The incredible warmth of the past two years laid waste to corals on the Great Barrier Reef. A new study, led by Terry Hughes and a large team of top Australian scientists, finds a strong correlation between the warm ocean temperatures over 2015/16 and the extent of coral bleaching, an often fatal paling of the colourful reef-building animals. The study also finds that there are very few stretches of the Great Barrier Reef left (<10%) that were not affected by the 3 large-scale bleaching events over the past 20 years.

The authors soberly conclude:

Securing a future for coral reefs, including intensively managed ones such as the Great Barrier Reef, ultimately requires urgent and rapid action to reduce global warming.

I wish I could say that this widespread death of corals comes as a surprise. It doesn’t. Scientific research, including my own, has been warning for almost two decades that the fate of the world’s coral reefs depends on actions to slow global warming. A look back at some old work on the subject shows just how critical a time this is for the climate, for coral reefs, and for scientists.

In a 2005 study, my first on the subject, a group of colleagues and I used the results of climate model simulations and data derived from satellites to assess how the likelihood of coral bleaching-level heat stress will change as the planet warms. This figure from the paper is an example of the projected frequency of bleaching ‘alerts’ during the 2030s in a business-as-usual emissions scenario using a particular model (brighter colours = higher frequency):

The green dots around the central Great Barrier Reef represent a bleaching-level heat stress occurring every 3-5 years. The orange dots around the northern Great Barrier Reef represent bleaching-level heat stress at least every 2 years, far too rapidly for many coral reefs to recover. Fast-forward another 20 years to the 2050s, and all of the Great Barrier Reef, as well as 98% of the rest of the world’s reefs, appear in red: bleaching-level heat stress happening every year.

The study ended as follows:

To ensure the world’s coral reefs are protected from climate change, the margin for error on emission controls may be small.

That statement rings true today, in more ways than one.

The research study arose out of a collaboration that I had arranged with scientists at NOAA. At the time, the George W. Bush Administration was clamping down on climate change research and communication of that research by federal agencies. The restrictions led to all manner of absurdities. Before giving a talk about the planned collaboration to a NOAA climate panel, I was actually cautioned not to say the words “climate change,” even though my talk was titled “Climate change and coral bleaching.”

When we finished the final draft of the paper, we realized that the higher-ups, who had to approve of work co-authored by NOAA researchers, were likely to object to the policy-tinged language in the conclusion. What to do? Changing a conclusion that flowed logically from the results was out of the question; even if we were open to a change, it seemed crazy to bend a scientific paper to suit the U.S. government when the lead author was not a government employee, let alone even an American.

Instead, we massaged the author list and the author information to avoid crediting NOAA and a political review of the work. One NOAA person involved in the project, albeit very peripherally, offered to not be listed as an author. It has always bothered me.

Today, the story of publishing that paper sounds almost quaint. The ‘war’ on science of the Bush years now looks like a minor skirmish compared to the nuclear holocaust of funding cuts, denialism, and obstructionism being pushed by the Trump Administration. And it is happening at the same time when scientists are pondering funeral arrangements for one of the natural wonders of the world, and pointing the finger at climate change.

There’s no sense wondering anymore if it is appropriate for scientists to speak up and be heard. We should be shouting from the rooftops.

Seriously, if not now, when?