Humid Heat Stress Further Threatens 1 Billion People Due to Poor Weather Station Coverage [Study]

Humid heat stress is a combination of intense heat and humidity which can affect the living organism's body temperatures and sweating, humans. In previous years, heat stress had caused dangerous or life-threatening risks such as heatstroke. There are also cases where this environmental stressor has led to fatalities, including both humans and animals.

While humid heat stress seems mysterious, modern meteorological apparatuses and equipment can detect the presence of heat and water vapor in the air, with the latter being what humidity is all about. The progress in forecasting and monitoring different weather and climatic elements over the past century has many countries worldwide prepared for any threats from our atmosphere.

However, a new study led by an international team of researchers, including from Australia and Singapore, found that humid heat stress has become an underestimated threat to 1 billion people living in urban informal settlements, especially communities with no effective adaptation strategies. The researchers attribute this threat to poor weather station coverage across the tropics.

The findings entail that global climate change assessments are potentially overlooking local impacts on communities, leading to the underestimation of dangerous heat and humidity in cities. The new research paper also raises concern that climate change is pushing humid heat stress to the maximum limit of what people can survive.

Humid Heat Stress

Findings about the impact of humid heat stress to a billion people living in urban informal settlements were published in the journal One Earth on January 19. The main premise of the study is the strong evidence that rising humid heat threatens the ability of tropical cities to maintain an environment conducive for human populations, regardless of age and gender.

In the research paper, the authors imply that global meteorological station networks have already reported the combined impacts of intense or extreme temperature and humidity, specifically above the theoretical limit of human survival 35 degrees Celsius. Yet, the risk of lower temperatures combined with humid heat stress has been reportedly overlooked, mainly on climate monitoring and the impact of climate change to an individual-level.

The Role of Climate Change

The One Earth study cites recent physiological studies on fit, healthy adults that show that significant heat stress can make the human body unable to thermoregulate, even below 31 degrees Celsius but in humid conditions. There are several weather, climatic, environmental, and health factors in relation to the impact of humid heat stress. Still, the phenomenon is driven by climate change, according to the research paper.

In addition to humid heat stress, extreme heat events like heat waves have increased in major cities across the United States over the past several decades, according to the United States Environmental Protection Agency (EPA). For instance, an average of two heat waves per year during the 1960s has increased to six per year since the 2010s and continued until the 2020s.