Liang Yongxiao, Gillett Nathan P, Monahan Adam H
School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia Canada.
Climate Research Division, Environment and Climate Change Canada, Victoria, British Columbia Canada.
Nat Clim Chang. 2024;14(6):608-614. doi: 10.1038/s41558-024-02017-y. Epub 2024 Jun 5.
Observational constraint methods based on the relationship between the past global warming trend and projected warming across climate models were used to reduce uncertainties in projected warming by the Intergovernmental Panel on Climate Change. Internal climate variability in the eastern tropical Pacific associated with the so-called pattern effect weakens this relationship and has reduced the observed warming trend over recent decades. Here we show that regressing out this variability before applying the observed global mean warming trend as a constraint results in higher and narrower twenty-first century warming ranges than other methods. Whereas the Intergovernmental Panel on Climate Change assessed that warming is unlikely to exceed 2 °C under a low-emissions scenario, our results indicate that warming is likely to exceed 2 °C under the same scenario, and hence, limiting global warming to well below 2 °C will be harder than previously anticipated. However, the reduced uncertainties in these projections could benefit adaptation planning.
基于过去全球变暖趋势与跨气候模型的预估变暖之间关系的观测约束方法，被政府间气候变化专门委员会用于减少预估变暖中的不确定性。与所谓的模式效应相关的东热带太平洋内部气候变率削弱了这种关系，并降低了近几十年来观测到的变暖趋势。我们在此表明，在将观测到的全球平均变暖趋势用作约束之前，去除这种变率进行回归分析，会得出比其他方法更高且更窄的21世纪变暖范围。政府间气候变化专门委员会评估认为，在低排放情景下变暖不太可能超过2°C，而我们的结果表明，在相同情景下变暖很可能超过2°C，因此，将全球变暖限制在远低于2°C将比之前预期的更难。然而，这些预估中不确定性的减少可能有益于适应规划。
