According to recent polling, climate change is seen as the single most threatening international challenge around the world, and there’s evidence that all that worry is taking a psychological toll. Adding to droughts, floods, extreme weather, and die-offs, psychologists are observing higher levels of anxiety, depression, and post-traumatic stress disorder in certain areas and professions. Even people who do not actively stress about global warming or view it as a major threat may still suffer psychological trauma from its effects.

An advisory released this August by the U.S. National Weather Service warned this year’s El Niño could be among the strongest ever recorded, lasting well into the first few months of 2016.

Ten years ago this month one of the United States’ deadliest and most costly storms, Hurricane Katrina, struck the Gulf Coast. In Louisiana, the storied city of New Orleans was dealt a particularly devastating blow. Hundreds died and the city suffered extensive damage as 80 percent of its neighborhoods flooded, prompting an exodus it is still recovering from.

While it is intuitively clear that economic growth is related to water security – understood here as both water availability and also exposure to water-related risks such as drought and floods – there has been very little empirical evidence of this relationship to date.

Karachi, the world’s second largest city by population, is emerging from the grips of a deadly heatwave. A persistent low pressure system camped over the Arabian Sea stifled ocean breezes and brought temperatures in excess of 113°F (45°C) to the city of 23 million people in June. The searing heat disrupted electricity and water service, making life nearly unbearable. All told, officials estimate the heatwave killed at least 1,200 Pakistanis, more than twice as many as have died in terrorist attacks this year.

“Tackling climate change could be the greatest global health opportunity of the 21^st century,” asserts the newest report by the Lancet Commission on Health and Climate Change.