The effects of climate change “are here now” and pose a “serious challenge” for the United States, said Alice Hill, White House senior advisor for preparedness and resilience, at the Wilson Center on July 29. [Video Below]

Is it possible to prepare for the unexpected? Could anyone have foreseen, for instance, a nuclear meltdown triggered by an earthquake-induced tsunami? Or a brutal band of transnational militants quickly capturing Iraq’s largest dam while attempting to establish a new Islamic caliphate? Perhaps not exactly, but that shouldn’t stop us from anticipating unlikely events, says Chad Briggs, a risk assessment expert and strategy director of consulting firm GlobalInt.

In 1986, global nuclear weapons stockpiles peaked at nearly 70,000 warheads. By the beginning of 2013, there were just over 17,000, with only 4,400 kept operational. This dramatic reduction was the fruit of a negotiation process that began in the late 1940s. In spite of incredible tensions between the United States and the Soviet Union, negotiators were able to make progress once they focused on building trust with small, pragmatic steps, rather than starting with the complete elimination of all weapons. [Video Below]

The fight for control over “the most dangerous dam in the world” is raging.

Since its capture by Islamic State (IS) militants on August 7 and subsequent attempts by Iraqi government and Kurdish forces to take it back, Iraq’s Mosul Dam has been one of the central components of the government’s surprising and rapid collapse in the country’s northern and western provinces. In fact, one might see the capture of the Mosul Dam as the moment IS ascended from a dangerous insurgent group to an existential threat to Iraq as a state.

Climate change poses a serious threat to U.S. national security and is becoming a “catalyst for conflict” in vulnerable countries, according to a panel of retired military leaders speaking at the Wilson Center on May 15. [Video Below]

In 2007, an influential analysis by 11 retired generals and admirals characterized climate change as a “threat multiplier” that could aggravate the conditions for conflict. Last week, in a follow-up report launched at the Wilson Center, members of the CNA Corporation’s Military Advisory Board framed climate change as a more direct and immediate risk, calling it a “catalyst for conflict.”