Fossil Fuels May Decrease Earth's Natural Capacity to Store Carbon

Aug 02, 2005

Rising fossil fuel emissions may actually decrease the Earth's natural capacity to absorb carbon dioxide from the atmosphere, according to a newly published study--which means that the warming of Earth's climate could accelerate even faster than scientists have anticipated.

The study, which was posted on-line this week by the journal Proceedings of the National Academy of Sciences, is based on a new computer simulation of the global carbon cycle developed by Inez Fung of the University of California at Berkeley and her colleagues, with support from the National Science Foundation (NSF)'s climate dynamics program.

Fung and her coworkers put particular emphasis on modeling how carbon dioxide emissions affect the strength and capacity of the environment's natural carbon repositories, including plants, soil, rain, clouds, bacteria, phytoplankton and oceans. The researchers also used observations from the past two centuries to project the coming century.

Their major finding was an inverse relationship between the rate at which carbon dioxide is emitted from the burning of fossil fuels like coal, oil and gas, and the capacity of land and ocean to absorb that carbon dioxide: the faster the emissions, the less effective were the carbon sinks.

There are a number of reasons for this, Fung explains. In the ocean, for example, carbon dioxide from the atmosphere mixes fairly rapidly into the upper layers, down to about 100 meters or so. Then from there it slowly leaks into the deep ocean, where it will stay sequestered for centuries. But rising global temperatures warm the upper layers and make the ocean more stratified, so that the carbon dioxide has a tougher time mixing further downward.

On land, meanwhile, climate warming tends to dry out the tropics and reduce plant growth there, which in turn reduces the rate of photosynthesis and carbon uptake.

Taking all the effects together, says Fung, "our finding implies that carbon storage by the oceans and land will lag farther and farther behind as climate change accelerates with growing carbon dioxide emissions, creating an amplifying loop between the carbon and climate systems."

The team's model used the low range of temperature increases for the 21st century, predicting a rise of 1.4 degrees Centigrade for a "business-as-usual" fossil fuel emission scenario. Overall, said Fung, the model agrees with others predicting large ecosystem changes, especially in the tropics.

"Carbon exchange among Earth's atmosphere, oceans and land, and its relationship to climate, is one of the most challenging issues in environmental sciences today," said Jay Fein, director of NSF's climate dynamics program. "Fung's results have important implications for future potential climate changes: climate warming would increase the airborne part of carbon dioxide derived from human activities, and would in effect amplify climate change."

Source: National Academy of Sciences

Explore further: Research finds numerous unknown jets from young stars and planetary nebulae

add to favorites email to friend print save as pdf

Related Stories

Agricultural trade appears unaffected by BC carbon tax

Jul 23, 2014

British Columbia's carbon tax does not appear to have had a measurable impact on international agricultural trade, despite concerns it would greatly reduce the BC industry's competitiveness, according to new analysis commissioned ...

Recommended for you

Exploring Mars in low Earth orbit

1 hour ago

In their quest to understand life's potential beyond Earth, astrobiologists study how organisms might survive in numerous environments, from the surface of Mars to the ice-covered oceans of Jupiter's moon, ...

Image: Hubble serves a slice of stars

2 hours ago

The thin, glowing streak slicing across this image cuts a lonely figure, with only a few foreground stars and galaxies in the distant background for company.

Lifetime of gravity measurements heralds new beginning

3 hours ago

Although ESA's GOCE satellite is no more, all of the measurements it gathered during its life skirting the fringes our atmosphere, including the very last as it drifted slowly back to Earth, have been drawn ...

NASA's IceCube no longer on ice

7 hours ago

NASA's Science Mission Directorate (SMD) has chosen a team at NASA's Goddard Space Flight Center in Greenbelt, Maryland, to build its first Earth science-related CubeSat mission.

User comments : 0