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Dryland ecosystems such as deserts play a more important role in the global carbon cycle than previously thought, research has revealed.

And one of the biggest contributors, responsible for a huge spike in the amount of CO2 absorbed in 2011, is located in Australia.

The findings suggest that the Australian savannah could be a giant carbon sink, and might even be a major driver for global carbon absorption - but the researchers warn it is not a complete solution to the problems caused by man-made climate change.

Research suggests that the Australian savannah (pictured) played a major role in the global absorption of carbon in 2011. Other vast carbon sinks in the Southern Hemisphere also had an effect, but Australia was said to be the major driver

Montana State University faculty member Ben Poulter and his collaborators explained their findings in the journal Nature.

They 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,' Poulter said, referring to the spike in 2011.

'La Niña-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.'

The team realised that the world's land carbon sinks in 2011 seemed to be absorbing an unusually large amount of carbon, Poulter said.

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.

Poulter and his collaborators investigated the phenomena with a variety of data sets and modeling approaches.

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 Niña-phase rainfall.

In particular, the sink in Australia would have been aided by the 2010 to 2011 La Niña.

After years of drought, the huge amount of rain would have given the Australian savannah a boost in plant growth, and thus carbon absorption.

Philippe Ciais, co-author and senior scientist at the Climate and Environment Sciences Laboratory in (LSCE), said the team was 'surprised' that there was no evidence of a similar event occuring in the past 30 years.

This suggested that the recent greening of drylands was responsible for some of the changes seen in carbon cycle dynamics.

This world map shows global temperature anomalies in 2008 compared to the 1950 to 1980 baseline period. Large areas of the central and eastern Pacific Ocean were cooler than the long-term average, linked to a La Niña episode that began in 2007

The authors discovered that certain ecosystems had become more sensitive to precipitation from 1982 to 1996 and 1997 to 2011.

This seems to have been due to the greening of desert vegetation.

The process 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,' 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.'

But 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.'

Poulter and his colleagues will now be investigating the role of fire and invasive species in dryland systems to further understand the mechanisms for dryland greening and the consequences this will have on the carbon cycle.