The globe is heading toward “severe, pervasive, and irreversible” climate change impact if left “unchecked,” according to a new United Nations report.

In its most comprehensive analysis, the U.N.’s synthesis report released Sunday, finds that the evidence behind human influence on climate change is overwhelming and undeniable, as greenhouse gas emissions are the “highest in history.”

ADVERTISEMENT

The report, written by more than 800 scientists from 80 countries and drawing from 3,000 contributing authors and experts, argues emissions must fall to a net zero by the end of the century. It says the window of opportunity to address the threat is shrinking.

“The report expresses with greater certainty than in previous assessments the fact that emissions of greenhouse gases and other anthropogenic drivers have been the dominant cause of observed warming since the mid-20th century,” according to the U.N. Intergovernmental Panel on Climate Change, which adopted the report on Saturday evening before releasing it on Sunday.

“The scientific case for prioritizing action on climate change is clearer than ever,” IPCC Chairman R.K. Pachauri said. “We have little time before the window of opportunity to stay within 2 degrees Celsius of warming closes.”

Pachauri added that to stay below the 2 degrees Celsius benchmark, at which scientists say catastrophic climate damage will occur, greenhouse gas emissions must drop by 50 percent or more in the next 25 years.

“There is no question that we are now seeing a wide range of consequential impacts on every continent across the oceans,“ Chris Fields, co-chair of an IPCC working group, said on a call with reporters Saturday evening.

The assessment finds that the atmosphere and oceans have warmed, the amount of snow and ice is diminishing, and the global concentration of carbon dioxide has increased to “unprecedented” amounts in the last 800,000 years.

“Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850,” the report, which is meant to serve as a guide for policymakers, states.

Over the last two decades, the report states, Greenland and Antarctic ice sheets have been losing mass, glaciers are shrinking worldwide, and snow cover in the Northern Hemisphere is decreasing.

The risks associated with “irreversible” climate change include increased extinction for a number of animal and plant species.

The climate change will “undermine food security” the report adds, and in a span of 36 years human health problems will be exacerbated due to warming.

This all means that global leaders need to act fast, said Michael Oppenheimer, a co-author of the report.

“We're going to have to either act fast or get very lucky: lucky if the climate turns out to be less sensitive to greenhouse gases than we think it is, or lucky with new technological developments falling into our laps,” Oppenheimer said on a call with reporter Saturday evening.

“And frankly, I don't want to lean too much on luck to get this problem solved, since the fate of the earth depends on it,” he added.

Action by global leaders and government officials will need to push countries toward a “pretty serious” transformation of the energy system.

Slashing emissions from the electricity sector to zero by mid-to-late century will be necessary, authors of the report pointed out.

One of the biggest challenges, is that climate change is not at the top of peoples’ priority lists.

A part of the report is the idea of tying climate change mitigation to other societal priorities.

It’s an idea that the U.S. is already planning to by having 38 federal agencies craft climate change adaption and sustainability plans that not only identify different agencies’ vulnerabilities, but also set up short and long-term steps to slash emissions and energy usage.

The report tries to provide greater insight and urges countries to look more at how society orients and organizes itself to get the job done in the climate fight.

The U.N. report is also meant to buttress government leaders' actions to fight climate change, as many try to set ambitious goals ahead of the Paris talks next year, where more than 180 countries will forge a global climate accord to slash emissions.

But there are concerns that political disagreements and economic restraints, which differ per country, will get in the way.

The U.N. IPCC report left out an article that many saw as critical, which would have presented a framework for how governments might think about the question of how dangerous climate change is, and how soon they need to act.

Oppenheimer, and Fields, two of the report's co-authors, told reporters that some of the same problems arising during negotiations, and difficulties countries have with agreeing on certain steps, probably caused the article to be taken out.

Still, the IPCC said, the report is a strong signal and body of evidence that more stringent steps need to be enforced to reverse the course the planet is already on.

The report also finds that, while estimates of the cost to cut emissions varies, global economic growth will not be strongly affected.

Under an ambitious mitigation scenario, the IPCC says, economic growth would be cut by roughly .06 percentage point.

The new report will likely embolden the Obama administration’s climate agenda and work to push other countries toward signing an ambitious climate treaty next year.

Sen. Barbara Boxer Barbara Levy BoxerThe Hill's Morning Report - Presented by Facebook - Biden, Harris launch Trump offensive in first joint appearance Bottom line Polls show big bounce to Biden ahead of Super Tuesday MORE (D-Calif.) said the report is “telling member of Congress and policymakers around the globe that we cannot just try to adapt.”

She added that she plans to work with her colleagues in Congress to “put a price on carbon, which is the most effective way to avert disastrous climate change.”

Alden Meyer, director of strategy and policy with the Union of Concerned Scientists, said the report should convince politicians that the “risks are clear.”

“Politicians can either dramatically reduce emissions, or they can spend the rest of their careers running from climate disaster to climate disaster. Thankfully, more and more leaders are waking up to the costs of dealing with runaway climate change that scientists have been warning about for years,” Meyer said.

Despite the consensus among scientists that human activity is the driving factor in climate change, a small minority of scientists and majority of Republicans in Congress disagree.

Republicans have tried brush aside the climate debate, arguing the president should be focused on the recent Ebola outbreak and rising terror group the Islamic State in Iraq and Syria instead of global warming.

Senior Republicans like Speaker John Boehner John Andrew BoehnerLongtime House parliamentarian to step down Five things we learned from this year's primaries Bad blood between Pelosi, Meadows complicates coronavirus talks MORE (Ohio), Senate Minority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellOcasio-Cortez to voters: Tell McConnell 'he is playing with fire' with Ginsburg's seat McConnell locks down key GOP votes in Supreme Court fight Video shows NYC subway station renamed after Ruth Bader Ginsburg MORE (Ky.) and Sen. Marco Rubio Marco Antonio RubioSunday shows preview: Justice Ginsburg dies, sparking partisan battle over vacancy before election Florida senators pushing to keep Daylight Savings Time during pandemic Hillicon Valley: DOJ indicts Chinese, Malaysian hackers accused of targeting over 100 organizations | GOP senators raise concerns over Oracle-TikTok deal | QAnon awareness jumps in new poll MORE (Fla.), brush aside the debate by saying they are not scientists.

Still, if the Senate flips on Tuesday, a Republican majority has vowed to attack and dismantle as many parts to the president’s climate plan as possible, specifically his signature regulations on carbon pollution from existing power plants, which has been hailed by other nations a bold step.

Read more from The Hill:

Kerry: UN climate report ‘another canary in the coal mine’