- Title: Stark coral warning issued by scientists
- Date: 24th January 2018
- Summary: LANCASTER, ENGLAND, UNITED KINGDOM (JANUARY 22, 2018) (REUTERS) (SOUNDBITE) (English) PROFESSOR NICK GRAHAM OF LANCASTER UNIVERSITY, STUDY CO-AUTHOR, SAYING: "We can have a future on this planet with ecosystems like coral reefs but it means tackling climate change urgently. If we can reach targets such as one point five degree warming then we will see a future on this planet with coral reefs. If we don't meet some of these targets and we allow global warming to continue and up to 3, 4 degrees it's very unlikely that coral reef ecosystems are going to survive on this planet."
- Embargoed: 7th February 2018 15:03
- Keywords: coral coral bleaching reef Great Barrier Reef Lancaster University Nick Graham climate change
- Location: GREAT BARRIER REEF, QUEENSLAND, AUSTRALIA / LANCASTER, ENGLAND, UNITED KINGDOM / UNDISCLOSED LOCATION
- City: GREAT BARRIER REEF, QUEENSLAND, AUSTRALIA / LANCASTER, ENGLAND, UNITED KINGDOM / UNDISCLOSED LOCATION
- Country: United Kingdom
- Topics: Science
- Reuters ID: LVA0067ZLYBMJ
- Aspect Ratio: 16:9
- Story Text: High ocean temperatures are harming tropical corals almost five times more often than in the 1980s, undermining reefs' ability to survive marine heat waves caused by man-made climate change, scientists have revealed.
The average time between severe "bleachings", when heat makes the stony-bodied creatures that make up coral reefs expel colorful algae, shortened to six years in 2016 from 25-30 years in the early 1980s, the Australian-led team wrote in the journal Science in January.
In the 1980s, bleachings happened during local heat waves, and then started to occur in the 1980s and 1990s during natural El Nino weather events that release heat from the Pacific Ocean.
One of the study's authors, Professor Nick Graham of Lancaster University, told Reuters: "Once they started occurring at a regional scale around the early 1980s they were hitting a given location roughly once every 25 years whereas by 2016 the frequency of these bleaching events had shortened to once every six years."
Corals die if bleachings are long-lasting, wrecking reefs that are nurseries for fish, a source of food to millions of people and a destination for scuba-diving tourists.
According to Graham: "Background temperatures are rising gradually in our oceans and bleaching often occurs when there's an anomaly, a temperature spike in the summer."
This is often associated with something like an El Nino event which causes exceptional temperatures but what's happening now is that because the background temperatures are so warm, smaller and smaller anomalies are causing bleaching and even warm summers outside of El Ninos are causing coral bleaching which is why we're seeing the frequency of these events shortening."
The worst bleaching was in 2015-16, when record ocean temperatures affected 75 percent of 100 reefs studied from Australia's Great Barrier Reef to the Caribbean.
Climate change will "inevitably" make underwater heat waves and bleachings more frequent, say the scientists.
The authors urged more action to limit greenhouse gas emissions under the global 2015 Paris climate agreement.
The Paris pact seeks to limit a rise in average global surface temperatures to "well below" two degrees Celsius (3.6 Fahrenheit) above pre-industrial times, ideally 1.5 C (2.7 F) by shifting from fossil fuels.
Corals are already under threat with warming of 1 C (1.8 F) so far, a U.N. panel of climate scientists says.
"We can have a future on this planet with ecosystems like coral reefs but it means tackling climate change urgently," said Graham.
"If we can reach targets such as 1.5 five degrees warming then we will see a future on this planet with coral reefs. If we don't meet some of these targets and we allow global warming to continue and up to 3, 4 degrees it's very unlikely that coral reef ecosystems are going to survive on this planet."
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