The goal of the Paris Climate Agreement to limit global temperature rises to 1.5˚C is still possible with more ambitious emission reductions, according to a new scientific study.
This target was recently only given a 1% chance of succeeding, while the less aspirational goal of capping increases at 2˚C by 2100 was given just a 5% chance.
However, the latest data shows the remaining ‘carbon budget’ for keeping temperature increases below 1.5˚C is around four times bigger than previously estimated in 2008.
Published in the journal Nature Geoscience, the study concludes that reducing CO2 emissions by the equivalent of around 20 years' worth of our current rates will result in a 66% chance of restricting warming to 1.5˚C this century.
“This paper shows that the Paris goals are within reach, but clarifies what the commitment really implies,” study co-author, Professor Michael Grubb of University College London, said.
“The sooner global emissions start to fall, the lower the risk not only of major climatic disruption, but also of the economic disruption should near-term action remain inadequate.”
Grubb had previously said in 2015 that delivering the Paris Climate Agreement was "incompatible with democracy”, as it would involve higher energy prices than people would accept.
However, re-assessing the carbon budget involved using evidence from multiple different models that the previous assessment did not.
It was found that strengthening Nationally Determined Contributions to correspond with a 10% reduction in proposed emissions for 2030 could be consistent with a scenario where warming rises less than 1.5˚C by 2100.
This would involve a smooth transition to slightly negative emissions after 2080, which may require challenging rates of deployment of CO2 removal technology, and might not be technically feasible or socio-economically plausible.
The study warns: “Longer-term deep decarbonisation also relies on many energy system innovation, including development and deployment on an unprecedented scale of renewable energy and carbon capture and storage.
“Given possible limits to rates of decarbonisation, near-term mitigation ambition and delays in mitigation start dates may strongly influence peak and 2100 warming.”
