International migration is a growing feature of the modern world. In 2020, the number of people living in countries other than where they were born reached 281 million. Their share of the global population also reached the highest level ever at 3.6 percent. At the end of 2021, 89,3 million people worldwide were forcibly displaced from their homes, most of whom were internally displaced. However, more than 36 million people globally are international refugees and asylum seekers. Two-thirds of all displaced people originated from Syria, Venezuela, Afghanistan, South Sudan, and Myanmar. Türkiye currently hosts the largest refugee population, with 3,8 million, followed by Colombia, Uganda, Pakistan, and Germany. Their displacement is often driven by conflict, persecution, violence, and human rights violations. But another cause of migration appears to be picking up pace: Climate change.
Climate change is expected to accelerate displacement both directly and indirectly. Sudden climate events such as flooding and storms often force people to relocate to nearby locations permanently. Slow climate change impacts such as sea-level rise, salinization of agricultural land, desertification, decreasing food security, and water scarcity could also lead to migration. As global temperatures rise, the band of the habitable zone in the northern hemisphere is expected to shift northward.
Equatorial areas designated as barely livable could grow from 1 percent of the land to almost one-fifth by 2070, covering vast areas in Africa, South Asia, Latin America, and Australia. This could also be accompanied by a northward shift of arable lands suitable for growing staple crops such as wheat. Sea level rise also presents an increasing rise to coastal communities. Over the past 30 years, the coastal populations in areas at high risk of sea level rise grew from 160 million to 260 million, 90 percent of which are in low-income countries and small island states.
Less visibly, these slow processes can also cause migration due to their long-term impacts, such as reduced incomes, deteriorating economic conditions, as well as a conflict caused by variable climate impacts and competition over dwindling natural resources. These cascading impacts were recently seen in Syria, where the worst drought in 800 years led to the desertification of formerly fertile farming land. As a result, crop yields fell, 800,000 people lost their income, and 85 percent of privately owned livestock died. 1,5 million rural workers moved to the outskirts of Syrian cities to find jobs as food prices increased. Given the significant uncertainties regarding climate change scenarios, the adaptation measures implemented, and other socio-economic, political and demographic factors, estimates for climate migrants vary widely from 25 million to 1 billion migrants by 2050, with 200 million being the most cited.
Climate change as a threat multiplier
In addition to its long-term impacts, climate change could also act as a threat multiplier, worsening economic conditions and political tensions and adding to the impacts of existing conflicts on displacement. While it remains hard to attribute an armed conflict or violence to climate change, there is a significant correlation between climate vulnerability on the one hand and violence and conflict on the other. It is estimated that 95 percent of all conflict displacements in 2020 occurred in countries vulnerable or highly vulnerable to climate change.
Climate change can also lead to vicious cycles. When conflict does erupt, it tends to securitize natural resources and infrastructure, reducing resilience to climate change impacts. For example, 95 percent of the water supply in the Gaza Strip is contaminated by sewage and seawater infiltration. In Syria, the conflict damaged half of the country's water distribution infrastructure, reducing water supply rates to 5–30 percent of pre-war levels.
The current global system is unprepared to deal with the economic impacts of climate change and its climate-related conflicts. It also lacks the mechanism to deal with the large-scale displacement that will accompany it. The recent recognition of the need for Loss and Damage compensation to countries worse affected by climate change indicates a growing recognition of the challenge. However, the best and the least costly solution for a future climate migration crisis is to limit the rise of global temperatures by reducing carbon emissions. Climate change is the largest environmental crisis we have faced, but it doesn't have to be a humanitarian crisis too.