Met Hadley UK says "Even with drastic cuts in emissions in the next 10 years, our results project that there will only be around a 50% chance of keeping global temperatures rises below 2 °C."

The report says: "This idealized emissions scenario is based on emissions peaking in 2015 and quickly changing from an increase of 2–3% per year to a decrease of 3% per year. For every 10 years we delay action another 0.5 °C will be added to the most likely temperature rise."

http://www.metoffice.gov.uk/climatechange/policymakers/policy/temperaturerises.html