Evidence is building to suggest that our forests may not be the climate change ‘get out jail free’ card we all want.

Australian Rivers Institute’s Assoc. Prof. Peter Pollard has researched rainforest lakes and rivers to test a provocative theory. The respiration of bacteria living and ‘breathing’ in these freshwater ecosystems is a major pathway for the return of rainforest carbon back to the atmosphere as the greenhouse gas carbon dioxide.

His concern is that we are underestimating the rate of return of these greenhouse gases to the atmosphere.

“A rainforest ecosystem has a carbon ‘budget’. That’s an equation that tells us how much carbon dioxide is removed from the atmosphere which should add up to the amount fixed back into the earth in trees and vegetation during photosynthesis, plus that returned via respiration,” he said.

”The enigma is that these numbers don’t quite add up – it’s almost as if there is a line item on this balance sheet missing. Hence rainforests are seen as ‘sinks’ of the greenhouse gas carbon dioxide — but are they really?”

“For years there has been a major gap in our knowledge of the global carbon cycle – it’s like we’re environmental accountants unable to reconcile the carbon budgets.”

For more information: Australian Rivers Institute, Griffith University, Skye Roberts, Tel: +61 (7) 5552 8654, skye.roberts@griffith.edu.au, www.griffith.edu.au/environment-planning-architecture/australian-rivers-institute