Nature Climate Change最新文献

Accurately assessing future precipitation changes presents one of the greatest challenges of climate change. In the tropics, changes in the Hadley circulation are expected to considerably affect precipitation in dry subtropical and wet equatorial regions. However, while climate models project a robust weakening of the Northern Hemisphere circulation in the coming decades, currently, there is low confidence in the magnitude of such weakening and its impact on regional precipitation patterns. Here we use emergent constraint analyses and observation-based Hadley circulation strength changes to show that the projected circulation weakening will probably be larger than in current predictions. The more pronounced weakening of the flow results in a doubling of the subtropical precipitation increase compared with current forecasts, specifically over Asia, Africa and the Pacific Ocean. Our findings provide more accurate tropical circulation and precipitation projections and have considerable societal impacts, given the scarcity of water in subtropical regions.

Correction to: Nature Climate Change https://doi.org/10.1038/s41558-024-02234-5, published online 21 January 2025.

Carbon dioxide removal (CDR) is critical to most net-zero pathways, especially given challenges due to slow decarbonization, hard-to-abate (H2A) economic activities and non-CO₂ GHGs. However, land-based CDR, which is the most widely deployed currently and in future projections, requires extensive land and water. Here we examine least-cost 1.5 °C overshoot pathways, finding that 78 of 81 scenarios would require all available sustainable CDR to compensate for H2A emissions and overshoot. Use of CDR to compensate for emissions from easier-to-decarbonize sectors such as electricity would leave less available to compensate for H2A emissions, increasing system-wide costs of net zero or rendering such goals impossible. Such usage, however, is allowed in many jurisdictions and is widespread in voluntary markets. We suggest that rapidly transitioning CDR usage to exclusively compensate for H2A emissions and overshoot is required to prevent lower costs for near-term actors leading to larger long-term system-wide costs.

Correction to: Nature Climate Change https://doi.org/10.1038/s41558-024-02238-1, published online 17 January 2025.

The Atlantic multidecadal variability (AMV) is a basin-scale mode of sea surface temperature (SST) variability in the North Atlantic, exerting a global impact, including contribution to the multidecadal Sahel drought and subsequent recovery and the post-1998 global warming hiatus. How greenhouse warming affects AMV remains unclear. Here, using models with multicentury-long outputs of future climate, we find an intensified AMV under greenhouse warming. Surface warming and freshwater input from sea-ice melt increase surface buoyancy, leading to a slowdown of the Atlantic meridional overturning circulation (AMOC). Reduced vertical mixing associated with suppressed oceanic deep convection results in a thinned mixed layer and its variability, favouring stronger AMV SST variability. Further, a weakened AMOC and the associated northward heat transport prolong the lifespan of the AMV, providing a long time for the AMV to grow. Thus, multidecadal global surface fluctuations and the associated climate extremes are likely to be more intense.

June 2024 was the twelfth month in a row with global mean surface temperatures at least 1.5 °C above pre-industrial conditions, but it is not clear if this implies a failure to meet the Paris Agreement goal of limiting long-term warming below this threshold. Here we show that in climate model simulations, the long-term Paris Agreement target is usually crossed well before such a string of unusually warm temperatures occurs.

The temperature goals of the Paris Agreement are measured as 20-year averages exceeding a pre-industrial baseline. The calendar year of 2024 was announced as the first above 1.5 °C relative to pre-industrial levels, but the implications for the corresponding temperature goal are unclear. Here we show that, without very stringent climate mitigation, the first year above 1.5 °C occurs within the first 20-year period with an average warming of 1.5 °C.