Climate change will lead to significant human displacement. The Intergovernmental Panel on Climate Change (IPCC) and other groups warn that the effects – including rising sea levels, heavier floods, more frequent and severe storms, drought and desertification – will cause large-scale population movements. How can we help these displaced people? I believe an international treaty could be the answer.

It’s important to take account of the different contexts and forms that climate change displacement may take. As Oli Brown of the International Organization for Migration has said, we need “international recognition of the problem, a better understanding of its dimensions and a willingness to tackle it”.

Existing law does not adequately provide for climate change displaced persons (CCDPs). There has been no coordinated response by governments to address human displacement due to climate change. And given the nature and magnitude of such displacement, ad-hoc measures may lead to inconsistency, confusion and conflict.

This can by addressed by collaboration among the international community. There seems to be a common interest in reaching a resolution, either by providing adaptation assistance or pre-emptive resettlement.

How a treaty could work

Parties to a treaty would be both developed and developing states. It would encompass those displaced internally and those who cross international borders. Most displacement will take place within a state.

The International Council on Human Rights Policy notes that “the most dramatic impacts of climate change are expected to occur in the world’s poorest countries”.

Assistance for those displaced internally would be shared by the home state and the international community. For those who have migrated across state borders, the treaty would outline the obligations of the CCDP and both the home and “host” states.

Significant numbers of people are likely to be displaced by climate change. Given that, en-masse designations of the status of climate change displaced persons through a process of request and determination by state parties and the treaty organisation is more workable and more appropriate than the individual satisfaction of definition-based criteria.

In the event of international displacement, the treaty would not compel state parties to the treaty to accept CCDPs. State parties may choose to enter bilateral displacement agreements between “home” and “host” states.

Keeping people at home

Any treaty would first contemplate providing pre-emptive assistance; then, if necessary, resettlement. It would prioritise those most at risk from the impacts of climate change. Providing assistance under the treaty could then be described as “anticipatory adaptation”.

Any treaty would largely operate prospectively, rather than reacting to a situation. Assistance to CCDPs would be based on a “bottom-up/top-down” assessment of their environment’s susceptibility to the effects of climate change. Ultimately, it would look at the likelihood of a place becoming uninhabitable.

The aim of the treaty, above all else, would be to enable people to stay in their homes as long as possible and, failing that, to move in a planned manner over time.

Determining whether people are displaced by climate change

A treaty would acknowledge problems in determining the impact of climate change on the displaced. It would also consider to which extent humans have contributed to a particular climate change event.

The treaty could adopt a “very likely” standard (greater than 90% probability) to identify “climate change events” as caused by human-induced climate change. Such a standard would provide increased certainty and targeted resource allocation, vital in the context of a treaty that could potentially apply to hundreds of millions of people.

Adopting a “very likely” standard means requests from state parties that might set the treaty in motion would overwhelmingly be about slow-onset, gradual displacement. This kind of displacement is more likely to be seen as a result of anthropogenic climate change than a sudden disaster.

Seeking progress where we can

It’s clear that there are obstacles to treaty-making. In terms of the UN Framework Convention on Climate Change (UNFCCC), the current negotiating process is unlikely to make significant progress. First the positions of major developed and developing states and their relationships with the climate must change. As has been noted, “since an agreement among the major emitters is unikely anytime soon, we should seek progress where we can, through whatever means and in any forums that are available”.

If the climate change problem is broken up and addressed in pieces, then it may be that any climate change displacement treaty could form one element of such a climate change governance approach, or part of any climate change “regime complex”.

A final point: in the Andes, if warming trends continue, many tropical glaciers may disappear within 20 years. This threatens the water supplies of over 70 million people. Bolivia’s ambassador to the United Nations, Pablo Solón, asks this question: “What do you do when your glacier disappears or your island is under water?”

One solution is a treaty for climate change displaced persons which sets out a framework for the collaborative provision of pre-emptive adaptation assistance – and, if necessary, relocation before glaciers melt and before islands are under water.

David Hodgkinson leads an international project team drafting a treaty for climate change displaced persons.