This Common Dreams article goes into the existing legal framework governing refugees and how it could be extended to define and benefit climate refugees. For example:

• The Refugee Convention of 1954 was set up in the wake of WWII and addresses “those who must leave their home countries due to war, violence, conflict, or any other kind of maltreatment”. So it doesn’t address environmental displacement or internal displacement, but it could be adapted to address these things.
• The “1998 Guiding Principles on Internal Displacement” are what they sound like – they have not been formally adopted and are not legally binding. They could be developed into a treaty and/or countries could just adopt the principles as part of their own internal legal frameworks, hopefully also offering aid to neighbors experiencing hardship.
• A “Global Compact for Migration” was adopted by the UN in 2018. It “promotes safe, orderly pathways for migrants, including planned relocation, visa options, and humanitarian shelter”. “Adopted” means the general assembly adopted it as another voluntary, legally non-binding set of principles. This also could be developed into a treaty and/or countries could incorporate the principles into their own internal legal frameworks.
• The United Nations Framework Convention on Climate Change is an actual treaty ratified by many countries including the United States Congress. Trump has announced the US is withdrawing from the treaty – which I don’t understand. I naively thought that if Congress ratified a treaty (which is extremely rare nowadays when win-win agreements are viewed by our cynical politicians as a loss of sovereignty), the executive branch didn’t have the right to unilaterally withdraw.
• “The Loss and Damage Fund was established in 2022 at COP27 to address the financial needs of communities severely impacted by climate change. The money would support rehabilitation, recovery, and human mobility.” It is underfunded of course.

I don’t want to be cynical, but the global political mood is just cynical at the moment. US politicians in particular are not in the mood to sign international agreements or even cooperate informally. So while I think it is good to pursue all of these ideas, I do not think it is a good idea to put all our eggs in this basket.

Climate crisis-fueled migration is already a driving force behind the rise of right-wing parties in the US and Europe, and this ugly feedback loop looks to just keep accelerating over time. As economic conditions in the destination countries deteriorate, the right-wingers are able to scapegoat migrants and that accelerates the feedback loop even more. The most rational way I can see to try to break the feedback loop is to address the environmental and economic conditions in the source countries. Aid and trade are the consensus center-left and center-right ways to do that. The right-wingers are probably aware of this, and so they sabotage both, which accelerates the feedback loop again. So they have no incentive to solve problems, because increasing problems fuel their agenda. Meanwhile more rational politicians can point to the rational solutions, but then when they can’t deliver them within a political cycle, real peoples’ real economic pain again accelerates the feedback loop. We could try to deliver the best economic performance possible as a strategy with some chance of success. Here, the current US administration is unpatriotically sabotaging the foundations of economic success such as R&D, education, and a strong central bank. Sorry for the doom and gloom as I am not seeing an easy way out of this political conundrum. Sit back and hope AI raises productivity in spite of our currently incompetent government and institutions?