A recent US Court of Appeals decision could have broad implications for how federal wildlife agencies consider potential climate change impacts on species and their habitat. Pursuant to the Endangered Species Act (ESA), the US Fish and Wildlife Service (FWS) or National Marine Fisheries Service (NMFS) must determine whether to list a species as endangered or threatened based on “the best scientific and commercial data available.” 16 U.S.C. § 1533(b)(1)(A). Given the inherent uncertainties and limitations of forecasting specific population changes (or habitat changes) on the basis of climate change projections, the Services may find that potential climate change impacts on a species are too speculative to support a decision to list a species. The US Court of Appeals for the Ninth Circuit, however, recently overturned a FWS decision not to list a species on that basis. In reviewing FWS’s decision not to list the arctic grayling, a cold-water fish species found in Montana, a three-judge panel found that FWS failed to adequately explain why uncertainty regarding future impacts of climate change justified its conclusion that listing the species was not warranted.

The court’s decision is in tension with current science and relevant case law and may be seen as inverting the regulatory framework for decisions by the Services whether to list species. The Services are required by the ESA to support a decision to list a species by demonstrating through use of the best available science that the species is in danger of extinction or threatened with becoming so endangered. This decision, on the other hand, arguably requires the Services to prove a negative in the face of uncertain climate change effects; i.e., that the best available science demonstrates that the species is not in danger of extinction or threatened with becoming so endangered.


To list a species as “endangered” the Services must find that the species is in danger of extinction throughout all or a significant portion of its range; a “threatened” species is one that is likely to become an endangered species within the foreseeable future. Listing decisions must rely on the best scientific and commercial data available. This statutory requirement is intended to avoid listing decisions based on insufficient information or conjecture and to “ensure that the ESA not be implemented haphazardly, on the basis of speculation or surmise.” Bennett v. Spear, 520 U.S. 154, 176-77 (1997). Nor can the Services list species out of an abundance of caution. To do so would “result in all or nearly all species being listed as threatened.” See Trout Unlimited v. Lohn, 645 F. Supp. 2d 929, 947 (D. Or. 2007).

While climate change models can provide a basis for making broad estimates of future climate conditions, it is widely recognized that those models do not provide reliable predictions of future conditions at narrow geographical scales or on short time horizons sufficient to support specific conclusions about the future condition of species or habitat at precise locations. Indeed, the most recent Intergovernmental Panel on Climate Change (IPCC) special report recognizes the limitations of these models. In particular, the current state of climate science does not support confident projections of mean precipitation or dryness at a regional scale, and specifically not to the localized level of any effects for a particular species or its habitat. For example, the “analyses show that projected changes in heavy precipitation are more uncertain than for temperature extremes.” IPCC Special Report at 3-32. Similarly, “whether there might be increases or decreases in water availability under higher global warming, is particularly uncertain in tropical and mid-latitude regions.” Id. at 3-38. Accordingly, there is significant disagreement and uncertainty regarding the sufficiency and accuracy of localized climate change projections for a species’ habitat or population persistence.

Summary of Arctic Grayling Case

Within the lower 48 states, the arctic grayling historically existed in Montana, Wyoming and Michigan. Today, it exists only in the Upper Missouri River Basin in Montana, and prefers cooler water temperatures. Temperatures over approximately 70 degrees Fahrenheit can cause physiological stress and impair biological functions such as breeding. Since the 1990s, wildlife advocates petitioned FWS to list the arctic grayling pursuant to the ESA. FWS concluded several times that listing was warranted but precluded by higher priority actions. Likewise, in 2010, FWS again concluded, based on a variety of threats including potential climate change impacts (warmer water temperatures and lower stream levels), that listing was warranted but precluded by higher priority actions. Shortly after the 2010 finding, FWS settled a number of lawsuits in a multi-district litigation, agreeing to address the Service’s backlog of listing decisions. Pursuant to that settlement agreement, FWS released a new finding in 2014 that provided additional analysis of the potential risks presented by climate and concluded that listing the arctic grayling was not warranted.

In its 2014 finding, FWS explained why, despite is previous “warranted but precluded” findings, potential future climate change impacts did not provide an adequate basis for listing the species. Specifically, FWS found that “[a]lthough water temperatures will likely increase with climate change in the future, the spring-fed sources of cool water will likely remain intact and within a temperature range suitable for Arctic grayling occupancy.” 79 Fed. Reg. at 49,405. Also, FWS found that “[i]ncreases in temperature and changes in precipitation are likely to affect the availability of water in the West. However, it is difficult to project how climate change will affect water availability because increased air and water temperatures may be accompanied and tempered by more frequent precipitation events.” Id. at 49,419. Thus, the Service concluded that “[u]ncertainty about how different temperature and precipitation scenarios could affect water availability make projecting possible synergistic effects of climate change on the Arctic grayling too speculative at this time.” Id.

On appeal, a unanimous Ninth Circuit panel struck down the 2014 FWS determination. Among other reasons, the court found arbitrary and capricious FWS’s conclusion that the effects of climate change were too speculative to warrant listing. The court stated that it is not enough for FWS to simply invoke scientific uncertainty to justify its action. Despite the explanations provided by FWS for its 2014 finding, the court declined to defer to or acknowledge those explanations and instead asserted that FWS failed to explain its 2014 finding. Specifically, the court stated that, “[b]y failing to explain why the uncertainty of climate change favors not listing the arctic grayling when the 2014 Finding acknowledges the warming of water temperatures and decreasing water flow because of global warming, FWS acted in an arbitrary and capricious manner.”

The court has granted the parties’ request to extend the deadline for rehearing motions to December 14, 2018, to afford the parties an opportunity to negotiate a timeframe for compliance with the court’s decision.

The Ninth Circuit’s determination could be read to suggest that the Services may not simply decline to list a species where the best available science does not demonstrate with certainty that the species is endangered or threatened, but instead must prove that the species is not threatened or endangered—at least when the Service revises its position on potential future climate change impacts. Such an approach could have significant implications for the Services’ evaluation of climate change impacts in future listing decisions and critical habitat designations, particularly where the Service is refining or revising a prior determination.

Source: Lexology

John Stewart
Editor, OutdoorWire.com
Resources Consultant, California Four Wheel Drive Association
Board of Directors, BlueRibbon Coalition