U.S. military facilities have not been consistent in assessing design risks from extreme weather and climate change, particularly in using projections to anticipate those impacts, says a June 12 U. S. Government Accountability Office report.

The U.S. Defense Dept., which has previously termed climate change a national security risk, says it concurs with GAO's recommendation to require better risk assessment in project planning.

According to the GAO report, DOD’s 2018 preliminary assessment of extreme weather effects at U.S. and overseas installations was based on reported past experiences rather than an analysis of future vulnerabilities based on the climate projections.

Fifteen of 23 bases GAO visited or contacted did consider some climate change effects in their plans as required by DOD guidance, but eight had not.

GAO noted that while Fort Irwin, Calif. worked with the U.S. Army Corps of Engineers to improve stormwater drainage after intense flash flooding caused significant damage to base infrastructure, Joint Base Pearl Harbor-Hickam in Hawaii "did not include such considerations in its plans, although it is located in an area subject to tropical storms and where further sea level rise is anticipated."

GAO also found that there is a lack of expertise among installation project designers ln how to incorporate into master plans projections that involve multiple future scenarios and different time periods, increasing climate change risk and undermining resilience efforts for major facility and infrastructure investments.

Among its recommendations, GAO says DOD and its units should update design standards to require installations to consider climate projections in project designs, identify authoritative sources and provide needed use guidance. The department concurred, according to GAO.

DOD manages a global real-estate portfolio with an almost $1.2 trillion estimated replacement value.