A small furry creature with dependable toilet habits is proving useful in attempts to chart the Earth's past climate change.
The Rock Hyrax is about the size of a guinea pig and lives in crevices in rock faces in Africa and Asia. Communities tend to stay in one place for a long time, and each generation teaches the next where to pee.
The result is layer upon layer of dried urine, which contains pollen, bits of leaves, grasses, and bubbles of air that can give a picture of the Earth's climate at a certain point in history. In one location in South Africa, a urine layer was found that stretches back 55,000 years.
A team from Montpelier University in France has been analysing this layer. "We are taking the piss, quite literally—and it is proving to be a highly effective way to study how climate changes have affected local environments," project leader Brian Chase told the Guardian.
Their results show that the region's climate was dramatically affected by the retreat of glaciers in Europe at the end of the last Ice Age. As the planet warmed, great lakes of meltwater formed behind ice barriers in parts of northern Europe. Eventually, these barriers broke, letting huge amounts of cold freshwater drain into the Northern Atlantic.
This dramatic freshwater infusion into the normally salty sea caused havoc with ocean currents, which are driven by temperature and salinity. The gulf stream, which normally brings warm water to northern Europe, was temporarily halted—plunging Northern Europe back into cold conditions once again.
What wasn't known previously was the effect that this had on the rest of the world. "This had a huge local impact in northern Europe but we did not know how the rest of the planet was affected," explained Chase. "Thanks to rock hyrax urine from the period, we have an answer. There was significant cooling in South Africa, and presumably the rest of the planet, at the time."
By studying how climate has changed in the past, it's hoped that some insight can be gleaned into how it may change as a result of human-induced global warming. A similar disruption of ocean currents is postulated by some as a consequence of current climate change.
"The aim of these studies—including our work on hyraxes—is to create a very accurate timeline of past climate events so we can understand what is causing them," said Chase. "Some researchers use ice cores. We just happen to use urine."
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