SONG CHEN/CHINA DAILY As the United States prepares for a radical course-correction on climate change, China is raising its game. Climate action has become yet another front in the competition between the world's two largest economies. Who will cross the net-zero-emissions finish line first? US president-elect Joe Biden is prepared to hit the ground running. He has declared that the US will return to the Paris Agreement on his first day in office, and vowed to put emissions reduction efforts and clean energy jobs at the center of his administration's economic policymaking, with the goal of reaching net-zero emission no later than 2050.