Climate change has put the existence of many species in danger, from polar bears to frogs to pandas. A change in our ecosystem will obviously have a profound effect on humans as well, but is it possible that climate change is already taking out a segment of our population?
There may be a "statistically significant" link between climate change and birth rates, a team of Japanese researchers concluded in a recent study in the journal Fertility and Sterility. Apparently, as temperatures have risen, the proportion of female babies born in Japan has increased while the proportion of male newborns in the country has decreased.
From 1968 to 2012, the ratio of male to female newborns in Japan has been on the decline, according to the study. Conversely, the proportion of "fetal deaths" among male babies where a spontaneous miscarriage occurred after 12 weeks of pregnancy increased during that same time period.
The researchers also looked at "one very hot summer in 2010 and a very cold winter in January 2011" to see how the birth rates of male and female babies were impacted by the extreme weather conditions. The summer of 2010 was Japan's hottest since 1898, according to Mother Jones. The team found similar results here, a lower ratio of male to female births and an increase in fetal deaths.
However, the researchers point out that climate change isn't the only thing affecting the number of male newborns. They also don't argue that there's a causal relationship between warmer temperatures and more female births.
If we look at the newborn gender ratio globally, the proportion of male babies has actually increased in recent decades. There were 107 boys per 100 girls born in 2011, according to data from the World Bank. But of course, some countries have disproportionate populations of male and female newborns, such as China.
There are many factors other than climate change that impact gender ratios, such as the practice of sex-selective abortions in some countries, the age of the parents and war. The researchers of this study argue that male fetuses are "especially vulnerable" to factors such as air pollution, chemical exposure and climate changes.
Mother Jones points out that similar studies in Finland and New Zealand didn't yield any strong connections between temperature and gender ratios. The Japanese researchers acknowledged this in their study, claiming that those countries don't experience temperature changes between summer and winter as dramatically as Japan. The country also warmed at a greater rate than the global average during the last century.
This is only one study, and the changes in the birth ratios aren't enormous, so there's probably no need for anyone to freak out over the fate of the male race just yet. But if this gets people to finally pay attention and do something about climate change, that certainly wouldn't be such a bad thing.
