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Unformatted text preview: 58 S C IEN T IF IC A MERIC A N M A R C H 2006 I n 1956 Roger Revelle and Hans Suess, geochemists at the Scripps Institution of Oceanography in California, pointed out the need to measure carbon dioxide in the air and ocean so as to obtain “a clearer understanding of the probable climatic effects of the predicted great indus- trial production of carbon-dioxide over the next 50 years.” In other words, they wanted to F gure out how dire the situ- ation would be today. That they had to argue the importance of such observations now seems astonishing, but at the time scientists did not know for certain whether the carbon diox- ide spewing out of tailpipes and smokestacks would indeed accumulate in the atmosphere. Some believed that it would all be absorbed benignly by the sea or be happily taken up by growing plants on land. Revelle and the young researcher he hired for this project, the late Charles David Keeling, realized that they had to set up equipment at remote locations, far from local sources and sinks of carbon dioxide, which would cause the measure- ments to vary erratically. One spot they chose was about as far from industrial activity and vegetation as anyone could get: the South Pole. Another was at a newly established weather station atop Mauna Loa in Hawaii. The Mauna Loa monitoring has continued (with just one brief interruption) from 1958 to this day. Being not so remote as Antarctica, Hawaii sees carbon dioxide levels rise and fall sharply in step with the Northern Hemisphere’s growing sea- son, but at the end of each and every year, the concentration of this heat-trapping gas always ends up higher than it was 12 Much of the carbon dioxide given off from the burning of acid balance of seawater. The repercussions for marine The Dangers of FRED BAVENDAM Minden Pictures COPYRIGHT 2006 SCIENTIFIC AMERICAN, INC. w w w.sciam.com S C IEN T IF IC A MERIC A N 59 months before. So it did not take long for the scientiF c com- munity to realize that Revelle was right—much of the carbon dioxide released into the atmosphere was destined to remain there. But his calculations were also correct in showing that a substantial fraction would end up in the sea. And it was clear to Revelle long ago that the part that went into the ocean would fundamentally alter the chemistry of seawater. Unlike some aspects of climate change, the reality of this effect—essentially the acidiF cation of the ocean—is not much debated, although its full implications are just now being revealed. How Unnatural? t h e h a l f- c e n t u ry r ecor d that Keeling produced is extremely valuable, but it is too short to place the current situation in context. Scientists have, however, been able to obtain a longer-term perspective by measuring air bubbles trapped in ice cores. ¡rom this natural archive they have learned that the atmospheric concentration of carbon dioxide was approximately constant for several thousand years and then began to grow rapidly with the onset of industrialization...
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This note was uploaded on 11/30/2009 for the course GEO 1006 taught by Professor Staff during the Spring '08 term at Minnesota.
- Spring '08