références en Anglais

The Antarctic Circumpolar Current (ACC) is the world's strongest ocean current and plays a disproportionate role in the climate system due to its role as a conduit for major ocean basins. This current system is linked to the ocean's vertical overturning circulation, and is thus pivotal to the uptake of heat and CO2 in the ocean. The strength of the ACC has varied substantially across warm and cold climates in Earth's past, but the exact dynamical drivers of this change remain elusive. This is in part because ocean models have historically been unable to adequately resolve the small-scale processes that control current strength. Here, we assess a global ocean model simulation which resolves such processes to diagnose the impact of changing thermal, haline and wind conditions on the strength of the ACC. Our results show that, by 2050, the strength of the ACC declines by ∼20% for a high-emissions scenario. This decline is driven by meltwater from ice shelves around Antarctica, which is exported to lower latit

Growing food is a precarious business, and losing access to key information makes it worse.

Several kinds of pressure can lead to the emergence of infectious diseases. In the case of zoonoses emerging from livestock, one of the most significant changes that has taken place since the mid twentieth century is what has been termed the "livestock revolution", whereby the stock of food animals, …

If the global consumption of fossil fuels continues to grow at its present rate, atmospheric CO2 content will double in about 50 years. Climatic models suggest that the resultant greenhouse-warming effect will be greatly magnified in high latitudes. The computed temperature rise at lat 80° S could start rapid deglaciation of West Antarctica, leading to a 5 m rise in sea level.

Global sea level rose faster than expected in 2024, mostly because of ocean water expanding as it warms, or thermal expansion. According to a NASA-led analysis, last year’s rate of rise was 0.23 inches (0.59 centimeters) per year, compared to the expected rate of 0.17 inches (0.43 centimeters) per year.

Amid President Donald Trump’s attacks on government scientists and science funding, researchers are arranging rallies to “Stand Up for Science” in Washington, D.C., and nationwide on March 7

JD Vance was supposed to be the inconsequential vice-president. But his starring role in Friday’s blowup between Donald Trump and Volodymyr Zelenskyy – where he played a cross between Trump’s bulldog and a tech bro Iago – may mark the moment that the postwar alliance between Europe and the US finally collapsed.

The tiny former Soviet republic’s determination not to be cowed by the Kremlin could provide a template for the west on how to hold back the tide of subversion and corruption

Thirteen of the ports with the highest supertanker traffic will be seriously damaged by just 1 metre of sea level rise, the analysis found. The researchers said two low-lying ports in Saudi Arabia – Ras Tanura and Yanbu – were particularly vulnerable. Both are operated by Aramco, the Saudi state oil firm, and 98% of the country’s oil exports leave via these ports.

On why collapse could be much closer than predicted: what happens when the Atlantic Ocean’s heart stops beating?

Visualize and download global and local sea level projections from the Intergovernmental Panel on Climate Change Sixth Assessment Report.

The idea that the AMOC is headed to collapse is very controversial, but it is clearly weakening. If the circulation did collapse, the consequences on both sides of the Atlantic Ocean would be immense—including large changes in temperature and a spike in weather-related disasters.

The Atlantic Meridional Overturning Circulation is the main driver of northward heat transport in the Atlantic Ocean today, setting global climate patterns. Whether global warming has affected the strength of this overturning circulation over the past century is still debated: observational studies suggest that there has been persistent weakening since the mid-twentieth century, whereas climate models systematically simulate a stable circulation. Here, using Earth system and eddy-permitting coupled ocean–sea-ice models, we show that a freshening of the subarctic Atlantic Ocean and weakening of the overturning circulation increase the temperature and salinity of the South Atlantic on a decadal timescale through the propagation of Kelvin and Rossby waves. We also show that accounting for upper-end meltwater input in historical simulations significantly improves the data–model agreement on past changes in the Atlantic Meridional Overturning Circulation, yielding a slowdown of 0.46 sverdrups per decade since 1950

Insurance costs are rising quickly across much of the country. Hurricanes are part of the reason, but it’s the other perils common across the Midwest and Great Plains that complicate costs.

The predicted El Niño is a worry, but it doesn’t guarantee the record-breaking heat we’re seeing in parts of the Northern Hemisphere.

Climate change should be at the heart of national security plans, say experts.

Jordanians now only have access to publicly distributed water a day and a half a week – prompting many to turn to illegal markets.

An extensive new multi-proxy database of paleo-temperature time series (Temperature 12k) enables a more robust analysis of global mean surface temperature (GMST) and associated uncertainties than was previously available. We applied five different statistical methods to reconstruct the GMST of the past 12,000 years (Holocene). Each method used different approaches to averaging the globally distributed time series and to characterizing various sources of uncertainty, including proxy temperature, chronology and methodological choices. The results were aggregated to generate a multi-method ensemble of plausible GMST and latitudinal-zone temperature reconstructions with a realistic range of uncertainties. The warmest 200-year-long interval took place around 6500 years ago when GMST was 0.7 °C (0.3, 1.8) warmer than the 19th Century (median, 5th, 95th percentiles). Following the Holocene global thermal maximum, GMST cooled at an average rate −0.08 °C per 1000 years (−0.24, −0.05). The multi-method ensembles and th

The story of Greenland keeps getting greener—and scarier. A new study provides the first direct evidence that the center—not just the edges—of Greenland's ice sheet melted away in the recent geological past and the now-ice-covered island was then home to a green, tundra landscape.

There is increasing concern that the Atlantic Meridional Overturning Circulation (AMOC) may collapse this century with a disrupting societal impact on large parts of the world. Preliminary estimates of the probability of such an AMOC collapse have so far been based on conceptual models and statistical analyses of proxy data. Here, we provide observationally based estimates of such probabilities from reanalysis data. We first identify optimal observation regions of an AMOC collapse from a recent global climate model simulation. Salinity data near the southern boundary of the Atlantic turn out to be optimal to provide estimates of the time of the AMOC collapse in this model. Based on the reanalysis products, we next determine probability density functions of the AMOC collapse time. The collapse time is estimated between 2037-2064 (10-90% CI) with a mean of 2050 and the probability of an AMOC collapse before the year 2050 is estimated to be 59±17%.