In a special “Rivers in Crisis” issue of Nature, the lead article, “Global Threats to Human Water Security and River Biodiversity,” presents damning evidence that manipulation of river systems — through the construction of canals, levees, hydroelectric projects, and other infrastructure — has caused serious and lasting biological damage to watersheds throughout both the developing and developed worlds. The authors (all 11 of them!) report that key rivers have become shadows of their former selves in terms of the amount of aquatic life they can support. Without drastically improved stewardship of waterways, “we are pushing these river systems toward catastrophe,” warns Peter McIntyre, an article co-author.

“Right now, half the world’s population – some 3 billion people – are under the age of 25,” began Laurie Mazur on the “Population, Climate, and Consumption” panel at the Society for Environmental Journalists 20th Annual Conference. “It’s the largest generation ever that’s coming of age, and the choices that those young men and women make about childbearing will determine whether world population…grows to anywhere between 8 and 11 billion by the middle of this century.”

“The good news is that everything we need to do to slow population growth is something we should be doing anyway,” she continued. Mazur is the author of A Pivotal Moment: Population, Justice, and the Environmental Challenge and director of the Population Justice Project.

She was joined on the panel by Brian O’Neill, who spoke about a new study examining the impact of demographics on carbon emissions, and Jack Liu, who spoke about the impact of household size on emissions in China.

The “Pop Audio” series offers brief clips from ECSP’s conversations with experts around the world, sharing analysis and promoting dialogue on population-related issues. Also available on iTunes.

“Slower population growth would not solve the climate problem, but it could make a contribution. It is neither a silver bullet nor a red herring,” said Brian O’Neill of the National Center for Atmospheric Research at the annual Society of Environmental Journalists’ conference in Missoula, MT. On Friday, he presented the results of a new demographic study as part of a panel, “Population, Climate, and Consumption,” moderated by Ken Weiss of the Los Angeles Times.

Excerpt from a First Take by Gayle Tzemach Lemmon at the Council on Foreign Relations:

Ten years after global leaders vowed to work toward eradicating extreme poverty, achieving universal primary education, reducing child mortality, and more, the eight Millennium Development Goals (MDGs) – particularly those relating to women – remain a distant hope. Though women were a focus of much discussion this week at the MDG summit in New York, the forward movement so far has been discouraging on the two MDGs directly relating to women: “promoting gender equality and empowering women” and “reducing by three-quarters the maternal mortality ratio.”

An MDG report released in June noted that when it comes to women, “progress has been sluggish on all fronts – from education to access to political decision-making.”

There are two Latin Americas according to demographers. In one of the most urbanized regions of the world, the population of some countries remains highly rural. While countries like Chile, Argentina, and Uruguay are close to 90 percent urbanized, much of Central America, as well as Ecuador, Paraguay, and Bolivia, are only about 50-60 percent urban.

Across the continent, Latin America’s total fertility rate has fallen from almost six children per woman in the 1960s to 2.2 children in 2005. Population growth rates are projected to continue to decline from 1.5 percent in 2010 to roughly 0.75 percent by 2020. But less-urbanized countries continue to experience high population growth in their rural areas, particularly among their large indigenous populations, who are not experiencing the same shifts from high to low fertility.

For example, since 1990, communities surrounding Guatemala’s Sierra de Lacandon National Park have grown by 10 percent each year, with birthrates averaging eight children per woman. These larger communities and households have led to agricultural expansion into the park, which has lost 10 percent of its forest canopy since 1990.

Rural-to-rural migration is also a key, but often overlooked, dynamic as migrants move to other rural areas in search of new land to farm. Between 1961 and 2001, Central America’s rural population increased by 59 percent. This increased population was accompanied by a 15 percent increase in deforestation, totaling some 13 million hectares.

Although many rural areas of Latin America have high fertility rates and expanding populations, they also have a high unmet demand for contraception. Indigenous populations are particularly underserved by health providers for many reasons, including cultural barriers, language, and accessibility. According to the Population Reference Bureau, an estimated 50 percent of indigenous women in the Ecuadorian Amazon do not want another child, yet 98 percent of them do not have access to a modern contraceptive method.

While reaching historically disadvantaged populations in rural communities is not easy, some programs have had considerable success—and saved money—by combining environmental and health efforts. For example, the Guatemalan NGO ProPeten trained more than 80 midwives and health promoters and developed a radio soap opera in both Spanish and Q’eqchi’ to deliver health services and environmental education to the communities living near the Maya Biosphere Reserve.

Given links between rural population growth and agricultural expansion, expanding access to family planning may not only be a cost-effective way to help women reach their desired family size, but also a smart investment in forest conservation and climate mitigation—and perhaps a down-payment on a more secure future for all.

“I’m thrilled to be back.” That was the sentiment that Roger-Mark De Souza relayed to me, in his famous lilting baritone, about becoming the new vice president of research and director of the climate program at Population Action International (PAI). De Souza has long been a leading voice on integrated development programs that feature population, health, and environmental (PHE) dimensions. But three years as the Sierra Club’s director of foundations and corporate relations took him away from day-to-day work on these issues.

In his new posts, Roger-Mark will lead PAI’s research team in establishing a strong evidence base and engaging new allies in the effort to support healthier women and families, according to PAI. “Roger-Mark’s diverse research experience makes him an ideal fit for PAI as we undertake critical projects on reproductive health, population and environment issues,” said PAI President and CEO Suzanne Ehlers in a press release.

Today, Kenya’s youth unemployment rate stands at 65 percent, among the highest in the world. Three in five unemployed Kenyans are 15 – 35 years old. The situation is exacerbated by a shrinking economy, political instability, and pervasive income inequality.

Significantly, youth are engaged in the informal sector, which is largely unregulated and subjects workers to low earnings and long hours, without any formal contract. Suffering under a slow-growing economy, youth, whether well educated or uneducated, have increasingly turned to crime and violence, serving as watu wa mkono (handymen) to the ruling elite and intimidating and harassing their political opponents.

If you have not had the (purely wonky) pleasure of playing with Google’s Public Data Explorer, do yourself a favor and direct your browser there now.

Born from Hans Rosling’s Gapminder, Google’s data explorer currently allows the user to choose from 24 different data sets, including information from the World Bank, U.S. Census Bureau, Eurostat, and Energy Information Agency. Users can then customize the dataset’s variables, save their work, and even embed the resulting chart, “unveiling the beauty of statistics for a fact-based world view,” as the Gapminder site puts it.