This week saw the release of a new study in PLOS ONE with the unwieldy title Identifying the World's Most Climate Change Vulnerable Species: A Systematic Trait-Based Assessment of all Birds, Amphibians and Corals. This text is from a press release from the University of Witwatersrand (Johannesburg, SA)
Vertebrate extinction rates are currently estimated to be 10–100 times greater than background, largely due to the effects of habitat loss, over-exploitation and invasive species. However, anthropogenic climate change is becoming a significant new threat...
Most species at greatest risk from climate change are not currently conservation priorities, according to an International Union for Conservation of Nature (IUCN) study that has introduced a pioneering method to assess the vulnerability of species to climate change.
Up to 83% of birds, 66% of amphibians and 70% of corals that were identified as highly vulnerable to the impacts of climate change are not currently considered threatened with extinction on The IUCN Red List of Threatened Species. They are therefore unlikely to be receiving focused conservation attention, according to the study.
“The findings revealed some alarming surprises,” says Foden, who conducted the study while formerly working for the IUCN Global Species Programme. “We hadn’t expected that so many species and areas that were not previously considered to be of concern would emerge as highly vulnerable to climate change. Clearly, if we simply carry on with conservation as usual, without taking climate change into account, we’ll fail to help many of the species and areas that need it most"...
Species that are highly climate change vulnerable but are not currently threatened potentially represent new priorities for conservation. These include 1,715–4,039 (17–41%) bird species, 698–1,807 (11–29%) amphibian species and 74–174 (9–22%) coral species, and represent 74–83%, 51–66% and 61–70% of all highly climate change vulnerable birds, amphibians and corals respectively.
Figure 4 from the study — Climate change vulnerability under different emissions scenarios.
Red, black, and blue lines represent the percentages of highly climate change vulnerable species under high (A2), mid-range (A1B) and low (B1) emissions scenarios for birds (A), amphibians (B) and corals (C) for 1975–2050 and 1975–2090. Optimistic and pessimistic estimates for missing biological trait data are represented by solid and dashed lines respectively.
When you see such a study, you need to ask how much warming are we talking about? I discussed the high emissions A2 scenario in The Earth's Climate — Rethinking "Rethinking Wedges". We get about 2.5° C of warming by 2060 under A2. The other scenarios (A1B, B) yield less warming under standard assumptions. Future warming is likely to be in the range coverd by these three scenarios. In Figure 4 above, we note that increasing bird and amphibian vulnerability rates begin to level off in 2060, though coral vulnerability does not.
The "higher" animals, the vertebrates and many invertebrates, are vulnerable to anthropogenic climate change in the 21st century because of the rapidity of the warming. When the environment changes in a radical way, animal species have exactly three options.
- Change (adapt)
- Move (migrate)
- Die (go extinct)
The swiftness of the warming precludes option #1 for most animals, and option #2 provides only limited, temporary protection in many cases. If this warming were occurring over 10,000 years, or 100,000 years, many animals might have a chance adapt to the change with only minor physiological or behavioral modifications. (Many species would still eventually go extinct.) Moreover, the limits of option #2 are made worse by the fact that many animals must exist in a hostile human-built environment. A large percentage of birds, amphibians and corals are therefore left only with option #3, as per this study.
This was an IUNC-sponsored study, as was mentioned in the opening quote. I will quote from a October 17, 2012 press release about the palms of Madagascar.
Hyderabad, India — Eighty three percent of Madagascar’s palms are threatened with extinction, putting the livelihoods of local people at risk, according to the latest update of The IUCN Red List of Threatened Species™ released today by the International Union for Conservation of Nature (IUCN).
The update brings the total number of species listed on The IUCN Red List to 65,518, of which 20,219 are threatened with extinction.
That's 31% of the assessed species. Today's study tells us that percentage is too low if climate change proceeds apace.
Again, I would like to bring your attention to the full name of this organization. It is called the International Union for the Conservation of Nature.
The Conservation of Nature — think about what that phrase actually means.