunities and an unprecedented opportunity to accelerate the move to a low carbon economy. It will also provide a platform for the U.K. and the E.U. to lead by example.

The time is right for action, and it must be taken quickly. We have the technologies to deal with this — or the scope to develop them. Action is affordable. Inaction is not. — © Guardian Newspapers Limited 2004

(Sir David King is scientific adviser to the U.K. Government.)

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