(p. D3) For decades, scientists have been trying to figure out what all the carbon dioxide we have been putting into the atmosphere has been doing to plants. It turns out that the best place to find an answer is where no plants can survive: the icy wastes of Antarctica.
As ice forms in Antarctica, it traps air bubbles. For thousands of years, they have preserved samples of the atmosphere. The levels of one chemical in that mix reveal the global growth of plants at any point in that history.
“It’s the whole Earth — it’s every plant,” said J. Elliott Campbell of the University of California, Merced.
Analyzing the ice, Dr. Campbell and his colleagues have discovered that in the last century, plants have been growing at a rate far faster than at any other time in the last 54,000 years. Writing in the journal Nature, they report that plants are converting 31 percent more carbon dioxide into organic matter than they were before the Industrial Revolution.
. . .
Since plants depend on carbon dioxide to grow, scientists have long wondered if that extra gas might fertilize them.
. . .
In the mid-2000s, atmospheric scientists discovered a powerful new way to measure plant growth: by studying an unimaginably rare molecule called carbonyl sulfide.
Carbonyl sulfide — a molecule made of a carbon atom, a sulfur atom and an oxygen atom — is present only in a few hundred parts per trillion in the atmosphere. That is about a million times lower than the concentration of carbon dioxide. Decaying organic matter in the ocean produces carbonyl sulfide, a gas that then floats into the atmosphere.
Plants draw in carbonyl sulfide along with carbon dioxide. As soon as it enters their tissues, they destroy it. As a result, the level of carbonyl sulfide in the air drops as plants grow.
. . .
But Dr. Campbell and his colleagues found that it hasn’t increased very much. As we have been adding carbonyl sulfide to the atmosphere, plants have been pulling it out. In fact, the scientists found, they have been pulling it out at a staggering rate.
“The pace of change in photosynthesis is unprecedented in the 54,000-year record,” Dr. Campbell said. While photosynthesis increased at the end of the ice age, he said, the current rate is 136 times as fast.
With all that extra carbon dioxide going into plants, there has been less in the air to contribute to global warming. The planet has warmed nearly 2 degrees Fahrenheit since 1880, but it might be even hotter if not for the greening of the Earth.
For the full commentary, see:
Carl Zimmer. “MATTER; A Global Greening.” The New York Times (Tuesday, April 11, 2017 [sic]): D3.
(Note: ellipses added.)
(Note: the online version of the commentary has the date April 5, 2017 [sic], and has the title “MATTER; Antarctic Ice Reveals Earth’s Accelerating Plant Growth.”)
The paper in Nature mentioned above is: