Focus Climat

Last month was the hottest January on record, blitzing the previous high and stunning climate scientists who expected cooler La Niña conditions to finally start quelling a long-running heat streak. 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.

A Dartmouth College research team came up with the estimated pollution caused by 111 companies, with more than half of the total dollar figure coming from 10 fossil fuel providers: Saudi Aramco, Gazprom, Chevron, ExxonMobil, BP, Shell, National Iranian Oil Co., Pemex, Coal India and the British Coal Corporation. For comparison, $28 trillion is a shade less than the sum of all goods and services produced in the United States last year.

Action urgently needed to save the conditions under which markets – and civilisation itself – can operate, says senior Allianz figure

No one knows when the next alert or request to save a chunk of US government-held climate data will come in. Such data, long available online, keeps getting taken down by US President Donald Trump's administration. For the last six months or so, Cathy Richards has been entrenched in the response. She works for one of several organisations bent on downloading and archiving public data before it disappears.

A superpower in the fight against global heating is hiding in plain sight. It turns out that the overwhelming majority of people in the world – between 80% and 89%, according to a growing number of peer-reviewed scientific studies – want their governments to take stronger climate action.

Global temperature for 2025 should decline little, if at all, from the record 2024 level. Absence of a large temperature decline after the huge El Nino-spurred temperature increase in 2023-24 will provide further confirmation that IPCC’s best estimates for climate sensitivity and aerosol climate forcing were both underestimates. Specifically, 2025 global temperature should remain near or above +1.5C relative to 1880-1920, and, if the tropics remain ENSO-neutral, there is good chance that 2025 may even exceed the 2024 record high global temperature.

Tipping elements within the Earth system are increasingly well understood. Scientists have identified more than 25 parts of the Earth’s climate system that are likely to have “tipping points” – thresholds where a small additional change in global warming will cause them to irreversibly shift into a new state. The “tipping” of these systems – which include the Atlantic Meridional Overturning Circulation (AMOC), the Amazon rainforest and the Greenland ice sheet – would have profound consequences for both the biosphere and people. More recent research suggests that triggering one tipping element could cause subsequent changes in other tipping elements, potentially leading to a “tipping cascade”. For example, a collapsed AMOC could lead to dieback of the Amazon rainforest and hasten the melt of the Greenland ice sheet.

Eat-Lancet report recommended shift to more plant-based, climate-friendly diet but was extensively attacked online [...] The report recommended that if global red meat eating was cut by 50%, the “planetary health diet” would provide nutritious food to all while tackling the harms caused by animal agriculture, which accounts for over 14% of all greenhouse gas emissions worldwide. It suggested individuals – particularly in wealthy countries – should increase their consumption of nuts, pulses and other plant-based foods while cutting meat and sugar from their diets.

Climate experts expressed shock and dismay at the move. “It would be a bit like unplugging the equipment that monitors the vital signs of a patient that is critically ill,” one said.

Recent projections suggest that large geographical areas will soon experience heat and humidity exceeding limits for human thermoregulation. The survivability limits modeled in that research were based on laboratory studies suggesting that humans cannot effectively thermoregulate in wet bulb temperatures (Twb) above 26 to 31 °C, values considerably lower than the widely publicized theoretical threshold of 35 °C. The newly proposed empirical limits were derived from the Twb corresponding to the core temperature inflection point in participants exposed to stepped increases in air temperature or relative humidity in a climate-controlled chamber. Despite the increasing use of these thermal-step protocols, their validity has not been established. We used a humidity-step protocol to estimate the Twb threshold for core temperature inflection in 12 volunteers.

2024 marks the first time since record keeping began that all of the 10 hottest years have fallen within the most recent decade.

During the Cold War, the US poured support into Arctic military outposts and climate research amid fears of a Russian invasion. Climate change is still on the military’s radar as a threat multiplier.

Countries must move rapidly to slash CO2 emissions from homes, offices, shops and other buildings—a sector that accounts for a third of global greenhouse gas pollution, the United Nations said Monday. Carbon dioxide emissions from the building sector rose around 5% in the last decade when they should have fallen 28%, according to a new report by the United Nations Environment Program (UNEP).

Injecting pollutants into the atmosphere to reflect the sun would be extremely dangerous, but the UK is funding field trials

As if there was any doubt, we can go ahead and officially add climate change to the list of things that we can’t count on billionaires to figure out for us. According to the New York Times, Breakthrough Energy, a joint venture between Bill Gates and a handful of other billionaires who at least nominally care about the environment, is laying off a significant portion of its staff, which will likely neuter its capability to lobby and influence policy.

The clear signs of human-induced climate change reached new heights in 2024, which was likely the first calendar year to be more than 1.5°C above the pre-industrial era, with a global mean near-surface temperature of 1.55 ± 0.13 °C above the 1850-1900 average.

Donald Trump’s administration is to reconsider the official finding that greenhouse gases are harmful to public health, a move that threatens to rip apart the foundation of the US’s climate laws, amid a stunning barrage of actions to weaken or repeal a host of pollution limits upon power plants, cars and waterways.

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.

The Trump administration is targeting climate organizations that received a Biden-era grant.

The U.S. military is canceling more than 90 studies, including some that U.S. Defense Secretary Pete Hegseth dismissed as climate change "crap." Military and intelligence officials have over the past decade identified potential security threats from climate change that include natural disasters in densely populated coastal areas and damage to American military bases worldwide.