Study warns of solar risk
Experts have warned against geoengineering as a way to reverse the effects of man’s impact on the climate.
Large-scale removal of carbon dioxide from the atmosphere and the use of aerosols to reflect sunlight back to space (solar geoengineering) are gaining popularity as strategies to counteract greenhouse gas emissions, especially with milestones like the 2 °C temperature target set by the Paris Agreement at risk of being missed.
In a new report, experts have investigated the consequences that the implementation and subsequent sudden termination of solar geoengineering could have on global biodiversity.
They compare changes in temperature and precipitation under a climate scenario in which geoengineering runs from 2020 until 2070 to a scenario with no geoengineering and intermediate emissions.
They found that rapid implementation of geoengineering could have a mix of positive and negative effects on biodiversity, but that abrupt termination causes changes in local climates that are 2 - 4 times more rapid than those caused by man-made climate change itself.
They find that, in many cases, rapid geoengineering threatens ecosystems by forcing species to move in one direction to maintain similar temperature conditions and a different direction for similar precipitation conditions.
Biodiversity-rich areas, such as tropical oceans and the Amazon basin, are particularly likely to be affected negatively, according to the modelling.
Overall, they found that geoengineering, and in particular its rapid termination, could cause irreversible loss of biodiversity.
The state has been published in the journal Nature.
In an accompanying opinion piece, UK academic Phil Williamson writes that the political contentiousness of geoengineering means that rapid initiation or termination are very real possibilities.
With negative emissions also having potential consequences for biodiversity, due to the land required for bioenergy, he argues that far more ambitious cuts in emissions are needed to avoid species extinctions.