Bleached corals, Fiji, April 2014

This week, the U.S. government announced it would be listing 20 coral species found in American waters as “threatened” under the Endangered Species Act. Part of the rationale is the threat posed by climate change and ocean acidification, a potentially groundbreaking policy move. What may be missed in this announcement is that the original proposal included a longer list of 66 coral species.

The decision begs a broad question. If we are considering the research on climate change and ocean acidification in the decision, then why not list all coral species as threatened?

The Coral Specialist Group of the IUCN, of which I’ve been a part, submitted a detailed comment to the U.S. proceedings. My meager contribution to the group’s terrific dissection of coral ecology and physiology was the argument that committed climate warming may alone be sufficient evidence for all coral species to be listed as threatened. Here is the excerpt, with wording vastly improved by my colleagues:

The projected increase in sea surface temperatures due to the physical commitment from the present accumulation of greenhouse gases due to anthropogenic activity, as well as the socioeconomic commitment (i.e. it is logistically impossible to instantly eliminate anthropogenic emissions, regardless of policy decisions, because of inertia to the existing energy system), is sufficient to cause frequent and higher magnitude heat stress for the majority of the world’s coral reefs by 2050 (Donner, 2009). The primary source of uncertainty in this forecast is the ability of the coral holobiont to acclimate and/or adapt to heat stress. The fact that the future abundance of coral species depends on a rate of adjustment to heat stress that is unprecedented in geological history should be sufficient to warrant a minimum status of threatened for all coral species.

The problem of coping with commitment, the title of that cited 2009 paper, was highlighted by a terrific new paper that happened to be released almost simultaneously with the U.S. coral decision. In “Commitment Accounting of CO2 emissions”, Stephen Davis and Rob Socolow calculate the committed emissions from the operation of new energy investments, like coal plants, over the expected lifetime of those investments (see Dot Earth for a lengthy discussion). They conclude that it would  be sensible to use committed emissions, rather than the annual emissions, to inform public policy.

The socioeconomic commitment or capital “lock-in” to future emissions has implications for everything from these species listings to oil pipeline decisions. We can’t perfectly project the future of each coral species, but we can say that the oceans are committed to physical and chemical changes which may be dangerous or fatal to corals. These changes do not guarantee widespread extinction or endangerment, given potential adaptability of many species and the potential refuges in the ocean, but certainly could classify as threatening.