Seventy-five percent of the world’s
coral reefs will be at risk of death or extreme damage within 20 years, and 95
per cent of the world’s reefs will be at risk by 2050, if human-caused climate
change continues unabated, according to a major new study.
The study, “Reefs at Risk”, was
released by the World Resources Institute, an environmental research think
tank, in collaboration with 23 other international academic, government, and
nongovernmental research agencies, including NASA, the National Oceanic and
Atmospheric Administration, and the United Nations Environment Program.
The findings, which represent the
most comprehensive study to date on the effect of warming seas on one of the
planet’s most valued ocean resources, are expected to have a profound impact
within the scientific community, and could ultimately serve to give advocates
of climate change policy a powerful data point for building their case.
The reef report’s authors make an
urgent call for policies to limit greenhouse gas emissions.
The World Resources Institute led
the last comprehensive study of coral reefs at risk, in 1998.
That study focused chiefly on local
threats, such as overfishing, overdevelopment in coastal regions, and chemical
pollutants in waters.
Those threats remain, concludes the
new report, but by far the greatest threat, and one that compounds the impacts
of all the local pollutants, is the rising levels of carbon dioxide in the
“The single greatest growing threat to coral
reefs is the rapid increase in greenhouse gases in the atmosphere, including carbon
dioxide (CO2), methane, nitrous oxide, and halocarbons,” the study concludes.
“Since preindustrial times,
atmospheric concentrations of all of these gases have increased significantly,
and in the case of CO2, which contributes the most to both warming and
acidification, concentrations have risen by over 35 percent.
During the past 10 years, almost 40
per cent of coral reefs have experienced thermal stress at am level sufficient
to induce severe coral bleaching….
Under a “business-as-usual”
scenario, our models suggest that roughly 50 per cent of the world’s reefs will
experience thermal stress sufficient to induce severe bleaching in five out of
ten years during the 2030s.
During the 2050s, this percentage is expected
to grow to more than 95 per cent.”
The report also includes detailed
maps of coral reefs around the globe, taken with satellite and geographic
information system technology, comprehensively detailing existing coral damage
and pollution levels.
The data reflected in those maps is 64 times more
detailed than the data in the 1998 report, said Burke.