Climate change creates new challenges for application of ESA's listing factors to individual species
Based on the recent federal report, Global Climate Change Impacts in the United States, the nation's ecosystems will soon experience massive stresses. According to this report (see Executive Summary too), our national ecosystems have already changed, and will endure massive changes:
- Ecosystem processes, such as those that control growth and decomposition, have already been affected by climate change;
- Large-scale shifts have occurred in the ranges of species and the timing of the seasons and animal migration, and are very likely to continue;
- Fires, insect pests, disease pathogens, and invasive weed species have increased, and these trends are likely to continue;
- Deserts and drylands are likely to become hotter and drier, feeding a selfreinforcing cycle of invasive plants, fire, and erosion;
- Coastal and near-shore ecosystems, including coral reefs, are already under multiple stresses. Climate change and ocean acidification will exacerbate these stresses;
- Arctic sea ice ecosystems are already being adversely affected by the loss of summer sea ice and further changes are expected;
- The habitats of some mountain species and coldwater fish, such as salmon and trout, are very likely to contract in response to warming.
When these large scale ecosystem concepts are applied to individual species, ESA implementation could become far more difficult than it already is. As frequently explained in Federal Register notices, Section 4 of the Endangered Species Act and its implementing regulations (50 CFR 424) set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. "A species or subspecies may be determined to be an endangered or threatened species due to one or more of the five factors described in section 4(a)(1) of the Act..."
(A) The present or threatened destruction, modification, or curtailment of its habitat or range;
(B) overutilization for commercial, recreational, scientific, or educational purposes;
(C) disease or predation;
(D) the inadequacy of existing regulatory mechanisms; or
(E) other natural or manmade factors affecting its continued existence."
In other words, when the ecosystem impacts, as discussed in the recent climate change report, is applied to the listing analysis, Factor A (habitat changes), C (disease), and E (other factors) can be expected to play a prominent role in virtually all future ESA listing evaluations. It will prove technically (and legally) challenging to assess the degree to which species are, or are not, threatened or endangered by climate change.
Nevertheless, the Intergovernmental Panel on Climate Change has estimated that if a warming of 3.5 to 5.5°F occurs, 20 to 30 percent of species that have been studied would be in climate zones that are far outside of their current ranges, and would therefore likely be at risk of extinction. Indeed, extinction rates of plants and animals have already risen considerably, with the vast majority of these extinctions attributed to loss of habitat or over-exploitation. There may, however, be a thin silver lining. As the climate change report also notes, "some of the benefits ecosystems provide to society will be threatened by climate change, while others will be enhanced."
SEE ALSO: New York Times.