Odds are 2-1 of temporary breach to Paris treaty's lower limit in 5 years

GENEVA (AN) — In just three years, the odds of temporarily breaching the 2015 Paris Agreement's "safe" temperature guardrail rose from 20% to 66%.

In 2020, the U.N. weather agency released climate predictions showing there was about a 20% chance that one of the next five years would show Earth has warmed by at least 1.5° Celsius above pre-industrial levels.

That's what climate scientists see as the barrier for avoiding the worst effects of global warming, which is why it's the preferred limit of the 2015 Paris Agreement. Under the treaty, the world also agreed to an upper limit: nations must hold the average temperature increase to no more than 2° above the 1850 to 1900 levels.

By 2022, however, the World Meteorological Organization upped its predictions to nearly even odds – a 48% chance – that the 1.5° mark would be reached.

And on Wednesday, just a year later, WMO put the odds at 66%. It now says global temperatures are likely to surge to record levels in the next five years, fueled by manmade global warming and a naturally occurring El Niño event.

That means there are 2-to-1 odds that the annual average near-surface global temperature between 2023 and 2027 will be more than 1.5° above pre-industrial levels for at least one year.

Sounding the alarm

The odds are near certain – a 98% chance – that the next five-year period and at least one of the next five years will be the warmest on record.

“This report does not mean that we will permanently exceed the 1.5° level specified in the Paris Agreement which refers to long-term warming over many years," WMO's Secretary General Petteri Taalas said.

"However, WMO is sounding the alarm that we will breach the 1.5° level on a temporary basis with increasing frequency," he said. “A warming El Niño is expected to develop in the coming months and this will combine with human-induced climate change to push global temperatures into uncharted territory."

There's only a 1-in-3 chance – 32% – that the five-year mean will exceed the 1.5° threshold, according to the United Kingdom’s Met Office, which works with WMO. But the chances of a temporary breach during one of those years has steadily risen.

“Global mean temperatures are predicted to continue increasing, moving us away further and further away from the climate we are used to,” said Met Office meteorologist Leon Hermanson,  who led the report.

El Niño likely will affect 2024 because it usually warms global temperatures a year after it develops. The annual mean global near-surface temperature for each year between 2023 and 2027 is predicted to be between 1.1°-1.8° higher than pre-industrial levels.