對於國際貿易規範而言，多邊貿易協定（如 WTO）與雙邊或區域貿易協定存在微妙的互動關係，亦即在多邊談判場域陷入膠著後，各國之談判重心與能量即會轉移至會員國數少的雙邊或區域性貿易協定。若將此一談判模式套用到國際環境規範，理論上，目前最受矚目的「聯合國氣候變化綱要公約」與「京都議定書」陷入談判困境時，各國政府理應會將該議題轉移到雙邊談判場域下發展。然而，各國在雙邊談判架構下處理氣候變遷或溫室氣體減量者卻寥寥無幾，反而「雙邊／區域性貿易協定」中處理氣候變遷或溫室氣體減量以外環境議題，卻呈現蓬勃發展的趨勢，且部分已開發國家歷經多次自由貿易協定之談判經驗，正逐步確立其自由貿易協定環境規定之規範重點與模式。此現象所引發的問題係，各國政府在雙邊或區域性自由貿易協定中所建構之環境規定內容為何？此類型之環境規定有無可能進一步反饋於多邊環境規範場域，協助既有多邊環境協定進行改革，或是自成一套新的多邊環境規範協定？有鑒於美國主導之自由貿易協定，呈現出環境議題在雙邊貿易談判下架構下最完整之發展圖像，本文在整理歸納美國自由貿易協定環境規定的發展軌跡後，得出美國並未企圖透過自由貿易協定解決如氣候變遷、溫室氣體減量等國際環境議題，而是立基於「貿易」的出發點，將自由貿易協定作為確保他國國內環境法規不會成為「非關稅之貿易障礙」，為其與開發中國家建立起跨國環境合作機制，增加他國環境保護措施與規範執行上能力等分析結果。惟受制於美國國內政治環境對於氣候變遷議題之消極態度，「美國模式」自由貿易協定環境規定對於目前聯合國氣候變遷綱要公約陷入之談判僵局，似未能如預期般發揮積極之作用。

Some research has pointed out two new developments of environmental regulations in bilateral trade agreements. The first is that the number of bilateral environmental agreement is far below that of bilateral trade agreement involving environmental clauses; the second is that the environmental issues negotiated and regulated under bilateral trade agreements focused on domestic regulatory standard and cross-states environmental cooperation mostly, instead of climate change and greenhouse gas reduction. These phenomena actually stir several interesting issues: Why do some countries want to take such negotiation strategy-incorporating environmental regulation in bilateral trade agreements? What are the rationales behind this kind of bilateral trade agreements with environmental regulations? Does the regulatory mode of bilateral trade agreement work more effectively and efficiently than that of multilateral trade or environmental agreements? Furthermore, is it possible that environmental regulations in bilateral trade agreement could be a new set of multilateral environmental regulations in future? This article chooses the U.S. FTAs as the target to demonstrate the main characteristics of the new trend of environmental rules. Through analyzing the pros and cons of the regulatory mode of U.S FTAs on environmental issues, this article finds out the negotiation topic of U.S. FTAs are guided by 2002 TPA; in other words, domestic policies is the crucial factor of shaping environmental rules in FTAs. Based on the research of U.S. FTAs, in the final section, it analyzes that what the role of free trade agreements play in contemporary multilateral environmental issues, and proposes suggestions that even though it is hard for the environmental rules of U.S. FTAs to become multilateral one in a short time, this kind of regulatory mode, especially the designs of cross-state environmental cooperation and public participation, could still stimulate other countries, and then, giving positive feedback to the progress of multilateral environmental regime.