Introduction
Introduction
Scientists warn that a warming planet threatens human health. A United Nations agency estimates climate change will cause 250,000 additional deaths annually between 2030 and 2050. The threat is multifaceted. Prolonged droughts are causing malnutrition in Africa, while extreme heat is leading to spikes in heat stroke in places as diverse as Baltimore and Paris. Across the globe, changing climes are worsening allergies and increasing the deadly reach of illnesses such as malaria, dengue fever and West Nile virus. But consensus is lacking about what to do. Some experts argue the threat is exaggerated because people will adapt to the changing climate. Others say nations must quickly reduce carbon emissions to limit global warming and protect human health. Environmental activists are amplifying that message. One ...