According to NASA, 2016 was the hottest year on record. This followed other record-breaking years in 2014 and 2015, and now 2017 is on pace to exceed them all. We’re in completely new territory and understanding how climate change will affect the livelihoods and security of eight billion people is a major concern.

In 2007, CNA Corporation brought together a dozen distinguished, retired three- and four-star generals and admirals–warfighters steeped in security–to study the projected impact of climate change. In 2007, this Military Advisory Board (MAB) published its findings. Among them:

• Climate change poses a serious threat to America’s national security.
• Climate change acts as a threat multiplier for instability in some of the world’s most volatile regions.
• Climate change will add to tensions even in stable regions.
• Climate change, national security, and energy dependence are interrelated global challenges.

Seven years later, the MAB gathered again. Despite state, national and international progress in climate mitigation and adaptation, members saw mounting evidence of climate-induced consequences and a troubling lack of urgency to act.

Five years of drought in Syria had caused massive internal displacement, resulting in civil war, thousands of dead, and millions forced into migration as refugees. In the Pacific, rising seas were forcing residents to leave their low-lying island homes. Commercial and cruise ships suddenly could make routine transit through the treacherous waters of the melting Arctic.

Extremist groups were rising in Mali, Somalia, and Nigeria, emboldened as already poor governance grew weaker amid drought. In North Africa, the Arab Spring raised issues of climate change. Wild fires and drought in Russia caused food riots. Meanwhile, the US military was increasingly called upon in extreme weather events: Super Typhoon Haiyan devastated the Philippines, requiring humanitarian assistance from more than 13,000 American troops. Tropical Storm Sandy ravaged the US East Coast, causing billions of dollars in damage, including on military bases from North Carolina to Maine.

In 2014, the MAB reconvened to publish its updated findings:

• Climate change remains a threat multiplier; in many areas threats are manifesting faster than anticipated, with the risks accelerating.
• Climate change is hastening instability in vulnerable areas of the world, serving as a catalyst for conflict.
• Rapid population growth—especially in coastal and urban areas—complicates our understanding of the strategic security risks.
• As the world’s population and living standards grow, issues at the nexus of water, food, and energy security will become more profound. Choosing how these finite resources are produced, distributed, and used will have increasing security implications.
• Climate change will challenge key elements of US infrastructure such as our power grid, transportation system, and military bases. Sea-level rise on near-shore bases and drought in weapons training areas will hamper military readiness, strain base resilience at home and abroad, and may limit our response to future demands, including increasing calls for humanitarian assistance and disaster relief. Impacts can be detrimental to the physical components of our national critical infrastructure, while also limiting capacities. (Consider just the first six months of this year—commercial flights were cancelled in the Southwest because of too much heat on runways, tropical storms and extreme weather shut down oil refineries in the Southeast, and sustained flooding in the Midwest killed more than a dozen people.)

Even though the impacts of climate change are more apparent in some world regions than others, the MAB cautioned that construing this as a regional issue or—worse—someone else’s problem will limit our ability to fully understand the consequences and cascading global effects.

While climate change often appears dire, it does present opportunities for leadership. By proactively addressing these risks, the US can strengthen and broaden alliances from the Asia-Pacific to Europe, and in doing so, compete more successfully with our adversaries for influence. Failure to act will compound risks to existing and future US national security objectives.

Cheryl Rosenblum is the executive director of the CNA Military Advisory Board, a dynamic group of 3- and 4-star admirals and generals from across the Military Services who examine climate change, energy, water, and food security and linkages to our national and global security.