Saying humanity is waging war with the planet, the head of the United Nations isn't planning to let just any world leader speak about climate change at Monday's special "action summit."

Only those with new, specific and bold plans can command the podium and the ever-warming world's attention, Secretary-General Antonio Guterres said.

So sit down, Brazil. Sit down, Saudi Arabia. Sit down, Poland.

"People can only speak if they come with positive steps. That is kind of a ticket," Guterres said. "For bad news don't come."

As if to underscore the seriousness of the problem, the UN's World Meteorological Organization released a science report Sunday showing that in the last several years, warming, sea level rise and carbon pollution have all accelerated.

Brazil's, Poland's and Saudi Arabia's proposals for dealing with climate change fell short, so they're not on Monday's summit schedule. The United States didn't even bother, according to a UN official, who spoke on condition of anonymity.

The bar isn't that high: Leaders from 64 nations, the European Union, more than a dozen companies and banks, a few cities and a state will present plans at the secretary-general's Climate Action Summit.

Guterres wants nations to be carbon-neutral by 2050 -- in other words, they will not add more heat-trapping greenhouse gases into the air than are removed by plants and perhaps technology each year. On Sunday, 87 countries around the world pledged to decarbonize in a way consistent with one of the international community's tightest temperature goals.

There is a sense of urgency, Guterres said, because "climate change is the defining issue of our time."

"For the first time, there is a serious conflict between people and nature, between people and the planet," Guterres said.

He wants countries to commit to no new coal power plants after 2020 and reduce carbon pollution by 45% in the next century. The purpose of the summit is to come up with new green proposals a year earlier than the 2020 deadline that is in the 2015 Paris climate agreement.

On Sunday, the United Nations announced that it will cut its own carbon pollution 25% in the next six years and 45% by 2030.

World leaders agreed in 2009 to try to keep warming to just 2 degrees Celsius (3.6 degrees Fahrenheit) since pre-industrial times. Then in 2015 they added a secondary, tougher goal, at the urging of small islands, to keep warming to just 1.5 degrees Celsius (2.7 degrees Fahrenheit).

The new weather agency report showed that the world has warmed already by 1.1 degrees Celsius (2 degrees Fahrenheit). So that means the goals are to limit further warming to 0.9 degrees Celsius (1.6 degrees Fahrenheit) from now or even 0.4 degrees Celsius (0.72 degrees Fahrenheit) from now.

Efforts to reduce carbon pollution need to be tripled to keep from hitting the 2-degree Celsius mark and must increase fivefold to limit warming to 1.5 degrees Celsius since pre-industrial times, the World Meteorological Organization report said.

As bad as that sounds, it's wrong and overly optimistic to use the mid-1880s as the benchmark, said Pennsylvania State University climate scientist Michael Mann. Mann said that many studies, including the WMO's, are overlooking that the world warmed 0.2 degrees Celsius (0.36 degrees Fahrenheit) from human causes between the mid-1700s and the 1880s.

The weather agency said the last five years were the warmest five on record and even 0.2 degrees Celsius (0.36 degrees Fahrenheit) hotter than the first half of the decade, a significant jump in just a few years.

"There is a growing recognition that climate impacts are hitting harder and sooner than climate assessments indicated even a decade ago," the 28-page report said.

If the world keeps temperatures to the 1.5-degree Celsius goal instead of the 2-degree one, 420 million fewer people will be exposed to heat waves and 10 million fewer will be vulnerable to sea level rise, NASA climate scientist Cynthia Rosenzweig said Sunday at a UN session.

A larger, more international report looking at climate change and oceans and ice will be released by the Intergovernmental Panel on Climate Change on Wednesday.

"This new WMO report highlights the importance of making more progress on reducing emissions of carbon dioxide," Cornell University climate scientist Natalie Mahowald said. "Hopefully this latest UN Climate Summit will motivate more action."