Immigrants from the Middle East have been a primary subject in the U.S. presidential campaign and a key factor in Great Britain’s Brexit vote. However, discussion has been missing of how drought, likely exacerbated by climate change, is a root cause of the influx of Middle East immigrants, both in the U.S. and Europe.

Because some percentage of Middle Eastern immigrants could be supporters of ISIS, the solution is a call for “War on ISIS.” This strategy by itself ignores the role drought has had in supporting the growth of the terror group and how reducing emissions and adapting to climate change could prevent future political instability in other parts of the world.

According to Peter Gleick of the Pacific Institute in his 2014 article, “Weather, Climate and Society,” starting in 2006, “Syria experienced a multi-season, multiyear period of extreme drought that contributed to agricultural failures, economic dislocations, and population displacement.”

The economic ramifications of that drought were one of the key elements that allowed ISIS to build its strength in the region.

Gleick’s paper says this dry period has continued and cites sources describing it as the ‘‘worst long-term drought and most severe set of crop failures since agricultural civilizations began in the Fertile Crescent many millennia ago.”

According to Gleik, between 2006 and 2009, “around 1.3 million inhabitants of eastern Syria were affected by agricultural failures. An estimated 800,000 people lost their livelihoods and basic food supports.” The drought returned in 2011, and Gleick’s sources say in that year the UN estimated “between 2 million and 3 million people were affected, with 1 million driven into food insecurity. More than 1.5 million people — mostly agricultural workers and family farmers — moved from rural land to cities and camps on the outskirts of Syria’s major cities of Aleppo, Damascus, Dara’a, Deir ez-Zour, Hama and Homs.”

These economic dislocations caused by water shortages and political instability placed millions of people in a position of food insecurity and financial jeopardy. What better conditions for a well-funded organization like ISIS to recruit unemployed young men so they could feed their families?

Drought was only one element that contributed to the growth of political instability and the flow of Middle Eastern immigrants to adjacent countries, Europe and the U.S. It is an example, however, of what climate change is predicted to do in the future.

Four primary climate change impacts will directly affect humans: drought, famine, severe weather, and sea level rise. The media stories that focus on these four elements rarely discuss the immigrants that will result.

Understanding that a precursor of ISIS growth was severe drought helps to recognize that climate change isn’t just about hotter summers. It is about tens of millions of people, and maybe more, unable to survive literally and/or economically where they once successfully thrived. Those people will become immigrants. Today’s immigrants from the Middle East are harbingers of what will be coming as climate change intensifies.

Military leaders globally have been preparing for the unrest likely to emerge in a world where millions of people will follow the path of the Syrian immigrants – displaced farmers and massive numbers of unemployed hungry people fleeing areas untenable for existence. How will countries accepting immigrants be able to provide social services? How will immigrants be accepted,and their basic needs addressed? How will they be protected from or stopped from participating in organized or spontaneous unrest, including affiliations with opportunistic terror groups. That protection will in part be provided by giving them economic support, making them less likely to take funding from sources intent on political or physical disruption.

Places like Bangladesh have already been affected by flooding from rising sea levels. GRID Arendal, a research center collaborating with the United Nations Environment Program, predicts that a 1.5-meter sea level rise will affect 17 million people in Bangladesh and 22,000 square kilometers, 16% of the land. A 2014 New York Times article pointed out that the country only contributes .3% of the emissions driving climate change but that “Bangladesh is at the top of everyone’s list” of countries at risk from sea level rise.

According to Atiq Rahman, executive director of the Bangladesh Center for Advanced Studies, the migrants that result from rising sea levels in his country “should have the right to move to the countries from which all these greenhouse gases are coming. Millions should be able to go to the United States,” he told the Times. Bangladesh is only one country that will be affected and thinking in much the same way.

Severe weather is the final major element that will directly affect humans. What happens when category 5 hurricanes, fueled by warmer ocean water and air temperatures, destroy communities? Even Hurricane Katrina, striking New Orleans, created U.S. immigrants (dislocation within our boundaries) and neighborhoods that have not been rebuilt. The image of New Orleans residents stranded on a highway overpass, something we only expect in other countries, not the U.S., reminds us that it can happen here, too. We are not immune.

To successfully implement a “War on ISIS” requires successfully implementing a “War on Climate Change” that will avoid political destabilization and unrest to minimize immigrant flows in other parts of the world. All parties in the current election cycle need to recognize this and that immigration related to climate change is likely to become a new norm. Unfortunately, the current campaign cycle has not made this a priority. Calls for a “War on ISIS” without recognizing the need to concurrently call for a “War on Climate Change” seems like an effort to treat the symptom of immigration with a Band-Aid rather than taking on the disease of climate change itself.