ScienceDaily, October 27, 2011
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Climate
scientists say the world's target to stay below a global warming of 2 degrees,
made at the United Nations conference in Copenhagen in 2009 and Cancun 2010
will require decisive action this decade.
A comprehensive
review of 193 emission scenarios from scientific literature to date has been
published in Nature Climate Change
by University of Melbourne and international scientists.
This study found
the target of 44 billion tons of carbon dioxide equivalent emissions (GtCO2eq)
by 2020 is a feasible milestone and an economically optimal approach for
countries to meet the internationally agreed 2 degree target.
Dr Malte
Meinshausen from the University of Melbourne's School of Earth Sciences and a
senior author on the study said the world is currently at 48 GtCO2eq and as
this research suggests, to reverse the growing emission trend this decade is
vital.
The study analysed
feasible emissions scenarios, which included a mix of mitigation actions
ranging from energy efficiency to carbon free technologies such as solar
photovoltaic, wind and biomass.
"Our study
revealed there are many emissions scenarios that are economically and
technologically feasible pathways to a 2 degree target, but that for countries
to get closer to this target they need to honour the higher end of their
pledges," he said.
Using a risk-based
climate model developed by Dr Meinshausen, an international team of scientists
led by Joeri Rogelj from ETH Zurich, Switzerland, analyzed how global
greenhouse gas emissions in 2020 can be managed with a long-term 2 degree
target.
By analysing the
emissions scenarios in the climate model, researchers were able to generate a
probabilistic projection of CO2 concentration in the atmosphere and global
temperature for the next hundred years.
And to determine in
particular, which scenarios provided the best possible chance of reaching the
global target of 2 degrees and moving to a zero carbon economy in the latter
half of the century.
"As long as we
keep emitting carbon dioxide, the climate will continue to warm. There is no
way around a zero carbon economy sooner or later if we want to stay below 2
degrees," Dr Meinshausen said.
A previous United
Nations Emissions Gap report in 2010 which summarised all comparable emissions
pledges by industrialized and developing countries, found 2020 emissions would
still rise well beyond 50 GtCO2eq.
By specifying the
level of 44 GtCO2eq, today's study suggests that countries' current pledges
made at Copenhagen and Cancun are insufficient to meet the economically optimal
milestone by 2020 to reach the 2 degree target.
In terms of
Australia, the Federal Government recently announced its emission trading
system to reduce its emissions by 5% to 25% below 2000 levels. Targeting the
500 top polluters is the cornerstone to the policy to achieve its 5% target.
"Our study
confirms that only by moving to the more ambitious end of the pledges, 25% in
the case of Australia, the world would be getting closer to being on track to
the 44 GtCO2eq, 2 degree milestone," he said.
"If the
international community is serious about avoiding dangerous climate change,
countries seem ill-advised by continuing to increase emissions, which they have
done so in the last ten years, which ultimately will lead to disastrous
consequences later on," he said.
"We can
anticipate Australia will be one of the countries hardest hit by climate change
due to recent years of droughts and floods. This is consistent with projections
that we are going to expect more of these kinds of extreme conditions in the
coming decades," he added.
"By our
calculations, the world needs to do more this decade, as otherwise the 2 degree
target to avert serious effects of climate change, is slipping out of
reach," he said.
Story Source:
The above story is reprinted from materials provided by University of Melbourne.Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- Joeri Rogelj, William Hare, Jason Lowe, Detlef P. van Vuuren, Keywan Riahi, Ben Matthews, Tatsuya Hanaoka, Kejun Jiang, Malte Meinshausen. Emission pathways consistent with a 2 °C global temperature limit. Nature Climate Change, 2011; 1 (8): 413 DOI:10.1038/nclimate1258
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