Rutgers researcher finds evidence sewing doubt for cause of long-held climate change beginning 15 M. years ago
The long-held theory that attributes the breakdown of Himalayan rocks 15 million years ago to Earth’s ultimate climate evolution may not be accurate, a Rutgers-led study found, according to an article on Rutgers Today.
Focusing on the long-term cooling that occurred before the recent global warming tied to greenhouse gas emissions from humanity, the report published in the journal "Nature Geoscience" could be a breakthrough in understanding the cause of long-term climate change, according to the article.
“The findings of our study, if substantiated, raise more questions than they answered,” said senior author Yair Rosenthal, a distinguished professor in the Department of Marine and Coastal Sciences at Rutgers University—New Brunswick. “If the cooling is not due to enhanced Himalayan rock weathering, then what processes have been overlooked?”
The leading hypothesis was that the collision of the prehistoric Indian and Asian continents caused Himalayan rocks to rise to the surface and succumb to weathering that captured and stored carbon dioxide, according to the article.
Along with lead author Weimin Si, a former Rutgers doctoral student, Rosenthal challenged the unconfirmed hypothesis, according to the article.
The rocks instead carried the emissions to rivers that, in turn, carried it to the oceans as dissolved inorganic carbon, which is used by algae to build their calcium carbonate shells.
Dead algae skeletons fall on the seafloor and get buried, locking carbon from the atmosphere in deep sea sediments, according to the article.
If weathering is increasing, then so should the levels of calcium carbonate in the deep sea floor. Yet Rosenthal’s study found that the calcium carbonate levels decreased over the last 15 million years, according to the article.
The findings were based on the study of dozens of deep sea sediment cores through an international ocean drilling program, according to the article.
The researchers also found that algae called coccolithophores adapted to the carbon dioxide decline over 15 million years by reducing their production of calcium carbonate, which was something never previously looked into in studies, according to the article.
Still, many scientists believe that ocean acidification from high carbon dioxide levels will reduce the calcium carbonate in algae, according to the article.
Yet Rosenthal and Si’s study suggest the opposite, and now their team is looking for alternative theories for Earth’s long-term climate change by studying the evolution of calcium and other elements in the ocean, according to the article.
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