BY BRENDAN MONTAGUE AND KYLA MANDEL IN PARIS

David Cameron flew into Paris to warn negotiators at the COP21 talks that politicians will be betraying future generations unless they deal with climate change.

But the prime minister’s emotional appeal was swiftly undermined when Dr James Hansen, the grandfather of climate science, said the UNFCCC was discussing measures that are “half arsed, half baked” and we are therefore “screwing the next generation.”

Hansen was as far back as 1988 the first to warn world leaders that global climate change was already taking place, and could soon result in catastrophic floods, drought, sea-level rise and extinctions.

And the former director of the NASA Goddard Institute for Space Studies was seemingly unimpressed by Cameron’s rhetoric – and policy of supporting fracking in the United Kingdom.

Asked by climate policy website Carbon Brief about fracking, he said: “Well, that’s screwing your children and grandchildren. Because if you do that, then there is no way way to avoid the consequences [of] multi-metre sea level rise. But we can’t do that.

Crystal Clear

“And that is what the science says crystal clear. And yet the politicians pretend not to hear it, or not to understand it.”

Hansen, who is attending a Conference of the Parties event for the first time, told the UN: “What I am hearing is that the heads of state are planning to clap each other on the back and say this is a very successful conference. If that is what happens, we are screwing the next generation, because we are doing the same as before.”

According to The Guardian, he added: “[A rise of ] 2C is definitely dangerous. We are at the point now where temperatures are hitting the 1C mark and are are on a path above 1C. Even if we reduce emissions 6 percent a year we will still get 1C.

HOW CLIMATE SCIENCE BECAME A POLITICAL ISSUE

Part 1: James Hansen: How Climate Change Became Political

Part 2: James Hansen: I Thought There Would Be a Rational Response

Part 3: How Free Market Thatcher First Called for Climate Action

“Instead we hear the same old thing as Kyoto [in 1997]. We are asking each country to cap emissions, or reduce emissions. In science when you do a well conducted experiment you expect to get the same result. So why are we talking about doing the same again? This is half-arsed and half-baked.”

Hansen told DeSmog UK during a moving interview published in October 2014 that when he first became aware that fossil fuel use was contributing to climate change, he assumed policymakers would simply introduce emissions regulations and avert any potentail threat.

“We had coal phase-out scenarios. I wasn’t thinking, ‘oh, this is really gonna happen out in the twenty-first century’, because I thought there would be a rational response,” he told DeSmog UK.

“There has not been: it’s as if we didn’t know. We might as well not know. Our fossil fuel use wouldn’t be much different. By and large, the emissions have just continued to accelerate.”