Climate change activists could gain even if they don't ultimately prevail in court by using ITLOS forum to put more pressure on US

A claimant in a climate change lawsuit against the United States would face several legal and evidentiary challenges in proving its case in an UNCLOS tribunal, including jurisdictional hurdles, causation issues, and the question of equitable apportionment of damages.¹²⁶ Nevertheless, regardless of whether the U.S. might ultimately prevail in such a case, acceding to the convention is fraught with political danger. Advocates of international climate change lawsuits see them as an acceptable way to achieve their environmental ends, including U.S. capitulation to a comprehensive climate change treaty:

Litigation or the threat thereof would emphasise the urgency of the need to agree [to] binding commitments on climate change and would put additional pres- sure on the negotiations process. Negotiators may feel more of a responsibility vis-à-vis the international community and have an additional lever in relation to their national governments. A high-profile court case would also engage a variety of actors in the debate and provide new momentum to find consensual solutions inside and outside the UNFCCC talks ... . Inter-State climate change litigation may help to create the political pressure and third-party guidance required to re-invigorate the international negotiations, within or outside the UNFCCC.¹²⁷

One law professor believes that “litigation will very likely play a role” in determining who will bear the costs of climate change and singles out the United States for special treatment, stating that “litigation efforts need to be primarily focused on the United States as the major hindrance to beginning the remedial process” (i.e., by failing to ratify the Kyoto Protocol).¹²⁸ Other proponents of the theory of anthropogenic climate change understand that there are precedents for using international courts to achieve purposes other than legal redress. For instance, the World Trade Organization “has similarly been strategically employed by governments to influence negotiations and clarify State obligations.”¹²⁹