The United States is on the warpath, and not for the first time. And as uncomfortable as it makes me feel, the battlefield is a hotspot for scientific innovation. While the Ukrainian front is a catalyst for artificial intelligence and autonomous robotics, the Cold War was a catalyst for climate research.
Thanks to the development of a huge nuclear submarine fleet, oceanography received a tremendous boost and we now know much more about ocean circulation and the properties of the deep sea. The internal stratification of the ocean determines the propagation of sound waves, which is still the only useful means of communication under water. We have knowledge of the atmosphere thanks to, among other things, the development of intercontinental missiles.
Polar research also benefited. Thanks to the enormous defense apparatus of the US, a large part of the Arctic region was opened up for scientific research. The Americans have for decades radar stations in the middle of the Greenland ice sheet, to detect Russian fighter jets and missiles at an early stage. For the construction of bases and runways, the material properties of snow and glacial ice had to be studied. Major steps in glaciology were thus made. To this day, the American armed forces provide air transport to and from a number of major military and research stations in Greenland. I once flew into the middle of the ice sheet in a ski-equipped Hercules C-130.
One day in 1958, the Americans explored northeastern Greenland. They were looking for locations where fighter planes could make an emergency landing. A logical location: although our view of the Earth is fundamentally distorted by flat world maps, northern Greenland is actually only 3,500 kilometers from Moscow and the industrial cities of the Urals.
On one of those reconnaissance flights a Greenlandic Grand Canyon captured in the photo. It is a barren, barren place in the mountains, where no glaciers flow. The valley has vertical walls one kilometer high. In that wall, just below the top, you could just make out a few caves in the grainy black and white photos. What if, geologists thought decades later, if we look in those caves for traces of an earlier climate? Traces of the past can teach us something about the near future.
Today’s unprecedented warming is taking place against a backdrop of steady cooling which was deployed about 65 million years ago. The lush vegetation of that time, on an Earth 15 degrees warmer than it is today, provided enough energy to the food chain to feed mega-dinosaurs and impossibly large insects almost everywhere. Palm trees grew on the poles. Since then it has cooled down considerably and we are in a period in which ice ages alternate with slightly less cold periods.
Dripstone caves indicated times when the ground was not permanently frozen
An important cause for the steady cooling appears to be the tectonic collision between India and Eurasia, which created the Himalayas. All that rock weathers, a process in which carbon dioxide is extracted from the atmosphere and bound to minerals. The decreasing concentration of carbon dioxide weakens the greenhouse effect and the earth slowly cools down.
Because of this slow cooling, analogues can be found in the geological past for the climate in the near future. We are on track to more than 1.5 degrees of warming by the end of this century, which resembles the climate of two million years ago. But maybe it will be 3 or 4 degrees, the last time we had that was ten million years ago, during a period we call the Miocene. The challenge is that it is not easy to find climate information that has been preserved for so long.
So in 2015, a team of Austrian, American and English researchers set out by plane, helicopter, an inflatable boat, three days on foot and finally abseiling 150 meters to the caves that had previously been photographed by American soldiers. There they found what they had hoped for: stalactites. These are formed when water seeps down from the surface through the rock and dissolves limescale along the way. When the water reaches the ceiling of the cave, the lime is deposited in stalactite formations. If there is permafrost above the cave, dripping stops and thus the growth of the dripstones.
The research team took samples that were dated in the lab. It turned out that the stalactites in the cave were formed in a number of periods between the 9 and 5 million years agointermittently. So there was no permafrost during those periods. Nowadays it freezes at 14 degrees in the cave. This means that during those stalactite periods it must have been at least 14 degrees warmer locally than it is now. The average temperature on Earth was then about 3 degrees warmer. The cave is therefore proof that the Arctic region is warming much more strongly than the global average. In addition, the dripstones have fluorescent banding, a sign that there was vegetation on the surface that grew in summer and not in winter.
In short, the Arctic region is extremely vulnerable and changeable, with large climate fluctuations, even if global temperatures rise only slightly. Discovered partly thanks to the Cold War. Today’s wars will also provide science with new knowledge. But is it worth it?
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