AI 中文总结
研究指出当前以算术平均法测量的全球平均地表气温变化高估了全球变暖速率，基于图像直方图方法发现其因SAT变化不对称而大于全球尺度SAT变化，通过数据表明两者在不同时期有差异，警示了该指标用于全球变暖速率评估的局限性。
AI 中文摘要
当前气候政策旨在减缓全球变暖速率，即全球平均地表气温（SAT）变化（ΔTmean），其通过算术平均法测量，假设SAT变化对称分布。但实际上，SAT变化本质上不对称，以往气候变化研究中其对ΔTmean解释的影响罕受关注。本研究基于图像直方图方法理论化认为，虽ΔTmean衡量地球整体SAT变化，但因SAT变化不对称分布，其值大于全球尺度SAT变化（ΔTgs）。结果表明，2000 - 2019年，相对于1979年全球SAT，ΔTmean比基于ΔTgs的值高0.19 - 0.23°C。在未来气候预测中，21世纪末（2080 - 2099年）不同排放情景下，ΔTmean与ΔTgs的差异达0.27 - 0.54°C。两者的巨大差异意味着全球存在净正区域尺度变暖效应，主要由北极放大效应导致。本文警示极端区域变暖效应可能对ΔTmean的解释产生重大影响，ΔTmean常用于气候评估和政策制定，说明了将其作为全球变暖速率唯一指标的局限性和注意事项。
英文摘要
Current climate policies are targeted at slowing down the global warming rate, or the global mean surface air temperature (SAT) change (ΔTmean), which is measured by the arithmetic mean approach under the assumption that SAT changes are symmetrically distributed. However, in reality, the SAT change is asymmetric in nature and its influence on the ΔTmean interpretation seldom received attention in previous research about climate change. This study theorizes, based on the image histogram approach, that while ΔTmean measures the Earth's overall SAT change, it yields a value larger than the global-scale SAT change (ΔTgs) because of the asymmetrical distribution of SAT change. Results show that ΔTmean is greater than that based on ΔTgs by 0.19-0.23°C from 2000-2019, relative to the global SAT in 1979. In future climate projections, where more significant inhomogeneous warming is expected, the disagreement between ΔTmean and ΔTgs reach 0.27-0.54°C by the end of the 21st century (2080-2099) under different emission scenarios. The large difference between ΔTmean and ΔTgs implies that there is a net positive regional-scale warming effect over the globe which is mainly contributed by Arctic Amplification. This paper constitutes a warning that extreme regional warming effects could have large impacts on the interpretation of ΔTmean, which is often considered in climate assessments and policies making, and illustrates the limitations and cautions inherent in using ΔTmean as the only indicator of the global warming rate.
