Nature Climate Change最新文献

As climate warms, trees are expected to track their ideal climate, referred to as ‘range shifts’; however, lags in tree range shifts are currently common. Disturbance events that kill trees may help catalyse tree migrations by removing biotic competition, but can also limit regeneration by eliminating seed sources, and it is unknown whether disturbance will facilitate or inhibit tree migrations in the face of climate change. Here we use national forest inventory data to show that seedlings of 15 dominant tree species in the interior western United States occupy historically cooler areas than mature trees, as expected with climate warming. However, the climatic differences between adults and seedlings are the result of widespread regeneration failures in the hottest portions of species’ ranges. Disturbances did not uniformly catalyse climatic range shifts; differences were species- and disturbance-specific. Assisted migration programmes may thus be needed to help trees adapt their ranges to climate change.

The Arctic experiences climate changes that are among the fastest in the world and affect all Earth system components. Despite expected increase in terrigenous inputs to the Arctic Ocean, their impacts on biogeochemical cycles are currently largely neglected in IPCC-like models. Here we used a state-of-the-art high-resolution ocean biogeochemistry model that includes carbon and nutrient inputs from rivers and coastal erosion to produce twenty-first-century pan-Arctic projections. Surprisingly, even with an anticipated rise in primary production across a wide range of emission scenarios, our findings indicate that climate change will lead to a counterintuitive 40% reduction in the efficiency of the Arctic’s biological carbon pump by 2100, to which terrigenous inputs contribute 10%. Terrigenous inputs will also drive intense coastal CO₂ outgassing, reducing the Arctic Ocean’s carbon sink by at least 10% (33 TgC yr⁻¹). These unexpected reinforced feedback, mostly due to accelerated remineralization rates, lower the Arctic Ocean’s capacity for sequestering carbon.

The effects of climate change on forest-defoliating insects are poorly understood, but could severely reduce forest productivity, biodiversity and timber production. For decades following its introduction in 1869, the spongy moth (Lymantria dispar) severely defoliated North American forests, but the introduction of the fungal pathogen Entomophaga maimaiga in 1989 suppressed spongy moth defoliation for 27 years. E. maimaiga, however, needs cool, moist conditions, whereas climate change is bringing hot, dry conditions to the range of the insect. Here we use an empirically verified eco-climate model to project that climate change will sharply reduce E. maimaiga infection rates, thereby increasing spongy moth defoliation. Recent rebounds in defoliation are consistent with our projections. Our work demonstrates that the effects of climate change on species interactions can have important consequences for natural ecosystems.

Mountain regions are particularly vulnerable to climate change impacts. Yet, little is known about local adaptation responses in African mountain regions, especially if these are incremental or transformational. First, using household questionnaires, we interviewed 1,500 farmers across ten African mountain regions to investigate perceived climate change impacts and adaptation responses. Second, through a reflective process involving all co-authors, we identified: (1) main constraints and opportunities for adaptation, and (2) if adaptation was incremental or transformational. Questionnaire data show that farmers in all sites perceive multiple impacts, and that they mostly respond by intensifying farming practices and using off-farm labour. We established that, while several constraints were shared across sites, others were context specific; and that adaptation was mostly incremental, but that certain attributes (for example, social capital) made three sites in East Africa slightly more transformational.

Under climate warming, earlier spring phenology has heightened the risk of late spring frost (LSF) damage. However, the intricate interplay among LSF, spring phenology and photosynthetic carbon uptake remains poorly understood. Using 286,000 ground phenological records involving 870 tree species and remote-sensing data across the Northern Hemisphere, we show that LSF occurrence in a given year reduces photosynthetic productivity by 13.6%, resulting in a delay in spring phenology by ~7.0 days in the subsequent year. Our experimental evidence, along with simulations using modified process-based phenology models, further supports this finding. This frost-induced delay in spring phenology subsequently leads to a decrease in photosynthetic productivity during the next year following an LSF event. Therefore, it is essential to integrate this frost-induced delay in spring phenology into current Earth system models to ensure accurate predictions of the impacts of climate extremes on terrestrial carbon cycling under future climate change.

Correction to: Nature Climate Change https://doi.org/10.1038/s41558-024-02110-2, published online 19 August 2024.

Marine heatwaves (MHWs), defined as extreme ocean warming episodes, have strengthened over the past decades. High-resolution climate models improve understanding of MHWs under global warming, but such events in the future Arctic are currently overlooked. In a high-resolution climate model, we find Arctic MHWs intensify on orders of magnitude during the warming twenty-first century, following sea ice retreat. However, with little sea ice coverage, strong interannual variability emerges, which could surpass the amplitude of former intensification. Furthermore, the enhancement of MHWs correlates with an order of magnitude increase in the rate of change in the temperature anomaly. Additionally, MHWs are found to be accompanied by stratification enhancement, which could surpass interannual variability of future stratification. Such extreme temperature fluctuations combined with stratification enhancement suggest major challenges for Arctic ecosystems, and may negatively impact food webs through direct physiological temperature effects, as well as indirectly through nutrient supply and taxonomic shifts.