Ever since 9/11, many have considered al Queda to be the leading threat to global security, but falling water tables in countries that contain more than half the world’s people and rising temperatures worldwide pose a far more serious threat. Spreading water shortages and crop-withering heat waves are shrinking grain harvests in more and more countries, making it difficult for the world’s farmers to feed 70 million more people each year. The risk is that tightening food supplies could drive up food prices, destabilizing governments in low-income grain-importing countries and disrupting global economic progress. Future security, Brown says, now depends on raising water productivity, stabilizing climate by moving beyond fossil fuels, and stabilizing population by filling the family planning gap and educating young people everywhere.

As fossil fuel prices rise, oil insecurity deepens, and concerns about climate change cast a shadow over the future of coal, a new energy economy is emerging. Wind, solar, and geothermal energy are replacing oil, coal, and natural gas, at a pace and on a scale we could not have imagined even a year ago. For the first time since the Industrial Revolution, we have begun investing in energy sources that can last forever. Plan B 4.0 explores both the nature of this transition to a new energy economy and how it will affect our daily lives.

Every day, we hear alarming news about droughts, pollution, population growth, and climate change—which threaten to make water, even more than oil, the cause of war within our lifetime. Diane Raines Ward reaches beyond the headlines to illuminate our most vexing problems and tells the stories of those working to solve them: hydrologists, politicians, engineers, and everyday people. Based on ten years of research spanning five continents, Water Wars offers fresh insight into a subject to which our fate is inextricably bound.