Climate change and human migration

Humans have always moved as a result of changes in their living environment. In the coming years, however, climate change and environmental degradation are likely to trigger unprecedented displacements, especially in South Asia and the Pacific. Although climate change-induced migration mainly happens within countries, always more people are displaced across borders and need international protection.

The interplay between climate change and displacement 

Climate change is causing population movements by making some parts of the world less liveable. Due to rapid global warming, extreme weather events are becoming more unpredictable, intense and frequent, increasing the risk of flooding, erosion, fires and desertification. At the same time, rising sea levels threaten to cause coastal flooding, erosion, saltwater intrusion and permanent inundation of low-lying areas.

Vulnerable communities are the most affected, due to climate impacts on the availability of food, water, land and other ecosystem services necessary for their health, livelihoods and survival. Even though people are trying to adapt to the effects of climate change and natural disasters, many are forced to relocate in order to survive.

A group of people affected by flooding. Photo: Eric Sales/Asia Development Bank

How many people migrate due to climate stressors? 

According to the Internal Displacement Monitoring Centre (IDMC), nearly 1,900 disasters in 2019 resulted in 24.9 million new displacements in 140 countries and territories. This is three times the number of displacements associated with conflict and violence.

Fifty countries and territories with most new displacements in 2019. Infographic: Internal Displacement Monitoring Centre (IDMC)

Tentative predictions indicate that there could be 200 million climate change-induced migrants by 2050. However, it is difficult to estimate the number of people who migrate or will migrate due to environmental or climatic pressures. The reason for this is twofold

  • it is difficult to determine the reasons for migration: climate stressors are usually one of multiple factors involved in a person’s decision to move. Other drivers may include conflict, political instability, persecution, low levels of economic development and other humanitarian and social factors. Climate change, moreover, is a risk or threat multiplier for other displacement drivers; and
  • there is lack of official data on internal movements: the vast majority of people displaced by climate-related threats remain within the borders of their countries (e.g. they move from rural to urban areas), but the movement of internally displaced people is often not officially documented.
Internally-displaced people pictured in Sudan. Photo: Yonas Tadesse/AFP via Getty Images

Where do most displacements take place? 

Countries with low adaptive capacities, vulnerable geographies and fragile ecosystems (e.g. small island states, the Sahel belt and low-lying deltas) are more exposed to the impacts of climate change. At the same time, most climate migrants are likely to come from rural areas, as their livelihoods often depend on agriculture and fisheries, sectors that are highly vulnerable to climate change. However, migration out of urban areas is also expected as sea-level rise may affect densely populated coastal areas.

In 2019, most of the migration was recorded in South Asia, East Asia and the Pacific, with India, the Philippines, Bangladesh and China each recording more than 4 million displacements.

Five countries with the most new displacements by disasters in 2019. Infographic: Internal Displacement Monitoring Centre (IDMC)

South Asia is home to some of the world’s most vulnerable countries to climate change. The World Bank estimates that, in the past decade alone, nearly 700 million people (half of the region’s population) were affected by one or more climate-related disasters. Climate change impacts include melting glaciers, droughts, severe typhoons, rising sea levels, mountain and coastal soil erosion, and saline water intrusion. For example, sea level rise threatens the very survival of the Maldives islands, with the risk of large-scale migration, but also significant portions of Bangladesh, India, Nepal and Sri Lanka, which are subject to recurrent flooding.

The floods in Bangladesh started late June 2020, and after briefly easing continued to worsen, destroying crops and driving people from their homes in several impoverished regions. Photo: Sultan Mahmud/AFP

According to consulting firm McKinsey, Southeast Asia is also at risk of experiencing the most serious consequences of climate change. Widespread displacement due to natural disasters is on the rise. Although people displaced by natural disasters tend to be short-term internal migrants, the impacts of the new climate conditions are likely to cause large-scale permanent migration, which will transcend international borders and increase the likelihood of regional instability. Sea-level rise predicted for the end of the century threatens 77% of Southeast Asians living along the coast or in low-lying river deltas.

In the Pacific Islands, sea level rise and coastal erosion are already impacting migration patterns. In 2013, the Teitiota family, residents of Kiribati, applied for protection in New Zealand from the effects of rising sea levels. In a landmark non-binding ruling, the UN Human Rights Committee found that although the Teitiota’s lives were not in immediate danger, asylum seekers have the right not to be returned to a country if doing so would cause a risk of irreparable harm to their right to life.

At least 11 islands across the northern Solomon Islands have either totally disappeared over recent decades or are currently experiencing severe erosion, an Australian study shows. Photo:

Climate migrants” or “climate refugees”? 

People displaced by climate disasters are often referred to as climate refugees. The term “climate refugee”, however, does not exist in international law. The 1951 Geneva Convention relating to the Status of Refugees defines a “refugee” as a person who has crossed an international border “owing to well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion” (Article 1). The 1969 Organization of African Unity (OAU) Convention and the 1984 Cartagena Declaration, additionally, extend the definition of refugee to those who leave the country because of “events seriously disturbing public order”. 

Since the 1951 Refugee Convention does not recognize the environment as a persecuting agent, individuals displaced by the effects of climate change and disasters might only be granted the legal status of refugee when these phenomena interact with violence, conflict or persecution. Against this backdrop, human rights lawyers are increasingly calling for the extension of international refugee protection to individuals displaced by environmental pressures.

People moving to higher ground as a river in India overflowed its banks. Photo: Joerg Boethling/Alamy

On the one hand, however, it is believed that broadening the scope of the Convention could weaken the refugee status; on the other, the creation of a new international treaty could involve a lengthy political process, in which States may not have an interest in embarking. Moreover, the creation of a special refugee status on climate change grounds could lead to the exclusion of categories of people in need of protection, especially those who migrate not only because of climatic or environmental factors.

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