[Coral-List] Reefs are threatened by global climate change!
Precht, William F
PrechtW at BATTELLE.ORG
Wed Oct 3 09:12:58 EDT 2007
In response to Gene Shinn's post of the following website http://ff.org/images/stories/sciencecenter/coral_reefs_and_global_warming.pdf to the list, I have received quite a number of emails asking for an explanation of my position on global climate change and coral reefs. In addition, this post has evoked some lively discussion on the list. It appears that The Center for Science & Public Policy and the Frontiers of Freedom Institute have misconstrued the interpretation put forth in a 2004 manuscript authored by myself and Rich Aronson. This article discussed range expansions and contractions of reef-building corals in response to climate flickers.
Range expansions and contractions are expected in response to changing temperatures, whether measured as air temps or SSTs (see meta-analysis papers by Root et al, Parmesan et al). The evidence from the coral literature supports this as well. Clearly, we should not be surprised that we are witnessing the range expansions of cold-sensitive corals at their latitudinal extremes. In addition, the geological literature is filled with similar examples in time and space. The question with regards to the ongoing global catastrophe is: what's happening to the corals in the insular tropics?
When you read the Precht & Aronson (2004) paper it is helpful to read the whole thing and not take out the tidbits that fit a prescribed story - which is exactly what they did! The anonymous author(s) of the piece ignored some of the main points of our paper, including, "On the other hand, geographic shifts will not mitigate expected ecological and economic losses resulting from the reduced functions of tropical reef systems"
Our concluding paragraphs (in Precht & Aronson 2004) further state that
"The staghorn coral thickets off Fort Lauderdale present an interesting case. Are these remnant populations, or are they the recent product of a chance recruitment event? Do they represent a temporary range expansion that is likely to be obliterated by the passage of the next subfreezing cold front, disease outbreak, or hurricane? Are they an indicator of global climate change? These possibilities are not mutually exclusive, but only through genetic analysis of populations and long-term monitoring will we be able to answer such questions definitively.
The fossil record of coral reefs is helping us predict the impacts of future climatic warming. Although it is likely that reef-building corals will expand their ranges to higher latitudes in response to global warming, geographic shifts of marginal reefs will not mitigate the expected ecological and economic losses due to localized coral mortality and reduced function in tropical reef systems. Understanding the causal links between climate change and the dynamics of reefs and other ecosystems will continue to be a challenge in the face of natural variability, uncertainties inherent in predictive models, and the complex impacts of human activity all over the planet."
Finally, this topic was also reviewed in the Pew Center's publication entitled "Coral Reefs & Global Climate Change" by Buddemeier, Kleypas and Aronson (2004)
Will Global Warming be Good for Reefs? (see page 17)
"About 5,000-6,000 years ago, an earthquake lifted a coral community out of the sea at Tateyama, Japan, at the same latitude as Tokyo. That community contained at least 72 species of corals, compared to the 35 now found in the vicinity (Veron, 1992, 1995). Tateyama sea-surface temperature (SST) was 1.2-1.7°C warmer at that time than at present, because the earth was experiencing a warm period known as the Altithermal, or Middle Holocene High (Veron and Minchin, 1992). This suggests that corals and reef-building could migrate to higher latitudes in response to global warming. Geographic shifts of reefs would not mitigate the ecological and economic problems caused by the loss of tropical reefs, but it would partly alleviate concerns about global biodiversity loss. The problem with comparing the effects of Altithermal warming and future warming is that little besides temperature would be comparable. Then, any human settlements in the area were small and primitive, and the coastline was essentially pristine. Today's corals would have to settle and survive in highly populated and developed areas with intensive agriculture, fishing, pollution, coastal construction, and other societal artifacts that make coastal waters inhospitable to coral communities. When Tateyama reaches the temperature levels of 5,000-6,000 years ago, the chemistry of the water will be less favorable to coral growth and reef building (Kleypas et al., 2001; Guinotte et al., 2003; see Box 7). With both suitable habitat and the potential for coral and reef growth reduced, future immigrant corals will face very different prospects than their predecessors."
I think our position is clear and it does not favor the view that the current aspects of global change are natural and will be good for reefs. On the contrary, we believe that human induced climate change is one of society's most pressing challenges - now and in the future - and that the survival of reefs as we know them is hanging in the balance.
Finally, it is interesting (and a bit disturbing) to see my words, photos and figures used in this unintended way. The way the report is prepared it looks as though Precht and Aronson either wrote the piece or endorsed it. We did neither, and while they gave full attribution when reproducing our figures and photos they did so without our permission.
William F. Precht
Senior Program Manager
Battelle Memorial Institute
Applied Coastal & Environmental Services
1400 Centrepark Blvd., Suite 1005
West Palm Beach, FL 33401
Email: PrechtW at Battelle.org
More information about the Coral-List