It has been a little under four years since 196 countries negotiated the Paris Agreement, under which they committed to taking steps to limit the increase in global average temperature this century to well below 2 degrees Celsius (3.6 degrees Fahrenheit) over preindustrial levels, and ultimately to limit that increase to 1.5 degrees C (2.7 degrees F). Under the agreement, each signatory submits its own national plan, setting targets for emissions reductions and specifying pathways by which it aims to meet those targets.

Despite the 2015 agreement, global carbon emissions increased 1.7 percent in 2017 and a further 2.7 percent in 2018; it has been estimated that the rate of increase in 2019 will be among the highest