Climate Change Could Stunt Human Height Growth, New Research Warns

Emerging research suggests that global warming and climate change could lead to a decline in average human height. A team of researchers from the University of California has found that exposure to extreme temperatures and high humidity during pregnancy can hinder a child's natural growth even before birth.

The study focused extensively on 200,000 children under the age of five in South Asia, a region identified as being at high risk. Lead researcher Katie McMahon noted that children whose mothers were exposed to temperatures exceeding 35°C combined with high humidity during pregnancy were found to be up to 13% shorter than their expected height. In South Asia, the lack of widespread air conditioning and a lifestyle heavily dependent on outdoor agriculture exacerbate this risk, as extreme weather in every trimester of pregnancy directly impacts physical development indicators.

This phenomenon draws parallels to historical shifts in human stature, often referred to as the "concertina effect." According to Professor Richard Steckel of Ohio State University, the height of Northern Europeans fluctuated significantly between the 9th and 19th centuries. Notably, during the "Little Ice Age" of the 17th century, average male height dropped by about 2.5 inches due to extreme cold and resulting disease. Researchers now fear that extreme heat will exert a similar negative pressure on modern populations as extreme cold did in the past.

Even the Netherlands, home to the world’s tallest people, is seeing a reversal in this trend. The Dutch Bureau of Statistics (CBS) reports that men born in 2001 are, on average, 1 cm shorter than those born in 1980. While migration is a factor, experts also point to poor dietary habits and childhood obesity. Similarly, the United States, which ranked third in global height during the 19th century, has now fallen out of the top 20, largely due to socio-economic inequality and limited access to healthcare.

The impact of environment and nutrition is further highlighted by the disparity between the two Koreas. Since the division following the 1950 war, people in North Korea are now approximately 8 cm shorter on average than their counterparts in South Korea. Such disparities prove that height is not solely determined by genetics but is heavily influenced by external conditions. According to Dr. Andrea Rodriguez-Martinez of Imperial College London, nearly one billion children globally are now at "extremely high risk" from climate change. Without immediate action to mitigate carbon emissions and enhance environmental adaptation, the physical stature of future generations in low- and middle-income countries could be severely impacted.