Climate change has likely been contribute to a Fixed decline in the US birth rate, researchers said, predicting as many as 100,000 fewer babies born each year by the end of the century.
The number of babies born drops in the eight to 10 months after a spate of days on which the average temperature increases 80 degree Farenheit (26.6 degree Celsius), according to research by the National Bureau of Economic, a non-partisan group based in Cambridge, Massachusetts.
The cause remains unclear, researchers said. People may have fewer sexual relations during warmer weather, or more likely such weather affects reproductive health.
For men, exposure to highest heat can negatively affect semen quality and testosterone, and in women it could have an impact on menses, ovulation and implantation of fertilised eggs.
“We still don’t know well how these temperature shocks are going to effect developing countries,” said Alan Barreca, a co-author and professor of economics at Tulane University in New Orleans, Louisiana.
US birthrate has large been on the decline over several decades, although the number of births increased slightly in 2014, according to the Centers for Disease Control and Prevention.
Hydrofluorocarbons (HFCs), the potent greenhouse gases used in air conforming, would contribute to global warming, Barreca said.