dissenting:

I respectfully dissent.

The Federal Aviation Administration (FAA) completed a Final Environmental Impact Statement (EIS) for the proposed runway extension at Maui’s Kahului Airport on October 2, 1997. The FAA’s Record of Decision (ROD), relying on the Final EIS in approving the runway extension, was signed on August 26, 1998. From the first serious consideration of this project in the 1980s until the preparation of the Final EIS, the FAA was aware that the introduction of alien species into the island ecosystem of Maui was a major concern. Considering the Final EIS as a whole, I reluctantly conclude that the FAA failed to take the requisite “hard look” at the likely impact of the extension on the introduction of alien species.

The Final EIS included a Biological Assessment prepared at the request of the FAA containing, among other things, projected increases in arriving flights due to the runway extension; a Biological Opinion prepared by the Fish and Wildlife Service in compliance with the Endangered Species Act; and numerous scholarly articles. The FAA thus possessed relevant information concerning the likely impact of the project on the introduction of alien species. But the FAA gave no indication, either in the Final EIS or in the ROD based on the Final EIS, that it evaluated or took critical aspects of this information into account. Indeed, far from taking a hard look, the FAA in the Final EIS and the ROD obscured the data and misstated its significance. In so doing, the FAA failed to comply with the National Environmental Policy Act.

I

The National Environmental Policy Act (NEPA) is a procedural statute requiring government agencies to evaluate the environmental impacts of proposed projects before approval in order to “prevent or eliminate damage to the environment and biosphere.” 42 U.S.C. § 4321 . NEPA requires a detailed statement of the environmental impacts of the proposed project on the human and natural environment. See 42 U.S.C. § 4332 (2)(c). The Supreme Court has interpreted this requirement to mean “that agencies [must] take a hard look at environmental consequences.” Robertson v. Methow Valley Citizens Council, 490 U.S. 332, 350 , 109 S.Ct. 1835 , 104 L.Ed.2d 351 (1989) (internal quotation marks and citation omitted). NEPA is not, however, a substantive statute. As the Court wrote in Methow Valley, “[i]f the adverse environmental effects of the proposed action are adequately identified and evaluated, the agency is not constrained by NEPA from deciding that other values outweigh the environmental costs.” Id.

The central flaw in the Final EIS is that the FAA' failed to admit or analyze the likely environmental consequences of increased non-stop overseas arrivals resulting from the proposed runway extension. The FAA is free to conclude that the likely benefits of the extension outweigh the likely adverse environmental consequences, but it cannot arrive at that conclusion without first adequately admitting and analyzing those risks. Because of the de *684 monstrable insufficiency of the Final EIS, I find it impossible to agree with the majority’s conclusion that the FAA took a “hard look” at the likely environmental consequences of its proposed action.

II

The Final EIS concludes that the proposed project will have no impact on the introduction rate of alien species. It states its conclusion several times, with only slight variations: “The forecast increase of-air passengers and air cargo to Maui ... may result in an increase in the potential for the introduction or introduction rate, of alien flora or fauna species into Maui. This forecast increase of passenger and cargo will occur with or without the Proposed Project.” FEIS § 3.11.3.2 (emphasis added). “A significant impact would occur if the proposed improvements would substantially increase the rate of introduction of alien pests. An insignificant impact would occur if the rate shows little or no increase. As the passenger levels and cargo/mail tonnage are similar in both the No-action and Proposed Project, the impact of the Proposed Project on alien species introduction rate is, in and b'y itself, insignificant.” Id. § 3.11.3.3 (emphasis added). “[T]he introduction of alien species is an existing problem, and will continue to be a problem in the future with or without the Proposed Project.” Id. § 5.1.6.1 (emphasis added). “The impact of alien species is a statewide problem and will not be fully resolved in this EIS. The issue will continue to be a significant problem with or without the Proposed Project, as alien species will continue to be introduced through other pathways, such as purposeful introductions, mail, and other ports-of-entry.” Id. § 5.1.6.1 (emphasis added).

The ROD echoes the Final EIS: “[Ajlien species introduction rate due to tourists currently traveling to Maui via airplane and ship, and cargo delivered to Maui by air and sea will continue to impact Maui’s listed or candidate species, and other plant and animal species with or without the proposed project.” ROD at 21-22 (emphasis added). “[T]he alien species introduction rate due to tourists currently traveling to Maui via airplane and ship and cargo delivered to Maui by air and sea will continue to impact Maui’s listed or candidate species, and other plant and animal species with or without the proposed project.” Id. at 22 (emphasis added). “By itself, the impact of the proposed project on the introduction rate of any alien species is insignificant.... ” Id. at 28 (emphasis added).

These statements are based on a deception. The FAA proposes the runway extension at Kahului Airport because fully-loaded, fully-fueled non-stop overseas flights cannot take off from the present runway. As a physical matter, non-stop overseas arrivals can land on the present runway, but as an economic matter, many such arrivals — particularly those from Asia — are not profitable unless they are combined with non-stop overseas departures by those same airplanes. Thus, while the proposed runway extension will permit fully-loaded, fully-fueled aircraft to leave Maui on non-stop overseas flights, the practical and environmentally significant impact of the extension is that many non-stop overseas arrivals will become economically feasible for the first time.

Yet, according to the FAA, the significance of the runway extension is the departures it will permit, not the arrivals it will produce: “Although the existing 7,000-foot-long runway adequately serves domestic and international aircraft arriving at Maui, these arrivals do not and will not require the proposed extension to maintain service to Maui. Conversely, the existing runway is not long enough and does not have adequate pavement strength to accommodate departing, non-stop flights fully loaded[.]” Id. at 4 (emphasis in original). This statement accurately conveys the purpose of the extension, but that purpose cannot be the basis for an *685 analysis of its environmental consequences.

The FAA nevertheless conflates the purpose and its environmental consequences. It writes:

Id. at 22 (emphasis in original). Pause for a moment to consider the second sentence. According to the FAA, the alien species introduction rate will remain the same “with or without the project” because alien species do not arrive on departing aircraft. This is willful sleight-of-hand. The issue is not alien species that arrive on departing aircraft. Nothing arrives on departing aircraft. The issue, as the FAA well knows, is alien species introduced by arriving aircraft.

Ill

The following data on arriving aircraft may be derived (with considerable effort) from Table 1-1 of the Biological Assessment. BA § 1.2. Without the proposed project, the FAA estimates that there will be 1,600 non-stop domestic overseas arrivals from the United States mainland in the year 2010. With the project, there will be an additional 1,460 such arrivals from the United States mainland. Without the proposed project, the FAA estimates that there will be 50 non-stop international overseas flights to Maui in the year 2010, all from Vancouver, Canada. With the project, there will be an additional 50 such arrivals from Vancouver.

The most critical issue, however, is the increased non-stop arrivals from Asia. There have been non-stop arrivals from North America to Maui for a number of years, but there have been virtually no non-stop arrivals from Asia. Because they are new, non-stop arrivals from Asia pose by far the greatest danger of introducing new alien species. According to Table 1-1, the proposed project will produce an increase in the yearly non-stop arrivals from Asia from 0 to 1,100.

In concluding that the introduction of alien species will be the same “with or without the proposed project,” the FAA emphasizes that the total number of people traveling to Maui will remain the same with or without the project. FEIS §§ 3.11.3.2, 3.11.3.3. But the issue is not merely the number of people; it is also the number of increased non-stop arriving flights, particularly those from Asia. According to the FAA’s own information, the airplanes themselves, not merely their passengers, are avenues for the introduction of alien species. As the Biological Opinion states, “The initiation of direct flights from Asia could increase the risk of Asian species being introduced that now have no direct route to Maui, particularly those organisms passively transported mthin the aircraft that ivould be released when the fuselage is opened.” BO at 25 (emphasis added).

Even if one assumes that there will be no overall increase in non-stop overseas flights from Asia to the Hawaiian islands and that non-stop overseas flights originally bound for Oahu will instead land in Maui, the increased arrivals on Maui are significant. BA § 5.4. One might think that, if the only result of the extension is to shift non-stop Asian overseas arrivals from Oahu to Maui, the overall impact on the Hawaiian islands, considered as a whole, would remain the same. But this is not the case. The environment immediately around Kahului airport and on Maui generally is more hospitable to alien species than the environment immediately surrounding the Honolulu airport and on Oahu generally. The more hospitable, and therefore more vulnerable, environment on Maui results from several factors. First, *686 the prevailing, trade winds on Maui blow from the Kahului airport toward adjacent sugar cane fields and wetlands, whereas the prevailing winds on Oahu blow from the Honolulu airport toward the ocean. Second, the Kahului airport is immediately adjacent to hospitable environments for alien species, such as cane fields and wetlands, whereas the Honolulu airport is isolated from hospitable environments by expanses of concrete. Third, due to its greater elevations and greater geographical diversity, Maui has a much larger number of hospitable environmental niches than does Oahu. It is therefore possible that some alien species that could never establish themselves on Oahu could easily do so on Maui. Finally, even if we indulge the counter-factual assumption that the two islands are equal in their vulnerability to introduction of alien species, the Biological Assessment concluded that “opening Maui to more direct overseas flights [in addition to Oahu] doubles the potential area available for colonization.” BA § 5.4.2.

The Biological Assessment states in its conclusion that “if the present aircraft flights are one of the pathways for alien species introduction into Hawaii, and if the Proposed Project results in more direct flights to Maui from the mainland U.S. and, in the future, from Asia, the Proposed Project could potentially increase the risk of alien species being introduced.” BA § 9.1 (emphasis added). This conclusion fails to face up to the information the FAA has in its possession. The two clauses introduced by “if’ purport to state hypothetical propositions. The first is not the least bit hypothetical. The FAA knows that aircraft flights are “one of the pathways for alien species introductions into Hawaii” and the FAA knoivs that this is particularly true for non-stop overseas flights. The second is hypothetical in the sense that it is a prediction rather than a fact, but the FAA itself has projected that the airport extension is likely to result in “more direct flights to Maui from the mainland U.S. and, in the future, from Asia,” including 1,100 non-stop flights per year from Asia where none exist today.

A Memorandum of Understanding (MOU) and Alien Species Action Plan (ASAP) prepared after the issuance of the Final EIS and attached as part of the ROD promise a future assessment of the impact of the runway extension on alien species introductions. The FAA’s proposed assessment will collect “extensive monitoring data to determine the relative risks associated with passengers, cargo, and the aircraft proper.” ROD at 57. Because the assessment is proposed for the future, it cannot be considered as part of the EIS and therefore cannot be considered as part of the hard look the FAA and affiliated agencies were required to do pri- or to approving this project. We said in Seattle Audubon Society v. Espy, 998 F.2d 699, 704 (9th Cir.1993), that an agency does not always need to “undertake further scientific study” before issuing an EIS, but that the agency must explain “why such an undertaking is not necessary or feasible.” The FAA has not explained why the assessment it now proposes was “not necessary or feasible” prior to the adoption of the Final EIS. The information contained in the EIS and its incorporated documents show the necessity for the assessment, and the very fact that the FAA is now proposing the assessment shows its feasibility.

IV

None of this matters to the majority. They conclude- that the FAA’s flight projections are unreliable. They write that “it is not necessarily true that ‘if you build it, they will come,’ ” supra at 680 (quoting City of Los Angeles v. FAA, 138 F.3d 806 , 807 (9th Cir.1998)), and that “airport demand projections are notoriously unreliable,” id. at 682 (citing City of Los Angeles, 138 F.3d at 807-08 & n. 2). They conclude that plaintiffs “seek too much from the EIS.” Id. And they conclude that “[t]he discussion in the EIS is reasonably thor *687 ough, and we aré satisfied that the FAA has made an informed decision.” Id.

The majority’s skepticism about the FAA’s projections is, I must say, convenient. Judge Kozinski quotes and cites his earlier opinion in City of Los Angeles to support his rejection of the FAA’s projections. In that case, Judge Kozinski sustained an EIS for a proposed expansion of the Burbank Airport that would have doubled the number of gates, tripled the number of parking spaces, and quadrupled the size of the terminal. He relied on FAA “airport demand projections” in that case that had no more (perhaps less) claim to accuracy than the demand projections in this case. He wrote in City of Los Ange-les, “The EIS estimates that the number of emplanements per year will grow from 1.7 million in 1990 to 5 million in 2010 whether or not the new terminal is built. Demand for an airport, says the FAA, depends much more on location than on how nifty the terminal is.” 138 F.3d at 807-08. In that case, Judge Kozinski used the FAA projections (which he now calls “notoriously unreliable”) to override what he described as the “common sense” of the opponents of the airport expansion. Id. at 808. As Judge Kozinski recognized in City of Los Angeles, airport demand projections are peculiarly within the expertise of the FAA. He should give as much deference to the FAA’s projections in this case as he gave to such projections in City of Los Angeles. The FAA’s projections of increased non-stop overseas arrivals may not be perfectly accurate, but they are entitled to more than an ad hoc rejection based on the “common sense” of the majority of this panel.

I do not agree with the majority that the plaintiffs in this case “seek too much.” They ask only that the FAA honestly confront the knowledge they have in their possession. I also do not agree that the discussion in the EIS of the critical issue— the threat of introduction of alien species by non-stop overseas arrivals — -is “reasonably thorough.” It is virtually non-existent, and what little discussion exists is dishonest.

Finally, while it is possible that the FAA has made an “informed decision,” we cannot know that this is so. For all we can judge, the FAA may have analyzed alien species introductions resulting from arriving overseas flights as part of its internal decision-making process. But if such an analysis was made, the FAA should have put it in the EIS where it belongs.

V

NEPA is a purely procedural statute. It does not require that an agency reach any particular decision in approving or disapproving a project. It does require, however, that the agency prepare a Final EIS that evaluates carefully and honestly the likely environmental consequences of a proposed action. The FAA has failed to perform its duty. Rather than taking a hard look at the possible environmental consequences, the FAA has deliberately averted its eyes from a well known environmental problem and from the potential consequences of its proposed action.

In failing to perform its duty under NEPA, the FAA has short-changed the political process .Congress had in mind when it required the preparation of environmental impact statements. Because the FAA has failed in its duty, and because the majority of this panel has acquiesced in that failure, we will never know what decision a properly informed political process would have produced.