How does cut11% work?
To keep the global temperature rise under 2°C by a probability of more than 67% and no temperature overshoots, the IPCC estimates that we have about 1060Gt of CO2 left. Taking feedback loops into account, that leaves 900Gt of CO2 left for fossil fuels and industries. This quota does not include land-use emissions and becomes smaller every year.
We share one atmosphere; CO2 emissions ought to be divided equally between all countries. Following the medium scenario of the World Population Prospects 2019, 117 tons of CO2 can be emitted per capita. A country's emission budget is then calculated on a per capita consumption basis - that is, if a Swedish person buys a doll made in China, the doll's emissions will be counted for Sweden.
A time estimate is given for when, following current emission rates, this country would meet its limit; for Sweden, emitting at 0.07 GtCO2, with a 4% yearly decrease, the limit will be met in 2035. To avoid going over that limit, Sweden should cut their emissions by 6% per year, starting from today. The same calculation is applicable to all countries, resulting in an 11% decrease for Very Highly Developed Nations – the biggest emitters on the globe.
Some countries are allowed to raise their emissions; Nigeria, for example, can increase its CO2 emissions by 3% per year starting today, and still stay within its budget by 2100. For other countries, this increase represents a deceleration in the rate at which emissions are growing; emissions can still increase, but at a slower rate than they currently are.
This model takes in account responsibility – who contributes most to climate change – by attributing reductions on a per capita consumption basis. It also allows less industrialised countries to further their development within the limits set by their carbon budget. It does not, however, take historical emissions into account.