Australian Rain Forests Have Stopped Sucking Up Carbon

Rain forests absorb carbon from the air, and they are 
considered a key ally in the fight against climate
change. But a study in an Australian rain
forest suggests after climate change might
turn these forests into carbon emitters. 

Tropical rain forests in Australia have stopped following the rules. 

Rain forests are supposed to be "carbon sinks." That means live trees in the forest absorb carbon from the air more than dead trees in that forest emit into the atmosphere. If you don't like climate change, rain forests are your friend. 

Or at least used to be, in Australia, anyway. Tropical rainforests there have begun to release more carbon into the air than they take in. 

The problem is that extreme temperatures, drought and arid air masses are killing trees. Queensland, Australia has also experienced an increasing number of cyclones, and the ones they're getting are becoming more severe.

These storms are killing more trees and making it harder for new ones to grow and take the fallen trees' place.

There's been more tree deaths than growth, so when trees die and begin to rot, they release stored carbon back into the air. 

The change in Australian rain forests isn't new, but it's newly discovered. And it is a change from what it always has been. 

The Smithsonian explains about how researchers looked at the rain forests plants:

"The tracked plants absorbed about 552 pounds of carbon per acre on average, each year from 1971 to 2000. Then, from 2010 to 2019, they emitted about 830 pounds of carbon per acre, on average, each year."

All this could have implications elsewhere.   

The Australian rain forests are the first to transition from so-called carbon sinks, which store carbon grabbed from the air, into areas that release carbon into the atmosphere. The researchers said they feared other rain forests around the world would suffer the same fate. 

"And that's really significant. It could be a sort of canary in the coal mine," said Dr. Hannah Carne of the Western Sydney University, according to the BBC.

"Current models may overestimate the capacity of the tropical forests to help offset fossil fuel emissions," Carle added. 

Especially since other rain forests might well follow the example of Australia. 

Per Smithsonian:

"No other rainforests have yet shown evidence of emitting more carbon than they absorb. The Amazon rainforest has shown an overall decline in carbon capacity, and part of it has become a carbon source due to human caused deforestation and forest - but its trees have responded to increased CO2 in the atmosphere by increasing their own growth."

But that ability to increase absorption might have a limit. And the research in Australia illustrates those limits might be close in places like the Amazon.