https://watson.brown.edu/costsofwar/papers/summary

EXECUTIVE SUMMARY Since President George W. Bush announced a “global war on terror” following Al Qaeda’s September 11, 2001 attacks on the United States, the U.S. military has engaged in combat around the world. As in past conflicts, the United States’ post-9/11 wars have resulted in mass population displacements. This report is the first to measure comprehensively how many people these wars have displaced. Using the best available international data, this report conservatively estimates that at least 37 million people have fled their homes in the eight most violent wars the U.S. military has launched or participated in since 2001. The report details a methodology for calculating wartime displacement provides an overview of displacement in each war-affected country and points to displacement’s individual and societal impacts. Wartime displacement (alongside war deaths and injuries) must be central to any analysis of the post-9/11 wars and their short- and long-term consequences. Displacement also must be central to any possible consideration of the future use of military force by the United States or others. Ultimately, displacing 37 million—and perhaps as many as 59 million—raises the question of who bears responsibility for repairing the damage inflicted on those displaced.

Some of the Costs of War Project’s main findings include:

• At least 800,000 people have died due to direct war violence, including armed forces on all sides of the conflicts, contractors, civilians, journalists, and humanitarian workers.  
• It is likely that many times more have died indirectly in these wars, due to malnutrition, damaged infrastructure, and environmental degradation.
• Over 335,000 civilians have been killed in direct violence by all parties to these conflicts.
• Over 7,000 US soldiers have died in the wars.
• We do not know the full extent of how many US service members returning from these wars became injured or ill while deployed.
• Many deaths and injuries among US contractors have not been reported as required by law, but it is likely that approximately 8,000 have been killed. 
• 21 million Afghan, Iraqi, Pakistani, and Syrian people are living as war refugees and internally displaced persons, in grossly inadequate conditions.
• The US government is conducting counterterror activities in 80 countries, vastly expanding this war across the globe.
• The wars have been accompanied by erosions in civil liberties and human rights at home and abroad.
• The human and economic costs of these wars will continue for decades with some costs, such as the financial costs of US veterans’ care, not peaking until mid-century.
• US government funding of reconstruction efforts in Iraq and Afghanistan has totaled over $199 billion. Most of those funds have gone towards arming security forces in both countries. Much of the money allocated to humanitarian relief and rebuilding civil society has been lost to fraud, waste, and abuse.
• The cost of the Iraq, Afghanistan, Pakistan, and Syria wars totals about $6.4 trillion. This does not include future interest costs on borrowing for the wars, which will add an estimated $8 trillion in the next 40 years.
• The ripple effects on the US economy have also been significant, including job loss and interest rate increases.
• Both Iraq and Afghanistan continue to rank extremely low in global studies of political freedom.
• Women in Iraq and Afghanistan are excluded from political power and experience high rates of unemployment and war widowhood.
• Compelling alternatives to war were scarcely considered in the aftermath of 9/11 or in the discussion about a war against Iraq. Some of those alternatives are still available to the US.