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The Arctic is at the forefront of global climate change and is encountering unprecedented winter warming. In February 2025, exceptionally high air temperatures and rainfall over Svalbard triggered widespread snowmelt and pooling of meltwater. Increasingly frequent winter thaw events are reshaping Arctic landscapes, signaling a dramatic shift towards a new Arctic.

Abstract

Ecosystem respiration (ER) is the largest contributor to terrestrial carbon loss. ER responds positively to increasing temperature, so a warming world is hypothesized to lead to additional CO2 release, potentially further exacerbating climate warming. The long-term influence of thermal changes on this carbon–climate feedback, however, remains unresolved. Here, by compiling data from 221 eddy covariance sites worldwide, we observe decreases in the temperature sensitivity and reference respiration rates of ER with increasing mean annual temperature, suggesting that ER adapts to temperature changes. Our results further reveal that thermal adaptation would eliminate 17.91–31.41% of the anticipated increase in the respiration of unadapted ecosystems under future warming scenarios, equivalent to a net carbon loss of 0.85–11.83 Pg C per year. The increase in respiration rates of terrestrial ecosystems in response to climate warming may thus be lower than predicted, with important consequences for modulating future terrestrial carbon–climate feedback.

Margaret Killjoy joins Elia J. Ayoub and Aydın Yıldız to talk about the very easy topic of apocalypse. What does that even mean? And how do we deal with that without falling into complete despair?

Ugo Bardi's take on ten elements potentially able to cause a global societal collapse.

Abstract

The Southwest United States is experiencing severe and persistent drought, although uncertainties regarding the causes limit our ability to predict changes in water availability. The severity of the current drought has been attributed to a combination of warming and natural changes in atmospheric circulation, suggesting that current rainfall deficits may improve as natural oscillations reverse sign. Here we use new leaf-wax stable isotope reconstructions and simulations for the mid-Holocene (6 thousand years ago) and demonstrate that moderate warming of the Northern Hemisphere can produce drought over the Southwest United States through an ocean–atmosphere response originating in the North Pacific. The patterns of ocean warming and rainfall change resemble the negative phase of the Pacific Decadal Oscillation, indicating that this mode can be excited by external forcings. A similar response to warming is evident in future projections, leading to sustained winter precipitation deficits through the mid-twenty-first century. However, the magnitudes of past and current precipitation deficits associated with this North Pacific response are systematically underestimated in models, possibly due to a weak coupling of ocean–atmosphere interactions. Projections may also underestimate the magnitude of this precipitation response to changes in the North Pacific, leading to greater drought risk in this already water-poor region.

The Southwest United States is currently facing its worst megadrought of the past 1,200 years. According to a recent study by the University of Texas at Austin, the drought could continue at least until the end of the century, if not longer.

Editor’s summary

Climate warms or cools depending on whether the net energy flux from incoming solar radiation is respectively greater or less than that of outgoing long-wave radiation at the top of Earth’s atmosphere. Satellite data have shown that an energy imbalance producing warming has strengthened between 2001 and 2023. Myhre et al. show that climate models with low climate sensitivity do not reproduce that trend in Earth energy imbalance. Their finding means that increasing concentrations of atmospheric greenhouse gases likely will cause even more warming than most current models predict. —Jesse Smith

Abstract

Climate forcings by greenhouse gases and aerosols cause an imbalance at the top of the atmosphere between the net incoming solar radiation and outgoing longwave radiation from Earth. This Earth energy imbalance has strengthened over the period 2001 to 2023 with satellite data. Here, we show that low climate sensitivity models fail to reproduce the trend in Earth energy imbalance, particularly in the individual longwave and shortwave contributions to the imbalance trend. The inability to produce a strong positive shortwave and strong negative longwave Earth energy imbalance trend is found to be a robust feature in the low climate sensitivity models, especially for models with a climate sensitivity below 2.5 kelvin. The negative longwave contribution to Earth energy imbalance is driven by surface temperature increases and is therefore most pronounced in high climate sensitivity models, whereas the shortwave contribution is generally positive and amplified by greater surface warming.

Abstract

Extreme weather events are becoming more frequent and intense due to climate change. Yet, little is known about the relationship between exposure to extreme events, subjective attribution of these events to climate change, and climate policy support, especially in the Global South. Combining large-scale natural and social science data from 68 countries (N = 71,922), we develop a measure of exposed population to extreme weather events and investigate whether exposure to extreme weather and subjective attribution of extreme weather to climate change predict climate policy support. We find that most people support climate policies and link extreme weather events to climate change. Subjective attribution of extreme weather was positively associated with policy support for five widely discussed climate policies. However, exposure to most types of extreme weather event did not predict policy support. Overall, these results suggest that subjective attribution could facilitate climate policy support.

Abstract

Global surface warming has accelerated since around 2010, relative to the preceding half century1,2,3. This has coincided with East Asian efforts to reduce air pollution through restricted atmospheric aerosol and precursor emissions4,5. A direct link between the two has, however, not yet been established. Here we show, using a large set of simulations from eight Earth System Models, how a time-evolving 75% reduction in East Asian sulfate emissions partially unmasks greenhouse gas-driven warming and influences the spatial pattern of surface temperature change. We find a rapidly evolving global, annual mean warming of 0.07 ± 0.05 °C, sufficient to be a main driver of the uptick in global warming rate since 2010. We also find North-Pacific warming and a top-of-atmosphere radiative imbalance that are qualitatively consistent with recent observations. East Asian aerosol cleanup is thus likely a key contributor to recent global warming acceleration and to Pacific warming trends.