Pledges made by so far by countries around the globe to cut greenhouse gas emissions fall strikingly short of the profound changes necessary to avoid the most catastrophic impacts of climate change, the United Nations said Friday.

The U.N. analysis comes as presidents and prime ministers face pressure to ramp up the promises they made as part of the Paris climate accord in 2015. Through the end of last year, roughly 75 countries representing about 30 percent of global emissions had updated their initial plans ahead of a key U.N. climate summit this fall in Scotland.

But so far, U.N. officials reported Friday, those more ambitious pledges are hardly ambitious enough. Even if countries follow through, their combined impacts would put the world on a path to achieve only a 1 percent reduction in global emissions by 2030, compared to 2010 levels. By contrast, scientists have said that emissions must fall by nearly 50 percent this decade for the world to realistically have a shot at avoiding devastating temperature rise.

“Current levels of climate ambition are very far from putting us on a pathway that will meet our Paris agreement goals,” said Patricia Espinosa, executive secretary of the U.N. Framework Convention on Climate Change. “While we acknowledge the recent political shift in momentum toward stronger climate action throughout the world, decisions to accelerate and broaden climate action everywhere must be taken now.”

Only two of the world’s 18 largest emitters — the European Union and the United Kingdom — submitted plans with substantially bolder emissions-cutting targets in 2020. So far, they are the exception among the globe’s biggest carbon polluters.

“One thing that gets lost in this report’s top-line findings is the deeply encouraging news that a number of countries put forward really bold climate targets last year, such as Colombia, Argentina, the United Kingdom and the European Union,” Helen Mountford, vice president for climate and economics at the World Resources Institute, said in a statement.

“The problem is that those taking ambitious action are being overshadowed by a few countries that are lagging behind, like Brazil and Mexico, which put forward new plans that have even weaker targets than what they put forward five years ago, and Australia and Russia, which did not strengthen their efforts at all. These laggards must stop fiddling while the world burns.”

China, the world’s largest emitter, has a developing economy that relies heavily on coal-burning power plants. The Chinese have no plans to begin scaling back their pollution until emissions levels peak around 2030. They have said they expect to stop adding to the global warming problem by 2060.

The United States, the world’s second-biggest emitter, only just rejoined the Paris accord. President Biden has made clear that he wants to put the country on a path to decarbonize the electricity sector by 2035, and to eliminate the nation’s carbon footprint 15 years after that.

“Nothing less than bold action in this decade can set the entire world on the path that we have confidence will get to net-zero emissions by 2050 — or earlier,” Biden’s climate envoy, John F. Kerry, told the U.N. Security Council this week. “For those that argue that climate action is just too expensive, study after study confirms that now at this moment in our history, inaction comes with a far higher price tag than action,” he added.

The U.N. analysis on Friday echoed the findings of another report from earlier this month, which found that the current national pledges to cut emissions are woefully weak. Even if countries were to meet their existing pledges, that study found, the world has only about a 5 percent chance to limit the Earth’s warming to “well below” 2 degrees Celsius (3.6 Fahrenheit) over preindustrial levels — a key aim of the international agreement.

Adrian Raftery, a University of Washington statistics professor and co-author of the study, and a colleague calculated that global emissions would need to fall steadily — about 1.8 percent each year on average — to put the world on a more sustainable trajectory. While no two countries are alike, that amounts to overall emissions reductions roughly 80 percent more ambitious than those pledged under the Paris agreement, he said.

In many respects, the race to slow the Earth’s warming amounts to a harrowing math equation. Emissions have risen about 1.4 percent annually on average over the past decade, not including the abnormal plunge in 2020 driven by the coronavirus pandemic.

In 2019, the world logged the highest emissions ever recorded, at 59 billion tons of carbon dioxide equivalent emissions, a category that includes not only carbon dioxide but also methane and other climate-warming agents. If that trend continues unchecked, scientists say, the world could begin to cross troubling climate thresholds within the coming decade.

The architects of the Paris accord knew that the initial pledges that countries made in 2015 were not enough to limit warming to acceptable levels — rather, they represented a down payment that made the unprecedented international agreement possible. The expectation was always that nations would grow more ambitious with time.

While there is evidence that is happening, the refrain from scientists and the United Nations alike has been that it is not happening nearly fast enough.

Global emissions have continued to rise. Countries have failed to hit even modest targets. And the consequences of a warming world have become ever more tangible, deadly and expensive.

“The warning signs are everywhere,” U.N. Secretary General António Guterres said earlier this month on the day the United States formally rejoined the Paris accord. “The six years since 2015 have been the six hottest years on record. Carbon dioxide levels are at record highs. Fires, floods and other extreme weather events are getting worse, in every region. If we don’t change course, we could face a catastrophic temperature rise of more than 3 degrees this century.”

Aubrey Webson, chair of the Alliance of Small Island States, a group of 44 islands and low-lying coastal states around the world that act as a bloc at international climate talks, said Friday that promises from countries to be carbon-neutral by 2050 are largely meaningless without more immediate, concrete plans to cut emissions.

“This report confirms the shocking lack of urgency, and genuine action,” Webson, an ambassador to the U.N. from Antigua and Barbuda, said in a statement. “We are flirting dangerously with the 1.5C warming limit that the world agreed we need to stay within. It is small island developing states like ours that will pay the ultimate price if we do not.”