If a major economy takes the lead, warming could be limited to 2 C, researchers say

October 26, 2015
An interactive website provides maps, figures, and results for all G20 countries. Credit: mitigation-contributions.org

Though most countries around the globe agree that warming must be limited to 2 degrees Celsius to avoid the raft of climate risks, they clash about who should do what to reach this target. Hence the issue of allocating greenhouse-gas emissions reductions will be key for the outcome of the world climate summit COP21 in Paris. Scientists now found what amount of emissions reductions it takes for a major economy to lead out of the climate gridlock. They conclude that effectively limiting climate change is possible if a major economy acts as a forerunner, while other nations follow and, importantly, by doing so they do not have to agree on common criteria for fairness.

"If either the European Union or the US would pioneer and set a benchmark for climate action by others, the negotiation logjam about fair burden sharing could be broken," lead author Malte Meinshausen from the Potsdam Institute for Climate Impact Research and the University of Melbourne says. "Our analysis shows that they would have to roughly double their current domestic 2030 emissions reductions targets, which would certainly require substantial efforts. Yet it seems to be one of the few options to stay on track for eventually limiting warming below 2°C and fend off a drastic increase of weather extremes and sea-level rise."

Two conflicting fairness criteria must be dealt with

While the UN Climate Change Convention holds up the formula of 'common but differentiated responsibility', the world is currently divided - simply speaking - into two main camps. One is in favor of distributive justice at some point in the future: emissions per person would be roughly the same in every country by 2050. This includes the EU and the US. The other camp, with China and India, calls for corrective justice: the emissions of the past should be taken into account to achieve equal cumulative emissions per person. This kind of fairness scheme would mean that those that emitted less in the past can emit more in the future on a per-capita basis.

Analyses of emissions reduction pledges and past negotiations show that, unsurprisingly, countries tend to adhere to the allocation principle which allows them to least reduce emissions, compared to their international competitors. Since China and India industrialized only recently, in the past they emitted less than the EU and the US did. Yet today China emits more than the EU and US combined on an absolute basis, and about the same as the EU on a per-capita basis.

"This seems less utopian than a uniform regulation"

"Now we have calculated how much a major economy would have to cut its greenhouse gas output if all the other countries would follow the emissions allocation scheme that is most favourable to them, so some base their reduction number on the equal per capita scheme, others include the historical emissions, and still the 2-degree limit is met," says co-author Louise Jeffery from the Potsdam Institute. The scientists call this concept diversity-aware leadership. "This seems less utopian than a uniform regulation," says Jeffery. "But it builds on the assumption that most economically relevant countries participate in one way or another and ensures that the global efforts are successful in limiting warming to 2 degrees."

In this scenario, the US national emissions reduction target would have to be roughly 50 percent instead of currently 22-24 percent below 2010 levels by 2030. Alternatively, the equivalent target for the EU would have to be about minus 60 percent instead of currently 27 percent below 2010 (27% below 2010 being equal to the announced 40% below 1990 target).

It's in the numbers: China will not take the lead

China could also take the lead, but beyond political considerations already the numbers show that this is unlikely. In fact, the quantification of the Chinese pledge indicates the largest gap between a leadership target and a currently proposed peaking by 2030. If China wanted to assume leadership, China would have to reduce emissions by 32 percent below 2010 levels by 2030. In a scenario of equalized cumulative per-capita emissions, it would only need to reduce them by 4 percent. This seems little, but would in fact be a most crucial contribution.

"If you look at what pledges the countries put on the table for Paris so far, it's clearly not enough to keep warming within the internationally agreed 2-degree limit, hence the current 'intended nationally determined contributions' can only be regarded as a first step in the right direction," says co-author Sebastian Oberthür from Vrije Universiteit Brussel. Based on IPCC databases, the scientists derived their proposition which is contrary to previous assumptions about allocation schemes. "If we postpone action until we have universal agreement on a fair allocation of reductions," he says, "the result will be fair only in that everybody will lose, because will hit us all."

"Our study thus anticipates the upcoming Paris climate summit, which will see countries make their mitigation contributions in an independent bottom-up manner," says Joeri Rogelj from the International Institute for Applied Systems Analysis. "This is a fundamental break with the past," he says, "and in this new landscape, our study introduces an important new concept which helps us understand how major countries can still assume a leadership role on this highly fragmented playing field."

Explore further: World on track for warming 'far above' 2C target: analysts

More information: Malte Meinshausen et al. National post-2020 greenhouse gas targets and diversity-aware leadership, Nature Climate Change (2015). DOI: 10.1038/NCLIMATE2826

An interactive webpage with the study's results is available at www.mitigation-contributions.org

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16 comments

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gkam
1.8 / 5 (10) Oct 26, 2015
It is up to the US and China to do this.

Of course, those who own the US do not want to pay for it, and China is a mess. Deniers and the greedy will wind up killing us all.
geokstr
2.5 / 5 (13) Oct 26, 2015
It is up to the US and China to do this.

Of course, those who own the US do not want to pay for it, and China is a mess. Deniers and the greedy will wind up killing us all.


While warmists recommend deliberately killing off only 98.1314% of the population. Every one of them believes they will be amongst the 1.8686% exempted due to their superior moral preening.
leetennant
3.7 / 5 (9) Oct 26, 2015
Yes, mass murder is what we're proposing. Those cheap, efficient, less-polluting and democratic alternative energy sources that help to mitigate the disastrous and catastrophic climate change impacts are... wait, what was I saying?
antigoracle
2.5 / 5 (11) Oct 26, 2015
If only 97% of the AGW Chicken Littles put their money where their ass (mouth) is and stopped using power and fuel, derived from fossil fuels, these CO2 targets would be met, overnight. Of course they won't since its much easier for these hypocrites to bray like the donkeys they are.
leetennant
3.7 / 5 (9) Oct 26, 2015
So I guess we can add economics and world energy demand to the subjects antigoracle doesn't understand...
antigoracle
2.3 / 5 (9) Oct 26, 2015
So I guess we can add economics and world energy demand to the subjects antigoracle doesn't understand...

So the jackass brays.
Tell us what's the implications on the economics and world energy demand, in meeting those CO2 targets.
jeffensley
3 / 5 (6) Oct 26, 2015
While this has been posted on a science-oriented website, it should be noted that statements like this are actually more pertinent in a political discussion. At best these predictions are based on models that are fairy-tale-like in their simplicity and naivete.
dlethe
2.1 / 5 (7) Oct 26, 2015
Note the study came from a blog site who's very existence depends on propagating anthropomorphic global warming rhetoric. To quote the home page, "This website provides graphical representations of mitigation contributions for each of the G20 countries and how they compare to the mitigation challenge.""

Was their research peer reviewed? No way. This so-called study is nothing more than junk science and propaganda. It has no place in phys.org
Vietvet
4.2 / 5 (5) Oct 27, 2015
@diethe

Thanks for your ignorant display. Nature Climate Change is not a blog site, it is a peer reviewed journal: https://scholar.g...Ch1I6wWi

"Nature Climate Change is dedicated to publishing the most significant research across the physical and social sciences on the impacts of global climate change."
http://www.nature...dex.html

Vietvet
4.2 / 5 (5) Oct 27, 2015
"The Potsdam Institute for Climate Impact Research (PIK), is a German government-funded research institute addressing crucial scientific questions in the fields of global change, climate impacts, and sustainable development. Ranked among the top environmental think tanks worldwide, it is one of the leading research institutions and part of a global network of scientific and academic institutions working on questions of global environmental change. It is a member of the Leibniz Association, whose institutions perform research on subjects of high relevance to society."
https://en.wikipe...Research

@diethe

You call that a blog site?
EnsignFlandry
2.3 / 5 (6) Oct 27, 2015
It is up to the US and China to do this.

Of course, those who own the US do not want to pay for it, and China is a mess. Deniers and the greedy will wind up killing us all.


China has already stated they will not reduce their greenhouse gas emissions. Occasionally they tout some minor project that uses "green energy", with an microminimal decrease in emissions, for propaganda purposes.

I suggest if Al Gore et.al., the Hollywood entertainment-political complex, and other rich environmental activists reduced their carbon footprint to that of the average middle-class American, greenhouse gas emissions would drop measurably. That won't happen, so the burden will fall on the middle class.
EnsignFlandry
2.1 / 5 (7) Oct 27, 2015
@diethe

Thanks for your ignorant display. Nature Climate Change is not a blog site, it is a peer reviewed journal: https://scholar.g...Ch1I6wWi


In other words,tNCC has an agenda, and its not objective research.
gkam
2.3 / 5 (6) Oct 27, 2015
Objective research IS the agenda. What do you have against science?
Returners
2.3 / 5 (6) Oct 27, 2015
One is in favor of distributive justice at some point in the future: emissions per person would be roughly the same in every country by 2050. This includes the EU and the US. The other camp, with China and India, calls for corrective justice: the emissions of the past should be taken into account to achieve equal cumulative emissions per person.


Riiight.

The nations who invented all modern science and technology should stop using any of it and go back to living like cavemen, and let the Indians and Chinese reap the rewards of our civilization's developments in all fields of science, technology, and medicine.

Here's another theory:

Make your own energy infrastructure from wind, solar, etc and quit bitching about it.

You hypocrites have nuclear weapons, but you have 400 million citizens who don't even have electricity.
Captain Stumpy
4 / 5 (4) Oct 27, 2015
Note the study came from a blog site
@dlethe
for starters, the study IS peer reviewed, from Nature (Journal) subsection classification Climate Change
Malte Meinshausen et al. National post-2020 greenhouse gas targets and diversity-aware leadership, Nature Climate Change (2015)
thus your comment was hasty and perhaps you should have read the study?
Was their research peer reviewed?
it was. read above, and try opening the study
This so-called study is nothing more than junk science and propaganda
so, if it is a journal study built upon the studies (see: references section of said study link above) then it is junk or propaganda? what do you call this study then? http://www.scienc...full.pdf

Captain Stumpy
3.7 / 5 (3) Oct 27, 2015
In other words,tNCC has an agenda, and its not objective research.
@flandry-floundering
and you can demonstrate this with evidence equivalent to a reputable peer reviewed journal study? you made a claim (see above quote) but provide no evidence (argument from ignorance and delusional conspiracist ideation) whereas we can demonstrate, with a peer reviewed study that there is an active attempt to get the scientifically illiterate to believe the anti-AGW propaganda (their non-evidence based delusional content)
http://www.drexel...nge.ashx

perhaps you should learn what constitutes evidence and reconsider your opinion based content vs factual scientific data
http://www.ploson...tion=PDF

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