The combination of slower growth in energy demand and a shift in the fuel mix away from coal and toward natural gas and renewables led to a significant slowdown in the growth of carbon emissions.

Carbon emissions from energy use rose by 0.5%, less than half 10-year average growth of 1.1% per year. However, this only partially reversed some of the unusually strong increase in 2018 (2.1%).

The sharp increase in carbon emissions in 2018 was driven in part by extreme weather effects. In particular, an increase in the number of unusually hot and cold days boosting the demand for energy. The hope was that as the weather effects returned to more normal levels in 2019, the level of carbon emissions would fall. Although the number of days of extreme weather did decline in 2019, carbon emissions continued to rise, albeit at a slower rate. As a result, average annual growth of emissions over 2018 and 2019 combined was actually greater than its 10-year average.