When butterflies migrate, it is for breeding and survival, not for fun. And mounting evidence shows that butterflies and many other species around the world are migrating to areas outside their current ranges as an adaptive response to climate change. See I. Chen, et al., Rapid Range Shifts of Species Associated with High Levels of Climate Warming, 333 Science 1024 (2011). Good for them, we might cheer. But there are problems. One is that not all species can migrate so easily and quickly. Another is that when species do succeed in adaptive migration, they wind up where they used to not belong. Projecting the adaptive migration story into the future thus does not produce a pretty picture—it leads to what ecologists call the no-analog future, a future in which today’s familiar communities of species have been torn apart and transformed, with some losses along the way, into new ecological groupings. See D. Fox, Back to the No-Analog Future?, 316 Science 823 (2007).
As hard as it is to envision what the new ecological assemblies might look like, it’s not hard to imagine that many species will have a rough time of it trying to make the transition. How can we help species that are in trouble? Usually when we ask that question, one iconic environmental law rises at the top of the list—the Endangered Species Act (ESA). For four decades, the ESA has served as the “emergency room” statute for imperiled species, lowering the boom on everything from dams to highways to anything else humans propose to do that could push a species closer to the brink. So, one obvious response to the stresses climate change poses to species is to pull out the ESA and put it to work. But one significant issue arises: the impacts on species of global ecological transformation induced by climate change are unlike anything the ESA has ever been used to manage. In short, it is going to be as much of a no-analog future for the ESA as it will be for the species it is designed to protect. This article examines what that means for the gatekeeper provision of the ESA: Section 4, which governs the identification of endangered and threatened species and designation of their critical habitat. All ESA regulatory and administrative programs flow from these two core functions. Both of these functions will inevitably confront new and difficult legal questions in response to the landscape created by climate change.
Section 4 directs the agencies charged with administering the ESA—the U.S. Fish and Wildlife Service (FWS) and the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NMFS)—to consider five threats to species: (1) the present or threatened destruction, modification, or curtailment of the species’ habitat or range; (2) overutilization of the species for commercial, recreational, scientific, or educational purposes; (3) disease or predation; (4) the inadequacy of existing regulatory mechanisms; and (5) other natural or manmade factors. 16 U.S.C. § 1533(a)(1)(A)–(E). Climate change unquestionably will trigger one or more of these factors for many species. It can modify habitat, increase disease or predation, or lead to other natural or manmade factors threatening a species. Existing regulatory mechanisms may be inadequate to address such threats. But connecting the ESA to climate change at that general level isn’t hard. What is difficult is figuring out how to implement the statute from there. The news and litigation surrounding the listing and critical habitat designation for the polar bear brought attention in that respect to section 4, but that represents only the beginning.
The listing function of section 4 is one area of concern. Section 4(a) requires FWS and NMFS to “determine whether any species is an endangered species or threatened species” based on existing threats. 16 U.S.C. § 1533(a)(1). A species is “endangered” if it is “in danger of extinction throughout all or a significant portion of its range,” and it is “threatened” if it is “likely to become and endangered species within the foreseeable future throughout all or a significant portion of its range.” 16 U.S.C. §§ 1532(6), (20). Neither of these concepts is defined further in the statute. Given that climate change is forcing species to migrate into a no-analog future, how do terms like “foreseeable future” and “significant portion of [the species’] range” apply?
The extensive uncertainties surrounding the trajectory of climate change under various emission scenarios and climate response models have already made the concept of foreseeable future a touchstone of controversy. The law of “foreseeable future” in the ESA context was quite sparse prior to 2009, with only two cases addressing the issue, neither of which involved climate change. Moreover, no agency rules or guidance were in place. In January 2009, however, the Department of the Interior (DOI) Solicitor issued an opinion concerning the meaning of “foreseeable future.” It concluded that the concept called for a species-specific determination rooted in the best available science allowing reliable predictions into the future. See Opinion M-37021 (Jan. 16, 2009). Although one can speculate that the prospect of climate change may have motivated the issuance of the opinion, climate change is never mentioned. Since the opinion’s issuance, several cases have upheld the agencies’ determinations concerning how far into the future the effects of climate change on species can be reliably projected. For example, one court concluded that NMFS reasonably limited the analysis to 2050 based on its assessment of the unreliability of scientific models post-2050. See Center for Biological Diversity v. Lubchenco, 758 F. Supp. 2d 945 (N.D. Cal. 2010) (analyzing NMFS’s decision not to list ice-reliant ribbon seal).
Climate change presents some new difficulties in analyzing a species’ range as well. In an effort to replace DOI’s prior “significant portion of range” policy, which had been successfully challenged in litigation and later withdrawn, in December 2011 FWS and NMFS issued a new draft policy on the interpretation of that phrase. 76 Fed. Reg. 76,987 (Dec. 9, 2011). Under this new approach, the agencies will list a species if it is endangered or threatened throughout all of its range or throughout a significant portion of its range. In either case, the species will be listed throughout all of its range. Also, adhering to prior policy, the agencies explained that “range” for purposes of the analysis includes only “the general geographical area within which the species can be found at the time FWS or NMFS makes any particular status determination.” Many environmental protection interest groups had argued that range should include lost historical range. FWS and NMFS explained they would consider lost historical range as part of the species status review, not as part of the range analysis. Notably, however, the agencies did not address questions such as how to account for the possibility that a species’ range might be shifting over time and what significance to attach to the species’ migratory departure from its prior occupied range. Presumably, the agencies could take the “snapshot” approach to determine the species’ current range at any time and account for the shifting of the range in determining the species’ status. In sum, it remains to be seen how the agencies and courts will deal with ranges that shift due to adaptive migration.
Species migration will also make defining what constitutes a “species” more complicated. This concept has also been the subject of some controversy even without climate change. For example, the ESA defines species to include not just the entire species or a subspecies, but also “any distinct population segment of any species of vertebrate fish or wildlife.” 16 U.S.C. § 1532(16). A 1996 policy on such “distinct population segments” or “DPSs” last addressed the issue, but it does not mention climate change. See 61 Fed. Reg. 4722 (Feb. 7, 1996). One question left open is how to treat a listed DPS if its adaptive migration unites it with another listed or unlisted population of the species. Are the two previously DPSs merged into one population? If so, is the “new” now-merged population listed or not? Similarly, neither the statute nor any currently effective agency promulgation addresses the status of hybrids resulting from the interbreeding involving one or two listed species. Hybrids and hybrid populations are both likely to become more common as species migrate. Yet their status remains somewhat unclear.
Critical habitat designation
When listing a species as endangered or threatened, FWS and NMFS must also “to the maximum extent prudent and determinable . . . designate any habitat of such species which is then considered to be critical habitat.” 16 U.S.C. § 1533(a)(3)(A). Critical habitat is defined in the statute to mean areas “within the geographical area occupied by the species . . . on which are found those physical or biological features (I) which are essential to the conservation of the species and (II) which may require special management considerations or protection.” Id. § 1532(5)(A)(i). It can also include areas outside the occupied area if such areas are “essential for the conservation of the species.” Id. § 1532(5)(A)(ii). In either case, areas that otherwise would qualify as critical habitat may be excluded for such designation if the agency concludes that “the benefits of such exclusion outweigh the benefits of specifying such are as part of the critical habitat” and excluding the area will not result in extinction of the species. Id. § 1533(b)(2).
Climate change presents a host of issues for this cluster of critical-habitat-related subsections, yet uncertainties remain. In some cases, FWS has mentioned climate change as a factor that could require “special management,” but it has not explained what that would entail. See 78 Fed. Reg. at 62,530 (Oct. 22, 2013) (proposed plant critical habitat). Broader questions also arise. For example, if it is known that an area a species currently occupies meets the criteria for critical habitat but that area is degrading, can that prospect justify a finding that designation of the area as critical habitat is not prudent? Current agency regulations define “not prudent” as a “designation of critical habitat [that] would not be beneficial to the species,” 50 C.F.R. § 424.12(a)(1)(ii). Designating habitat that is likely to become degraded would arguably not benefit the species. Or, could such conditions be taken into account when weighing whether to exclude a particular parcel if the benefits are seen as diminishing substantially over time? See Opinion M-37016 (Oct. 3, 2008) (not discussing the issue).
Conversely, if it is known that an area not currently occupied by the species is likely as a result of climate change to transition into habitat meeting the criteria of critical habitat, can that prospect make the future habitat area “essential for the conservation of the species” and thus eligible for designation? On the one hand, current agency regulations state that one element of critical habitat is “space for individual and population growth,” 50 C.F.R. § 424.12(b)(1). On the other hand, areas outside the geographical area presently occupied by a species may be designated “only when a designation limited to its present range would be inadequate to ensure the conservation of the species.” Id. § 424.12(e). Although that seems restrictive, it might be satisfied in cases where a species is likely to migrate. The agencies have come close to this approach. In one instance, FWS designated unoccupied habitat as critical habitat for a coastal bird species in order to offset loss of the species’ habitat to climate change. The stated rationale, however, was that the unoccupied habitat once was occupied and would need to be restored manually. 77 Fed. Reg. 36,728 (June 19, 2012). There have been several other proposed or final designations taking these offset approaches. In no case, however, has FWS or NMFS taken the “future habitat” offset approach. Its legality is therefore an open question.
In sum, although climate change could change the way many provisions of the ESA operate, the section 4 listing and critical habitat provisions are perhaps the most important to consider in this respect. As this article demonstrates, many potential legal issues lurk on the horizon for section 4 as a result of climate change. It behooves all ESA practitioners to begin considering how best to implement the statute to make it resilient over the course of our entry into the no-analog future.