Climate change is the world’s greatest environmental threat. It is also increasingly understood as a threat to domestic and international peace and security – recognized by the Department of Defense as a “threat multiplier,” by Secretary of State John Kerry as “perhaps the world’s most fearsome weapon of mass destruction,” and by President Obama, in an address to graduates of the United States Military Academy, as “a creeping national security crisis.” The Supreme Court’s temporary blocking of the Clean Power Plan highlights the Federal-State divide over how to address climate change, but because of its national security dimension, climate change also raises unique separation of powers issues between the president and Congress with regard to how the military can respond.

In November 2015, experts from a variety of fields gathered at the Peace Palace in The Hague for the Planetary Security Conference, one of the first large-scale conferences on environmental security and what is hoped to be the start of an annual series. The conference report gives a sense of the diverse discussions held in the Netherlands.

The ongoing violence in Syria exhibits the potential for water problems – a historic drought, in this case – to exacerbate existing social and political problems and contribute to humanitarian crises. In a recently released infographic, Circle of Blue combined data from the European Commission Joint Research Center’s Global Conflict Risk Index and the World Resources Institute’s Aqueduct Water Risk Atlas to identify 10 hotspots around the world where water “could play a role in developing or exacerbating humanitarian crises” in 2016.

Despite evidence that natural resources play a major role in many conflicts – 40 percent of all civil wars since the end of the Cold War, according to an estimate by the UN Environment Program – a study conducted by Arthur G. Blundell and Emily E. Harwell for the NGO Forest Trends reveals that most ceasefire and peace agreements do not address natural resources.

One of the hidden costs of climate change is the displacement of millions of people in some of the poorest regions of the globe. The existing international refugee regime is ill-suited to cope with those seeking refuge from environmental disasters. Countries must get serious about developing coordinated plans to address the issue, lest they be caught by surprise when another humanitarian crisis hits.

The sexual and reproductive health and rights of women and girls must be protected, even – especially – during “the toughest of times, in the hardest of places,” said Kate Gilmore, deputy executive director of the United Nations Population Fund (UNFPA), at the Wilson Center on December 3. [Video Below]

The new climate deal coming out of Paris commits governments to hold the rise in average global temperatures to “well below” two degrees Celsius compared to preindustrial levels. An important dimension of this agreement calls for subsequent work on limiting the increase to 1.5 degrees. This is an important win for islands and other low-lying countries, and for humanity.