by Scenarios of an impending hellish summer on earth, with unprecedented heat waves due to climate change, have flooded the internet.
But little attention has been paid to a major new study by an international team of scientists on the evolution of global warming and its still unknown effects on the oceans.
About 89% of the heat accumulated by the Earth in total for almost half a century (1971-2020) is stored there, they point out.
The rest, they explain, goes “about 6% on land, 1% in the atmosphere, and 4% in the molten cryosphere.” That is, on the Earth’s surface where water is in solid form, like snow and ice.
But in the last 15 years of this period, i.e. between 2006 and 2020, the heat accumulation has reached almost the cumulative levels of 1960 to the mid-2000s.
This is a significant acceleration, which is particularly worrying.
It is no coincidence that “the last 10 years have been the warmest decade for the oceans since at least the 1800s”, underlines NASA.
“2022 was the warmest year in the oceans and the highest global sea level on record,” he adds.
This year, the bad omens started early.
Data from the University of Maine’s Climate Change Institute showed that in mid-March the global average sea surface temperature – between latitudes 60 degrees north and 60 degrees south – was the warmest on record .
Over the past two months, the average temperature has risen by almost two tenths of a degree Celsius, according to the university’s prestigious Climate Reanalyzer platform.
And off the east coast of North America, the temperature has been measured locally up to 13.8 degrees Celsius warmer than the 1981-2011 average.
Ocean “kettles”?
Compared to pre-industrial levels, the average sea surface temperature is estimated to have increased by about 0.9 degrees Celsius.
This could indeed fall far short of the Paris Agreement targets – according to many overwhelmed experts – of limiting the increase in the Earth’s average temperature to 1.5 degrees Celsius.
But on the surface of the seas – which correspond to 71% of the surface of the planet – this increase has been exponential in recent years.
Of the 0.9 degrees Celsius, 0.6 have been recorded over the past 40 years.
It also takes “much more energy to heat water than land”, explains the BBC. In addition, “the oceans absorb heat well below their surface”.
As long as their surface temperatures continue to rise, experts warn of an increasingly bleak future.
The effects will become visible with the loss of biodiversity and the extinction of entire marine species, at all levels of the food chain.
Due to thermal expansion, sea levels will rise, possibly accelerating the melting of glaciers to a catastrophic rate and putting other ecosystems in immediate danger.
Coastal flooding will become more intense. But they won’t be the only ones.
Increased sea surface heat means more extreme events, such as cyclones.
Starting another vicious circle, rising ocean temperatures mean less ability to absorb carbon dioxide from the atmosphere.
Today, as things stand, they absorb about a quarter of greenhouse gas emissions.
However, as the scientific journal Nature pointed out in a recent related article, “although the marine ‘carbon sink’ is larger than expected, it remains insufficient to contain global warming”.
More likely when it gets destroyed over time…
The climate… “the chicken and the egg”
A series of articles in the international press point out that the new findings have caused deep concern, even concern, in the scientific community.
The fear is that this trend of rapidly rising sea surface temperatures could signal a sudden acceleration of climate change.
They are not sure though.
In fact, they cannot even accurately attribute the causes of the phenomenon.
Some scientists believe that the warming of the oceans is part of the regular cycle of the El Niño phenomenon.
In fact, meteorologists are warning that this year we will see extreme outbreaks of the phenomenon.
Other scientists wonder if this is to blame for the record average sea surface temperature.
“It’s an unusual pattern,” Gabriel Vecchi, professor of geosciences at Princeton University, told the AP.
Ben Webber, a senior lecturer in climatology and a member of the research group at the Center for Ocean and Atmospheric Sciences at the University of East Anglia, expressed a similar concern to the Guardian.
He called it an “anomaly” that temperatures stay so above average for so long at this time of year.
“It’s very unusual,” he said. “This is moving in an unprecedented direction and could take us into uncharted waters.”
