Rutgers University scientists, reporting in the journalScience, say that global ocean levels are rising twice as fast today as they were 150 years ago, and warming from human activities appears to be the culprit. The speed of the rise today is two millimeters per year, compared to one millimeter annually for the past several thousand years. While the figures may not sound dramatic, it seemingly confirms scientific concerns of acceleration in global warming.
The findings are based on drilling studies along the New Jersey coast, tidal gauges and satellite images. They establish a steady millimeter-per-year rise from 5,000 years ago until about 200 years ago. “With solid historical data, we know it is definitely a recent phenomenon,” said Rutgers researcher Kenneth G. Miller. “The main thing that’s changed since the 19th century and the beginning of modern observation has been the widespread increase in fossil fuel use and more greenhouse gases,” he added.
Interestingly, the findings by Miller’s team argue against some widely held tenets of geological science. Miller claims, for example, that ocean heights 100 million years ago and earlier were 150 to 200 meters lower than scientists had previously thought. Changes at these levels can only be caused by the Earth’s crust shifting on the ocean floor. Miller’s findings, therefore, imply less ocean-crust production than scientists had widely assumed.