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Conservation Science for a Healthy Planet

Slightly warmer temperatures and moderate CO2 [275 ppm] ~120,000 years ago led to superstorms and abrupt multi-meter sea-level rise

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October 12, 2017  Elsevier read full ScienceDaily article here
While strong seasonal hurricanes have devastated many of the Caribbean and Bahamian islands this year, geologic studies on several of these islands illustrate that more extreme conditions existed in the past..[per a] new analysis [showing] that the limestone islands of the Bahamas and Bermuda experienced climate changes … even more extreme.
…[The study] demonstrates that during a global climate transition in the late last interglacial (approximately 120,000 years ago)… abrupt multi-meter sea-level changes occurred. Concurrently, coastlines of the Bahamas and Bermuda were impacted by massive storms generated in the North Atlantic Ocean…
….During the last interglacial, sea levels were about 3-9 meters higher than they are now. The geologic evidence indicates that the higher sea-levels were accompanied by intense “superstorms,” which deposited giant wave-transported boulders at the top of cliffed coastlines, formed chevron-shaped, storm beach ridges in lowland areas, and left wave runup deposits on older dunes more than 30 meters above sea level. These events occurred at a time of only slightly warmer global climate and CO2 (about 275 ppm) was much lower than today….
…The authors emphasize “the LIG record reveals that strong climate forcing is not required to yield major impacts on the ocean and ice caps.” In our industrial world, rapidly increasing atmospheric CO2 has surpassed 400 ppm, levels not achieved since the Pliocene era about 3 million years ago, while global temperature has increased nearly 1 °C since the 1870s….

P.J. Hearty, B.R. Tormey. Sea-level change and superstorms; geologic evidence from the last interglacial (MIS 5e) in the Bahamas and Bermuda offers ominous prospects for a warming Earth. Marine Geology, 2017; 390: 347 DOI: 10.1016/j.margeo.2017.05.009

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