What if it’s not increased scarcity that’s most disruptive about climate change, but variability? Cullen Hendrix explains how new research on water conflict suggests that’s the case in last month’s most popular story.

It’s been 20 years since the Environmental Change and Security Program was founded to shed light on the new security issues of our times, so in honor of this anniversary, we’ve rounded up the 20 most popular stories of all time.

An estimated 1.8 billion people today are between the ages of 10 and 24 and 85 percent of them live in developing economies and/or fragile states. Such youthful age structures can lead to a number of challenges, including increased potential for instability, and countries with large numbers of young people must find ways to address their unique needs.

We started the last top 10 post tracking the dramatic battle over Iraq’s Mosul Dam and the most popular of August took a closer look. Cameron Harrington and I explain that this isn’t the first time water has played a major role in the fighting, while also exploring ways it could be a peacemaker.

As Islamic State of Iraq and the Levant rebels were steadily pushing into Iraq last month, ultimately threatening the country’s largest dam, water conflict was a popular topic on the blog.

“The greatest challenge we have today is that we have a world that is pushing back on rights,” said Dr. Babatunde Osotimehin, executive director of the United Nations Population Fund (UNFPA), at the Wilson Center. [Video Below]

Adaptation, mitigation, or suffering – those are the three choices people the world over face when confronted with climate change, wrote guest contributor Paul Wapner in one of last month’s most popular posts. Joining him were new posts on population, climate, and peacebuilding efforts in Africa and how “smart city” technologies are being applied in growing urban areas around the world.

Over the last two decades, social accountability has emerged as a strategy to make health services more responsive to community needs. It’s an approach that creates a space for “interaction between citizen engagement and government responsiveness,” said Jonathan Fox, professor of international development at American University at the Wilson Center May 5. [Video Below]