The nations of the world — including the U.S. — unanimously approved a landmark climate report warning that we need far stronger climate policies to stop catastrophic climate change than the world agreed to in Paris in 2015.

“This latest report underscores the danger that Donald Trump poses to the planet,” as leading climate expert Michael Mann told ThinkProgress. It “makes clear we need to reduce emissions dramatically, vastly exceeding our Paris targets. Yet Trump probably poses the single greatest threat to meeting those targets.”

The bombshell in this “Special Report on Global Warming of 1.5ºC” from the world’s foremost scientific panel on climate change (the IPCC) is that on our current emissions path, we will cross a key threshold of dangerous climate change (1.5ºC or 2.7°F) by 2040.

Equally shocking is that — absent much stronger global action and a very sharp reversal of Trump’s anti-climate policies — we would hit an even more worrisome threshold of catastrophic climate change (2°C or 3.6°F) just two decades after that.


Human-caused warming reached 1°C [1.8°F] above pre-industrial levels in 2017. At the present rate, global temperatures will hit 1.5°C around 2040 and 2°C soon after 2060. CREDIT: IPCC. Back in December 2015 in Paris, the world’s nations unanimously committed to an ongoing effort of increasingly deeper emissions reductions aimed at keeping total warming “to well below 2°C [3.6°F] above preindustrial levels.”

The Paris Climate Accord further committed the world “to pursue efforts to limit the temperature increase to 1.5°C [2.7°F] above preindustrial levels, recognizing that this would significantly reduce the risks and impacts of climate change.”

Two key points of the new report are, first, that the impacts from 1.5°C warming will be very dangerous for humanity, but, second, the difference between these two targets is still significant: “Coral reefs, for example, are projected to decline by a further 70–90% at 1.5°C with larger losses (>99%) at 2ºC.”

Coral reefs are estimated to support a quarter of all marine life and are a major food source for half a billion people.


As the planet warms from 1.5°C to 2°C, the risks grow rapidly for some very dangerous tipping points, including the irreversible collapse of the West Antarctic ice sheet (which would raise sea levels 20 feet).

The report notes that “Limiting global warming to 1.5°C rather than 2°C is projected to prevent the thawing” of as much as 1 million square miles of permafrost. And that matters because the northern permafrost contains twice as much carbon as the atmosphere does today.

This means that the possibility of a runaway catastrophe — where warming of 2°C or more thaws a huge area of permafrost, and the resulting carbon emissions create, say, another 1° C of warming that in turn releases yet more heat-trapping gases from the permafrost — is on the table.

The new IPCC report says that keeping total warming to 1.5°C is still technologically possible, but it would require “rapid and far-reaching transitions in energy, land, urban and infrastructure (including transport and buildings), and industrial systems…. These systems transitions are unprecedented in terms of scale.”

Here is a chart showing the kind of abrupt reversal of emissions trends needed:

Realistically, though, the election of Donald Trump — who has started undoing every serious U.S. climate policy and announced he will abandon the Paris Accord — already makes such an abrupt reversal extremely unlikely.


“Given the present political debate, I don’t see much chance of these near-term cuts happening,” as Texas A&M climatologist Andrew Dessler explained to ThinkProgress in an email. “Overall, I’m worried people will look at this and conclude that we’re totally screwed and give up.”

That, however, would be a mistake because as bad as 1.5°C warming is, 2°C is even worse — and warming of 3°C (5.4°F) to 4°C (7.2°F) would be worst of all, pushing us toward what would inevitably destroy human civilization as we have come to know it.

Indeed, the Trump Administration is so indifferent to a livable climate — and fate of our children and grandchildren to come — that they simply take for granted that we are headed to 7°F warming.

In a massive environmental impact statement released in August to justify rolling back Obama-era fuel-economy standards for cars and light trucks, the Trump team simply assumed that Earth will warm 7°F by century’s end. And since this apocalypse supposedly can’t be stopped, freezing car standards at 2020 levels simply won’t matter much — if you buy into this suicidally defeatist denial of climate science.

The IPCC’s report takes pains to note that such an outcome isn’t inevitable — though limiting warming to under 2°C requires going far beyond the Paris agreements, which Trump has already rejected.

Bizarrely, the Trump administration decided to simultaneously accept and reject the new report.

In a statement, the State Department said “acceptance of this report by the panel does not imply endorsement by the United States of the specific findings or underlying contents of the report.” It added, “We reiterate that the United States intends to withdraw from the Paris agreement at the earliest opportunity absent the identification of terms that are better for the American people.”

Trump does not agree that preserving a livable climate for your children and grandchildren is “better for the American people” than the alternative. It is now up to the American people to decide whether we disagree.