The October 2018 Intergovernmental Panel on Climate Change (IPCC) Special Report increased the Global Carbon Budget for a likely (66%) probability of keeping global temperature increases below the dangerous 1.5 degrees. As a result, we have modified and simplified our charts. The revised carbon budget is 420,000 Mt CO2. Many calculations and charts are still based on the 2014 IPCC report and are biased towards population sharing. (We are working on updating this.)

Global Emissions

The global targets are based on the IPCC carbon budgets. There are no official targets but we have calculated what the targets would be if the limits for remaining around 1.5oC or under 2oC were followed, and using the known emissions for the years 2011 to 2015 and projected emissions from 2016 to 2020. Global targets are specified as Carbon Dioxide (CO2).


We have calculated what the Canada, Ontario and Toronto must do to meet these targets.


The following charts are an example of what global emission reductions need to be along with the cumulative emissions resulting from the suggested limits. These charts assume that emissions are reduced at the same rate each year. There is a history of global emissions here.

Suggested Global Emissions Reduction Targets

The following chart represents the targets for keeping the total global emissions under the cumulative limits for a likely (66%) chance of keeping global temperatures from rising more than 1.5 (green) and 2 (blue) degrees C.

Global Emission Reduction Targets


Cumulative Emissions Due to Suggested Targets

The horizontal lines represent the maximum cumulative emissions for a likely (66%) chance of keeping global temperatures from rising more than 1.5 (orange) and 2 degrees  C (red). The other lines represent the cumulative emissions if we follow the targets for 1.5 (green) and less than 2 degrees C (blue).

Click on the charts to see them full size

The emission reduction targets for remaining around 1.5 or below 2 degrees C are in this table (compared to 2011 emissions).




Less than 2oC


11% above
38,900 MtCO2

11% above
38,900 MtCO2


100% (by 2023)

27,200 MtCO2



15,500 MtCO2



3,800 MtCO2

What happens if we do not reduce our annual emissions?

According to CarbonBrief in 2016:

[T]here are just over four years’ worth of current emissions left before it becomes unlikely that we’ll meet the 1.5 C target without overshooting and relying on unproven “negative emissions” technologies to remove large amounts of CO2 out of the air later in the century."


Strategies for reducing emissions

Carbon pricing

Negative emissions