A new analysis finds that swift action by politicians is the single most important factor in limiting global warming. The costs of delays outweigh any possible benefits of waiting for more scientific research into the mechanisms of climate change.
The scientists published their findings in two studies in the journal Nature. This contradicts claims by governments stating that they should delay action on climate change until there is more scientific evidence. Speeding up action could also lead to significant cost savings.
Joeri Rogelj, a climate-policy analyst at the Swiss Federal Institute of Technology in Zürich, and his colleagues assessed the relative importance of the uncertainty in limiting the rise in global temperatures¹. The researchers compared emissions and costs in more than 500 different scenarios. They revealed that the timing of global action will have the greatest effect on whether the world meets given climate targets, like keeping the global temperature rise to less than 2˚C above pre-industrial levels.
The results render scientific uncertainties almost irrelevant to meet the 2˚C target, states Rogelj. In December 2011, 195 countries pledged that by 2015 they would set targets to reduce emissions starting in 2020. If this is what is going to happen, there is a 56% chance of keeping the temperature increase below 2˚C². Delaying any action until 2025 would decrease that chance to 34%. Starting in 2015 would improve the odds to 60%. This would also make any action cheaper.
“Probabilistic cost estimates for climate change mitigation” by Joeri Rogelj, David L. McCollum, Andy Reisinger, Malte Meinshausen and Keywan Riahi, 2 January 2013, Nature.
“All in the timing” by Steve Hatfield-Dodds, 2 January 2013, Nature.