By Dr. Koko Warner, Perry World House Visiting Fellow

Introduction: Climate Change Risks and Vulnerability

As the adverse impacts of climate change emerge, affected societies will be required to understand and collectively act upon policies intended to increase environmental and social sustainability. The recently released Intergovernmental Panel on Climate Change (IPCC) Working Group II report on climate change impacts, vulnerability, and adaptation provide a sobering overview of quickly unfolding impacts for society. Based on such understanding, addressing adverse climate impacts may require profound shifts in the (coordinated) actions of institutions, communities, and individuals.

Climate stressors interfere with many of the factors that facilitate a safe, dignified, sustainable life in some areas of the world. Extreme events, changing weather patterns, glacial melt, coastal inundation, and desertification – interact with other factors that affect how well and where people can live (Fig. 1). These stressors contribute to insecurities in livelihoods, food systems, health, social stability, and others that are often considered factors in migration, displacement, and planned relocation. More evidence and scenarios are needed on how these risks interact with other societal processes, and how these interactions play out over time. More evidence and scenarios are also needed on how groups of people may behave and what options can be created for them now and in the future, particularly in space-constrained settings such as small island developing states.

Fig. 1: Range of Climate Impacts and Anticipated Risks to Society and Nature


Range of Climate Impacts and Anticipated Risks to Society and Nature

Source: UNFCCC n.d.

Four Patterns of Human Mobility with Climate Stressors

Processes such as unexpected variations in weather patterns, extreme events, and slow-onset processes which may bring glacial melt, sea level rise, and desertification increasingly affect human mobility patterns. Some of the most exposed and vulnerable regions include areas like low-lying islands and deltas, coastal zones, glacial-fed water systems, and regions subject to persistent drought.

Drawing on an expanding body of research and observation, Fig. 2 illustrates four potential patterns of climate-related mobility of concern to small island developing states (SIDS). These four patterns suggest ways climate change impacts may affect human mobility in combination with other factors. The four patterns raise questions about how the interactions between climatic stressors and mobility may affect SIDS, particularly on issues related to people in precarious situations, planning and implementation, and non-refoulement.

Fig. 2: Four patterns of human mobility with climate stressors relevant to SIDS


Fig. 2: Four patterns of human mobility with climate stressors relevant to SIDS

Source: Author, image created by Carolin-Anna Trieb for Munich Re Foundation Dialogforum 1.3.2017 (Warner 2017)
  • Pattern 1: Disaster displacement and return. Increased frequency and magnitude of weather-related extreme events, such as hurricanes and cyclones that threaten the safety and well-being of people, destroy infrastructure, and require people to relocate. If normalcy and necessary services are re-established following such shocks, it is assumed that return is possible. This displacement can be within national borders, or cross-border. This may be a relatively short-term type of displacement with people returning once conditions return to normal.
  • Pattern 2: Weather-dependent livelihood systems deteriorate, triggering movements in search of alternative sustenance. Changes in weather patterns that contribute to longer-term drying trends that affect access to essential resources such as water and negatively impact the sustainability of a variety of environment-related livelihoods including agriculture, forestry, fishing, etc. The availability of alternative livelihoods or other coping capacities in the affected area is anticipated to affect the scale and form of human mobility that may take place. In cases where people who have moved attain work, they may be able to send remittances home and may return in the medium-term. For slow-onset events, such as intensified drought and rising sea levels, as compared to rapid-onset weather events like hurricanes, cyclones, and typhoons, the urgency to move may be less pressing since the environment and the harm associated with it change more slowly. If alternative livelihoods are not available within a reasonable time frame for the would-be migrant, then moving away may be the best or only option available, even in slow-onset situations.
  • Pattern 3: Climate stressors interact with conflict, triggering movement at larger scales. Some movements resemble familiar migration and displacement patterns, but other movements occur in circumstances of complex humanitarian crises. Climatic-related human mobility can amplify factors contributing to communal unrest and undermining social cohesion. Competition over natural resources may exacerbate pressures that contribute to tension and may interact with movements of people. In recent decades, droughts and other climatic stressors have afflicted areas already torn by strife, contributing to large scale movements, food insecurity, and humanitarian situations. Return depends upon establishing peaceful conditions.
  • Pattern 4: Longer-term deterioration in the habitability of regions could trigger spatial population shifts. Heat waves, rising sea levels that salinize and inundate coastal and low-lying aquifers and soils, desertification, loss of geologic sources of water such as glaciers and freshwater aquifers could affect many regions of the world and put life-sustaining ecosystems under pressure to support human populations. Large scale movements of people could first move towards cities, but if these cities are in low lying coastal zones (70% of the world’s megacities today are in such areas) then additional spatial populations shifts at a large scale could occur over time. Return would hinge on re-establishing suitable parameters for human existence.

Translating Current and Future Mobility Patterns to Meaningful Policies and Practices

Insights from this literature have relevance as the international community, regions, and governments formulate policy intended to avert, minimize, and address adverse climate change impacts in ways that build societal resilience.

These patterns raise questions related to risks and temporal dimensions of human mobility that the international community may face in the future (table 1).

Table 1: Risks and temporal dimensions of human mobility in the context of climate change (Source: Author)
Table 1: Risks and temporal dimensions of human mobility in the context of climate change (Source: Author)

Policy Gaps and Work ahead to Build Resilience

Situations such as extreme storms, coastal inundation, heat waves or slow onset climatic processes like sea level rise, ocean acidification, glacier melt, and desertification, could in the future, contribute to such precarious situations and prevent people from returning to their areas of origin because of threats to safety and livelihoods. Risks arise where these gaps leave countries without provisions to address the needs of people on the move in relation to climatic stressors, including when they may cross borders.

Many of the challenges associated with the current and future interactions between climatic stressors and factors affecting migration, displacement, and planned relocation fall outside of current governance arrangements for migration and asylum. When considering geographically extensive consequences of climate impacts, current policy frameworks ranging from climate change to migration and asylum do not yet prepare States and the international community for the full spectrum of issues related to return migration. Without addressing such issues, States may be hesitant to commit to actions that facilitate regular migration or contribute to burden-sharing for hosting arriving groups.

In response to these unfolding challenges, several governance frameworks anchored in United Nations values, including under the United Nations Framework Convention on Climate Change (UNFCCC) process through its Task Force on Displacement, the Global Compact for Safe, Orderly and Regular Migration (GCM), and the Global Compact on Refugees (GCR) propose ways forward that aim to preserve the dignity of individuals and support national, regional, and global action.

Averting situations in which people move into precarious situations. An issue running through recent advances in migration and asylum policy frameworks (the global compacts related to migration (GCM), and refugees (GCR) deals with protecting people in precarious situations, and the commitment of countries and regions to incorporate the needs of these people in their regular planning processes. Both compacts make marked statements about protecting human rights, and modest reference to the gaps that arise when these people do not fit squarely into a category where international law currently offers protection.

Both GCM and GCR gesture towards people who flee across borders and for whom return may not be immediately possible, such as those affected by storms, floods, droughts, or other such disruptions. The GCM mentions access to protection in emergency situations, including providing “temporary or permanent protection and reception schemes for migrants compelled to leave their countries of origin temporarily or permanently in cases when return is not possible, due to sudden-onset natural disasters, slow-onset environmental degradation, emergency situations, and other life-endangering circumstances, including by providing humanitarian visas, private sponsorships, access to education for children, and temporary work permits” (para 19(f)).

Planning and coordination. Provisions for scenarios in which people may need to or choose to move could go farther to focus on the full range of planning and development, including adaptation planning and ex ante measures that minimize risks of involuntary movements of people.

In this regard, the Paris Agreement offers a preliminary set of climate impact scenarios that countries can use to inform such planning. Scenarios, also informed by IPCC reports and the best available science, can inform plans that consider climate change impacts expected in the range between 1.5 °C and 2 °C global average temperatures above pre-industrial levels. This range of scenarios can inform country and regional plans that anticipate where and how people live and work. The international community can incorporate such scenarios into programming that anticipates a range of potential societal reactions including human mobility that affects climate resilient sustainable development aspirations.

Planning and scenarios can also inform national legislation and regional coordination. In 2018 the international community, under the UNFCCC, endorsed recommendations “to facilitate orderly, safe, regular and responsible migration and mobility of people, as appropriate and in accordance with national laws and policies, in the context of climate change, by considering the needs of migrants and displaced persons, communities of origin, transit and destination, and by enhancing opportunities for regular migration pathways, including through labor mobility, consistent with international labor standards, as appropriate” (decision 10/CP.24 recommendations of the Task Force on Displacement para 1(i(vi)).

Non-refoulement. The GCM places attention on the process of return and post-return reintegration somewhat more than the legal safeguards preventing return, such as reference to the principle of non-refoulement if it is not safe for people to go back to their area of origin. One possibility for advancing this part of the discussion would be to make the link to contingency plans – what would countries and regions do in cases where return became less possible or likely? Exploring regional climate scenarios of such issues would offer more concrete ways for countries to discuss arrangements that would contribute substantially to international preparedness for as-yet unforeseen large movements of people in relation to climate impacts.

Through that lens, an indicator of the future efficacy of the global compacts and the taking up of the Task Force on Displacement recommendations would be that countries of origin, transit, and destination put in place contingency arrangements showing how they intend to manage large scale movements of people.


Climate change is a central issue of human welfare and sustainable development. Climate change-related human mobility – displacement from storms, the struggle for climate-proof livelihoods, or the search for habitable places when return to homelands isn’t possible anymore – requires a new level of resilience to enable progress towards human well-being and climate resilient sustainable development.

With so many current challenges, countries struggle to keep up with the complexity of mobility today, let alone the future as the full impacts of anthropogenic climate change unfold. The migration and refugee research community acknowledge that, at present, people that do move in relation to climate stressors mostly stay within their national borders. Current migration and refugee compacts acknowledge climate change. At present, however, governments with climate affected people within their national borders do not have an international framework to address any climate-related protection gaps.

The Paris Agreement provides a touchstone against which the global community can assess climate trajectories and possible scenarios for impacts on society, including scenarios that may include movements of people including large movements of people over time. This future-oriented perspective of climate policy adds value to the global community by emphasizing risk management and a nuanced spectrum of options and solutions for affected people and countries.

This article was written for Perry World House’s 2022 Global Shifts Colloquium, ‘Islands on the Climate Front Line: Risk and Resilience,’ and made possible in part by a grant from the Carnegie Corporation of New York. The views expressed are solely the author’s and do not reflect those of Perry World House, the University of Pennsylvania, or the Carnegie Corporation of New York.

Section 2 of this contribution includes the author’s inputs to a previous Perry World House Global Shifts Colloquium including climate change and migration.