Subtitle: You have to go back a ways
James Lovelock has written that sea level rise is a trustworthy indicator of the “Earth’s heat balance.” Aradhna Tripati, UCLA assistant professor in the department of Earth and space sciences and the department of atmospheric and oceanic sciences, sees a discrepancy between current concentration of CO2 in the atmosphere and the existing ocean level.
As Tripati and colleagues reported Oct. 8 in the online edition of the journal Science (via Climate Progress), “The last time carbon dioxide levels were apparently as high as they are today — and were sustained at those levels — global temperatures were 5 to 10 degrees Fahrenheit higher than they are today, the sea level was approximately 75 to 120 feet higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland.”
The reason for the discrepancy? Until recent decades, levels of carbon dioxide have varied only between 180 and 300 parts per million.
In 1800 the level of CO2 was 280 ppm. There has been a 100 ppm rise in the concentration of CO2 and, as Climate Progress commentator Jeande Beagles opines, we have yet to pay for that increase. The price tag? We can expect to see much higher sea levels.
There is general consensus among climate scientists that modern-day levels of carbon dioxide are unprecedented over the last 800,000 years. The authors of the new study, “Coupling of CO2 and Ice Sheet Stability Over Major Climate Transitions of the Last 20 Million Years,” contend that the levels over the last 15 million years have been lower than modern levels.
Thus, as the saying goes, for those who have expressed concern that in the past decade sea level rise has been at an unimaginable rate of increase, “you ain’t seen nothing yet.”