OSLO (Reuters) -
World powers are running out of time to slash their use of
high-polluting fossil fuels and stay below agreed limits on global
warming, a draft U.N. study to be approved this week shows.
It says nations will have to impose drastic curbs on their still rising greenhouse gas emissions to keep a promise made by almost 200 countries in 2010 to limit global warming to less than 2 degrees Celsius (3.6 Fahrenheit) over pre-industrial times.
Temperatures
have already risen by about 0.8 C (1.4F) since 1900 and are set to
breach the 2 C ceiling on current trends in coming decades, U.N. reports
show.
"The window is shutting
very rapidly on the 2 degrees target," said Johan Rockstrom, head of
the Stockholm Resilience Centre, and an expert on risks to the planet
from heatwaves, floods, droughts and rising seas.
"The debate is drifting to 'maybe we can adapt to 2 degrees,
maybe 3 or even 4'," Rockstrom, who was not among authors of the draft,
told Reuters.
Such rises would
sharply raise risks to food and water supplies and could trigger
irreversible damage, such as a meltdown of Greenland's ice, according to
U.N. reports.
The draft, seen
by Reuters, outlines ways to cut emissions and boost low-carbon energy,
which includes renewables such as wind, hydro- and solar power, nuclear
power and "clean" fossil fuels, whose carbon emissions are captured and
buried.
It said such low-carbon sources accounted for 17 percent
of the world's total energy supplies in 2010 and their share would have
to triple - to 51 percent - or quadruple by 2050, according to most
scenarios reviewed.That would displace high polluting fossil fuels as the world's main energy source by mid-century.
CARBON CAPTURE
Reports by the Intergovernmental Panel on Climate Change (IPCC), the group meeting in Berlin, will help governments, which aim to agree a deal to slow climate change at a Paris summit in December 2015. Few nations have outlined plans consistent with staying below 2 degrees C.
Another report by the IPCC last week in Japan showed warming already affects every continent and would damage food and water supplies and slow economic growth. It may already be having irreversible impacts on the Arctic and coral reefs.
The
new draft shows that getting on track to meet the 2C goal would mean
limiting greenhouse gas emissions to between 30 and 50 billion tonnes in
2030, a radical shift after a surge to 49 billion tonnes in 2010 from
38 billion in 1990.
The shift would reduce
economic output by between 2-6 percent by 2050, because of the costs of
building a cleaner energy system based on low-carbon energies that are
more expensive than abundant coal, the IPCC said. Capturing carbon
dioxide is also expensive, it added.
China and the United States are the top emitters.
One
option is to let temperatures overshoot the 2C target while developing
technology to cool the planet by extracting greenhouse gases from the
atmosphere, the draft says. The draft that would add to risks of warming
and push up costs.
Extracting
carbon from nature includes simple measures such as planting more
trees, which soak up carbon as they grow, or capturing and burying
greenhouse gases from electricity-generating plants that burn wood or
other plant matter.
"In
Europe there is no incentive" said Jonas Helseth, director of
environmental group Bellona Europe who chairs a group of scientists and
industry experts looking at burying emissions from renewable energy.
The
IPCC draft report is the third and final study in a U.N. series about
climate change, updating findings from 2007, after the Japan report
about the impacts and one in September in Sweden about climate science.
The
September report raised the probability that human actions, led by the
use of fossil fuels, are the main cause of climate change since 1950 to
at least 95 percent from 90. But opinion polls show voters are
unpersuaded, with many believing that natural variations are the main
cause.
(Reporting By Alister Doyle; Editing by Andrew Heavens)
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