Eminent coral scientists have given world leaders in Bali more reason to act urgently against climate change, by producing a new report that warns coral reefs will disappear within decades if atmospheric CO2 levels continue to rise.
Their paper, published today in the prestigious Science magazine, is the most compelling scientific case yet that unchecked global warming will be a disaster for coral reefs and the 100 million people and one million species depending on them.
CO2 concentration in the earth’s atmosphere is currently 380 parts per million (ppm) but the authors say if future emissions exceed 450ppm we risk losing reefs.
“This is a very ambitious target and should represent yet another reality check for world leaders meeting in Bali,” lead author UQ Professor Ove Hoegh-Guldberg said.
Reducing CO2 emissions must also be accompanied by reducing reef risks such as overfishing, pollution and unsustainable coastal developments, a cross-section of the report’s authors (all of whom are members of the Coral Reef Targeted Research and Capacity Building for Management Program, CRTR) said at UQ.
Tools needed to reduce stress on coral reefs already exist, and include: increased protection of river catchment and coastal areas; co-management arrangements between governments and local communities; improved catchment, water quality and environmental flow measures; fishing regulation enforcement; restoration of reefs and coastal vegetation; and sustainable tourism.
The study has found serious consequences follow on from even small increases in CO2.
“The warmer and more acidic oceans caused by the rise of CO2 from the burning of fossil fuels threaten to destroy coral dominated reef ecosystems, exposing people to flooding, coastal erosion and the loss of food and income from reef-based fisheries and tourism,” Professor Hoegh-Guldberg said.
“This is happening just when many nations are hoping that growing industries like tourism and fisheries will allow them to develop beyond their often impoverished state.
“Increased CO2 not only warms the climate but also dissolves in sea water making it more acidic.
“This, in turn, decreases the ability of corals to produce calcium carbonate, which is what the all-important framework of coral reefs is made of.”
The study used information built up over the past decade to project how reefs will look if emissions are or are not controlled.
“It is a sobering thought that we have used the lower range of the United Nations’ Intergovernmental Panel on Climate Change (IPCC) scenarios in our analysis yet still envisage serious if not devastating ramifications for coral-dominated reefs.
“Emission pathways that include higher CO2 (600 to 1000 ppm) and global temperatures of 3°to 6°C defy consideration as credible alternatives,” the report said.
Next generation reef scientists and managers have been meeting at UQ this week for an international forum to develop policies to sustain the world’s coral reefs. More than 50 postgraduate and postdoctoral students from 20 countries have attended.
“These future leaders in coral reef science have honed their leadership skills and discovered how to grow their influence among those networks which manage and set policy for coral reefs worldwide,” UQ Senior Deputy Vice-Chancellor and paper co-author Professor Paul Greenfield said.
The CRTR, based at UQ, is a leading international coral reef research initiative that provides a coordinated approach to credible and scientifically-proven knowledge for improved coral reef management.
Its partners include the Global Environment Fund, the World Bank, University of Queensland, the United States National Oceanic and Atmospheric Administration and approximately 40 research institutes and other third-parties around the world.