By IANS,
Washington : Ice core and ocean deposit comparisons show complex links between carbon dioxide levels, ocean currents and climate and may help explain past, present and future climate trends.
Researchers presented new data from their analysis of ice core samples and ocean deposits dating as far back as 90,000 years ago and suggest that warming, carbon dioxide (CO2) levels and ocean currents are tightly interrelated.
These findings provide scientists with more data and insights into how these phenomena were connected in the past and may lead to a better understanding of future climate trends.
With support from the National Science Foundation (NSF), Jinho Ahn and Edward Brook, both geoscientists at Oregon State University, analysed 390 ice core samples taken from Antarctic ice at Byrd Station, according to an NSF release.
The samples offered a snap shot of the earth’s atmosphere and climate dating back between 20,000 and 90,000 years. Sections of the samples were carefully crushed, releasing gases from bubbles that were frozen within the ice through the millennia. These ancient gas samples were then analysed to measure the levels of carbon dioxide contained in each one.
Ahn and Brook then compared the CO2 levels from the ice samples with climate data from Greenland and Antarctica that reflected the approximate temperatures when the gases were trapped and with ocean sediments in Chile and the Iberian Peninsula.
Data from the sediments provided the scientists with an understanding of how fast or slow the ocean currents were in the North Atlantic and how well the Southern Ocean was stratified during these same time periods.
The researchers discovered that elevations in CO2 levels were related to subsequent increases in the earth’s temperature as well as reduced circulation of ocean currents in the North Atlantic.
The report appeared in Friday’s edition of Science.