Tag Archives: Coral Bleaching

It is possible, but unlikely, that the Great Barrier Reef can be saved

April 10, 2017UncategorizedClimate Change, Climate Change, Coral Bleaching, Global Warming, Global Warming, Great Barrier ReefGreg Laden

Here’s a video from the Guardian on the current status of the reef:

This is going to take a while. If there is a major bleaching event every year for a few years, the reef could essentially die off right away, but most likely, there will still be a few years where coral can spread, and a few years that are not too bad. So one must adjust expectations.

Let me put this a different, perhaps cynical but probably realistic, view. In about four years from now, there will be some bone-headed global warming denier standing on a boat off shore in Australia, showing us a section of really nice, well preserved, ecologically healthy reef. That person will tell us that climate scientists predicted that the Great Barrier Reef would be dead by now, but look, it isn’t!

The truth is that the reef is already severely damaged, and will recover only if water temperatures in the area cool down. That is not going to happen. A very likely scenario is that the living reef becomes a very limited phenomenon, so you will always be able to find a bit here or there that looks good, but the vast majority of the reef will not be alive.

Once a large area of the reef is dead — meaning specifically that the thin growth layer on the coral formation’s surface, where the living coral are, is dead — it will begin to dissolve and erode. The total dissolution and erosion of the geological structure is impossible, it will simply become a giant fossil. But, the minimum depth of the reef formation will increase to the point where there won’t be much sunlight, so recovery will be even less likely. Reefs start in shallow water, and then grow upwards as sea level rises (as it did in the past). The Great Barrier Reef is located on formerly dry land. With future sea level rise moving the sea surface up, and erosion of a dead coral structure pushing the surface of the reef down, we will reach a situation where the current location of the Great Barrier Reef is simply not a place a coral reef of this kind can exist, even if the sea temperatures and other conditions improve.

Personally, I don’t see any hope, medium and long term, for this natural feature. I think we need to preserve optimism where it is realistic, but very much avoid it when it isn’t. I’m not sure where we are at this time in relation to this particular outcome of human greenhouse gas pollution. I don’t see how two bad years in a row are not going to be followed by two more bad years in a row, given the steady increase in sea temperatures. However, climate systems to vary in the region, maybe it is possible. Maybe in three years we’ll be looking at a remarkable recovery. But, it is almost positively certain that over the next decade or two the frequency of bad years will go up and the best years will become unlivable for most of the coral.

NOAA declares third ever global coral bleaching event

October 8, 2015UncategorizedClimate Change, Climate Change, Coral Bleaching, coral reef, Global WarmingGreg Laden

This just out from NOAA:

As record ocean temperatures cause widespread coral bleaching across Hawaii, NOAA scientists confirm the same stressful conditions are expanding to the Caribbean and may last into the new year, prompting the declaration of the third global coral bleaching event ever on record.

Waters are warming in the Caribbean, threatening coral in Puerto Rico and the U.S. Virgin Islands, NOAA scientists said. Coral bleaching began in the Florida Keys and South Florida in August, but now scientists expect bleaching conditions there to diminish.

“The coral bleaching and disease, brought on by climate change and coupled with events like the current El Niño, are the largest and most pervasive threats to coral reefs around the world,” said Mark Eakin, NOAA’s Coral Reef Watch coordinator. “As a result, we are losing huge areas of coral across the U.S., as well as internationally. What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it’s likely to last well into 2016.”

While corals can recover from mild bleaching, severe or long-term bleaching is often lethal. After corals die, reefs quickly degrade and the structures corals build erode. This provides less shoreline protection from storms and fewer habitats for fish and other marine life, including ecologically and economically important species.

This bleaching event, which began in the north Pacific in summer 2014 and expanded to the south Pacific and Indian oceans in 2015, is hitting U.S. coral reefs disproportionately hard. NOAA estimates that by the end of 2015, almost 95 percent of U.S. coral reefs will have been exposed to ocean conditions that can cause corals to bleach.

The biggest risk right now is to the Hawaiian Islands, where bleaching is intensifying and is expected to continue for at least another month. Areas at risk in the Caribbean in coming weeks include Haiti, the Dominican Republic and Puerto Rico, and from the U.S. Virgin Islands south into the Leeward and Windward islands.

Oct-Jan 2016 outlook: NOAA’s 4-month bleaching outlook, showing threat of bleaching continuing in the Caribbean, Hawaii, and Kiribati, and perhaps expanding into the Republic of the Marshall Islands. (Credit: NOAA)

The next concern is the further impact of the strong El Niño, which climate models indicates will cause bleaching in the Indian and southeastern Pacific Oceans after the new year. This may cause bleaching to spread globally again in 2016.

“We need to act locally and think globally to address these bleaching events. Locally produced threats to coral, such as pollution from the land and unsustainable fishing practices, stress the health of corals and decrease the likelihood that corals can either resist bleaching, or recover from it,” said Jennifer Koss, NOAA Coral Reef Conservation Program acting program manager. “To solve the long-term, global problem, however, we need to better understand how to reduce the unnatural carbon dioxide levels that are the major driver of the warming.”

This announcement stems from the latest NOAA Coral Reef Watch satellite coral bleaching monitoring products, and was confirmed through reports from partner organizations with divers working on affected reefs, especially the XL Catlin Seaview Survey and ReefCheck. NOAA Coral Reef Watch’s outlook, which forecasts the potential for coral bleaching worldwide several months in the future, predicted this global event in July 2015.

The current high ocean temperatures in Hawaii come on the heels of bleaching in the Main Hawaiian Islands in 2014?only the second bleaching occurrence in the region’s history?and devastating bleaching and coral death in parts of the remote and well-protected Papah?naumoku?kea Marine National Monument in the Northwestern Hawaiian Islands.

“Last year’s bleaching at Lisianski Atoll was the worst our scientists have seen,” said Randy Kosaki, NOAA’s deputy superintendent for the monument. “Almost one and a half square miles of reef bleached last year and are now completely dead.”

Coral bleaching occurs when corals are exposed to stressful environmental conditions such as high temperature. Corals expel the symbiotic algae living in their tissues, causing corals to turn white or pale. Without the algae, the coral loses its major source of food and is more susceptible to disease.

The first global bleaching event was in 1998, during a strong El Niño that was followed by an equally very strong La Niña. A second one occurred in 2010.

Satellite data from NOAA’s Coral Reef Watch program provides current reef environmental conditions to quickly identify areas at risk for coral bleaching, while its climate model-based outlooks provide managers with information on potential bleaching months in advance.

The outlooks were developed jointly by NOAA’s Satellite and Information Service and the National Centers for Environmental Prediction through funding from the Coral Reef Conservation Program and the Climate Program Office.

For more information on coral bleaching and these products, visit: http://www.coralreefwatch.noaa.gov/satellite/index.php.

PHOTO: Extensive stand of severely bleached coral at Lisianski Island in the Papahanaumokuakea Marine National Monument in Hawaii, documented during an August 2014 NOAA research mission. (Credit: NOAA)

The outlook for Hawaiian coral is bleak

September 2, 2015UncategorizedClimate Change, Climate Change, Coral Bleaching, Global Warming, Global Warming, HawaiiGreg Laden

Marine biologists from the University of Queensland is looking at coral reefs in Hawaii and what they see is not good.

They used high resolution images to track coral bleaching and death. Recently coral reefs in Hawaii suffered their first known mass bleaching event, caused by unusually warm waters associated with the now famous “Blob” of warm sea water in the Pacific.

An overall warming trend (anthropogenic global warming) along with the additional effects of a growing El Niño seem to be causing this.

This phenomenon is happening now. Ove Hoegh-Guldberg, chief scientist at Global Change Institute (Queensland) noted. “the coral bleaching we are uncovering in Hawaii is just the tip of the iceberg in terms of what we expect to unfold over the next few weeks. Ocean heat has not fully dissipated since last year’s bleaching event, adding stress to corals that haven’t fully recovered and which may not be strong enough to survive another bleaching event.”

The research team will continue to measure bleaching on the Hawaiian reefs for the remainder of the year. With increasingly warm waters in the region, this is a story to watch closely.

More information here.