The U.S. should have a federal policy on sustainability, says a report from the National Research Council. The government is not organized to deal with complex and long-term challenges that sustainability poses for the economy, natural resources, and social well-being, according to the report. Each agency has a different mandate or a single area of expertise, making it difficult to address issues such as managing an ecosystem. This situation also dissuades collaboration on issues that cut across agency missions, according to the report. A national sustainability policy would foster teamwork among agencies, the report says. It identifies four challenges that are of top national importance for sustainability: understanding connections among energy, food, and water quality and supply; managing ecosystems so they are diverse and healthy; improving the resilience of communities to natural disasters and other extreme events; and protecting human health and well-being. It also recommends that agencies invest in long-term research projects that will help inform sustainability strategies.