Earth's carbon sinks keeping up with CO2

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BOULDER, Colo., May 17 (UPI) -- Earth's ecosystems are still capable of soaking up more carbon as greenhouse gases accumulate in the atmosphere, a U.S. study finds.

Researchers with the National Oceanic and Atmospheric Administration say the research contradicts several recent studies that suggested the world's natural "carbon sinks" have reached or passed their capacity, and in fact total capacity has increased roughly in line with rising emissions, ScienceNews.org reported.

"The sinks have been more than able to keep up with emissions," Pieter Tans, an atmospheric scientist at NOAA's Earth System Research Laboratory in Boulder, Colo., said.

Measurements of the greenhouse gas carbon dioxide show levels are rising steadily, from 316 parts per million in 1959 to 392 parts per million today.

Forests can sequester carbon dioxide through photosynthesis, while oceans take it up proportionally as levels rise in the air, researchers said.

Researchers monitored 42 marine sites where carbon dioxide levels have been measured for decades to analyze how much CO2 was in the atmosphere above each of these sites over time.

"Less carbon dioxide has remained in the atmosphere, relative to the amount of fossil fuel emissions, today compared to 50 years ago," Tans said.

Exactly how the sinks are keeping up is unclear, researchers said.

One possibility is that forests are regrowing in parts of the world more than scientists had thought, or the oceans may be taking up significantly more carbon than had been estimated, they said.