A new report released this week by the Lancet medical journal details “unequivocal and potentially irreversible” growing threats to public health from climate change. The report finds that the delayed action on climate change worldwide has jeopardized human life and livelihoods over the past 25 years, with harms “far worse than previously understood.”

A related briefing produced by the American Public Health Association for U.S. policymakers, highlighted worrisome trends that are affecting Americans’ health right now.

Exposure to dangerous heat is increasing.

The briefing notes that between 2000 and 2016, Americans, on average, saw temperatures rise by around 1 degree C. Today, an additional 14.5 million Americans suffer through heat waves each year. The 1995 Chicago heat wave offers a case study in the impact of severe heat on human health. When temperatures exceed 100 degrees F, deaths spike. In that heat wave, more than 500 people died in a single day.

Daily deaths and peak daily temperatures in Cook County, Illinois, June 1 — August 30, 1995. From July 11 to July 27, 1995, there were about 700 additional deaths compared with expected levels, including 465 fatalities recorded on death certificates as heat-related. Source: The Lancet

Allergy season is becoming longer.

Rising temperatures are extending the number of days in which ragweed pollen is prevalent, especially in the northern states. Americans faced significantly longer exposure to ragweed pollen in 2016 compared to 1990. In parts of the country, allergy season is three weeks longer than it was a little more than two decades ago. Allergies and asthma are a growing challenge for health professionals.

Change in number of days of exposure to ragweed pollen, a significant cause of hay fever, between 1990 and 2016 for selected cities. Source: The Lancet

Disease-carrying insects are covering more ground.

Lyme disease is the most commonly reported vector-borne disease in the United States. Warmer temperatures, milder winters and changes in seasonal patterns are causing ticks to arrive sooner and linger for longer. They are also reaching larger swaths of the United States, and it’s taking a toll on Americans’ health. The number of reported Lyme disease cases tripled between 1995 and 2015, according to the Centers for Disease Control.

Geographic spread of Lyme disease in the U.S. based on county-level data between 2000 and 2015. Source: The Lancet

While many people see climate change as a distant threat, its impacts are being felt today. The Lancet report finds that human-caused climate change “threatens to undermine the past 50 years of gains in public health.” But it also notes that cutting pollution by shifting to clean sources of energy, like wind and solar, could be “the great health opportunity of the 21st century.”


Mina Lee writes for Nexus Media, a syndicated newswire covering climate, energy, policy, art and culture. You can follow her at @minalee89.