Global warming takes toll on Africa’s coral reefs

JOHANNESBURG (Reuters) – Global warming is taking a toll on
coral reefs off east Africa, which will likely be killed off in
a few decades if sea surface temperatures continue to rise, a
leading researcher warned on Tuesday.

“Dangerous climate change has already happened for coral
reefs,” Dr David Obura told a conference on climate change
science in Johannesburg.

Kenyan-based Obura, a researcher with CORDIO (Coral Reef
Degradation in the Indian Ocean), said there had been
“catastrophic mortality” among shallow-water coral reefs off
East Africa following a 1997-98 El Nino event that pushed up
sea surface temperatures in the Indian Ocean.

“There was a 70 to 75 percent mortality during the El Nino
in 1997-98 in shallow water reefs off East Africa,” he said.

Models suggested that the events of 1998 could be repeated
on a regular basis in 20 to 50 years’ time because of rising
sea surface temperatures.

Such a scenario would have grim consequences for the
region’s rich corals, which are crucial to East Africa’s
tourist industry, as they are a magnet for scuba diving
enthusiasts.

“They (corals) can survive a bleaching. It is akin to a
fever in mammals,” Obura said. But if the stress was too great
on the corals, then they died off.

Coral bleaching refers to the whitening of corals from a
loss of pigment.

This is a signal of ecosystem stress which can be triggered
by sedimentation, pollution, or rising temperatures, among
other factors still being disentangled by scientists.

Scientists maintain global temperatures are rising rapidly
because fossil fuel emissions from cars, industry and other
sources are trapping the Earth’s heat.

The Intergovernmental Panel on Climate Change, a group of
2,000 scientists which advises the United Nations, projects a
further rise of 1.4-5.8 degrees centigrade by 2100. Even the
lowest forecast would be the biggest century-long rise in
10,000 years.