UPDATED 1/16/2014 1:10 EST: This article has been updated to reflect that Gore's comments doesn't refer to all of the IPCC's suggestions, only some of the more radical geo-engineering measures.
The next big report from the U.N.'s Intergovernmental Panel on Climate Change (IPCC) is due out in April, and according to a draft seen by Reuters, it's not going to be enough to just reduce our greenhouse gas emissions anymore. If the world wants to achieve its target for reducing global warming by 2100, the report says, governments may have to start extracting the gases back out of the air:
A 29-page summary for policymakers, seen by Reuters, says most scenarios show that rising world emissions will have to plunge by 40 to 70 percent between 2010 and 2050 to give a good chance of restricting warming to U.N. targets.
...It says the world is doing too little to achieve a goal agreed in 2010 of limiting warming to below 2 degrees (3.6 Fahrenheit) above pre-industrial times, seen as a threshold for dangerous floods, heatwaves, droughts and rising sea levels.
To get on track, governments may have to turn ever more to technologies for "carbon dioxide removal" (CDR) from the air, ranging from capturing and burying emissions from coal-fired power plants to planting more forests that use carbon to grow.
But some of the more radical geo-engineering solutions, such as putting sulphur dioxide into the atmosphere to block sunlight, are nothing short of "insane, utterly mad and delusional in the extreme," Al Gore commented Wednesday.
"The fact that some scientists who should know better are actually engaged in serious discussion of those alternatives is a mark of how desperate some of them are feeling due to the paralysis in the global political system," Gore added.
Taking the most radical measures possible to curb emissions, the draft says, is the only way we can have more than a 66 percent chance of keeping warming below 2 degrees Celsius. Once the world overshoots that limit -- which some scientists argue is too high -- we won't be able to back on track even with CDR technologies. We're currently at .8 degrees warming.