Breaching 1.5 degrees may only be temporary, the WMO said. But it would mean the world has crossed a critical climate threshold, a signal of how quickly climate change is accelerating. And as temperatures surge, there is a 98% likelihood that at least one of the next five years, and the five-year period as a whole, will be the warmest on record, the WMO reported.
Countries pledged in the Paris Climate Agreement to limit global warming to well below 2 degrees – and preferably to 1.5 degrees – compared to pre-industrial temperatures. Scientists consider 1.5 degrees of warming as a key tipping point, beyond which the chances of extreme flooding, drought, wildfires and food shortages could increase dramatically.
In its annual climate update, the WMO said that between 2023 and 2027, there is now a 66% chance that the global average temperature will breach 1.5 degrees Celsius – or 2.7 degrees Fahrenheit – of warming for at least one year.
“This report does not mean that we will permanently exceed the 1.5 degrees Celsius level specified in the Paris Agreement which refers to long-term warming over many years. However, WMO is sounding the alarm that we will breach the 1.5 degrees Celsius level on a temporary basis with increasing frequency,” said WMO Secretary-General Professor Petteri Taalas, in a statement.
The temperature increases are fueled by the rise of planet-heating pollution from burning fossil fuels, as well as the predicted arrival of El Niño, a natural climate phenomenon with a global heating effect.
“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,” Taalas said. “This will have far-reaching repercussions for health, food security, water management and the environment. We need to be prepared.”
The current hottest year on record is 2016, which followed a very strong El Niño event. El Niño tends to ramp up the temperatures the year after it develops, which could put 2024 on track to be the hottest year on record.
The world has already seen around 1.2 degrees of warming, as humans continue to burn fossil fuels and produce planet-heating pollution. And despite three years of cooling La Niña, temperatures have soared to dangerous levels. The last eight years were the warmest on record.
The report stated that the chance of temporarily exceeding 1.5 degrees Celsius has risen steadily since 2015, when the WMO put the chance of breaching this threshold at close to zero.
The annual mean global near-surface temperature for each year between 2023 and 2027 is predicted to be between 1.1 degrees Celsius and 1.8 degree Celsius higher than the 1850-1900 average, said the WMO. That refers to the period before the sharp increase of planet-heating pollution from burning fossil fuels.
“Global mean temperatures are predicted to continue increasing, moving us away further and further away from the climate we are used to,” said Leon Hermanson, a Met Office expert scientist who led the report, in a statement.