How much more CO2 can we produce?

A United nations report published in November 2014 estimates the difference between foreseeable emissions and the maximum emissions if we want to limit global warming to 2°C:
  • To have a 66% probability of limiting warming to 2°C, we can emit at most a total of 1000 Gigatonnes of CO(between 630 et 1180, according to IPCC working group 3)
  • At the moment, we emit each year 54 Gigatonnes of CO2, and this increases regularly. Without special action, we will emit 87 Gigatonnes of CO2 per year by 2050.
  • A quick division (1000 / 54) shows that at this rate, we will have used up our carbon quota in 18 years ; emissions would then have to fall immediatly to 0 to remain on target, which is of course impossible.
  • The report proposes a gradual decrease : 42 Gigatonnes per year in 2030, 22 Gigatonnes per year in 2050, to reach "zero emissions" - 100% clean energy - by the second half of the century.
  • The pledges made up till now (if they're held) will limit emissions to 58 Giga tonnes per year in 2030, and are therefore not sufficient (58-42=16 Gigatonnes too much per year).

1 Gigatonne = 1 billion tons.The goal of 42 gigatonnes per year in 2030 corresponds to an increase of 14% compared to 1990, and a decrease of 14% compared to 2010. The goal of 22 gigatonnes per year in 2050 corresponds to a decrease of 40% compared to 1990, and a decrease of 55% compared to 2010. 
To be precise, this figure is in gigatonnes of CO2e, ie CO2 or other greenhouse gases. If you consider only CO2, the quantity that can be emitted is lower, around 600 gigatonnes.

The more we wait, the more difficult it will be to limit global warming to 2°C.

According to Price Waterhouse, limiting global warming to 2°C is already irrealistic. If it's not too late for 2°C, it's defintely urgent to act. And if it's too late for 2°C, then it's urgent to act to avoid even higher global warming.

Some figures

World CO2 emissions in 2012: 33 Gigatons (= 33 billion tons), or 54 Gigatons if all greenhouse gases are included. With a slightly positive trend: in 2014, greenhouse gas did not increase in 2014 or in 2015:

Swiss CO2 emissions in 2012 : 56 million tons CO2-e (including aircraft emissions), i.e. 7 tons per person, with a slight decrease since 2010. If you include emissions due to imported goods (grey energy), each person is responsible for the emission of 12 tons of CO2-e.
Source : Changements climatiques en Suisse, OFEV, 2013
Association Climat Genève