By Meghna Murali
Measuring the temperature of the oceans across the world is a difficult task. Water exists in various forms. Each layer of the ocean has a different temperature. Thus, researchers have always found it difficult to produce an average temperature of the ocean. Now, it seems like the scientists and researchers from Scripps Institution of Oceanography at the University of California, San Diego have come up with a solution for this problem. This discovery could potentially give us all the possible reasons for the sudden increase in global warming.
Global warming is ‘ocean warming’
Any change in the earth’s atmosphere directly affects the oceans. With vast emission of gases, the core of the earth heats rapidly. The planet begins to gain energy. Ultimately, all of the energy gets absorbed by the oceans. Thus, if one wants to measure the rate of global warming, measuring the temperature of the ocean can produce accurate results.
Considering climatic changes and the vast nature of oceans, scientists came up with a method which involved the study of noble gases in the earth’s atmosphere. The concentration of the noble gases in the air has a direct relationship with the ocean’s temperature. The team used ice cores from Antarctica to measure global ocean temperatures over the past 24,000 years. These ice cores were a repository of noble gases which were trapped in the form of bubbles. Xenon, Krypton and Argon were among the few noble gases that were found in these ice cores. The cold water in the Antarctic region absorbed the above-mentioned noble gases, while the warm water released them into the atmosphere. Thus, the ratio of these gases created a balanced atmosphere and scientists were able to establish an average ocean temperature.
A thermometer for the ocean
Ice samples were collected from Antarctica during the course of the West Antarctic Ice Sheet (WAIS) Divide coring project. Samples were collected for six field seasons. The ice was drilled in the form of cylindrical samples with a length of 3.7 meters. The last sample was taken at a depth of 11,000 feet in the year 2011. Since the atmosphere of the earth mixes on a scale of weeks to months, scientists observed samples which were 8000 to 20,000 years old. They collected data for every 250 years and then averaged the entire data to produce the average global ocean temperature.
“The reason this study is so exciting is that previous methods of reconstructing ocean heat content have very large age uncertainties, [which] smooths out the subtler features of the record,” said co-author Sarah Shackleton, a graduate student in the Severinghaus lab at Scripps. “Because WAIS Divide is so well dated, this is the first time that we’ve been able to see these subtle features in the record of the deglaciation. This helps us better understand the processes that control changes in ocean heat content.”
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