The world may be celebrating the new climate deal in Paris, but many scientists and environment groups have sounded a note of caution.
Climate scientists warned of a gaping hole -- the lack of a detailed roadmap for cutting greenhouse gases that cause the problem.
The new accord , embraced by 195 nations on Saturday, aims to cap warming to “well below” two degrees Celsius above pre-industrial levels, and to “pursue efforts” to limit the increase to 1.5C.
Roadmap on mitigation?
“This is an historic agreement,” said Steffen Kallbekken, director of the Centre for International Climate and Energy Policy. “But this ambitious temperature goal is not matched by an equally ambitious mitigation goal,” he said, using the scientific term for the drawing-down of heat-trapping gases.
To have a two-thirds chance of limiting warming to two degrees, emissions would have to fall by 40-70% by mid-century, according to the Intergovernmental Panel on Climate Change (IPCC), the UN’s climate science body.
And to reach the 1.5C target -- also embraced in the pact -- those mid-century cuts would have to be even deeper: 70 to 95%.
Without these hard numbers -- dropped from an earlier draft -- the climate pact “does not send a clear signal about the level and timing of emissions cuts”, Kallbekken cautioned.
How to get there?
Many scientists highlighted the imbalance created by boosting the ambition of the temperature target on one hand, while removing the yardsticks against which progress toward that goal could be measured, on the other.
“How are we going to reach our objective unless we set out in the right direction?” asked Professor Bill Collins at the University of Reading in Britain, pointing to the need to slash carbon dioxide output by 70% before by mid-century. “Until governments accept this, we should restrain our optimism.”
Keveh Madani, a professor at Imperial College London, said international summits were better at setting aspirational goals than laying out a pathway for achieving them. “What matters more is how to get to the target,” he noted.
Major emerging nations, especially India, were reluctant to include quantifiable milestones that could constrain the use of fossil fuels in growing their economies.
But scientific reality is unyielding, said Miles Allen at Oxford University.
Stabilising greenhouse gases “in the second half of this century will require net carbon dioxide emissions to be reduced, in effect, to zero,” Allen said. “It seems governments understand this, even if they couldn’t quite bring themselves to say so.”
What about now?
Other scientists voiced concern about the fact that the new accord allows several years to pass before ramping up emissions reduction efforts.
“For all that is encouraging in the agreement, the time scales -- or the lack thereof -- are worrying,” said Ilan Kelman of University College London. “Little substantive will happen until 2020 whilst clear deadlines for specific targets are generally absent.”
Jean Jouzel, a leading French climate scientist and a former vice chair of the IPCC, questioned the feasibility of the 1.5C target, saying it could only be achieved by overshooting the mark and pulling back, which could take decades or longer.
The global thermometer has risen nearly 1C so far, he and others noted, and CO2 already lingering in the atmosphere will still push it up, even if the world stopped emitting greenhouse gases in future.
“1.5C is a dream,” he added. “It’s too ambitious, though I understand the position of the most vulnerable countries that fought for it.”
Mixed report card
Greenpeace,and major environment groups gave a mixed report card on the many details in the accord.
“This deal puts the fossil-fuel industry on the wrong side of history,” Greenpeace International executive director Kumi Naidoo said. “But it’s what happens after this conference that really matters.”
Green groups however agreed that by striving to limit warming to 1.5 degrees C over pre-Industrial Revolution temperatures, the agreement would have an impact.
“The Paris Agreement marks a new form of international cooperation -- one where developed and developing countries are united by a common and fair framework,” said Jennifer Morgan, global director of the climate programme at the World Resources Institute (WRI), a Washington-based think tank.
Goal posts moved too far?
Tim Gore, policy director at British charity Oxfam, said a provision aiming to cap global warming at 1.5C would require an unprecedented global effort.
“The 1.5C degree target is an important moral victory, but -- as we have heard -- it may yet ring hollow unless we see significant increases in action in the years ahead,” Gore said.
More critical Friends of the Earth said prosperous nations had pushed through an empty accord.
“Rich countries have moved the goal posts so far that we are left with a sham of a deal in Paris,” said Sara Shaw, an activist with Friends of the Earth International. “Through piecemeal pledges and bullying tactics, rich countries have pushed through a very bad deal.”