The effects of climate change on coral reefs is fairly well-known; most schoolchildren have seen side-to-side comparisons of lively, healthy coral reefs juxtaposed with bleached, lifeless ones, caused by pollution and other human activities. However, new research published in Current Biology indicates that coral reefs are in danger from a new, faster-moving phenomenon.
According to this new study, extreme spikes in ocean temperatures can cause entire coral reef systems to decay and collapse in a matter of days. The heat kills the tissue on the coral reefs, leaving them vulnerable to microbes which then cover the stripped skeletons, dissolving them within as little as a few days. This dissolution results in the entire structure of the coral reef collapsing, decimating an entire ecosystem almost immediately. The effects of these collapses and the frequency with which they occur cannot be overstated, as the thorough destruction of the reef ensures that it cannot be revived even by a concerted effort.
The combination of slow coral bleaching and heatwaves could have a disastrous effect on all of the planet, including humans. The report indicates that the benefits derived by humans from coral reefs “span from coastal protection to subsistence and industrial fisheries”, and that these industries depend on the structural integrity of the coral reefs’ 3-D structures, which are greatly compromised by ongoing climate change as well as ocean heatwaves.
Though these severe ocean heatwaves were previously rare, it appears that they are worsening in temperature as well as frequency. In fact, though the study focused on the effects of ocean heatwaves during the heatwave that hit Australia’s Great Barrier Reef in 2016, researchers determined that this heatwave phenomenon affected 37% of coral reefs globally between 2014 and 2017. Due to their severity and rapid effects, the study argues that these climate change-induced ocean heatwaves are a phenomenon distinct from normal coral reef bleaching, and considers these events to be further compelling evidence that something must be done to drastically lessen global heating in order to control these deadly events.