 In 2003 he was one of 22 Nobel Laureates who signed the Humanist Manifesto.In 2015, Kroto signed the Mainau Declaration 2015 on Climate Change on the final day of the 65th Lindau Nobel Laureate Meeting.The declaration was signed by a total of 76 Nobel Laureates and handed to then-President of the French Republic, François Hollande, as part of the successful COP21 climate summit in Paris.