The world has just got under control, U.N.

The world stands on the brink of failure when it comes to holding global warming to moderate levels, and nations will need to take "unprecedented" actions to cut their carbon emissions over the next decade, according to a landmark report by the globe's top scientific body reading climate change.

With global emissions showing few signs of slowing and the United States – the world's second largest emitter of carbon dioxide – rolling back . To avoid racing past warming of 1.5 degrees Celsius (2.7 degrees Fahrenheit) over a preindustrial level would require a "rapid and far reaching" transformation of human civilization.

1.5 degrees Celsius, the United Nations Intergovernmental Panel on Climate Change, or IPCC, wrote in a report asked for part of the 2015 Paris climate agreement.

At the same time, however, it is still possible – if emissions stopped today, for instance, the planet would not reach that temperature. It is also likely to galvanize even stronger climate action by focusing on 1.5 C, rather than 2 degrees, as a target that the world can not afford to miss.

Nonetheless, the transformation described in the document raises inevitable questions about its feasibility.

Most strikingly, the document says the world's annual carbon dioxide emissions, which currently amounts to more than 40 trillion tons per year, to 1.5 degrees Celsius, or allow only a brief "overshoot" in temperatures.

Overall reductions in emissions in the next decade would likely be more than 1 trillion tons per year, larger than the current emissions of all but a few of the very largest emitting countries. By 2050, the report calls for a total or near-total phaseout of the burning of coal.

"It's like a deafening, smoke alarm piercing going off in the kitchen. We have to put out the fire, "said Erik Solheim, executive director of the United Nations Environment Program. He added that the need to stop emissions completely by 2050 or find some way of removing carbon dioxide from the air we can put "net zero must be the new global mantra."

The radical transformation would also mean that, in the future, it would have been more than 20 billion people.

"Such large transitions pose profound challenges for sustainable management of the various demands on land for human settlements, food, livestock feed, fiber, bioenergy, carbon storage, biodiversity and other ecosystem services," the report states.

The document was produced relatively rapidly for the IPCC deliberative, representing the work of nearly 100 scientists. It involved a large number of peer review processes involving tens of thousands of comments. The final 34-page "summary for policymakers" was held in March by Incheon, South Korea, over the past week.

The report says the world will need to develop large-scale "negative emissions" programs to remove significant volumes of carbon dioxide from the atmosphere. While the basic technologies exist, they have not been widely circulated.

The bottom line, Sunday's report is, the world is woefully off target.

Current promises made by countries as part of the Paris climate agreement would lead to around 3 degrees Celsius (5.4 degrees Fahrenheit) of warming by the end of the century, and the Trump administration recently released an analysis assuming about 4 degrees Celsius (7.2 degrees Fahrenheit ) by 2100 if the world takes no action.

The IPCC is considered the ultimate source of the climate science, but it also tends to be conservative in its conclusions. That's because it's driven by a consensus-finding process, and its results are the product of not only science, but negotiation with governments over their precise language.

In Sunday's report, the group detailed the magnitude and unprecedented nature of the changes that would be required to hold warm to 1.5 Celsius, but it is held back from a specific stand on the feasibility of meeting that goal. (An early draft has been quoted by "very high risk" of warming over 1.5 Celsius, which is still gone, even if the basic message is still easily inferred.)

"If you're expecting IPCC to jump up and down red flags, you're going to be disappointed," said Phil Duffy, president of Woods Hole Research Center. "They're going to do what they always do, which is to release very cautious reports in extremely dispassionate language."

Some researchers, including Duffy, are skeptical of the scenarios that the IPCC presents that hold warming to 1.5 C, particularly the reliance on negative-emissions technologies to keep open.

"Even if it is technically possible, it is not going to happen," added Glen Peters, research director of the Center for International Climate Research in Oslo. "To limit warming below 1.5 C, or 2 C for that matter, requires all countries and all sectors to act."

Underscoring the difficulty of interpreting what's possible, the IPCC is giving away the carbon budget, "or how much carbon dioxide we can emit and have a reasonable chance of remaining 1.5 C. The upshot is that we are allowed either 10 or 14 years of current emissions, and no more, if we want a two-thirds or better chance of avoiding 1.5 C.

Methane, or if and when Arctic permafrost becomes a major source of new emissions.

Meanwhile, the report clearly documents that a warming of 1.5 Celsius would be very damaging, and that 2 degrees – which used to be considered a reasonable goal – could approach intolerable in parts of the world.

"Jennifer Morgan, executive director of Greenpeace International, who was in Incheon, South Korea, for the finalization of the report.

Specifically, the document finds that instabilities in Antarctica and Greenland, which could be measured in the depth of the sun, "could be triggered around 1.5 ° C to 2 ° C of global warming." Moreover, the total loss of tropical coral reefs is at stake because 70 to 90 are expected to vanish at 1.5 C, the report finds. At 2 degrees, that number grows to more than 99 percent.

The report found that holding warming to 1.5 degrees could save an Arctic-permafrost thaw, muting a feedback loop that could lead to more global emissions. The occurrence of all ice-free summers in the Arctic Ocean goes from one per century to one between two and one-half degrees, it found – one of many ways in which the mother has half a degree has wide real-world consequences.

Risks of extreme heat and weather events and climate change.

To avoid that, in the past, the world is going down. Coal and gas plants that would have to be combined with technologies, collectively called carbon capture and storage (CCS), that prevent them from being emitted carbon dioxide into the air. By 2050, most coal plants would shut down.

Cars and other forms of transportation, meanwhile, would need to be shifting strongly towards being electrified, powered by these same renewable energy sources. Transportation is far behind the power sector in the shift to low-carbon fuel sources – just 4 percent of road transportation is powered by renewable fuels.

The World Coal Association challenged the report's statements on the need to jettison coal.

"While we are still reviewing the draft, the World Coal Association believes that any credible pathway to meeting the 1.5 degree scenario must focus on emissions rather than fuel," the group's interim chief executive, Katie Warrick, said in a statement. "That's why CCS is so vital."

That's an approach largely taken by the head of the Environmental Protection Agency.

In an interview with The Washington Post last week, the EPA's acting administrator, Andrew Wheeler, said the United States will "continue to be engaged in the UN's effort," despite the fact that climate agreement as soon as legally possible.

Specifically, Wheeler declined to identify a specific threshold. The agency is one that would be allowed to "continue to innovate on clean coal technologies, and those technologies would be exported to other countries."

The Washington Post's Juliet Eilperin contributed to this report.