Ambitious 1.5C Paris climate target is still possible, new analysis shows

The highly ambitious aim of limiting global warming to less than 1.5C remains in reach, a new scientific analysis shows.

The 1.5C target was set as an aspiration by the global Paris climate change deal in 2015 to limit the damage wreaked by extreme weather and sea level rise.

It was widely seen as impossible because analysis at the time indicated it required carbon emissions to fall to zero within seven years, a speed deemed “incompatible with democracy” by one climate economist.

However, an updated analysis using the latest data shows the global carbon emissions budget that meets the 1.5C goal is significantly bigger than thought, equivalent to 20 years of current annual emissions.

The scale of the challenge remains huge but it means that, if the world’s nations ratchet up their emissions cuts in future as intended under the Paris deal, the expected “severe, widespread, and irreversible impacts” on people and the natural world could be avoided.

“It is looking more hopeful that we can really achieve the Paris goals,” said Prof Michael Grubb, a climate economist at University College London and one of the team that produced the new analysis published in the journal Nature Geoscience.

In 2015, Grubb said the massive scale and speed of carbon cuts needed to meet the 1.5C target were “incompatible with democracy”.

But the new work has changed his mind, showing there is more room for emissions than thought. He also said carbon emissions have stopped growingsooner than expected, especially in China, and that renewable energy costs are plummeting unexpectedly quickly. “We are in the midst of an energy revolution,” he said.

Prof Myles Allen at Oxford University, who was part of the team that produced the new analysis of the 1.5C goal, said they used several methods to make a fresh estimate of the necessary carbon budget, including updating measurements of the emissions and warming that have already occurred. Previous computer models had also projected more rapid warming in the expectation that, for example, sun-blocking pollution particles would be cleaned up more quickly than it has in reality.

“A lot of people said 1.5C is simply not possible,” said Allen. But the new work revealed that for a 66% chance of meeting the 1.5C target in 2100, the budget is 240bn tonnes of carbon, assuming that other greenhouse gases such as methane are also controlled. This means the target could be met if strong action is taken. The scientists also warned that carbon cuts need to happen sooner rather than later, starting with countries strengthening their Paris pledges in 2018.

A commonly used scenario for ambitious carbon cuts, called RCP2.6 by the Intergovernmental Panel on Climate Change, projects ever bigger carbon cuts as time passes. But Grubb pointed out that this would eventually require annual drops in carbon emissions only previously seen when economies collapsed in the 1930s depression, the second world war and at the end of the Soviet Union.   

Read more https://www.theguardian.com/environment/2017/sep/18/ambitious-15c-paris-climate-target-is-still-possible-new-analysis-shows

Courtesy of Guardian News & Media Ltd