In the negotiations to form a so-called traffic light coalition of the Social Democratic Party (SPD), the Green Party and the FDP following the 2021 German elections, Busen was part of his party's delegation in the working group on environmental policy, co-chaired by Rita Schwarzelühr-Sutter, Steffi Lemke and Stefan Birkner.Britt-Marie Lakämper (October 21, 2021), SPD, Grüne, FDP: Diese Politiker verhandeln die Ampel-Koalition Westdeutsche Allgemeine Zeitung.
