Most members of IEMA will undoubtedly have heard of Marginal Abatement Cost Curves, which are regularly used in climate change circles to help visualise complex data about carbon costs and emissions volumes. Below is an example of such a “curve” which illustrates the potential for different technologies to reduce greenhouse gas emissions in the USA.

If we look at the chart we can see that the technologies are ranked in ascending order of cost per tonne CO2equivalent (tCO2e)– that is to say that those projects that have the lowest cost (per tCO2e reduced) are on the left and those with the highest cost are on the right. Technologies below the line actually make a saving (a negative cost) over their lifetime – perhaps because they reduce energy consumption as well as carbon.