Impact of solar geoengineering on wildfires in the 21st century in CESM2/WACCM6
Impact of solar geoengineering on wildfires in the 21st century in CESM2/WACCM6
复制标题
DOI：
10.5194/acp-23-5467-2023
复制
发表时间：
2023-05
影响因子：
6.3
通讯作者：
W. Tang;S. Tilmes;D. Lawrence;Fang Li;Cenlin He;L. Emmons;R. Buchholz;Lili Xia
中科院分区：
文献类型：
--
作者：
W. Tang;S. Tilmes;D. Lawrence;Fang Li;Cenlin He;L. Emmons;R. Buchholz;Lili Xia
抽象的。我们量化了21世纪野火烧毁面积和碳排放的未来变化，其中包括四种共享社会经济路径（SSP）情景和两种基于SSP 5 -8.5的太阳地球工程情景，目标表面温度由SSP 2 -4.5 -太阳辐照度降低（G6 solar）和平流层硫酸盐气溶胶注入定义（G6硫）-并探索驱动太阳能地球工程对火灾影响的机制。这项研究是基于完全耦合的气候化学模拟与模拟火灾发生（燃烧面积和碳排放）使用全大气社区气候模式版本6（WACCM 6）作为社区地球系统模式版本2（CESM 2）的大气组成部分。在全球范围内，野火烧毁的总面积预计将增加在21世纪的情况下没有地球工程和减少在两个地球工程的情况下。到世纪末，这两种地球工程情景的燃烧面积和火灾碳排放量不仅低于其基础气候情景SSP 5 -8.5，而且低于目标气候情景SSP 2 -4.5。地球工程通过降低地表温度和风速以及增加相对湿度和土壤水分来减少野火的发生，但北方地区除外，因为与现在相比，地球工程增加了野火的发生。这导致全球减少燃烧面积和火灾碳排放量的世纪结束时，相对于他们的基本气候情景SSP 5 -8.5。然而，与气候变暖相比，地球工程也减少了降水，这抵消了部分火灾减少。总体而言，不同驱动因素对火烧面积的影响大于火灾碳排放。一般来说，平流层硫酸盐气溶胶方法比太阳辐照度减少方法具有更强的减少火灾的效果。
Abstract. We quantify future changes in wildfire burned area and carbon emissions in the 21st century under four Shared Socioeconomic Pathways (SSPs) scenarios and two SSP5-8.5-based solar geoengineering scenarios with a target surface temperature defined by SSP2-4.5 – solar irradiance reduction (G6solar) and stratospheric sulfate aerosol injections (G6sulfur) – and explore the mechanisms that drive solar geoengineering impacts on fires. This study is based on fully coupled climate–chemistry simulations with simulated occurrence of fires (burned area and carbon emissions) using the Whole Atmosphere Community Climate Model version 6 (WACCM6) as the atmospheric component of the Community Earth System Model version 2 (CESM2). Globally, total wildfire burned area is projected to increase over the 21st century under scenarios without geoengineering and decrease under the two geoengineering scenarios. By the end of the century, the two geoengineering scenarios have lower burned area and fire carbon emissions than not only their base-climate scenario SSP5-8.5 but also the targeted-climate scenario SSP2-4.5. Geoengineering reduces wildfire occurrence by decreasing surface temperature and wind speed and increasing relative humidity and soil water, with the exception of boreal regions where geoengineering increases the occurrence of wildfires due to a decrease in relative humidity and soil water compared with the present day. This leads to a global reduction in burned area and fire carbon emissions by the end of the century relative to their base-climate scenario SSP5-8.5. However, geoengineering also yields reductions in precipitation compared with a warming climate, which offsets some of the fire reduction. Overall, the impacts of the different driving factors are larger on burned area than fire carbon emissions. In general, the stratospheric sulfate aerosol approach has a stronger fire-reducing effect than the solar irradiance reduction approach.