Amazon Carbon Sink Shrinks

Posted on by Mark Nykanen

Intriguing and disturbing news out of the Amazon this week, thanks to an eye-opening report in Wired. There have been repeated attempts by denialists, over the past decade in particular, to push the notion that increasing carbon dioxide in the atmosphere will allow plants to flourish ever more prodigiously. Proponents rarely have included research showing that increasing temperatures also greatly stress plants, including, of course, vital crops necessary to avert starvation on a grand scale.

Scientists focusing on the Amazon rainforest for upwards of forty-plus years have examined thousands of trees to track how much CO2 trees actually absorb in their growth cycles. Absorption of the greenhouse gas keeps it out of the atmosphere and helps slow global warming.

Keeping such a close eye on those developments in the Amazon is critical because it’s the world’s largest rainforest, cycling 18 billion tons of carbon dioxide each year through 6 million square kilometers of trees. To put those daunting numbers into perspective, we’re looking at the Amazon sucking in two times more carbon than all the CO2 emitted annually by fossil fuels worldwide.   As Wired reports, “Mess with this system and the consequences will reverberate around the world.”

Well, mess with it is exactly what we’ve done to this vital part of earth’s lungs. It turns out that as carbon dioxide levels increase trees in some parts of the Amazon are, in fact, getting bigger faster, but they’re also doing something else that is disproportionately more damaging to the world—they’re dying sooner because they’re “riding the high of resource abundance until they suddenly flame out,” in the telling words of Wired.

When the trees die, they release their CO2 back into the atmosphere.

For now, scientists say the Amazon rainforest is still absorbing more carbon than it’s releasing, but the data indicate that yet another tipping point looms. Wired concludes on this note: “As skeptics have long asserted and scientists themselves suspected, models of the future of Earth’s climate did indeed get it wrong. But not in the way anyone would hope…They were ‘too optimistic.’” (The interior quote hails from one of the lead scientists on the project.)

Here’s the link to the full story in Wired:

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