Abstract Aerosols interact with radiation and clouds. Substantial progress made over the past 40 years in observing, understanding, and modeling these processes helped quantify the imbalance in the Earth's radiation budget caused by anthropogenic aerosols, called aerosol radiative forcing, but uncertainties remain large. This review provides a new range of aerosol radiative forcing over the industrial era based on multiple, traceable, and arguable lines of evidence, including modeling approaches, theoretical considerations, and observations. Improved understanding of aerosol absorption and the causes of trends in surface radiative fluxes constrain the forcing from aerosol‐radiation interactions. A robust theoretical foundation and convincing evidence constrain the forcing caused by aerosol‐driven increases in liquid cloud droplet number concentration. However, the influence of anthropogenic aerosols on cloud liquid water content and cloud fraction is less clear, and the influence on mixed‐phase and ice clouds remains poorly constrained. Observed changes in surface temperature and radiative fluxes provide additional constraints. These multiple lines of evidence lead to a 68% confidence interval for the total aerosol effective radiative forcing of ‐1.6 to ‐0.6 W m−2, or ‐2.0 to ‐0.4 W m−2 with a 90% likelihood. Those intervals are of similar width to the last Intergovernmental Panel on Climate Change assessment but shifted toward more negative values. The uncertainty will narrow in the future by continuing to critically combine multiple lines of evidence, especially those addressing industrial‐era changes in aerosol sources and aerosol effects on liquid cloud amount and on ice clouds.

中文翻译：

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气候变化的全球气溶胶辐射强迫


摘要 气溶胶与辐射和云相互作用。过去 40 年来，在观测、理解和建模这些过程方面取得的实质性进展有助于量化由人为气溶胶（称为气溶胶辐射强迫）引起的地球辐射收支失衡，但不确定性仍然很大。这篇综述基于多种、可追溯和可论证的证据，包括建模方法、理论考虑和观察，提供了工业时代气溶胶辐射强迫的新范围。对气溶胶吸收和表面辐射通量趋势原因的进一步了解限制了气溶胶-辐射相互作用的强迫。坚实的理论基础和令人信服的证据限制了气溶胶驱动的液云液滴数量浓度增加引起的强迫。然而，人为气溶胶对云液态水含量和云分数的影响尚不明确，对混合相云和冰云的影响仍然很少受到限制。观察到的表面温度和辐射通量的变化提供了额外的约束。这些多重证据得出总气溶胶有效辐射强迫为 ‐1.6 至 ‐0.6 W m−2 或 ‐2.0 至 ‐0.4 W m−2 的 68% 置信区间，可能性为 90%。这些区间的宽度与政府间气候变化专门委员会上次评估的宽度相似，但转向了更多的负值。通过继续批判性地结合多种证据，特别是那些涉及工业时代气溶胶来源变化以及气溶胶对液体云量和冰云影响的证据，未来的不确定性将会缩小。