The period 2023-2027 will almost certainly be the hottest ever recorded on Earth, under the combined effect of greenhouse gases and the El Niño weather phenomenon, which are driving up temperatures, the UN warned on Wednesday.
In addition, global temperatures are expected to soon exceed the most ambitious goal of the Paris climate agreements, warns the World Meteorological Organization.
“There is a 98% chance 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 said.
It estimates a 66% chance that the global average annual surface temperature will exceed pre-industrial levels by 1.5°C for at least one of the next five years.
The 2015 Paris Agreement aims to keep global average temperature rise to well below 2°C above pre-industrial levels from 1850 to 1900 and if possible to 1.5°C above those same levels. levels.
Virgin territory
The data published on Wednesday “does not mean that we will permanently exceed the 1.5°C threshold of the Paris Agreement, which refers to long-term warming over many years”, underlined the Secretary-General of WMO, Mr. Petteri Taalas, quoted in a press release.
“However, the WMO is sounding the alarm by announcing that the 1.5°C threshold will be temporarily crossed and this, more and more frequently”, he underlined.
“An El Niño episode should develop in the coming months. Combined with human-caused climate change, it will drive global temperatures to unprecedented levels,” said the climate scientist.
And to leave no illusions about the seriousness of the situation, the Finn insisted on the need to prepare because “the repercussions on health, food safety, water management and the environment will be considerable”.
El Niño, is a natural climatic phenomenon generally associated with an increase in temperatures, increased drought in some parts of the world and heavy rains in others.
It last occurred in 2018-2019 and gave way to a particularly long episode of almost three years of La Niña, which causes the opposite effects and in particular a drop in temperatures.
In early May the WMO estimated that there was a 60% chance of El Niño developing by the end of July and an 80% chance by the end of September.
Typically, El Niño raises global temperatures within a year of its onset, or 2024 for this cycle.
Despite the moderating effect of La Niña, the past eight years have been the hottest on record and 2016 holds the record.
Greenhouse gases – the three main ones are CO2methane and nitrous oxide – which are at record levels in the atmosphere, trapping heat there and driving up temperatures.
Since the 1960s
“Global average temperatures are set to continue to rise, taking us further and further away from the climate we are used to,” said Leon Hermanson, expert scientist with Britain’s national weather service, the Met Office.
It is WMO’s principal center for annual to decadal climate forecasts.
This year’s predictions, which begin at the end of 2022, come from 145 ensemble members, contributed by 11 different institutes.
“Confidence in global average temperature forecasts is high, as hindcasts reveal that all measurements are highly reliable,” the WMO said.
Global average land and sea surface temperatures have increased since the 1960s.
In 2023, they are expected to be above the 1991-2020 average in almost all regions except Alaska, South Africa, South Asia and parts of Australia , according to the WMO. Parts of the South Pacific Ocean will likely be cooler than average.