Tens of millions of people will move or be dislocated by environmental events over the next several decades. Some will be forced from their homes because of disasters; others will choose to leave as they foresee an intolerable future. Departures may be short term—once the waters recede, the rains come, or earthquake‐shaken towns rebuild, people will return to their home communities. For many, however, their movement from home may be permanent.

Mobility in the context of environmental causes—called here, environmental mobility—is due to a variety of causes, both geophysical (earthquakes, extreme heat, fires) and weather‐related (drought, flood, storms, sea‐level rise, extreme heat). It has been a part of human existence from the beginning (think Noah and the flood); and there were calamitous earthquakes and hurricanes before CO2 levels began to rise. But the scientific evidence is clear that the pace of environmental displacement is increasing in our current era and that the climate crisis is plainly a significant contributing factor. The World Bank, looking at migration within three regions of the world, estimates that the effects of climate change could force more than 140 million persons to move within their home states over the next several decades. The Internal Displacement Monitoring Centre has reported that in 2019, 25 million people were displaced within their countries by the impacts of disasters, nearly three times the number of persons displaced that year because of conflict and violence. Over 95% of disaster displacements were weather‐related.

States and regional and international organizations have developed structures and operations for responding to the human needs that arise from catastrophic environmental events. The Interagency Standing Committee (IASC) coordinates efforts of international organizations and NGOs to provide assistance and protection in situations of complex emergencies, including floods, cyclones and droughts. Significant aid is also provided bilaterally.

Despite the many international and regional meetings and working groups and billions of dollars spent on emergency relief efforts, there is no overall system for global governance of environmental mobility (McAdam, 2011).¹ The international refugee regime—the most fully articulated system for dealing with displacement—is not applicable to most forms of environmental mobility for two reasons. First, persons forced to move due to environmental causes are unlikely to come within the definition of refugee (which requires persecution based on a limited set of grounds). Second, most environmental mobility occurs within states—thus, persons who move do not qualify as refugees (who, as defined in international law, must be outside their countries of origin or places of habitual residence). The Guiding Principles on Internal Displacement pertain, inter alia, to persons forced to flee their homes because of disasters. The Principles, however, are not binding on States (except to the extent they restate existing human rights norms), and they provide no international mandate for the protection and assistance of IDPs.

The Nansen Initiative’s Agenda for the Protection of Cross‐Border Displaced Persons in the Context of Disasters and Climate Change, followed by the creation of the Platform on Disaster Displacement, provides important, although limited, steps towards global governance. Its purpose is to “enhance understanding, provide a conceptual framework, and identify effective practices for strengthening the protection of cross‐border disaster‐displaced persons.” (P. 15.) But the Nansen Initiative establishes neither norms nor operational institutions at the global level, nor does it purport to define responsibilities of the international community regarding environmental migration.

Establishing a comprehensive global structure to prevent, respond to and provide solutions to situations of environmental mobility—and to support regional structures addressing these issues—should be a top priority for the international community as it confronts the climate crisis. But there is a prior question that needs to be considered before developing new international processes or institutions: What is basis for, and scope of, the responsibility of international community to respond to environmental mobility? It is to that question that this Commentary is addressed.

Existing international commitments of states provide a starting place for answering this question. In the Sustainable Development Goals, states pledge to take steps to “facilitate safe, orderly, regular, and responsible migration and mobility of people, including through implementation of planned and well‐managed migration policies.”² One can see this commitment from a state perspective—as about constructing policies that effectively manage migration to promote state interests. But I think that misses the primary focus on facilitating migration and mobility, which recognizes the overall good of human mobility. This migrant‐centred view is supported by SDG’s declaration that migration policies must fully respect “human rights and the humane treatment of migrants regardless of migration status, of refugees and of displaced persons.”³

Importantly, the GCM makes clear that persons moving because of environmental events are included within its ambit. Thus, states are called on to adopt “adaptation and resilience strategies to sudden‐onset and slow‐onset natural disasters, the adverse effects of climate change, and environmental degradation… taking into account the potential implications for migration.” States also commit “to address the vulnerabilities of persons affected by sudden‐onset and slow‐onset natural disasters, by ensuring that they have access to humanitarian assistance that meets their essential needs with full respect for their rights wherever they are, and by promoting sustainable outcomes that increase resilience and self‐reliance.” And they further agree to develop practices and policies that provide legal routes for persons forced to leave their home states due to environmental causes to remain in places of safety where return to their countries of origin is not possible.⁵

Persons moving because of environmental events are also protected by generally applicable human rights norms. These include, as Jane McAdam has detailed, rights to life, non‐exposure to cruel, inhuman and degrading treatment and an adequate standard of living and means of subsistence and freedom to enjoy one’s culture and practice one’s religion (McAdam, 2011: 164‐66). And there is growing recognition of a right not to be returned to a place where environmental conditions threaten protection of fundamental human rights.⁶

One can draw from these commitments an international affirmation of the responsibility of states to (1) help people stay in their home communities (through prediction, risk reduction, prevention and adaptation), (2) respect the rights and provide for the needs of persons on the move due to environmental causes, and (3) find solutions (safe return or integration in a new state) for environmental migrants.

There is an additional normative consideration that should guide the development of a system of global governance for environmental mobility. Most movement due to environmental causes is weather‐related (from extreme heat and drought to storms and sea‐level rise), and it is well established that climate change has contributed to these causes. Not every hurricane or drought is the result of human activities. But we can say with certainty that the dramatic rise in CO2 levels caused by humans has been a significant factor in the rising number and intensity of extreme weather situations, which in turn have resulted in increased human movement. The important point is that those forced to move because of environmental causes largely reside in States that have not been the major sources of high and increasing CO2 emissions. This argues for a responsibility of States to help prevent, reduce and remedy the dramatic externalities produced by their actions (including the actions of their citizens and private sector).

In many cases, states are able to respond to migration and mobility resulting from environmental causes, particularly when affected persons return home after a short stay elsewhere. But when events occasion mobility that is beyond the capacity of states to prevent or adequately respond to, the international community has a role to play. As noted, the harshest impacts of environmental events, visited upon poor persons in developing states, are due to the actions of distant persons, private entities and states. Absent an effective system for meting out liability to states and private actors or for states acting alone to remedy the harm, the international community should seek to mitigate the impact.

Together, these considerations suggest that a well‐functioning system of global governance of environmental mobility would recognize and affirm that the international community, as a whole, has a responsibility.

Crucially, these principles are stated in terms of responsibilities (of the international community, regional organizations and states) and rights (of persons who move or may be forced to move) (see Faist, this issue). They thus suggest an important shift in how we think about global governance of migration—from an approach that too frequently pursues the interests of states in managing migration to one that recognizes the duty of the international community to acknowledge the harms its members inflict on others and its unique ability to remedy those harms.