Mers et océans

OA - Liste

« L’océan mondial, qui abrite la majorité des espèces vivantes sur Terre (50 à 80 % selon les estimations), génère plus de 60 % des services écosystémiques qui nous permettent de vivre, à commencer par la production de la majeure partie de l’oxygène que nous respirons. Il absorbe environ 30 % des émissions de CO2 générées par l’humanité, ce qui provoque son acidification.
L’océan mondial régule à plus de 80 % le climat de la Terre. Il joue un rôle majeur dans la température terrestre.
 »
Source : Wikipedia

Coalition citoyenne pour la protection de l’Océan

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océan

juillet 2026

Increasing instability of the ocean, ice and atmosphere threatens farming, finance and society. We all need to wake up to that fact.
Weather cycle threatens harvests worldwide, adding to inflation already fuelled by the Iran war
Daily Sea Surface Temperature
A vast system of Atlantic currents that delivers warmth to northern Europe is at risk of collapse, according to a growing body of research. The latest study to warn of its demise finds there is at least a 10 percent chance that a collapse may already be “locked in.”
European scientists warn of consequences for weather patterns, the global climate and marine life

juin 2026

Nearly every indicator of climate change is flashing red. But we still hold the tools available to bring the planet back into balance
Projections of near-term climate change are a potential research tool. However, for that tool to be most useful, the physical basis for a prediction must be made clear. The basis for our projection of record 2026 global temperature is high climate sensitivity, with its implication that aerosol cooling was still increasing during the period 1970-2005. One consequence, global sea surface warming, already has important effects. Causes of climate change must be understood for policy purposes. Figures in this post and our recent papers are continually updated on our website.[1] We are also now on Substack[2].
The Trump administration is dismantling a $368 million deep-ocean observation system that was put in place a decade ago to monitor coastal environments, marine ecosystems and powerful currents that affect the global climate.
Global effort needed to limit effects of pollution, industrial fishing and climate crisis, World Ocean Assessment says
In the icy waters of the Southern Ocean, whales and other marine mammals rely on krill to survive. But as the market for human dietary supplements and animal feeds booms, and climate change reduces krill populations, scientists worry there may not be enough to go around.
You may have heard the rumors of a "monster El Niño." It's not the first time we've heard forecasts like this in Australia, but this time, they aren't coming out of nowhere. Early signs in the Pacific have been building for months and forecasts now point to a high likelihood of a moderate to strong El Niño developing in 2026.
Brutal El Nino, drought, war threatens food supply

mai 2026

A five-year study found that warming oceans are causing Maine’s underwater kelp forests to disappear and be replaced by turf algae.
A fire fighter tackles a wildfire
The process of relocating people from New Orleans should start immediately, as the city has reached a “point of no return” that will see it surrounded by the ocean within decades due to the climate crisis, a stark new study has concluded. Ongoing sea-level rise and the rampant erosion of wetlands in southern Louisiana will swallow up the New Orleans area within a few generations, with the new paper estimating the city “may well be surrounded by the Gulf of Mexico before the end of this century”.

avril 2026

Climate models show considerable discrepancies in their future projections around the Atlantic, mainly due to uncertainties in the fate of the Atlantic Meridional Overturning Circulation (AMOC). Climate models suggest a reduction in AMOC strength of 32 ± 37% by 2100 (90% probability, Shared Socioeconomic Pathways 2-4.5 scenario, Coupled Model Intercomparison Project Phase 6). To refine this estimate and reduce its uncertainty, we use four different observational constraint methods. The best one, which provides the lowest leave-one-out error, integrates a large set of observable variables using ridge-regularized linear regression—a method unusual in climate science. It gives an estimate of the AMOC slowdown of 51 ± 8% (90% probability), i.e., a weakening ∼ 60% stronger than suggested by the multimodel mean. This refinement mainly results from correcting a bias in South Atlantic surface salinity, consistent with recent studies emphasizing its role in the proximity to an AMOC tipping point. This more substantial
Beneath the surface of the Pacific, a massive pool of heat is preparing to reshape global weather patterns. Time is running out to prepare for a climate shock of unprecedented scale. As 2026 unfolds, the Pacific Ocean is priming a catastrophic El Niño that threatens to cripple global food systems, trigger widespread economic instability, and shatter planetary temperature records.
The critical Atlantic current system appears significantly more likely to collapse than previously thought after new research found that climate models predicting the biggest slowdown are the most realistic. Scientists called the new finding “very concerning” as a collapse would have catastrophic consequences for Europe, Africa and the Americas.

mars 2026

Models are converging on prediction of an El Nino beginning this year, peaking in early 2027. After overlooking the possibility of an El Nino this year, some reporting is jumping on a “Super El Nino” bandwagon. El Nino strength and frequency are important, especially the issue of whether these are modified by global warming. However, the more important knowledge that needs to be extracted from near-term global warming concerns interpretation of ongoing, extraordinary, acceleration of ocean surface warming. Impacts of this ocean warming include a factor of two greater warming over land, increased extreme precipitation, and poleward movement of subtropical conditions.

février 2026

The Gulf Stream is part of the Atlantic Meridional Overturning Circulation (AMOC). The AMOC is a tipping element and may collapse under changing forcing. However, the role of the Gulf Stream in such a tipping event is unknown. Here, we investigate the link between the AMOC and Gulf Stream using a high-resolution (0. 1°) stand-alone ocean simulation, in which the AMOC collapses under a slowly-increasing freshwater forcing. AMOC weakening gradually shifts the Gulf Stream near Cape Hatteras northward, followed by an abrupt northward displacement of 219 km within 2 years. This rapid shift occurs a few decades before the simulated AMOC collapse. Satellite altimetry shows a significant (1993–2024, p < 0.05) northward Gulf Stream trend near Cape Hatteras, which is also confirmed in subsurface temperature observations (1965–2024, p < 0.01). These findings provide indirect evidence for present-day AMOC weakening and demonstrate that abrupt Gulf Stream shifts can serve as early warning indicator for AMOC tipping.