Environmental change and natural disasters have always been major drivers of migration. However, climate change predictions for the 21st century indicate that even more people are expected to be on the move as weather-related disasters such as extreme precipitations and temperatures become more frequent and intense (IPCC, 2014), and changes to climate conditions impact on livelihoods.

While no internationally accepted definition for persons on the move due to environmental reasons exists to date, IOM has put forward a broad working definition which seeks to capture the complexity of the issues at stake:

“Environmental migrants are persons or groups of persons who, predominantly for reasons of sudden or progressive change in the environment that adversely affects their lives or living conditions, are obliged to leave their habitual homes, or choose to do so, either temporarily or permanently, and who move either within their country or abroad” (IOM, 2011:33).

People migrating for environmental reasons do not fall squarely within any one particular category provided by the existing international legal framework. Terms such as "environmental refugee" or "climate change refugee" have no legal basis in international refugee law. There is a growing consensus among concerned agencies, including UNHCR, that their use is to be avoided. These terms are misleading and could potentially undermine the international legal regime for the protection of refugees.

All persons moving for environmental reasons are protected by international human rights law. In addition, persons displaced within their country due to natural or human made disasters are covered by provisions laid out in the Guiding Principles on Internal Displacement. This coverage is contingent on the extent to which a country has adopted the Guiding Principles.


  • The movement of people is and will continue to be affected by natural disasters and environmental degradation. Climate change is expected to have major impacts on human mobility.
  • Environmental migration may take many complex forms; forced and voluntary, temporary and permanent, internal and international.
  • The concept of “vulnerability” needs to be put at the centre of current and future responses to environmental migration. The most vulnerable may be those who are unable to or do not move (trapped populations).
  • Environmental migration should not be understood as a wholly negative or positive outcome – migration can amplify existing vulnerabilities but can also allow people to build resilience. 


Intergovernmental Panel on Climate Change (IPCC)

2014       Fifth Assessment Report (AR5). IPCC, Geneva. Available at www.ipcc.ch/report/ar5/index.shtml

International Organization for Migration

2011       Glossary on Migration, 2nd Edition. International Migration Law No. 25, IOM, Geneva.
Available at http://publications.iom.int/bookstore/index.php?main_page=product_info&cPath=56&products_id=1380


For more information, please see the IOM Outlook on Migration, Environment and Climate Change.