ABC News ran an Associated Press (AP) story titled, “Climate change is hurting coral worldwide. But these reefs are thriving.” The article is misleading in at least three ways: first coral reefs are not in decline all over the globe as the AP writers assert; Second, temperature changes are only one kind of stressor for corals, the story downplays other factors that evidence suggests play as big or even a bigger role when coral reefs have declined; Third, it provides no evidence that climate change is behind recent ocean warming, rather it assumes this, ignoring natural factors like shifts in oceanic oscillations which have historically caused temperature changes. Indeed, recent research shows that large parts of the oceans inhabited by coral, have actually seen a decline in temperatures over the past two decades.
Waters that get too warm cause corals to expel their colorful algae and turn white. They can survive if temperatures fall but they are left more vulnerable to disease and may eventually die.
Derek Manzello, coordinator of the National Oceanic and Atmospheric Administration’s Coral Reef Watch, said that so far this year, at least 35 countries and territories across five oceans and seas have experienced mass coral bleaching.
Manzello said climate models suggest that all of the world’s coral will be suffering severe bleaching every year beginning around 2040.
Warmer waters are not necessarily bad for coral reefs. Indeed, as detailed in Climate at a Glance: Coral Reefs, coral has existed continuously for the past 60 million years, surviving temperatures and carbon dioxide levels significantly higher and lower than what is occurring today. Indeed, coral thrive in warm water, not cold water and recent warming has allowed coral to expand their range poleward, while still thriving near the equator. So it is simply false to make the universal claim, as Kelly Drinnen, education and outreach specialist for the Flower Garden Banks, did in the AP story that “coral reefs are declining all over the globe.”
Indeed, as discussed across several Climate Realism posts, here and here, for example, despite repeated bleaching events in recent years, the Great Barrier Reef, the world’s largest coral reef system, recently experienced its two highest years of coral extent. This is just one instance demonstrating the resilience and adaptability of corals to temperature changes. Coral bleaching is not the same as coral death, and most corals that have bleached have recovered.
Although it is certainly true that waters that warm too much, too fast can cause coral bleaching, ocean warming is neither a necessary nor sufficient condition to cause such bleaching at all coral reefs under every set of conditions. Indeed, temperature changes are not the only cause of bleaching, or even the primary one in many instances. As discussed at Climate Realism, here and here, for example, inappropriate commercial fishing, terrestrial run-off and pollution from farms and urban development along the coasts, sedimentation, chemicals in some sun screens, and periods of rapidly cooling waters have all been linked to bleaching events and declines in local coral populations.
Yes, you read that right, data indicates that ocean cooling has occurred across vast swaths of the eastern and central Pacific ocean over the past two decades, refuting the claim that any coral bleaching there has been caused by warming.
The concerns expressed about future bleaching and the mass decline of corals contained in the story are not borne out by actual trend analyses, in fact, but rather are generated by computer model projections. Yet time and again, Climate Realism has shown computer models do a poor job of reflecting reality.
In the end, neither ABC nor the AP provided any evidence that climate change is harming coral reefs—asserting a connection between climate change and coral decline and backing it up with verifiable proof are two different things, and the latter is lacking in the ABC/AP story. Despite some coral reefs declining in recent years, overall coral are doing well, with little evidence coral is declining globally. The one thing contained in the ABC/AP story that I believe is likely true is that Flower Garden Banks National Marine Sanctuary is a natural wonder, filled with a variety of life and beautiful to behold. Unless increased tourism and pollution screws it up, it is likely to remain that way, because there is little evidence the recent modest warming poses a threat.