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Climate change has changed the evolution of mankind – and may be shrinking us

Climate change may be shrinking people because being smaller keeps you cooler, a study suggests.

Changes in the climate have led to “significant” fluctuations in the size of the human body and brain over the last million years, a new study finds.

Cambridge University researchers have discovered that temperature has a large bearing on the average body size, with colder, harsher climates making it bigger and warmer ones shrinking it.

Larger size is thought to act as a buffer against colder temperatures because less heat is lost from a body when its mass is large relative to its surface area. Meanwhile, smaller size helps cool a person down by releasing more heat from their bodies.

Brain size also changed significantly over time but not “in tandem” with body size, suggesting factors other than the climate were also involved.

A defining trait of the evolution of our genus is a trend of increasing body and brain size; compared to earlier species such as Homo habilis, we are 50 per cent heavier and our brains are three times larger. But the drivers behind such changes remain highly debated.

“Our study indicates that climate – particularly temperature – has been the main driver of changes in body size for the past million years,” said Professor Andrea Manica, of Cambridge University.

“We can see from people living today that those in warmer climates tend to be smaller, and those living in colder climates tend to be bigger. We now know that the same climatic influences have been at work for the last million years,” she said.

The researchers say there is good evidence that human body and brain size continue to evolve. The human physique is still adapting to different temperatures, with on average larger-bodied people living in colder climates today.

However, because other factors such as health and nutrition also play a key role in body size it is difficult to say whether people are actually shrinking in the warming – or rather growing less than they would otherwise have done in a stable climate, researchers say.

Brain size in our species appears to have been shrinking since the beginning of the Holocene – around 11,650 years ago.

The increasing dependence on technology, such as an outsourcing of complex tasks to computers, may cause brains to shrink even more over the next few thousand years.

slimfern

20 of the strangest phobias

Deipnophobia – Fear of dinner conversations

Emetophobia – The Fear of Vomiting

Coulrophobia – Fear of clowns

Ergophobia – Fear of work

Aurophobia – The fear of finding gold

Mageirocophobia – Fear of cooking

Pogonophobia – Fear of beards

Pentheraphobia – Fear of the mother-in-law

Alliumphobia – Fear of garlic

Chorophobia – Fear of dancing
Arachibutyrophobia – Fear of peanut butter sticking to the roof of your mouth

Hippopotomonstrosesquippedaliophobia – Fear of long words

Somniphobia – Fear of falling asleep

Papaphobia – Fear of the Pope

Chaetophobia – Fear of hair

Globophobia – Fear of balloons

Xanthophobia – Fear of the colour yellow

Genuphobia – Fear of knees
Siderophobia – Fear of stars

Phobophobia – Fear of phobias

slimfern
@slimfern posted:

20 of the strangest phobias

Deipnophobia – Fear of dinner conversations

Emetophobia – The Fear of Vomiting

Coulrophobia – Fear of clowns

Ergophobia – Fear of work

Aurophobia – The fear of finding gold

Mageirocophobia – Fear of cooking

Pogonophobia – Fear of beards

Pentheraphobia – Fear of the mother-in-law

Alliumphobia – Fear of garlic

Chorophobia – Fear of dancing
Arachibutyrophobia – Fear of peanut butter sticking to the roof of your mouth

Hippopotomonstrosesquippedaliophobia – Fear of long words

Somniphobia – Fear of falling asleep

Papaphobia – Fear of the Pope

Chaetophobia – Fear of hair

Globophobia – Fear of balloons

Xanthophobia – Fear of the colour yellow

Genuphobia – Fear of knees
Siderophobia – Fear of stars

Phobophobia – Fear of phobias

I have mild emetophobia .

Baz

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