IS AN ice age on its way? A new way of working out the age of ocean currents
could tell us.
You usually find out how long water has been in a current by measuring levels
of the radioactive isotope carbon-14, which has a half-life of 5000 years. It is
created by cosmic rays at the ocean鈥檚 surface, but levels gradually fall off
once currents take it down to the ocean floor. But Phillipe Collon鈥檚 team at
Columbia University in New York City have found a way to measure levels of
argon-39 instead.
鈥淲ith a half-life of just 269 years it gives more detail on the global water
conveyor belt,鈥� Collon says. That would let them spot changes in 1000-year-old
ocean currents, which are thought to cause large climate swings such as ice
ages.
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