The Impact of Climate Change on our Brains

Call it what you want — global warming or climate change — but we can all agree that it isn’t beneficial for any- one. In fact, the latest studies are beginning to show just how much of an impact cli- mate change has had in the past, is currently having, and may have on the way human beings evolve in the future.

In case you haven’t noticed, we have big heads — and that’s no joke. Human beings have unusually large brains, with capacity for language, abstract thought and consciousness. Until now, scientists and academics have struggled to find the reason for this, but lately a new theory suggests that the mystery behind these big-brained heads of ours lies in climate change.

Mark Maslin, geography professor at University College London, introduced the idea in 2009 and elaborated on it in a recent paper. Millions of years ago, slow changes in the Earth’s orbit dramatically impacted the east African climate, and may have played a vital role in driving human evolution, according to what’s known as the pulsed climate-variability hypothesis. “It seems modern humans were born from climate change,” Maslin said in a press statement, “as they had to deal with rapid switching from famine to feast — and back again. The climate of east Africa seems to go through extreme oscillations, from having huge, deep freshwater lakes surrounded by rich, lush vegetation to extremely arid conditions — like today — with sand dunes in the floor of the Great Rift Valley. These changes resulted in the evolution of a new species with bigger brains and also forced humans to disperse out of east Africa.”

The co-author of the study, Dr. Susanne Shultz of the University of Manchester, said, “We found that around 1.9 million years ago a number of new species appeared, which we believe is directly related to new ecological conditions in the East African Rift Valley, in particular the appearance of deep freshwater lakes. Among these species was early Homo erectus, with a brain 80 percent bigger than its predecessor.”

The recent ecological shifts in Africa might have made our brains larger, but they also might have made our tempers shorter. If you’ve stood in line for concert tickets on a hot, muggy day and almost punched someone in the face be- cause they tried to wriggle their way in front of you, you know what we’re talking about. Turns out, temperatures can often alter our moods and behaviors; extremely high temperatures can be blamed for the aggressiveness that sometimes bubbles away inside of us. Hotheaded? Literally, some scientists believe.


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