美国华盛顿大学Edward Blanchard-Wrigglesworth团队近日揭示越来越多的北方火灾减少了未来的全球变暖和海冰损失。相关论文于2025年6月3日发表在《美国科学院院刊》杂志上。

生物质燃烧可以通过气溶胶的排放及其对辐射、云微物理、地表和大气反照率的后续影响来影响气候。过去十年，北方地区的生物质燃烧排放量（BBE）大幅增加，预计随着气候变暖，排放量将继续增加。气候模型模拟气溶胶过程，但历史和未来的耦合模型比对项目（CMIP）模拟没有主动火灾成分，BBE被规定为外部强迫。

研究组表明CMIP6使用了未来北方BBE情景，这些情景具有不切实际的近零趋势，对气候趋势有很大影响。通过根据观察到的趋势对北方排放量的增加进行敏感性实验，结果发现，北方BBE的增加使全球变暖减少了12%，北极变暖减少了38%，减少了海冰的损失。由于北半球气溶胶强迫和随后的温度响应的半球差异，热带降水向南移动。

这些变化源于气溶胶对云的影响，增加了云滴数浓度、云光学深度和低云量，最终减少了北纬地区的地表短波通量。该研究结果强调了现实的北方BBE在气候模型模拟中的重要性，以及改善对北方排放趋势和气溶胶-气候相互作用的理解的必要性。

附：英文原文

Title: Increasing boreal fires reduce future global warming and sea ice loss

Author: Blanchard-Wrigglesworth, Edward, DeRepentigny, Patricia, Frierson, Dargan M. W.

Issue&Volume: 2025-6-3

Abstract: Biomass burning can affect climate via the emission of aerosols and their subsequent impact on radiation, cloud microphysics, and surface and atmospheric albedo. Biomass burning emissions (BBEs) over the boreal region have strongly increased during the last decade and are expected to continue increasing as the climate warms. Climate models simulate aerosol processes, yet historical and future Coupled Model Intercomparison Project (CMIP) simulations have no active fire component, and BBEs are prescribed as external forcings. Here, we show that CMIP6 used future boreal BBEs scenarios with unrealistic near-zero trends that have a large impact on climate trends. By running sensitivity experiments with ramped up boreal emissions based on observed trends, we find that increasing boreal BBEs reduces global warming by 12% and Arctic warming by 38%, reducing the loss of sea ice. Tropical precipitation shifts southward as a result of the hemispheric difference in boreal aerosol forcing and subsequent temperature response. These changes stem from the impact of aerosols on clouds, increasing cloud droplet number concentration, cloud optical depth, and low cloud cover, ultimately reducing surface shortwave flux over northern latitudes. Our results highlight the importance of realistic boreal BBEs in climate model simulations and the need for improved understanding of boreal emission trends and aerosol–climate interactions.

DOI: 10.1073/pnas.2424614122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2424614122