In 2001, Danish political scientist Bjorn Lomborg burst onto the international scene with his bestselling and controversial book The Skeptical Environmentalist. The onetime member of Greenpeace said that climate change is real and that human activity is clearly contributing to it, but he said the best science didn’t support the apocalyptic visions put forth by people like Earth in the Balance author and former Vice President Al Gore.

Lomborg went on to create the Copenhagen Consensus, a think tank that applies cost-benefit analysis to problems facing the global poor and works with Nobel laureates, policymakers, philanthropists, and researchers to develop pragmatic, relatively low-cost solutions to issues such as tuberculosis, malaria, lack of education, and access to food.

His new book is called Best Things First and it presents what Lomborg says are “the 12 most efficient solutions for the world’s poorest people.” He argues that for about $35 billion a year—a little more than half of what the U.S. spends annually on humanitarian aid—these policies could save 4.2 million lives and generate an extra $1.1 trillion in value every year.