A leading group of international climate scientists is warning that “large-scale strategies” are needed immediately to reduce greenhouse gas emissions and avert “catastrophic circumstances” that threaten every part of the world.

In a paper published yesterday in the journal Science, 21 researchers from 14 countries said climate change is already damaging the planet more than scientists had projected, endangering everything from food supply to the existence of island nations.

Heat waves are intensifying in North America and Europe. Underwater heat waves are killing deepwater habitats and coral reefs. Insect populations are dwindling, threatening the food chain. And larger, more frequent wildfires, such as the blazes that have killed more than 100 people in California since 2017, are destroying forests and communities around the world.

“All of these things are happening faster than we thought,” Rachel Warren, one of the authors, said in an interview. “There are more floods, more wildfire, more sea-level rise, more melting ice.” Warren is a professor of global change and environmental biology at the University of East Anglia in the United Kingdom.

The paper comes four days before the United Nations convenes its Climate Action Summit in New York City to address what the organization calls “the global climate emergency.” U.N. Secretary-General António Guterres has invited world leaders to bring “realistic plans” to cut their nations’ greenhouse gas emissions by 45% over the next decade.

The Science paper underscores the urgency. It exhorts the international community to limit global warming to 1.5 degrees Celsius over preindustrial levels by 2100 and warns about widespread harm if the global mean surface temperature rises by 2 degrees in that period.

Investments costing between $2 trillion and $4.5 trillion a year could prevent a 2-degree temperature increase and avoid $500 trillion in damages by 2200, the paper says.

It draws extensively from a special report released in October by the United Nations’ Intergovernmental Panel on Climate Change that warned about the danger of global temperatures rising 2 degrees above those recorded from 1850 to 1900. The paper’s lead author, Ove Hoegh-Guldberg, who is director of the Global Change Institute at the University of Queensland in Australia, also was the lead author of the special IPCC report (Climatewire, Oct. 15, 2018).

“We’re trying to change the message we’re projecting from ‘This is going to happen’ to ‘This is already happening, and to prevent this from getting worse, action needs to be ramped up,’” Warren said. “Scientists are very, very concerned. The picture for humans and ecosystems is really pretty grim if we don’t achieve this.”

Nations have pledged to reduce greenhouse gas emissions under the Paris Agreement signed in 2015, but those pledges are proving to be inadequate, Warren said.

Drawing on 73 papers and studies, most of them published in the past two years, the international team of scientists described the vast harm that has been caused already by global temperatures rising 1 degree Celsius over preindustrial levels.

“Deep and fundamental changes are under way in biological systems with just 1.0° C of global warming so far,” the paper says.

Climate change endangers people by intensifying hurricanes, heat waves and drought and by reducing crop yields, seafood supplies and fresh water, the paper says. Climate change also endangers ecosystems such as coral reefs, which have faced extensive damage already.

A 1.5-degree temperature increase will require “extensive adaptation,” the paper says, adding that “there are limits to adaptation ... and it may not be feasible to protect all coastal regions from erosion and loss of land.”

Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news atwww.eenews.net.