Farming and forestry hold the keys to resolving global warming, because carbon trading by itself “is nowhere near sufficient” to deal with the crisis, prominent scientist Tim Flannery said last week.
Addressing the CarbonExpo 2008 conference on the Gold Coast, Professor Flannery said there needs to be a renewed emphasis on working with the living planet to address global warming, because
By digging up vast quantities of fossil fuel and releasing its carbon into the atmosphere, humans are knocking off-balance the biological systems that create the conditions that make the planet habitable.
“In my view, the global carbon trading scheme is absolutely necessary in order to deal with this crisis,” Prof. Flannery said.
“But it is nowhere near sufficient.
“Carbon trading deals with something that has been foregone or hasn’t happened — a negative emission or non-existent emission.
"What plants do is pull carbon dioxide from the atmosphere and sequester that carbon dioxide in measurable amounts in the biosphere.
"It’s perhaps best termed ‘atmospheric cleansing’.”
He proposed three “wedges” that harness living plants, two of them involving agriculture.
• Raising the soil carbon levels of the world’s extensive grasslands by just 2pc would sequester hundreds of gigatonnes of atmospheric carbon, Prof Flannery observed, and could be done using technologies already well understood.
“There are improved grazing technologies that include holistic management, rotational grazing and so forth, widely practised today,” he said.
“Holistic management, for example, is practised over about 10 million acres globally.
"(The practice) has demonstrably increased carbon content in soils by up to three percent.”
• A second agriculture-specific technology is biochar, the inert material created when organic material is burnt slowly under conditions which limit oxygen.
The process releases a gas that can be converted to biofuel, while the biochar itself embodies carbon that will stay stable in the soil for hundreds, perhaps thousands of years.
“The charcoal has residual nutrients in it,” Prof. Flannery said. “It helps with soil moisture retention, so it makes moisture available for plants for longer. It also helps address acid imbalance in soils.
“One of the most astonishing potentials for that charcoal is its ability to reduce nitrous oxide emissions.
"It does that by altering the microbial balance in the soils, keeping the nitrogen around longer and making it available to plants rather than bacteria that will nitrify it and lead to nitrous oxide emissions.
“Those sorts of technologies are going to be supremely important for humanity.”
• But the most urgent action needs to be the protection, and regeneration, of tropical forests.
Plants and trees literally grow from the air, Prof Flannery observed, drawing on soil water and minerals to help power a process that turns atmospheric carbon dioxide and other elements into wood, bark, flowers and sap.
He suggested that protecting existing tropical forest, and regrowing them where possible, would make an enormous contribution to carbon sequestration efforts.
“Eighteen percent of all anthropogenic carbon today comes from the destruction of those forests," he said.
"Since the large-scale destruction of those forests began around 200 years ago, the destruction of plant matter on earth, living plant matter, has added about 300 gigatonnes of carbon to the atmosphere.
“Not only has it added that carbon, it has weakened the life force that regulates our planetary system.”
On all key measures, Professor Flannery said, the pace of global warming is as bad, or worse, than the Intergovernmental Panel on Climate Change (IPCC) forecast earlier in the decade.
Carbon dioxide is accumulating in the atmosphere faster than forecast, oceans are rising faster than forecast, and the temperature increase on the planet’s surface is tracking the IPCC’s worst-case scenario.
* Tim Flannery was a founding member of the Wentworth Group of Concerned Scientists. He is the author of The Future Eaters and The Weather Makers.
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