By Anna Salleh for ABC Science Online
Posted 5 hours 0 minutes ago
The 5 per cent carbon pollution reduction target set by the Federal Government this week would only help avert catastrophic global warming if it was adopted by all countries, says CSIRO climate scientist Dr Michael Raupach.
The Government's targets are part of the Carbon Pollution Reduction Scheme that is set to begin in July 2010.
Dr Raupach, a contributing author to reports by the IPCC and chair of the Global Carbon Project, carried out an analysis of the scheme using 2007 International Panel on Climate Change (IPCC) data.
His results suggest that if all countries agreed to a 5 per cent cut by 2020, this would be enough to stabilise the atmospheric concentration of greenhouse gases at the upper range of 445-490 parts per million of CO2 equivalents.
"That's the lowest realistic trajectory that the IPCC has spoken about," Dr Raupach said.
"And even that lowest realistic trajectory carries climate risks."
Dr Raupach says the IPCC data predicts that at this level of greenhouse gas stabilisation, temperatures will still rise between 1.5 degrees Celsius to 3C.
He says this scenario includes a sea level rise of at least one metre, major crop failures due to heat stress, major disruptions to water supplies, the death of the Great Barrier Reef and catastrophic affects on the Pacific Islands.
While many climate scientists are calling for emission cuts of between 20 to 40 per cent by 2020, Dr Raupach says a global cut of around 5 per cent by 2020 can be seen as the absolute minimum that is required to avert catastrophic global climate change.
Growth too rapid
He says half of the world's emissions come from developing countries - representing about 80 per cent of the world's population - which are growing too rapidly to meet a 5 per cent target.
"The developing countries have no way of meeting a 5 per cent global target which is ... the minimum we need for climate protection right now," Dr Raupach said.
He says international climate change negotiations have already recognised that developed countries have to cut emissions faster than developing countries.
"That's already widely accepted. Everybody agrees that this has to happen. The huge argument is by how much," Dr Raupach said.
He says developing nations need to commit to emitting less than their current growth rates imply, and developed nations need to compensate for this.
"If developing nations increase their emissions by 30 per cent through [to 2020], a 30 per cent reduction in developed nations would see the world as a whole come to 2020 with the same emissions as in 2000," Dr Raupach said.
"It's all in trade-offs at the moment."
The Australian Government says it will reduce greenhouse emissions by up to 15 per cent if there is an international agreement to do so.
Its long-term target will be a 60 per cent reduction in greenhouse gas emissions from 2000 levels by 2050.
Climate change economist Dr Frank Jotzo, an adviser to the Garnaut Climate Change Review, says ruling out greater reductions by 2020 is a mistake.
"Australia's per capita emissions levels are double that of Europe and four times the world average," he said.
"That means Australia's fair share is to cut faster than others, in per capita terms."
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