As the planet warms, increasing worry about the impact that may have on infectious diseases

NEW YORK (AP) — People around the world are living longer, healthier lives than they were just half a century ago.

Climate change threatens to undo that progress.

Across the planet, animals — and the diseases they carry — are shifting to accommodate a globe on the fritz. And they’re not alone: Ticks, mosquitos, bacteria, algae, even fungi are on the move, shifting or expanding their historical ranges to adapt to climatic conditions that are evolving at an unprecedented pace.

These changes are not happening in a vacuum. Deforestation, mining, agriculture, and urban sprawl are taking bites out of the globe’s remaining wild areas, contributing to biodiversity loss that’s occurring at a rate unprecedented in human history. Populations of species that humans rely on for sustenance are dwindling and getting pushed into ever-smaller slices of habitat, creating new zoonotic-disease hotspots. Meanwhile, the number of people experiencing extreme repercussions of a warming planet continues to grow. Climate change displaces some 20 million people every year — people who need housing, medical care, food, and other essentials that put strain on already-fragile systems that are growing ever more stressed.

All of these factors create conditions ripe for human illness. Diseases old and new are becoming more prevalent and even cropping up in places they’ve never been found before. Researchers have begun piecing together a patchwork of evidence that illuminates the formidable threat climate-driven diseases currently pose to human health —...