PARIS — The Paris Agreement to try to cap global warming at 1.5°C was a stunning political victory for poor countries threatened by climate change. But scientists tasked with explaining how to get there are less than thrilled.

The United Nations (UN) climate science panel announced last week it would deliver — at the request of governments — a “special report” in 2018 on the risks and impacts associated with a 1.5°C target.

But even as three-quarters of the 195 nations which sealed the historic deal in December gather tomorrow for a formal signing ceremony at the UN, experts warn that marshalling thousands of scientists to map a pathway to 1.5°C may be mission impossible.

Some bridle against politicians meddling with the scientific agenda. Others insist the goal just cannot be reached.

“1.5°C is almost certainly not feasible without an overshoot,” said Dr Peter Frumhoff, chief scientist at the Union of Concerned Scientists in Washington, expressing a view shared — if not frequently articulated — by climate experts.

The global economy simply cannot be weaned off fossil fuels quickly enough, they argue.

Even under optimistic scenarios, he told Agence France-Presse, greenhouse-gas emissions may push Earth past the 1.5°C threshold by 2050, perhaps sooner.

Last year, the hottest year on record, was a full degree Celsius above the pre-industrial benchmark against which global warming is measured.

And even if every oil-, gas- or coal-burning engine in the world were switched off tomorrow, lingering molecules of carbon pollution in the atmosphere would continue pushing temperatures up.

A LIVEABLE FUTURE

“The question then becomes whether this is a one-way ticket or whether we can return,” said Dr Joeri Rogelj, a climate modeller at the International Institute for Applied Systems Analysis in Laxenburg, Austria.

“And that depends on whether we can remove large quantities of carbon dioxide (CO2) from the atmosphere.”

The technology for sucking CO2 out of the air is well beyond our reach on anything approaching a global scale, scientists agree, yet virtually all scenarios for a 2°C world — much less a 1.5°C cap — depend on it.

The special 1.5°C report of the UN’s Intergovernmental Panel on Climate Change (IPCC) should “not fixate on developing unachievable” scenarios for cutting greenhouse gases, said Dr Glen Peters, a senior researcher at the Center for International Climate and Environmental Research in Oslo (CICERO).

On current trends, scientists say we are heading for a 4°C warmer world. Another concern is timing.

A MORAL TARGET

Going into the UN climate conference in Paris last year, 2°C was the agreed-upon ceiling.

But rising seas, record-breaking superstorms and crippling droughts prompted poor countries and island nations most at risk to demand a lower cap. Emerging giants and oil exporters balked, fearful of the constraints on their fossil fuel-dependent economies.

“China was against it, India was against it, Saudi Arabia fought us tooth and nail to the very end,” recalled Dr Saleemul Huq, director of the International Centre for Climate Change and Development in Dhaka.

“Getting 1.5°C into the agreement was a moral target,” said Dr Huq. “It’s our leverage, the whip we will use to hit everybody on the back so they can go faster. Whether we achieve it or not is going down a dark track. From now on, it’s about raising ambition.” AFP