https://www.sciencedaily.com/releases/2019/08/190827111120.htm > Despite advances in solar, wind, and other renewable energy sources, fossil fuels remain the primary source of the climate-change-causing carbon emissions. In order to halt global warming at the 2 degrees Celsius limit set by the Paris Agreement, we must reduce and eventually stop or completely offset carbon released into the atmosphere by burning of oil, coal, and gas. > "It has long been theorized that raising carbon prices would provide an incentive to reduce emissions through energy efficiency improvements," explained lead author Rong. "So, we looked to history to determine how cost increases have affected energy use efficiency in the past."