Human activities are changing the global cycling of carbon between land, oceans and atmosphere, according to CSIRO's Dr Graeme Pearman, Chairman of the Fifth International Conference on Carbon Dioxide.
"There is no doubt about this change. There is also no doubt that CO2 is increasing in the atmosphere and will continue to do so as we continue to burn fossil fuels," Dr Pearman said in summing up the Conference which discussed the latest in atmospheric changes to carbon dioxide, the major greenhouse gas.
"Of the two hundred scientists at this meeting, not one would believe that the changes we humans are forcing on our planet are without some risk.
"In the four years since the last CO2 meeting in this series, we have seen an explosion of information. The latest measurements of carbon dioxide show that the Southern Ocean hold a key to the carbon cycle because it absorbs as much as 20 per cent of the carbon that humans are putting into the atmosphere.
"Careful work in the northern hemisphere is showing that the boreal forests in Eurasia and North America are also absorbing large amounts of carbon.
"With all this work, nothing that was presented here suggests that policymakers or the community should relax, or believe that greenhouse has gone away or will go away," Dr Pearman warned.
"The latest science also reveals surprising gaps in our knowledge of the carbon cycle and how it will respond over the next century to the continual emissions of CO2 into the atmosphere. This uncertainty reflects the complexity of the earth," Dr Pearman said.
Commenting on sceptics' reporting of the greenhouse issue, Dr Pearman said that scepticism was an important part of science, but the significant attention given in some quarters to a few sceptics completely unbalanced discussion of climate change.
"This has been a very exciting conference because all the issues, including the uncertainties, have been laid bare. It is a pity that some of the sceptics who refuse to acknowledge the risks associated with carbon dioxide increases are actually the ones who are most dogmatic about climate change.
"If policymakers simply assume that through the next century the plants and oceans will continue to absorb CO2 from the atmosphere in the same way as they have this century, they are probably wrong. But at this stage, our knowledge is not complete enough to confidently predict changes.
"Nearly all the models show that there will be significant changes in vegetation across the world, but there are major differences when forests, grasslands and woodlands are considered in detail.
"Many policymakers seem to believe that the science is solved. We do need more accurate predictions of changes to the atmosphere. But unless we understand CO2 better we will have a poor insight into whether CO2 reduction policies are really working," Dr Pearman said.
More information:
Dr Graeme Pearman 0418 585 291 or 03 9239 4650
Paul Holper 0419 894 427