USGS chief: Coral killed by pineapples, goats (and climate)

“The Intergovernmental Panel on Climate Change, the United Nations’ climate science body, says coral reefs are forecast to decline 70% to 90% if global warming reaches 1.5 degrees Celsius, while more than 99% would be lost under 2 C.”

E & E News Adam Aton, E&E News reporter

This story was updated on Sept. 9.

At an international conference last year, the U.S. Geological Survey director acknowledged climate change is harming coral reefs but focused his presentation on a smaller, politically safer problem: sediment.

USGS Director James Reilly traveled in September 2019 to the archipelago nation of Palau for the U.S. Coral Reef Task Force meeting, a twice-annual gathering of officials from the United States and its freely associated states in the Pacific: Palau, the Marshall Islands and the Federated States of Micronesia.

Reilly gave little to no data about corals’ response to warming, despite acknowledging it as one of the species’ top global threats. And his presentation concluded with a call for scientists to focus on “characterizing the affects [sic] of climate change” — an ambiguous statement that some experts say has been used by opponents of climate action to question scientific consensus and delay policy.

Reilly did get specific about some of the ways human activity harms coral. He talked about federal research into the links between reef damage and goat grazing, as well as sedimentation caused by U.S. military testing.

And his presentation outlined the billion-dollar dangers to coastal communities from losing even just 1 meter of reef.

E&E News used the Freedom of Information Act to obtain Reilly’s presentation materials, titled “Understanding Our Coral Reefs: USGS Science Today and Tomorrow.” The documents include his slides as well as speaking notes.

After this story published, USGS said Reilly’s presentation had focused on the “geological aspects” of coral science “in accordance with an agenda specified by the attendees. Nevertheless, the Director felt not mentioning the threats of climate change would be an oversight given its impacts on coral reefs globally.”

Reilly’s presentation came about six months before the Great Barrier Reef’s most recent mass bleaching, the latest sign that the world’s coral reefs are struggling to survive hotter oceans.

Scientists have pegged the central threat to coral as rising temperatures.

NOAA calls climate change “the greatest global threat to coral reef ecosystems,” and USGS says that rising temperatures are “the number one stress factor responsible for coral mortality across the globe.”

The Intergovernmental Panel on Climate Change, the United Nations’ climate science body, says coral reefs are forecast to decline 70% to 90% if global warming reaches 1.5 degrees Celsius, while more than 99% would be lost under 2 C.

Warming has already pushed coral “past the tipping point,” said Rob Dunbar, a Stanford University professor who studies coral.

After reviewing Reilly’s presentation, Dunbar said there should be no question about corals’ response to rising temperatures.

“We don’t need a huge number of [new] studies documenting whether corals are sensitive to a warming ocean. The answer is yes, very certainly. And the director of the USGS knows this — he’s got quite a few really good coral scientists that work out of various laboratories. … He cited some of their work in his presentation. So he’s certainly heard of that. I think it’s pure politics that prevents him from being able to say this in public briefings,” said Dunbar, who also serves on a board for the National Academy of Sciences.

Dunbar said it appeared that Reilly had minimized climate in favor of the more neutral issue of sediment — a decision that he said smacked of political pressure.

“I think that’s a travesty. I think we ought to put all our cards on the table,” he said, adding that USGS has done excellent research on both warming and sediment, which is indeed important.

Sedimentation harms coral by smothering its ability to feed and reproduce. The problem is mostly local compared with the global problem of climate change, though both stressors can reinforce each other’s damage, said Robert van Woesik, a Florida Institute of Technology professor who studies coral.

“In a nutshell, climate change is having a huge impact to coral reefs around the globe, and we need to reduce those global impacts, but also, we need to … reduce local pollution so local reefs can maintain some form of resilience in a changing climate,” van Woesik said in an email.

Reilly’s presentation outlined some of the USGS research on changing ocean conditions, along with the different processes of harm from ocean acidification and climbing temperatures. Warming causes coral to starve and bleach, he said, while acidification weakens the reef structure.

The presentation said USGS “has led in-depth research … to understand how local stressors can magnify the risks of global ocean acidification.” He showed a slide of “Global Climate Change” topping a list of the “scientific consensus on the top 5 stressors causing coral-reef ecosystem degradation.”

Between the risks of sediment and climate, though, Reilly included detailed data only for sediment.

His presentation materials suggested USGS climate science was in flux.

“While the exact number of data locations changes due to funding and other considerations,” his notes said, “the USGS has been involved in research at a number of regional sites around the globe that provided scientific information and data critical to communities and decision-makers at all levels for planning and assessment purposes.”

As an example, Reilly’s presentation included an underwater photo of an angular dome — the Ocean Carbon System by USGS researcher Kim Yates. Reilly’s notes said it was perhaps the only autonomous seafloor-mounted system of its kind for monitoring changes in ocean acidification, temperature and other conditions.

The project lost funding in 2016, his notes said, so it’s now deployed on other experiments as needed.

On sediment, Reilly’s slides included more scientific detail.

On the Hawaiian island of Molokai, he said, human activities have increased the watershed’s sediment load by more than a hundredfold, especially because of pineapple farming and overgrazing by feral goats.

Scientists identified 3% of the drainage area as causing 50% of the sediment, allowing targeted restoration, according to Reilly’s presentation. After four years of fencing out goats from an experimental area, he said, erosion fell by half.

Along with pictures of reefs damaged by sediment, Reilly’s presentation featured detailed modeling of corals’ economic benefits. He showed color-coded maps that forecast how coral degradation could affect coastlines, refined down to a scale of tens of meters.

Reilly’s notes said the countries attending his presentation had requested USGS scientific assistance on coral, but his notes warned him that the State Department would be in the room and he should not “venture into diplomatic waters without more information.”

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