An international team of climate scientists has come up with a practical way to address the carbon squabbles that have dogged international climate negotiations.
They have developed a simple way for countries to calculate their emission targets under any global carbon sharing proposal. The method also gives insights into how one country’s targets impact others.
To meet a warming limit of two degrees Celsius, worldwide emissions need to be cut by more than five per cent per year, over the next several decades.
“These requirements are becoming very difficult,” says Professor Michael Raupach, from the Fenner School of the Environment and Society, who led the research.
"To share future total carbon emissions equally between all people, developed countries such as USA and Australia would have to reduce their carbon emission footprints at rates of over 15 per cent per year.
"At the other end of the scale, if both developed and developing nations continue to emit carbon at present rates, developing countries will not get access to a reasonable share of the remaining carbon quota.
"We need to find a sweet spot in the middle, and this approach assists in locating it," Professor Raupach said.
The team's results are published in Nature Climate Change, as part of a set of four papers reporting the current state of global carbon emissions and assessing future scenarios.
The papers come ahead of the United Nations Climate Summit of world leaders in New York on 23 September, which UN Secretary-General Ban Ki-moon hopes will lead to a global agreement in 2015 to cut carbon emissions and fight climate change.
At the 2009 Copenhagen meeting, world leaders reached a non-binding agreement to limit global warming to two degrees Celsius over the pre-industrial average, but they have yet to agree on tougher emissions targets and how the cuts will be shared between nations.
"We have about 30 years to clean up our act if we want to stay below a global warming of two degrees," Professor Raupach says.
"The keys to this approach are simplicity and transparency – you don't need a supercomputer."
Two decades of stalled climate negotiations have been frustrating, Professor Raupach adds.
"It's like responding to an illness by opting to ignore the diagnosis, and instead wait for a crisis. Ignoring climate change is both perilous and unnecessary - humanity has solved far harder problems than this in its history. We have the capacities to meet this challenge."
- Le Quéré et al. (2014) Global Carbon Budget 2014. Earth System Science Data Discussions (manuscript in discussions), http://dx.doi.org/10.5194/essdd-7-521-2014
- Friedlingstein et al. (2014) Persistent growth of CO2 emissions and implications for reaching climate targets. Nature Geoscience, http://dx.doi.org/10.1038/ngeo2248
- Raupach et al. (2014) Sharing a quota on cumulative carbon emissions. Nature Climate Change, http://www.nature.com/doifinder/10.1038/nclimate2384
- Fuss et al. (2014) Betting on Negative Emissions. Nature Climate Change (commentary)
- Data and figures: http://www.globalcarbonproject.org/carbonbudget
- Data interface for exploring data: http://www.globalcarbonatlas.org
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Twitter: #carbonbudget, @gcarbonproject