The world faces an increased risk of terrorism because of climate change.

A warming world will drive famine, drought and natural disasters, creating the sort of societal and economic upheaval that strengthens terrorists’ recruiting efforts, a new report warns.

“As the climate is changing, so too are the conditions within which non-state armed groups such as Boko Haram and ISIS operate,” according to the report commissioned by the German government. “Climate change contributes to creating a fragile environment in which these groups can thrive.”

Climate change creates a number of scenarios in which terrorists can exploit vulnerable populations. In areas plagued by drought and famine, terrorists can wield diminishing natural resources such as water to exert control over people.

A similar scenario played out in 2015, when ISIS closed Iraq’s Ramadi dam so its fighters could more easily attack. The terrorist group also taxed water in Raqqa to raise funds and used it to flood people out of their homes. ISIS was accused of poisoning drinking water on several occasions as well.

“The scarcer resources become, the more power is given to those who control them,” according to the report.

In 2007, Syria was hit with one of the worst droughts in the country’s history, devastating its agricultural sector and throwing millions into extreme poverty. While the drought didn’t spark Syria’s current civil war or the rise of ISIS, food shortages and overcrowding helped to destabilize the country.

Likewise, Nigeria’s Lake Chad, which is shrinking due to a severe drought, is becoming a hot spot for Boko Haram recruitment. The lake supports the livelihood of 80 percent of the basin’s population, making the region particularly vulnerable. In March, the United Nations adopted a resolution on the humanitarian crisis in Lake Chad, emphasizing the role climate change has played in the region’s devastation.

“These groups can offer alternative livelihoods and economic incentives,” according to the report. “This is a strategy that creates a sense of belonging to groups claiming to be able to provide a better quality of life.”

The report points to the Taliban’s boost in recruitment during Afghanistan’s drought in 2006.

“Instability and turbulence are rising around the world and climate change is helping to drive them.” the report concludes. “We must pay attention to the early stages of the conflict-cycle, anticipate risks arising from climate change and take preventive measures.”