Coral reefs could be saved by geoengineering

At-risk tropical coral reefs could be bought time by limiting the amount of warming experienced by the world’s oceans in the future suggest Bristol University researchers. The scientists used computer models to investigate how shallow-water tropical coral reef habitats might respond to climate change over the coming decades. “If sea surface temperatures continue to rise, our models predict a large habitat collapse in the tropical Western Pacific which would affect some of the most biodiverse coral reefs in the world. To protect shallow-water tropical coral reefs, the warming experienced by the world’s oceans needs to be limited,” said Dr Elena Couce, lead-author of the study published in Geophysical Research Letters. Shallow-water tropical coral reefs are amongst the most productive and diverse ecosystems on the planet but they are currently in decline due to increasing frequency of bleaching events, linked to rising temperatures and fossil fuel emissions. The team applied statistical bioclimatic envelope models to determine whether limiting global temperatures via an artificial means called solar radiation geoengineering could help save the coral reefs. Their findings suggest that the decline of suitable habitats for coral reefs could be slowed if geoengineering is effectively employed. However, the researchers also discovered that over-engineering the climate could be detrimental as tropical corals do not favour overly-cool conditions. Solar radiation geoengineering also leaves a carbon dioxide problem known as ‘ocean acidification’ unchecked. “The use of geoengineering technologies cannot safeguard coral habitat long term because ocean acidification will continue unabated. Decreasing the amount of carbon dioxide in the atmosphere is the only way to address reef decline caused by ocean acidification,” said Dr Couce This was the first attempt to model the consequences of solar radiation geoengineering on a marine ecosystem and the researchers say that a lot more work is needed to fully understand the consequences of deliberate human intervention in the climate system.