The fever no longer wants to fall back. After land temperatures, these are global oceanic temperatures that spray all recordswith devastating consequences for marine ecosystems. Since March 2023, the oceans have been suffocated under extreme temperatures over a period of 450 days. A phenomenon that goes beyond the most pessimistic projections of climatologists.
Thanks to a study from the University of Reading (England), We now know why. This was published on January 28 in the journal Environmental Research Letters and the results are frankly alarming.
A thermal excitement that accelerates
Thanks to the analysis of satellite data since 1985, the researchers fell on this conclusion: Heat absorption speed has multiplied by four in 40 years. The researchers have established a clear correlation between the increase in the temperature of the oceans and the intensification of the earth’s radiative assessment (difference between the solar radiation absorbed by the earth and the infrared radiation which it emits towards space).
It is the latter which determines the average temperature of the earth and It now displays a surplus that has doubled since 2010. This means that there is more solar energy absorbed by our planet than infrared energy returned to space. The oceans, real thermal tanks, now absorb 90 % of this excess heat.
To illustrate the acceleration of the warming of the oceans, Christopher Merchant, professor of oceanography in Reading, uses the image of a bathtub. In the 1980s, warming was comparable to a thin net of hot water. Today, the flow has increased considerably: The tap is open at full speedand the water temperature rises very quickly.
The oceans, victims of a triple penalty
This accelerated warming Results from several convergent factors. First, greenhouse gases, mainly from the fossil fuels industry, constitute the main cause, representing 44 % of excess heat during the El Niño years. Hot phases of a natural climate cycle in the peaceful ocean, characterized by abnormally high surface temperatures.
By an unexpected reversal, Atmospheric depollution efforts have caused a perverse effect : The decrease in sulfuré aerosols, especially in international maritime transport and Chinese industry, has reduced the training of sea clouds, which act like the reflective shields of our planet. This modification of the oceanic albedo (proportion of solar radiation reflected by the surface of the ocean towards space) has been combined with the effects of El Niño, which itself instilled an additional increase of 0.1 to 0.2 ° C in the global system.
Merchant explains: ” These are the oceans dictating the tempo of global warming on a planetary scale ».
The repercussions of this thermal disturbance are already before our eyes. The month of April 2024 scored a dramatic tilting point: 77 % of coral reefs on the planet underwent massive whitening, jeopardizing not only a quarter of marine biodiversity, but also the subsistence of a billion human beings depending on these ecosystems.
In tropical areas, overheated water masses feed meteorological phenomena of formidable intensity. Do you remember Héragan Hélène? It was the perfect example: in the space of 24 hours, this tropical system drew from these thermal tanks the energy necessary to transform from a category 1 storm in a category 4 monster, before S ‘ shoot on the Floridian coast. Two weeks later, Hurricane Milton ravaged everything in its path, in the same place.
Climate models for 2045 are not more radiant : ocean thermal accumulation of the next two decades could surpass that of previous forty years. Even if these simulations have uncertainties, they rarely be mistaken on major trends. In such a situation, the institutional inertia of political decision -makers is one of our worst enemies, because it mortgages our ability to adapt to changes already in progress and limit irreversible damage. And This is precisely what is happening. “” The cascading consequences – fires, droughts, floods – will only get worse. It is urgent to become aware of it, but especially that governments understand that upcoming upheavals are likely to be much faster than they anticipate »Merchant alert
- The oceans undergo unprecedented warming, accelerated by the massive absorption of excess heat.
- Several factors, including the increase in greenhouse gases and the decrease in marine clouds, aggravate this trend.
- The consequences will be catastrophic: in danger marine ecosystems, more violent hurricanes and destructive climatic impacts to come in the next decade.
