Contributor(s): Dr Alina Averchenkova, Professor Barry Buzan, Professor Kathy Hochstetler, Dr Miriam Prys-Hansen, Professor Stacy Vandeveer | Great powers are also great polluters, particularly when it comes to the global greenhouse gas effect. Through the 2015 Paris Agreement and recent international conferences, all major powers - from the United States to China, India, Brazil, Russia and the EU - have committed to bringing greenhouse gas emissions under control and decarbonising their economies by 2050.