Interpretations of the Paris climate target

In the 2015 UNFCCC Paris Agreement, article 2 expresses the target of “Holding the increase in global temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C … recognizing that this would significantly reduce the risks and impacts of climate change”1. Different interpretations of the precise meaning of the phrases ‘increase in global temperature’2 and ‘pre-industrial’3 could have large effects on mitigation requirements and corresponding social, policy and political responses. Here we suggest that levels of current global mean surface warming since pre-industrial times that are higher than those derived by Millar et al. could have been calculated using alternative, but equally valid, assumptions as the ones made by those authors.

在2015年《联合国气候变化框架公约》巴黎协定中，第2条提出了“将全球气温升幅控制在工业化前水平以上远低于2°C之内，并努力将气温升幅限制在1.5°C……认识到这将大大降低气候变化的风险和影响”的目标。对“全球气温升幅”和“工业化前”这些措辞的确切含义的不同解读，可能会对减缓要求以及相应的社会、政策和政治应对措施产生重大影响。在此我们提出，自工业化前以来的当前全球平均地表变暖水平可能高于米勒等人所推算的水平，这可能是使用了与那些作者所做的不同但同样有效的假设来计算的。