[JURIST] US President Barack Obama and Chinese President Xi Jinping [profiles] on Saturday formally committed their nations to the Paris Agreement [Nature backgrounder], a pact seeking to reduce carbon emissions and halt climate change. The world’s first comprehensive climate pact, the Paris Agreement will only come into force after it is ratified by at least 55 nations comprising more than half of the world’s carbon emissions. The US and China signings are a big step forward for the Paris Agreement, as the two nations are responsible for roughly 40% of the world’s total carbon emissions. Leaving to the particular signatories how, the agreement seeks to keep global warming below two degrees Celsius.

The Paris Agreement was reached during the twenty-first annual conference of parties, known as COP21 [official website] and achieved the goal of limiting global temperature rise to 2 degrees Celsius, aiming for only a 1.5 degree temperature rise. According to many experts, climate change [JURIST backgrounder] as a result of global greenhouse gas emissions is one of the most pressing and controversial environmental issues facing the international community today. In July US President Obama and Brazilian President Dilma Rousseff announced an agreement [text] to address climate change [JURIST report]. Both countries pledged to reduce carbon emissions by increasing the use of wind and solar power sources to 20 percent of each nation’s electricity production by 2030.