THE world must take big steps to combat climate change — now.
If it does, the cost of a greener, healthier future will be surprisingly small.
But to avoid ecological catastrophe, it will probably need technologies that suck in carbon dioxide and bury it.
That’s the message of the third and final part of a major assessment by the United Nations’ Intergovernmental Panel on Climate Change, released in Berlin yesterday, that focuses on what can be done to stop runaway global warming.
More than 200 scientists and economists assessed 900 “mitigation scenarios” to control carbon dioxide emissions.
“Large-scale changes in energy systems and land use” are required to keep global warming to just 2 degrees higher than the pre-industrial world, the report found.
As a result, the world must give up about 5 per cent of likely growth in consumption by 2100 — growth that in that time is expected to be 300 to 900 per cent.
Dutch economist Reyer Gerlagh said growth in emissions was tied to economic and population growth.
“We need tough action, way beyond what anyone has in mind,” he said.
“But if you implement drastic policy effectively it’s actually not expensive at all. It’s not half as painful as people think.”
However, none of the climate agreements in place were enough to limit warming to the 2 degrees agreed to by countries through the UN as the limit for avoiding climate change’s worst impacts.
The key was to “decarbonise” electricity generation, which would have flow-on effects in industry, buildings and transportation, the report said.
It warned delays to beyond 2030 would make it much harder to meet the 2-degree goal.
By 2050, low-carbon electricity (from renewables, nuclear or carbon-capture) must increase from 30 per cent to more than 80 per cent of power generation. And to hit the target, by 2100 there must be no use of fossil fuels at all.
Because it will take time to switch to a low-carbon economy, the report foresees the need for bio-energy with carbon capture and storage technology — using trees and crops to extract carbon from the atmosphere, burn them for fuel, then capture and bury emissions for centuries.
The report said there was “limited evidence on the potential for large-scale deployment” of this technology, but many future scenarios required it to work in order to avoid further warming.
Australian National University economist Frank Jotzo, a lead author of the report, said: “the idea of going to negative emissions later in the century carried the danger of policy-makers taking a raincheck on emissions cuts now”.
Environment Minister Greg Hunt said Australia would reduce its emissions by 5 per cent on 2000 levels by 2020, and would consider more action next year.