PARIS, Feb 6, 2025 (BSS/AFP) - Last month was the hottest January on 
record, Europe's climate monitor said Thursday, despite expectations that 
cooler La Nina conditions might quell a streak of record-breaking global 
temperatures.

The Copernicus Climate Change Service said January was 1.75C hotter than pre-
industrial times, extending a persistent run of historic highs over 2023 and 
2024, as human-caused greenhouse gas emissions heat the planet.

Climate scientists had expected this exceptional spell to subside after a 
warming El Nino event peaked in January 2024 and conditions gradually shifted 
to a cooling La Nina phase.

But the heat has lingered at record or near-record levels ever since, 
sparking debate among scientists about what other factors could be driving 
warming to the top end of expectations.

"This is what makes it a bit of a surprise... you're not seeing this cooling 
effect, or temporary brake at least, on the global temperature that we were 
expecting to see," Julien Nicolas, a climate scientist from Copernicus, told 
AFP.

La Nina is expected to be weak and Copernicus said prevailing temperatures in 
parts of the equatorial Pacific Ocean suggested "a slowing or stalling of the 
move towards" the cooling phenomenon.

Nicolas said it could disappear completely by March.

Scientists warn that every fraction of a degree of warming increases the 
intensity and frequency of extreme weather events like heatwaves, heavy 
rainfall and droughts.

- Ocean warmth -

Last month, Copernicus said that global temperatures averaged across 2023 and 
2024 had exceeded 1.5 degrees Celsius for the first time.

This did not constitute a permanent breach of the long-term 1.5C warming 
target under the Paris climate accord -- but was a clear sign that the limit 
was being tested.

Copernicus said Arctic sea ice in January hit a monthly record low, virtually 
tied with 2018. Analysis from the United States this week put it at the 
second-lowest in that dataset.

Overall, 2025 is not expected to follow 2023 and 2024 into the history books: 
scientists predict it will rank as the third hottest year yet.

Copernicus said it would be closely monitoring ocean temperatures throughout 
2025 for hints about how the climate might behave.

Oceans are a vital climate regulator and carbon sink, and cooler waters can 
absorb greater amounts of heat from the atmosphere, helping to lower air 
temperatures.

They also store 90 percent of the excess heat trapped by humanity's release 
of greenhouse gases.

"This heat is bound to resurface periodically," said Nicolas.

"I think that's also one of the questions -- is this what has been happening 
over the past couple of years?"

Sea surface temperatures have been exceptionally warm over 2023 and 2024, and 
Copernicus said readings in January were the second highest on record.

"That is the thing that is a little puzzling -- why they remain so warm," 
Nicolas said.

- Debate -

Bill McGuire, a climate scientist from University College London, said it was 
"astonishing and frankly terrifying" that January remained at record highs 
despite La Nina emerging.

Joel Hirschi, from the UK's National Oceanography Centre, said record warmth 
persisting into La Nina was not unprecedented, pointing to similar patterns 
after recent El Nino phases.

"Global sea surface temperatures are a bit lower than in 2024 and will likely 
remain lower as we move further into 2025," he said, cautioning against 
reading too much into a single month's data.

Scientists are unanimous that burning fossil fuels has largely driven long-
term global warming, and that natural climate variability can also influence 
temperatures from one year to the next.

But natural warming cycles like El Nino could not alone explain what had 
taken place in the atmosphere and seas, and answers were being sought 
elsewhere.

One theory is that a global shift to cleaner shipping fuels in 2020 
accelerated warming by reducing sulphur emissions that make clouds more 
mirror-like and reflective of sunlight.

In December, a peer-reviewed paper looked at whether a reduction in low-lying 
clouds had let more heat reach Earth's surface.

"It's really still a matter of debate," said Nicolas.

The EU monitor uses billions of measurements from satellites, ships, aircraft 
and weather stations to aid its climate calculations.

Its records go back to 1940, but other sources of climate data -- such as ice 
cores, tree rings and coral skeletons -- allow scientists to expand their 
conclusions using evidence from much further in the past.

Scientists say the current period is likely the warmest the Earth has been 
for the last 125,000 years.