Scientists look at new evidence that climate change is accelerating
UNEP's 2009 Year Book is in part confirming the concerns of 2,000 scientists meeting this week in Copenhagen over the accelerating pace of climate change.
Nairobi, 10 March 2009 – The UN Environment Programme's 2009 Year Book is in part confirming the concerns of 2,000 scientists meeting this week in Copenhagen over the accelerating pace of climate change.
The meeting on 10-12 March, which takes place nine months before the major UN climate change talks in Copenhagen, will see the scientists look at new evidence that global warming is accelerating even faster than had been forecast by the International Panel on Climate Change (IPCC).
The 2009 UNEP Year Book, produced on behalf of the world's Environment Ministers, was launched in February at the UNEP Governing Council. As pointed out in the Year Book, the IPCC had estimated that sea levels might rise by between 18cm and 59cm in the coming century – but many researchers now believe the rise will be even higher in part as a result of new assessments of ice sheets in Greenland and Antarctica.
One study now estimates a sea level rise of between 0.8 and 1.5 metres, while another suggests a sea level rise of two metres in the coming century from outflows of ice from Greenland alone.
A one-metre rise in sea levels world-wide would displace millions of people. Around 100 million people in Asia, mostly Bangladesh, eastern China and Vietnam; 14 million in Europe and eight million each in Africa and South America.
2008 had the second smallest area of Arctic sea-ice left following the summer thaw since satellite monitoring began in 1979. The National Snow and Ice Center in the United States found that the minimum sea-ice cover, which occurred on 12 September, was somewhere over 4.52 million square kilometers.
"While 2008 saw 10 per cent more ice cover than in 2007, the lowest figure on record, it was still more than 30 per cent below the average for the past three decades. Taken together, the two summers have no parallel," says the Year Book.
• For the second year in a row, there was an ice-free channel in the Northwest Passage through the islands of northern Canada.
• 2008 also witnessed the opening of the Northern Sea Route along the Arctic Siberian coast-the two passages have probably not been open simultaneously since before the last ice age some 100,000 years ago.
• The Greenland ice sheet, which could raise sea levels by six metres if it melted away, is currently losing more than 100 cubic km a year-faster than can be explained by natural melting.
• Losses from the West Antarctic ice sheet have increased by 60 per cent between 1996 and 2006, while losses from the Antarctic Peninsula increased by 140 per cent.
The Year Book argues that urgent action is needed to curb greenhouse gas emissions, not least because some of the natural carbon storage systems or 'sinks' may be losing their absorption capacity raising the spectre of a runaway greenhouse effect. Studies in 2008 indicates that one key 'sink'-the oceans-are now soaking up 10 million tones less C02.
The Year Book also flags up increasing concern among scientists about releases of greenhouse gases such as methane from the Arctic as ice melts and permafrost thaws in part as a result of new studies indicating that the western Arctic is warming 3.5 times more than the rest of the globe. This concern has taken on even greater importance as a result of two recently published studies.
• A study focusing on North America suggests that upwards of 60 per cent more carbon could be stored in the permafrost than previously supposed.
• An international study has now doubled the amount of soil-carbon in the permafrost across the entire Arctic.
• Marine researchers have discovered more than 250 plumes of methane bubbling up along the edge of the Continental shelf northwest of Svalbard.
• The International Siberian Shelf Study has found higher concentrations of methane offshore from the Lena River delta.
• Researchers calculate that, once underway, thawing of the east Siberian permafrost – thought to contain 500 billion tones of carbon – would be irreversible and that over a century 250 billion tones could be released.
Monitoring of methane levels in the atmosphere indicates that concentrations rose in 2007 and 2008 after nearly a decade of stability. Intriguingly higher concentrations were detected in both the northern and southern hemispheres.
Meanwhile, the Year Book raises concerns over another carbon sink – forests. Rising temperatures may be stressing trees leading to photosynthesis and thus carbon sequestration halting sooner in summer months. Stressed forests may also be more vulnerable to pollution, disease and pests, again undermining their carbon storage potential.