Climate researchers use pebbles to draw parallels between warming and floods

Taking lessons from extreme floods and landscape changes over 50 million years ago, researchers have predicted a worrying future for our warming world. The study,  published in Scientific Reports on 6 September, explains a cause-and-effect relationship that researchers believe exists between the Earth’s water cycle and global warming. Researchers used one such ’exceptional’ episode of warming — which occurred around 56 million years ago — to strike a comparison with the phenomenon in recent decades. Researchers measured the impact that this warming had on the hydrologic (water) cycle using sediment samples from the **Pyrenees mountain** range that borders Spain and France. “The Spanish Pyrenees offer sediments that allow us to observe the ancient river channels and to determine their size,” researchers  were quoted as saying in a University of Geneva press release. This ancient episode lasted 10,000 to 20,000 years, during which global average temperatures saw a rise of 5-6 degrees Celsius over a ‘very short’ period in Earth’s **geological timescale** , the study explains. [caption id=“attachment_5136111” align=“alignnone” width=“1280”] Representational image. Wikimedia Commons[/caption] This warming likely caused ****floods****  and **landscape changes** , the researchers said, evident from the size of pebbles and slope of rivers. They used both these parameters — pebble size and river slope — to find the how fast these rivers flowed and the volume of water they discharged at the time. They found that the impact on landscapes worldwide was severe – enough to turn what could once have been lush green landscape to arid, pebble-filled plains. Lead researcher of the study, Sébastien Castelltort, cites an “obvious analogy” of these changes with current global warming phenomena , too. They found the intensity of today’s floods was eight times as much as floods 56 million years ago. There are lessons to be learned from this event, according to Castelltort, and more so now – with  temperatures  rising at a much faster pace. While the researchers admit they do not fully understand how these patterns in rains and floods could have changed, their findings warn of more **intense floods** , **seasonal variations** and **warmer summers** from global warming in the present. “Our study proves that the risks associated with global warming may be far greater than we generally think,” Castelltort concludes.