Potentially dangerous consequences for biodiversity of solar geoengineering implementation and termination

Abstract

Solar geoengineering is receiving increased policy attention as a potential tool to offset climate warming. While climate responses to geoengineering have been studied in detail, the potential biodiversity consequences are largely unknown. To avoid extinction, species must either adapt or move to track shifting climates. Here, we assess the effects of the rapid implementation, continuation and sudden termination of geoengineering on climate velocities-the speeds and directions that species would need to move to track changes in climate. Compared to a moderate climate change scenario (RCP4.5), rapid geoengineering implementation reduces temperature velocities towards zero in terrestrial biodiversity hotspots. In contrast, sudden termination increases both ocean and land temperature velocities to unprecedented speeds (global medians >10 km yr) that are more than double the temperature velocities for recent and future climate change in global biodiversity hotspots. Furthermore, as climate velocities more than double in speed, rapid climate fragmentation occurs in biomes such as temperate grasslands and forests where temperature and precipitation velocity vectors diverge spatially by >90°. Rapid geoengineering termination would significantly increase the threats to biodiversity from climate change.

CESM1(WACCM) Stratospheric Aerosol Geoengineering Large Ensemble Project

“…Finally, the chosen setup is not meant to suggest a reasonable application of geoengineering, because of the increasing risk of an abrupt termination of geoengineering and a rapid adjustment of temperatures back to uncontrolled conditions (Trisos et al 2018). Responsible geoengineering should only be applied in addition to, and not as a substitute to, aggressive decarbonization to reduce the risks of climate change (e.g., Wigley 2006;Tilmes et al 2016).…”

“…New insights into these research areas are expected based on this novel multiple-member ensemble dataset. Understanding the processes that lead to regional changes could motivate further exploration into how one could expand climate objectives, for instance, through different design choices, such as the locations or seasons of injection.Finally, the chosen setup is not meant to suggest a reasonable application of geoengineering, because of the increasing risk of an abrupt termination of geoengineering and a rapid adjustment of temperatures back to uncontrolled conditions (Trisos et al 2018). Responsible geoengineering should only be applied in addition to, and not as a substitute to, aggressive decarbonization to reduce the risks of climate change (e.g., Wigley 2006;Tilmes et al 2016).…”

The Regional Hydroclimate Response to Stratospheric Sulfate Geoengineering and the Role of Stratospheric Heating

“…In the equatorial region of the Pacific, this weakening of the divergent circulation in the tropics is eventually also accompanied by a weakening of the east‐west gradient in topical Pacific SSTs which leads to a further enhancement of the drying to the west and wetting to the east. An El Niño‐like response to sulfate geoengineering and large volcanic eruptions have been found in previous studies (e.g., Khodri et al, ; Maher et al, ; Trisos et al, ). Khodri et al () argued for the important role of volcanic aerosol induced cooling over Africa for the El Niño‐like signal in the year following volcanic eruptions.…”

What's hot in conservation biogeography in a changing climate? Going beyond species range dynamics

“…New avenues of research are needed to guide ecosystem management, inform conservation policy and design nature‐based solutions to global change. Proposed mitigation measures to reduce net carbon emissions and offset global warming, such as crop biofuels and solar geoengineering themselves may have consequences for ecosystems processes and species range dynamics, recently also addressed through model‐based forecasting (Dagon & Schrag, ; Hof et al, ; Trisos et al, ). Similarly, new approaches of nature‐based solutions to biodiversity conservation consider interesting strategies such as trophic rewilding—the reintroduction of species to promote self‐regulation of biodiverse ecosystems (Svenning et al, ).…”