Humidity, often neglected or underestimated, is a very serious problem yet it does not figure in climate change policies by governments, finds a study. Researchers from the University of Tokyo have effectively integrated humidity data from hundreds of cities into Heat Stress Indicators (HSIs) for the first time, and they have evaluated how well these indicators predict deaths from heat-related causes.Their findings, published in the journal PNAS Nexus, show that global warming was the previous term for climate change, and with good reason: Globally speaking, temperatures are rising.
Beyond air temperature, there are other factors to consider, the researchers argued. Humidity, or the concentration of water in the air, is one such factor that is crucial in some regions of the world. Humidity has an impact on our body’s capacity to release heat through sweat, which is the result of water evaporating off our skin.
Among WHO regions, South-East Asia is most vulnerable to this, she added, at a regional workshop for mental health, held in Indonesia, last week.
“An estimated 260 million people live with a mental health condition and more than 200,000 people die by suicide every year,” she said, noting that climate change is worsening mental health.
It is also putting an extra burden on the health systems, Wazed said.
This evaporative cooling is less effective and eventually unfeasible in high humidity settings. Qiang Guo from the varsity’s Department of Global Health Policy said that HSI and its implications may differ based on environments.
Guo and his team used climate data from 739 cities across 43 countries to create eight HSIs. They found that the relationship between daily temperature and humidity is the key factor affecting HSI performance.
Humidity-incorporating HSIs have shown effectiveness in predicting heat-related mortality in regions like coastal areas in the US, Peru, South Korea, and Japan.