Why a carbon budget approach matters
Climate targets usually consist of a cut in pollution to be achieved by a certain point in time, for example -40% greenhouse gas emissions below 1990 levels by 2030. However, of equal importance to the end point is how much pollution is released along the way: this is known as a ‘carbon budget’. In order to meet the climate goal agreed in Paris of limiting global warming to "well below" 2°C and even to 1.5°C, it is the carbon budget, the total amount of CO2 released, that counts. The fewer emissions, the fewer greenhouse gases will accumulate in the atmosphere and contribute to global warming.
Each of the graphs shows a pathway to full decarbonisation over time. However, the amount of pollution released under each pathway, represented by the light blue shape, varies significantly. Once greenhouse gases are in the atmosphere they stay there. The fewer total emissions released, the lower the concentration of carbon, and the smaller the effect on global temperature rise.
EU policy should strive for a concave emission reduction curve, and at the very least should ensure a linear pathway. In order to ensure such a linear trajectory remains in line with the latest climate science, it should be complemented by a ratchet up mechanism that enables continuous and increasing climate action over time.