Global Summers with Extreme Rain: Potential Impacts on Respiratory Health

Studies show extreme rainfall has acute effects on people with respiratory diseases (WikiCommons)

A ‘guerilla rainfall’ characterized the summer in Tokyo, while flooding permeated southwestern Connecticut and Long Island, New York. As extreme rainfall events disrupted our summers, it also seemed to have been infiltrating our health. 

In April 2024, a group of scientists explored the overlooked impacts of extreme rainfall, finding that it elevates the risk of infectious diseases and has significant associations with respiratory deaths. With extreme rainfall becoming more frequent due to the effects of climate change, this finding could indicate danger. 

Researchers hypothesize that the increases in pollen and drops in atmospheric pressure after storms cause rainfall to impact respiratory diseases. The associations of increased risk of respiratory mortality were strongest for asthma, followed by chronic obstructive pulmonary disease. Heightened humidity increases the growth of bacteria and molds, explaining the increased risk of infectious disease. The multicity study, focused on East Asia, presents compelling evidence that these extreme rainfall events could heighten mortality risks for respiratory diseases. 

The study found that in Japan, where rains of intensity are expected every five years, there were between 3.08 to 5.38 excess respiratory deaths per 10,000 people from 1980 to 2020. 

Yet, extreme rain causing health risks is not only a fearful truth for Tokyo, as these weather events have increased in frequency globally. In August 2024, the National Weather Service issued flash flood emergencies in the Northeast of the US, warning Americans of exceedingly rare conditions in which extreme rainfall leads to severe threats to life and catastrophic damage. Mudslides washed out roads, necessitating swift-water rescues. Meanwhile, Myanmar was hit by heavy rainfall in May 2024, while floods and storms overwhelmed India, Pakistan, and Nepal in June and July of the same year. Moreover, Hong Kong experienced a record hourly rainfall in the following September. 

With increasing rainfall throughout the world, researchers raise an alarming truth that these weather events not only result in infrastructural damage but negatively affect human well-being and health. Although the study doesn’t account for the impact on respiratory health beyond fatalities, it still signifies a frightening truth for those with respiratory diseases. 

The health impacts of extreme rain often have prolonged effects. For instance, when extreme flooding occurred in the Dominican Republic, East Africa, and the eastern states of the US, the death tolls did not take into account the ongoing health impact of flooding once the water levels subsided. Flooding and excessive rainfall have grave effects on lung health even after the rainfall, as contaminants in the flood water contain toxins, pesticides, and water-borne pathogens, among others. These sediments dry and form airborne dust, which locals then breathe in. A study done in the Netherlands showed significant associations between contact with flood waters and acute respiratory infections. Cleaning operations after the extreme rain, as well as skin-to-skin contact with the flood water, are key risk factors for these infections. 

Multiple studies indicate that excessive rainfall causes potentially deadly health implications. While scientists continue to research these effects in more depth, climate activists stress the importance of calling attention to the disturbing results of these studies.