MacMartin Douglas G, Ricke Katharine L, Keith David W
Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14850, USA
Scripps Institution of Oceanography and School of Global Policy and Strategy, University of California, San Diego, CA, USA.
Philos Trans A Math Phys Eng Sci. 2018 May 13;376(2119). doi: 10.1098/rsta.2016.0454.
Solar geoengineering refers to deliberately reducing net radiative forcing by reflecting some sunlight back to space, in order to reduce anthropogenic climate changes; a possible such approach would be adding aerosols to the stratosphere. If future mitigation proves insufficient to limit the rise in global mean temperature to less than 1.5°C above preindustrial, it is plausible that some additional and limited deployment of solar geoengineering could reduce climate damages. That is, these approaches could eventually be considered as part of an overall strategy to manage the risks of climate change, combining emissions reduction, net-negative emissions technologies and solar geoengineering to meet climate goals. We first provide a physical-science review of current research, research trends and some of the key gaps in knowledge that would need to be addressed to support informed decisions. Next, since few climate model simulations have considered these limited-deployment scenarios, we synthesize prior results to assess the projected response if solar geoengineering were used to limit global mean temperature to 1.5°C above preindustrial in an overshoot scenario that would otherwise peak near 3°C. While there are some important differences, the resulting climate is closer in many respects to a climate where the 1.5°C target is achieved through mitigation alone than either is to the 3°C climate with no geoengineering. This holds for both regional temperature and precipitation changes; indeed, there are no regions where a majority of models project that this moderate level of geoengineering would produce a statistically significant shift in precipitation further away from preindustrial levels.This article is part of the theme issue 'The Paris Agreement: understanding the physical and social challenges for a warming world of 1.5°C above pre-industrial levels'.
太阳辐射地球工程是指通过将部分阳光反射回太空来故意降低净辐射强迫，以减少人为气候变化；一种可能的方法是向平流层添加气溶胶。如果未来的减排措施不足以将全球平均气温升幅限制在比工业化前水平高不到1.5°C，那么有限度地额外部署一些太阳辐射地球工程措施有可能减少气候损害。也就是说，这些方法最终可能会被视为管理气候变化风险的总体战略的一部分，该战略将减排、负排放技术和太阳辐射地球工程结合起来以实现气候目标。我们首先对当前研究、研究趋势以及为支持明智决策而需要解决的一些关键知识空白进行物理科学综述。接下来，由于很少有气候模型模拟考虑这些有限部署的情景，我们综合先前的结果来评估在一个否则峰值接近3°C的超调情景中，如果使用太阳辐射地球工程将全球平均气温限制在比工业化前水平高1.5°C时的预计响应。虽然存在一些重要差异，但由此产生的气候在许多方面更接近于仅通过减排实现1.5°C目标的气候，而不是没有地球工程措施的3°C气候。这在区域温度和降水变化方面都成立；实际上，没有哪个区域的大多数模型预测这种适度的地球工程水平会使降水产生统计学上显著的偏离工业化前水平的变化。本文是主题为“《巴黎协定》：理解工业化前水平以上升温1.5°C的世界所面临的物理和社会挑战”的一部分。
