English references

Analysis of six extreme heatwaves found when temperature and humidity were accounted for, all were potentially deadly for older people

Climate change is causing measurable harm globally1,2. Political and legal efforts seek to link these damages with specific emissions, including in discussions of loss and damage (L&D)3,4; however, no quantitative definition of L&D exists5,6, nor is there a framework to link past and future emissions from specific sources to monetized, location-specific damages. Here we develop such a framework, which is integrated with recent efforts to estimate the social cost of carbon7. Using empirical estimates of the non-linear relationship between temperature and aggregate economic output, we show that future damages from past emissions—one component of L&D—are at least an order of magnitude larger than historical damages from the same emissions. For instance, one tonne of CO2 emitted in 1990 caused US$180 in discounted global damages by 2020 ($40–530) and will cause an additional $1,840 through 2100 ($500–5,700). Thus, settling debts for past damages will not settle debts for past emissions. In other illustrative esti

​"Extreme heatwaves like the one impacting the Western US this month are one of the catastrophic disasters these companies predicted their conduct would bring about," said Public Citizen.

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.

El Niño could fuel extreme weather and raise temperatures to record highs this year, but how sure can we be that it will return?

The world seems headed into another El Nino, just 3 years after the last one. Such quick return normally would imply, at most, an El Nino of moderate strength, but we suggest that even a moderately strong El Nino may yield record global temperature already in 2026 and still greater temperature in 2027. The extreme warming will be a result mainly of high climate sensitivity and a recent increase of the net global climate forcing, not the result of an exceptional El Nino, per se. We find that the principal drive for global warming acceleration began in about 2015, which implies that 2°C global warming is likely to be reached in the 2030s, not at midcentury.

Welcome to the Global Climate Highlights 2025 report, compiled by the Copernicus Climate Change Service (C3S). The Global Climate Highlights 2025 report provides authoritative climate data and concise insight on a global scale about 2025's climate conditions, covering surface and sea surface temperature, heat stress, sea ice extent in the Arctic and Antarctic, among others.

The world seems headed into another El Nino, just 3 years after the last one. Such quick return normally would imply, at most, an El Nino of moderate strength, but we suggest that even a moderately strong El Nino may yield record global temperature already in 2026 and still greater temperature in 2027. The extreme warming will be a result mainly of high climate sensitivity and a recent increase of the net global climate forcing, not the result of an exceptional El Nino, per se. We find that the principal drive for global warming acceleration began in about 2015, which implies that 2°C global warming is likely to be reached in the 2030s, not at midcentury.

Climate change is making it challenging to identify future host cities.

The world's oceans absorbed a record amount of heat in 2025, an international team of scientists said Friday, further priming conditions for sea level rise, violent storms, and coral death.

A new international analysis published in Advances in Atmospheric Sciences on 9 January finds that the Earth's ocean stored more heat in 2025 than in any year since modern measurements began. The finding is the result of a major international collaboration led by the Institute of Atmospheric Physics at the Chinese Academy of Sciences, involving more than 50 scientists from 31 research institutions worldwide. The 2025 heat increase was 23 Zetta Joules (23,000,000,000,000,000,000,000 Joules of energy), which is equivalent to ~37 years of global primary energy consumption at the 2023 level (~620 Exa Joules per year). The assessment combines data from major international data centers and independent research groups, including three observational products (Institute of Atmospheric Physics at the Chinese Academy of Sciences; Copernicus Marine; and NOAA/NCEI) and an ocean reanalysis (CIGAR-RT) from three continents: Asia, Europe, and America. These groups confirm that the 2025 ocean heat content (OHC) reached the h

The datasets used to diagnose the modern history of the planet’s climate — and to proclaim that the world is now very near to 1.5 degrees Celsius (2.7 degrees Fahrenheit) of warming — typically begin with the year 1850. The new one goes all the way back to 1781. This extended time frame matters because greenhouse gases in the atmosphere increased 2.5 percent between 1750 and 1850, enough to have caused some warming that the data hasn’t accounted for.

Global temperature in 2025 declined 0.1°C from its El Nino-spurred maximum in 2024, making 2025 the second warmest year. The 2023-2025 mean is +1.5°C relative to 1880-1920. The 12-month running-mean temperature should decline for the next few months, reaching a minimum about +1.4°C. Later in 2026, we expect the 12-month running-mean temperature to begin to rise, as dynamical models show development of an El Nino. We project a global temperature record of +1.7°C in 2027, which will provide further confirmation of the recent global warming acceleration.

2024 was the hottest year on record [1], with global temperatures exceeding 1.5 °C above preindustrial climate conditions for the first time and records broken across large parts of Earth’s surface. Among the widespread impacts of exceptional heat, rising food prices are beginning to play a prominent role in public perception, now the second most frequently cited impact of climate change experienced globally, following only extreme heat itself [2]. Recent econometric analysis confirms that abnormally high temperatures directly cause higher food prices, as impacts on agricultural production [3] translate into supply shortages and food price inflation [4, 5]. These analyses track changes in overall price aggregates which are typically slow-moving, but specific food goods can also experience much stronger short-term price spikes in response to extreme heat.

Heat waves that already affect the population of the Metropolitan Area of Barcelona (AMB) could significantly intensify in the future, with temperature increases of up to 6ºC and a general reduction in relative humidity in cities by the end of the century.

Heat caused 2,300 deaths across 12 cities, of which 1,500 were down to climate crisis, scientists say

Heatwaves can lead to considerable impacts on societal and natural systems. Accurate simulation of their response to warming is important for adaptation to potential climate futures. Here, we quantify changes of extreme temperatures worldwide over recent decades. We find an emergence of hotspots where the hottest temperatures are warming significantly faster than more moderate temperatures. In these regions, trends are largely underestimated in climate model simulations. Globally aggregated, we find that models struggle with both ends of the trend distribution, with positive trends being underestimated most, while moderate trends are well reproduced. Our findings highlight the need to better understand and model extreme heat and to rapidly mitigate greenhouse gas emissions to avoid further harm.

Identifying the socio-economic drivers behind greenhouse gas emissions is crucial to design mitigation policies. Existing studies predominantly analyze short-term CO2 emissions from fossil fuels, neglecting long-term trends and other GHGs. We examine the drivers of all greenhouse gas emissions between 1820–2050 globally and regionally. The Industrial Revolution triggered sustained emission growth worldwide—initially through fossil fuel use in industrialized economies but also as a result of agricultural expansion and deforestation. Globally, technological innovation and energy mix changes prevented 31 (17–42) Gt CO2e emissions over two centuries. Yet these gains were dwarfed by 81 (64–97) Gt CO2e resulting from economic expansion, with regional drivers diverging sharply: population growth dominated in Latin America and Sub-Saharan Africa, while rising affluence was the main driver of emissions elsewhere. Meeting climate targets now requires the carbon intensity of GDP to decline 3 times faster than the global

In a rapidly changing climate, evidence-based decision-making benefits from up-to-date and timely information. Here we compile monitoring datasets (published at https://doi.org/10.5281/zenodo.15639576; Smith et al., 2025a) to produce updated estimates for key indicators of the state of the climate system: net emissions of greenhouse gases and short-lived climate forcers, greenhouse gas concentrations, radiative forcing, the Earth's energy imbalance, surface temperature changes, warming attributed to human activities, the remaining carbon budget, and estimates of global temperature extremes. This year, we additionally include indicators for sea-level rise and land precipitation change. We follow methods as closely as possible to those used in the IPCC Sixth Assessment Report (AR6) Working Group One report.

Recent simulations using the Community Earth System Model (CESM) indicate that a tipping event of the Atlantic Meridional Overturning Circulation (AMOC) would cause Europe to cool by several degrees. This AMOC tipping event was found under constant pre-industrial greenhouse gas forcing, while global warming likely limits this AMOC-induced cooling response. Here, we quantify the European temperature responses under different AMOC regimes and climate change scenarios. A strongly reduced AMOC state and intermediate global warming (C, Representative Concentration Pathway 4.5) has a profound cooling effect on Northwestern Europe with more intense cold extremes. The largest temperature responses are found during the winter months and these responses are strongly influenced by the North Atlantic sea-ice extent. Enhanced North Atlantic storm track activity under an AMOC collapse results in substantially larger day-to-day temperature fluctuations. We conclude that the (far) future European temperatures are dependent o