[URBANTH-L]global warming - the point of no return

[Angela Jancius]

Countdown to global catastrophe
Climate change: report warns point of no return may be reached in 10 
years, leading to droughts, agricultural failure and water shortages
By Michael McCarthy, Environment Editor

24 January 2005

The global warming danger threshold for the world is clearly marked for 
the first time in an international report to be published tomorrow - and 
the bad news is, the world has nearly reached it already.

The countdown to climate-change catastrophe is spelt out by a task force 
of senior politicians, business leaders and academics from around the 
world - and it is remarkably brief. In as little as 10 years, or even 
less, their report indicates, the point of no return with global warming 
may have been reached.

The report, Meeting The Climate Challenge, is aimed at policymakers in 
every country, from national leaders down. It has been timed to coincide 
with Tony Blair's promised efforts to advance climate change policy in 
2005 as chairman of both the G8 group of rich countries and the European 
Union.

And it breaks new ground by putting a figure - for the first time in 
such a high-level document - on the danger point of global warming, that 
is, the temperature rise beyond which the world would be irretrievably 
committed to disastrous changes. These could include widespread 
agricultural failure, water shortages and major droughts, increased 
disease, sea-level rise and the death of forests - with the added 
possibility of abrupt catastrophic events such as "runaway" global 
warming, the melting of the Greenland ice sheet, or the switching-off of 
the Gulf Stream.

The report says this point will be two degrees centigrade above the 
average world temperature prevailing in 1750 before the industrial 
revolution, when human activities - mainly the production of waste gases 
such as carbon dioxide (CO2), which retain the sun's heat in the 
atmosphere - first started to affect the climate. But it points out that 
global average temperature has already risen by 0.8 degrees since then, 
with more rises already in the pipeline - so the world has little more 
than a single degree of temperature latitude before the crucial point is 
reached.

More ominously still, it assesses the concentration of carbon dioxide in 
the atmosphere after which the two-degree rise will become inevitable, 
and says it will be 400 parts per million by volume (ppm) of CO2.

The current level is 379ppm, and rising by more than 2ppm annually - so 
it is likely that the vital 400ppm threshold will be crossed in just 10 
years' time, or even less (although the two-degree temperature rise 
might take longer to come into effect).

"There is an ecological timebomb ticking away," said Stephen Byers, the 
former transport secretary, who co-chaired the task force that produced 
the report with the US Republican senator Olympia Snowe. It was 
assembled by the Institute for Public Policy Research in the UK, the 
Centre for American Progress in the US, and The Australia Institute.The 
group's chief scientific adviser is Dr Rakendra Pachauri, chairman of 
the UN's Intergovernmental Panel on Climate Change.

The report urges all the G8 countries to agree to generate a quarter of 
their electricity from renewable sources by 2025, and to double their 
research spending on low-carbon energy technologies by 2010. It also 
calls on the G8 to form a climate group with leading developing nations 
such as India and China, which have big and growing CO2 emissions.

"What this underscores is that it's what we invest in now and in the 
next 20 years that will deliver a stable climate, not what we do in the 
middle of the century or later," said Tom Burke, a former government 
adviser on green issues who now advises business.

The report starkly spells out the likely consequences of exceeding the 
threshold. "Beyond the 2 degrees C level, the risks to human societies 
and ecosystems grow significantly," it says.

"It is likely, for example, that average-temperature increases larger 
than this will entail substantial agricultural losses, greatly increased 
numbers of people at risk of water shortages, and widespread adverse 
health impacts. [They] could also imperil a very high proportion of the 
world's coral reefs and cause irreversible damage to important 
terrestrial ecosystems, including the Amazon rainforest."

It goes on: "Above the 2 degrees level, the risks of abrupt, 
accelerated, or runaway climate change also increase. The possibilities 
include reaching climatic tipping points leading, for example, to the 
loss of the West Antarctic and Greenland ice sheets (which, between 
them, could raise sea level more than 10 metres over the space of a few 
centuries), the shutdown of the thermohaline ocean circulation (and, 
with it, the Gulf Stream), and the transformation of the planet's 
forests and soils from a net sink of carbon to a net source of carbon."