The International Society for Reef Studies released today a consensus statement highlighting the role of climate change as the ultimate cause of coral bleaching that is now threatening a global loss of coral reef ecosystems.
The society calls on all nations and negotiators at the Paris Climate Change Conference to commit to limiting CO2 concentrations to no more than 450ppm the short-term, and reducing them to 350ppm in the long-term.
This should keep average global temperature increase to less than 2oC (or 3.6oF) in the short term and 1.5 oC (or 2.7 oF) in the long term, relative to the pre-industrial period. This would prevent global collapse of coral reef ecosystems and allow coral reefs to survive in perpetuity.
Coral reefs are structures created by coral animals and are among the most biologically diverse ecosystems on the planet. They provide goods and services worth at least US$30 billion per year (and possibly much more) and support (through such activities as fisheries and tourism) at least 500 million people worldwide.
Coral reefs, however, are threatened with effective collapse under rapid climate change. In particular, increasing sea temperatures are causing widespread coral bleaching and mortality. In addition, elevated carbon dioxide levels are causing ocean acidification that may further accelerate coral reef loss. The death of corals leads in turn to the loss of most of the fish and invertebrate populations that they support.
Over recent decades, 33-50% of coral reefs have been largely or completely degraded by a combination of local factors and global climate change. Reefs in many regions have lost half or more of their live corals. Additional extensive degradation will inevitably occur over the next two decades as temperatures continue to rise.
As a result of reef ecosystem destruction, a quarter of all marine species are at risk, while the associated economic losses will expose hundreds of millions of people to decreasing food security and increased poverty.
If average global surface temperatures increase by 2°C or more, relative to the pre-industrial period, the resultant ocean warming, along with acidification, will lead to continued widespread destruction of coral reef ecosystems over the next few decades. The emission reduction pledges submitted to date by the international community fall well short of what is required to avoid this biodiversity catastrophe.
The International Society for Reef Studies (ISRS) is the leading international association for coral reef scientists and managers. Its members carry out and publish work that promotes scientific knowledge and understanding of coral reef ecosystems. The consensus statement was authored by Ove Hoegh-Guldberg of the University of Queensland, with Mark Eakin, Gregor Hodgon and Charlie Veron, and reviewed by a large team.