Large government bureaucracies are often slow to adapt to changing realities, such as the catastrophic threats we face in a warming world. The US Department of Homeland Security (DHS) is no exception. New research from Brown University’s Costs of War Project shows that the DHS has been overly focused on foreign and foreign-inspired terrorism, while violent attacks in the US have more often come from domestic sources. A combination of willful ignorance and institutional inertia caused the agency to miss the rise in white supremacy and domestic terrorism that led to the January 6, 2021, insurrection at the US Capitol.

The new data from Dr Erik Dahl, Associate Professor of National Security Affairs at the Naval Postgraduate School, show that just one of the 46 failed terror plots in the US from 2018 through 2020 was directed by a foreign organization. In contrast, 29 plots were planned or carried out by domestic groups. In 2019, DHS finally acknowledged the growing threat of targeted violence and domestic terrorism borne mainly of far-right ideology and white supremacy and issued its first strategy document identifying these threats.

While we know now that the threat of violent attacks from domestic sources outnumber those from foreign sources, a bigger source of insecurity still is that of climate change. On October 21, the DHS released its first-ever “Strategic Framework for Addressing Climate Change,” acknowledging the importance of climate as a source of disruption and threat to security. As the COP26 UN climate meetings start this week, it’s time for a recognition that climate change is in fact a more expensive, more deadly, and more real threat to lives and to the US economy than the threat of what we call terrorism.

The “War on Terror” – a phrase born in the George W Bush administration – needs to be retired both as an action and a concept. The word “terrorism” instills a sense of fear and gives carte blanche for the US government to intervene around the globe. As a response to the 9/11 attacks, the US military has waged wars that have directly caused nearly 1 million deaths and indirectly caused many times that. The footprint of DHS itself has grown globally, as it is now the third largest US civilian agency overseas. Dahl’s data show that foreign interventions by the US keep the fear of Americans focused abroad, without any statistical evidence that groups in other countries pose a significant source of threat to American safety.

The concept of “counterterrorism” has led the US into over 85 countries, including in the Middle East and Africa, with the US spending trillions of dollars fighting unwinnable wars. The US Department of Homeland Security has spent over $1tn since its creation in 2003, and the Department of Defense has spent trillions more fighting wars in Afghanistan, Iraq, and elsewhere – wars that have made the globe no safer.

Instead of wasting trillions of dollars and millions of lives fighting a war on terror, the US should be mobilizing to combat climate change. Federal spending should be channeled toward clean energy projects, other decarbonization efforts, and adaptation for a changing climate. The increase in extreme weather events has already cost the US hundreds of billions of dollars in weather-related damages and the frequency and severity of these types of events will only increase unless swift and sweeping actions are taken. Climate-related disasters have killed more Americans from flooding and wildfires than the 2,996 people who died in the 9/11 attacks. Wildfires have resulted in over 3,200 deaths in the U.S. since 2000, according to recent research in The Lancet. Hurricane Katrina alone killed over 1,800 people in 2005. The Atlas of Mortality from the World Meteorological Organization finds that the US accounts for 38% of global economic losses from caused by weather, climate, and water hazards.

It’s time for the US to shift toward the biggest threat to our security, and to direct federal resources accordingly. Let’s retire the “War on Terror” and fight the battles that will more significantly save lives and livelihoods.

• Heidi Peltier is a senior researcher at the Watson Institute for International and Public Affairs at Brown University and director of programs for the Costs of War Project