Published on Thursday 19 July 2012 00:38
Natural changes in seawater chemistry are a key cause of climate change, a new study suggests.
Experts at the University of Toronto and the University of California Santa Cruz have found that the impact of continental collisions and divisions over millions of years has a major impact on global warming.
The geological activity causes the dissolution or creation of massive gyspum deposits which scientists have found alters the sulphate content of the ocean and the atmosphere. That in turn affects the climate.
Researchers believe that “times of high sulphate concentrations in ocean water correlate with global cooling, just as times of low concentration correspond with greenhouse periods”.
Professor Ulrich Wortmann, of the Department of Earth Sciences at the University of Toronto and lead author of the study, said: “While it has been known for a long time that gyspum deposits can be formed and destroyed rapidly, the effect of these processes on seawater chemistry has been overlooked.
“The idea represents a paradigm shift in our understanding of how ocean chemistry changes over time and how these changes are linked to climate.”
He added: “Seawater chemistry is characterised by long phases of stability, which are interrupted by short intervals of rapid change. We’ve established a new framework that helps us better interpret evolutionary trends and climate change over long periods of time. The study focuses on the past 130 million years, but similar interactions have likely occurred through the past 500 million years.”
The research is being published in the journal Science this week.