Greenhouse gas emissions are continuing to increase, making climate mitigation more challenging: UN report

Greenhouse gas emissions are continuing to increase, exacerbating the challenge world leaders face in preventing the impacts of climate change from worsening, the United Nations warns in its latest climate report.

Emissions in 2019 were about 12% higher than they were in 2010 and 54% higher than they were in 1990, largely due to increases in fossil fuel production, industrial activities and methane emissions, the report, released Monday by the U.N.'s Intergovernmental Panel on Climate Change, states.

As a result, human-caused climate change is already affecting many weather and climate extremes in every region across the globe, leading to widespread adverse impacts and related losses and damages to nature and people, according to the report.

The window of opportunity to secure a livable and sustainable future is "rapidly" closing, the report states. It will take a "quantum leap in climate action" to mitigate global warming, U.N. Secretary-General António Guterres said in a statement.

"Humanity is on thin ice -- and that ice is melting fast," Guterres said.

Continued greenhouse gas emissions will lead to increased warming, and every increment of increased warming will intensify hazards, but deep and rapid reductions in emissions would slow warming down within about two decades, the report states. However, some future changes, like sea level rise, are unavoidable or irreversible but can be limited with deep, rapid and sustained cuts in global greenhouse gas emissions, according to the report.

The authors emphasized, again, that the world must reach net zero by the early 2050s to limit warming to 1.5 degrees Celsius, which means any manmade carbon or greenhouse gas emissions would be eliminated or removed.

The report also lays out why that goal is so important, saying that any incremental warming beyond that amount will worsen hazards such as extreme heat and severe precipitation and increase the risks of species loss, more extreme heat days that could be dangerous to human health, and decreased yields from crops or fisheries.

"The choices and actions implemented in this decade will have impacts now and for thousands of years," the U.N. advised in the report.

The report synthesizes nearly a decade of work from the IPCC, which brings together the best climate scientists around the world to create definitive reports to guide international and domestic climate policies and goals. The language has been accepted by every country that participates in the Paris Agreement and will be used as the backdrop for climate negotiations for the rest of the year when countries are expected to submit critical updates in their plans to reduce emissions.

The literature is being framed by civil society groups as the last U.N. climate report before the world starts to run up against these critical deadlines to limit warming to 1.5 degrees Celsius, or 2.5 degrees Fahrenheit -- cutting global emissions nearly in half by 2030 and reaching net zero by 2050.

The report, which encompasses about 200 years of warming, is extremely important because it "represents the most comprehensive collection of the knowledge on climate change," Stephanie Roe, global climate and energy lead scientist for the World Wildlife Fund, told ABC News.

"It clearly lays out, essentially, the main causes and drivers of climate change, impacts from climate change and also the solutions to climate change in a way that is much more accessible and clear and succinct for policymakers, decision-makers and the general public," Roe said.

Many groups see the report as yet another call to action rather than a reason to despair.

"This IPCC report is both a blistering condemnation of major emitters' inaction and a sound blueprint for a much safer and more equitable world," Ani Dasgupta, president and CEO of the World Resources Institute, said in a statement.

The IPCC remains "hopeful" despite the dire warnings of the report, which offers a "narrow" path to secure a livable future if the world corrects course in a rapid manner, Dasgupta added.

"This involves deep emission reductions from every sector of the economy, as well as much greater investments to build resilience to climate impacts and support for people facing unavoidable climate losses and damage," Dasgupta said.

The report was approved by all 195 countries that participate in the Paris Agreement, making it the definitive summary of climate science and solutions going into the next few years of global climate talks.

Approval for the report was initially delayed over a battle between rich and developing countries over emissions targets and financial aid to vulnerable populations, The Associated Press reported.

Negotiations over the wording of key phrases of text took place among large countries such as China, Brazil, Saudi Arabia, the European Union and the U.S. over the weekend, and wording was finalized on Sunday, according to The AP.

Guterres has proposed a "Climate Solidarity Pact" to G-20 countries, which would require all big emitters to make extra efforts to cut emissions, and wealthier countries mobilize financial and technical resources to support emerging economies in a common effort to keep the goal of staying below 1.5 degrees of warming "alive."

"Every country must be part of the solution," Guterres said. "Demanding others move first only ensures humanity comes last."