Global greenhouse gas emissions are on a catastrophic trajectory and developed nations will fall short of a pledge made more than a decade ago to mobilize $100 billion a year by 2020 to help developing nations transition to greener economies and adapt to climate change, two reports concluded Monday.

The findings raise the stakes for — and threaten to undermine — the success of a United Nations climate summit, known as COP26, that is set to begin in Glasgow, Scotland, next week and could determine whether the world can effectively reset its climate trajectory.

Greenhouse gas emissions are on a path to increase 16 percent by the end of the decade compared with 2010, setting the world on a dangerous course of continued warming, the United Nations said in a report synthesizing the Nationally Determined Contributions — or commitments — of 192 nations to reduce emissions.

Without more-ambitious pledges, the world is projected to warm 2.7 degrees Celsius (4.9 degrees Fahrenheit) by the end of the century compared with the end of the 1800s — far above the Paris climate accord’s goal of limiting warming to “well below” 2 degrees Celsius (3.6 Fahrenheit) compared with preindustrial levels, and, if possible, to 1.5 degrees Celsius (2.7 degrees Fahrenheit).

“The message from this update is loud and clear: Parties must urgently redouble their climate efforts,” said Patricia Espinosa, executive secretary of the U.N. Framework Convention on Climate Change.

What is COP26?
World leaders will gather in Glasgow, Scotland, from Oct. 31 to Nov. 12 for the 26th annual United Nations conference on climate change. (Joy Yi/The Washington Post)

She said that “overshooting the temperature goals will lead to a destabilized world and endless suffering, especially among those who have contributed the least” to climate change.

A separate report Monday from Canadian Environment Minister Jonathan Wilkinson and Jochen Flasbarth, his German counterpart, said rich countries would probably meet their goal of providing $100 billion annually to developing nations in 2023 — three years behind schedule.

The pair was tasked by COP26 President Alok Sharma with coming up with a plan to deliver the funds — an issue he has called “totemic.” The failure of rich countries to meet their goal has fueled mistrust among developing nations, which historically have done less to fuel climate change but are disproportionately vulnerable to its consequences.

The issue is poised to be a major sticking point at COP26, where slowing the world’s warming will depend on good faith and collective action. Many developing nations have said their climate pledges are conditional on receiving outside support.

“I’m disappointed, as are developing countries,” Flasbarth told reporters Monday. “But … there is a lot of money already on the table. There is a lot of support and it will increase and it has to increase.”

The report, which is based on projections from the Organization for Economic Cooperation and Development, estimates that financing will reach or surpass $100 billion in 2023 and exceed $110 billion in 2025. Many analysts have said the initial $100 billion-a-year goal is insufficient.

Mohamed Adow, director of Power Shift Africa, a Nairobi-based think tank, said the inability of rich countries to keep their promise is “utterly shameful.”

“Poor nations will not be conned,” he said, “and the leaders of the developed world need to pull their finger out and get this money on the table if COP26 is going to be a success.”

Eddy Pérez, international climate diplomacy manager for Climate Action Network Canada, said that while the “level of honesty” from rich countries about missing their collective target is welcome, the gap is “unacceptable.”

“The question today is: Does this document actually show the urgency that it is for rich countries to massively scale up climate finance flows during the COP … and the clear answer is no,” he said. “The message that is coming from this document is you need to wait until 2023 to see if we will be able to deliver the $100 billion.”

The report doesn’t name and shame individual countries, but says that “all developed countries have to step up efforts.” It said one reason developed nations have missed their target is because “private finance mobilization underperformed against expectations.”

Efforts to marshal the funding have been complicated by debates about whether the aid should take the form of loans or grants. Determining how much has been mobilized has been difficult because of a lack of uniformity in how countries account for climate finance.

An analysis last month from the OECD found that developed nations marshaled $79.6 billion in 2019 — up 2 percent from 2018, but $20 billion short of the promise. Final totals for 2020 aren’t yet available, but officials said it was becoming clear the goal hadn’t been met. The OECD estimates funding ranging from $83 billion to $88 billion this year.

President Biden announced last month at the U.N. General Assembly that he would work with Congress to double U.S. funding provided each year to help low-income nations combat climate change to $11.4 billion by 2024.