What a Serbian cave tells you about the weather 2,500 years ago
weather depends partly on what the northern polar jet stream is up to. Jet streams are powerful and persistent winds that snake around the Earth from west to east, several miles above the surface. The meanderings of the northern polar jet stream can bring cold air down from the Arctic over the American Midwest, or send waves of Atlantic storms crashing into Ireland or Scandinavia.
As with most sorts of weather, scientists suspect that the flow of the jet streams is being affected by climate change. Data from the past century and a half suggest that the northern jet stream has become stronger over that time. But a century is not all that long in climatic terms, and it is not entirely clear whether the strengthening is a natural phenomenon.
In a paper published in Geology, Miaofa Li at Fujian Normal University and Slobodan Markovic at University of Novi Sad, in Serbia, shed new light on that question. Climate scientists routinely examine ancient air trapped in polar ice to glean insights into the state of the climate hundreds or even thousands of years ago. The researchers point out that something very similar can be accomplished by looking at the chemical makeup of rock formations in a pair of Serbian caves.
As with many caves, the floors of both Cerjanska Cave and Prekonoska Cave, both in Serbia’s south-east, are dotted with thin spires of rock called stalagmites. These are formed, very slowly, by water as it drips down from the rock above. Each droplet carries dissolved minerals.
If water drips onto the same spot over many years, a stalagmite gradually forms as the minerals are deposited. Crucially, analysing the minerals from which the stalagmite is made can reveal information about the water that made it. The
. Read more on livemint.com
