UN experts: Human action causes 'extreme climate events'

The Earth's climate is changing at a "rapid and intensifying" pace, top scientists have warned following the release of a new United Nations report looking into global emissions.

The planet is getting so hot that temperatures in about a decade will probably blow past a level of warming that world leaders have sought to prevent, according to the report, released on Monday, which calls the situation a "code red for humanity."

The authoritative once-every-several years Intergovernment Panel on Climate Change (IPCC)  report, which calls climate change clearly human-caused and "unequivocal," makes more pinpointed and warmer forecasts for the 21st century than it did last time in 2013.

"This report tells us that recent changes in the climate are widespread, rapid and intensifying, unprecedented in thousands of years," said Ko Barrett, IPCC Vice Chair.

She warned unless there were "immediate, rapid and large scale reductions" in greenhouse gas emissions the aim of limiting warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) would be "beyond reach".

Each of five scenarios for the future, based on how much carbon emissions are cut, passes the more stringent of two thresholds set in the 2015 Paris climate agreement.

World leaders agreed then to try to limit warming to 1.5 degrees Celsius since the late 19th century because problems mount quickly after that.

The limit is only a few tenths of a degree hotter than now because the world has already warmed nearly 1.1 degrees Celsius (2 degrees Fahrenheit) in the past century and a half.

The report says the world will cross the 1.5 degrees Celsius warming mark in the 2030s which is about 10 years earlier than the IPCC predicted in a special report in 2018.

"What's new in this report is that we can now attribute many more changes at the global and regional level to human influence," Barrett added, stating it was now "indisputable" that human activities were causing climate change.

The 3,000-plus-page report from 234 scientists said warming is already accelerating sea level rise, shrinking ice and worsening extremes such as heat waves, droughts, floods and storms.

Tropical cyclones are getting stronger and wetter, while Arctic sea ice is dwindling in the summer and permafrost is thawing. All of these trends will get worse, the report said.

It added some harm from climate change — dwindling ice sheets, rising sea levels and changes in the oceans as they lose oxygen and become more acidic — are "irreversible for centuries to millennia".

The world is "locked in" to 15 to 30 centimeters (6 to 12 inches) of sea level rise by mid-century, said report co-author Bob Kopp of Rutgers University.

More than 100 countries have made informal pledges to achieve "net zero" human-caused carbon dioxide emissions sometime around mid-century, which will be a key part of climate negotiations this fall in Scotland.

The report said those commitments are essential.