Grazing Land Management

Inland Aust responsible for massive spike in CO2 absorption in 2011

Beef Central, 26/05/2014

Australian dryland ecosystems from deserts to dry-shrublands play a more important role in the global carbon cycle than previously thought and were responsible for the huge spike in the amount of Carbon Dioxide that was absorbed globally in 2011, research by Montana State University (MSU) faculty member Ben Poulter has found.

Inland Australia was responsible for a massive spike in Carbon Dioxide absorption in 2011. Image: Ben Poulter.

Inland Australia was responsible for a massive spike in Carbon Dioxide absorption in 2011. Image: Ben Poulter.

The findings have demonstrated to international researchers that inland Australia, when exposed to increased rainfall and in turn grows more vegetation, becomes a giant ‘carbon sink’ and may be a major driver for global carbon absorption.

Mr Poulter and his collaborators have explained their findings in the scientific journal Nature.

They have urged global ecologists to include the emerging role of dryland ecosystems in their research.

“Our study found that natural events in Australia were largely responsible for this anomaly,” Mr Poulter said.

“La Nina-driven rainfall during 2010 and 2011, as well as the 30-year greening up of its deserts and other drylands contributed to significant changes across the globe.”

Mr Poulter said he realised during recent research in Europe before he joined MSU that the world’s land carbon sink in 2011 seemed to be absorbing an unusually large amount of carbon.

Carbon dioxide moves constantly between land, oceans, vegetation and the atmosphere.

When one of those absorbs more carbon dioxide than it releases, it’s referred to as a carbon sink.

Mr Poulter and his collaborators investigated the phenomena with a variety of data sets and modeling approaches, as reported by ScienceDaily.

They discovered surprising interactions between climate extremes and desert greening that increased in importance over the past 30 years.

They eventually discovered surprising interactions between climate extremes and desert greening that increased in importance over the past 30 years.

Further study showed that the dryland systems in the Southern Hemisphere, specifically Australia, had particularly high productivity in response to increased La Nina-phase rainfall.

“What surprised us was that no analogous biosphere response to similar climatic extremes existed in the past 30 years, prompting us to explore whether documented dryland-greening trends were responsible for changes in the carbon cycle dynamics,” said Philippe Ciais, co-author and senior scientist at Climate and Environment Sciences Laboratory.

The authors discovered that an increase in the precipitation sensitivity of a range of ecosystems processes occurred between the periods of 1982-1996 and 1997-2011.
One of those processes was the greening of desert vegetation.

Together those processes led to a four-fold increase in net carbon uptake to precipitation over the past 30 years.

“Novel responses of the biosphere have been predicted to occur following human activities that have caused unprecedented changes in atmospheric carbon dioxide concentrations, climate and land cover,” Mr Poulter continued.

“Our study provides new evidence that interactions among these human activities are now also impacting dryland biomes. These findings have global implications that should be considered in monitoring networks and earth system models.”

The large 2011 land carbon uptake is not expected to lead to long-term increases in ecosystem carbon accumulation, according to the researchers.

“Dryland systems have high rates of carbon turnover compared to other biomes,” Ciais said.

“We can expect the carbon to be quickly respired or consumed in wildfires, already partly reflected by the high atmospheric carbon dioxide growth rate in 2012.

 

HAVE YOUR SAY

Your email address will not be published. Required fields are marked *

Your comment will not appear until it has been moderated.
Contributions that contravene our Comments Policy will not be published.

Comments




Get Beef Central's news headlines emailed to you -
FREE!