Article Tags: Doug L. Hoffman
There have been a rash of bogus reports in the news media about rapidly rising sea-levels supposedly caused by global warming. Sea-levels are notoriously hard to measure on a global basis since land also rises and sinks due to tectonic activity. With historical records mostly unreliable how can we tell if current conditions are normal for Earth 14,000 years after a deglaciation? A new report, based on calcium growths in caves on the Mediterranean island of Mallorca, says that sea levels around 81,000 years ago were higher than today. Higher sea-levels imply less glacial ice and warmer temperatures than today as well. Even more interesting is that this occurred during a warm period called marine isotope stage (MIS) 5a, which was more than 30,000 years after the Eemian interglacial ended and glaciation had resumed. This could mean that current theories about how ice age glacial periods start are wrong.
Scientists have long made a strong connection between Earth’s climate and sea-levels. Warmer climate means less glacial ice and higher ocean water levels. This means that during glacial periods, often called ice ages, sea-levels drop because more water is trapped in glacial ice. Scientists know from paleoclimate records that the end of a glacial period occurs quickly and is accompanied by wild swings in climatic conditions. But because the buildup of large amounts of glacial ice depends on precipitation it was thought that descent into a new glacial period was a more gradual affair. A report in Science, entitled “Sea-Level Highstand 81,000 Years Ago in Mallorca,” authored by Jeffrey A. Dorale and colleagues, not only claims that sea-levels were higher than modern levels during ages past but that there have been significant swings in sea levels after the last interglacial warm period ended.
Source: theresilientearth.com