BERLIN: The world has a likely chance of meeting the UN's target on global warming provided it cuts annual greenhouse gas emissions 40-70 per cent by 2050, a top expert panel said Sunday.
The cost will not be crippling, but the longer it takes to switch to cleaner energy sources, the harder and more expensive it will be to limit warming to two degrees Celsius (3.6 degrees Fahrenheit) in line with UN aims, it said. The panel warned starkly that on present trends the planet would be 3.7-4.8 C warmer by 2100, a level many scientists say could be catastrophic.
"There is a clear message from science: to avoid dangerous interference with the climate system, we need to move away from business as usual," said Ottmar Edenhofer, co-chairman of the UN expert group that compiled the report.
While most scenarios for meeting the target "require substantial investments", he said, this "does not mean that the world community as a whole and the world economy needs to sacrifice economic growth." UN climate chief Christiana Figueres said the findings challenged governments to make the world carbon-neutral in the second half of the century.
"We cannot play a waiting game where we bet on future technological miracles to emerge and save the day," she said in a statement. The report is the third and final chapter of a mammoth overview by the UN's Intergovernmental Panel on Climate Change (IPCC), its first since 2007.
Compiled by hundreds of experts over four years, it collates the available science on climate change, seeking to inform national policies and the faltering global effort, which Figueres oversees, to formulate a pact by 2015 on curbing emissions. It warns that delaying further mitigation to 2030 would "substantially increase the difficulty" of reaching the 2C goal.
For a 66 per cent or "likely" chance of meeting the 2C target, said the document, the concentration of greenhouse gases in the atmosphere should be contained at about 450 particles per million of CO2 equivalent (ppm CO2eq) in 2100, compared to 430 ppm CO2 in 2011. This would entail a 40-70 per cent emissions reduction from 2010 to 2050, nearing zero by 2100.
