The United States already has a worse infant mortality rate than Latvia and Israel, and according to researchers, climate change could make it even worse.
Alan Barreca of Tulane University, Melanie Guldi of the University of Central Florida, and Olivier Deschenes of the University of California-Santa Barbara analysed birth rates in the US in the 20th Century and found that not only has climate change decreased the US birth rate, but it could also be harmful to newborns.
The researchers found that when the temperature gets above 80 degrees, the birth rate 9 months later drops significantly. As the percentage of days topping 80 increases due to climate change, they shifts the birth habits of American couples.
“Using the average (unweighted) number of monthly births over our sample period (295,000), the effect size at 9 months implies a reduction of 1,165 fewer births across the whole United States in that one month,”said the researcher in a new study.
“The fact that the largest effect is observed at 9 months is consistent with hot days having an immediate impact on reproductive health and/or coital frequency around the time when conception would have occurred.”
This effect does create a slight rebound in the few months afterwards, but the shift will create a drag on the total number of births in the US. That downward shift could exacerbate problems for the US economy.
“Using our estimates from the post-1970 period, we project a 2.6% decline in births in the United States, or about 107,000 births per year,” said the researchers. “Thus, climate change will exacerbate the already ‘below replacement’ birth rates in the United States and similar developed countries, which may adversely affect the sustainability of social programs, like Social Security.”
Since more people will conceive in cooler months, the Researcher’s model predicts that the shift will also move a large number of births from spring into the heart of summer. Studies have shown that the exposure to higher temperatures during the third trimester increase the risks of negative health shocks such as low birth weight.
Thus, there will be an increase in the number of negative outcomes for newborns. From the study:
“We find that August births will increase by 4% relative to April births using our core model. Our back-of-the envelope calculations suggest that these shifts may lead to a 0.4% increase in the relative risk of low birth weight. As with other early-life health shocks, recent evidence suggests there may be long-term consequences to this increased in utero exposure to high temperatures. Taken together, these impacts suggest that fertility is an important and understudied cost of climate change in the United States and other countries.”
The researchers point out that these effects will be felt even more in developing countries, as one of the most effective methods of mitigating the damage is access to air conditioning.
So add unborn fetuses to the growing list of people impacted by climate change.
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