Photo: JONATHAN NACKSTRAND/AFP/Getty Images

The United Nations’ Intergovernmental Panel on Climate Change is considered the gold standard for assessing the scientific consensus on global warming; if there is an overarching criticism of IPCC reports, it’s that they’re a little too conservative in their presentation of the threat at hand. So when a draft of its newest report stated that if the planet warms beyond 1.5 degrees Celsius it would create ocean conditions “poised to unleash misery,” there’s reason for alarm. A really loud alarm, considering that a 1.5-degree scenario is all but locked in due to emissions that have already left the smokestack.

The report, which leaked to the French News agency AFP and focuses on the oceans and the planet’s stores of frozen water known as the cryosphere, states that if warming isn’t halted at 1.5 degrees Celsius, sea levels will rise high enough to displace around 280 million people. (If perspective is needed, that’s four times the current number of worldwide refugees, which is a record high. And that’s to say nothing of other forms of climate displacement.) By 2100, the draft states that “annual flood damages are expected to increase by two to three orders of magnitude.” That means flood damages will increase either 100- or 1,000-fold — in a world where king tides are already causing cities like Miami to flood on a regular basis, and where Indonesia just announced announced a new inland capital because Jakarta is sinking. By 2050, low-lying cities and small island nations will face “extreme sea-level events” every year. At two degrees, the report anticipates that the frequency of extreme El Niño events will double, leading to greater risk of forest fires and cyclones.

Sea life will take also take a profound hit, as “the same oceans that nourished human evolution are poised to unleash misery on a global scale,” the report warns. Fish stocks could decline substantially from their already depleted numbers. Last year, the U.N. determined that a third of all fisheries were being tapped at an unsustainable rate. In the sea at large, the number of fish and marine life declined by 50 percent between 1972 and 2012.

The draft of the 900-page report is intended to be released in late September following an IPCC meeting in Monaco from September 20 to 23, and follows up on another U.N. report on disastrous land use policies, in which the panel called for a revolution in land use policy: Current agricultural practices use up soil 10 to 100 times faster than it can replenish.

The dangers of a world of two degrees of warming were established last year, in an IPCC report that predicted the possibility of a climate catastrophe. New York’s David Wallace-Wells described life on that Earth:

At two degrees, the melting of ice sheets will pass a tipping point of collapse, flooding dozens of the world’s major cities this century. At that amount of warming, it is estimated, global GDP, per capita, will be cut by 13 percent. Four hundred million more people will suffer from water scarcity, and even in the northern latitudes heat waves will kill thousands each summer. It will be worse in the planet’s equatorial band. In India, where many cities now numbering in the many millions would become unliveably hot, there would be 32 times as many extreme heat waves, each lasting five times as long and exposing, in total, 93 times more people. This is two degrees — practically speaking, our absolute best-case climate scenario … Barring the arrival of dramatic new carbon-sucking technologies, which are so far from scalability at present that they are best described as fantasies of industrial absolution, it will not be possible to keep warming below two degrees Celsius.

As far as hopes to limit warming to two degrees go, a particularly unnerving detail from the IPCC cryosphere draft involved the state of the world’s permafrost (ground that remains frozen for at least two consecutive years). If emissions continue at their current rate, at least a third and as high as 99 percent of permafrost could melt by 2100, releasing what has been described as a “carbon bomb” of greenhouse gases like nitrous oxide and methane, which are 300 and 25 percent more effective at trapping heat than carbon dioxide. Alone, permafrost and other sources of ground methane emissions could cut the 1.5-degree carbon budget — the amount of carbon the economy can heave into the atmosphere without going above a certain temperature — by five years. At least that methane won’t be lonely: In a sort of accidental prescience on Thursday, President Trump announced the rollback of regulations determining how much methane can be released while drilling for natural gas.