Tackling climate change is one of the most demanding challenges of humanity in the 21st century. Still, the efforts to mitigate the current environmental crisis do not seem enough to deal with the increased existential risks for the human and other species. Persson and Savulescu have proposed that our evolutionarily forged moral psychology is one of the impediments to facing as enormous a problem as global warming. They suggested that if we want to address properly some of the most pressing (...) problems that cause catastrophic harm to our existence, we should enhance our moral behavior by biomedical means. The objective of this paper is, precisely, to reflect on whether a Moral Bio-Enhancement (henceforth MBE) program would be a viable option to confront the climate emergency. To meet this goal, I will propose the Ultimate Mostropic (hereafter UM) thought experiment, a hypothetical situation where we have already discovered the UM, an available, safe (without any deleterious secondary effects), extremely cheap and effective pill to enhance our cognitive, affective and motivational abilities related to morality. After briefly presenting the main argument of Persson and Savulescu regarding MBE and climate change, I will point out some of the difficulties that make MBE a daunting but exciting philosophical and scientific debate. In order to overcome these complications, I will describe the UM thought experiment, which involves two scenarios of the MBE program: (a) the state-driven, compulsory and universal enterprise, and (b) the initiative of voluntary individuals. I will show that the shortcomings of MBE programs through the UM in both scenarios make Persson and Savulescu’s proposal a not appealing pathway to mitigate climate change. In the final section, I will suggest that an inaccurate attribution of responsibilities underlies their proposal and that the collective inaction problem should be redirected primarily through a reinforcement of the political nature of the solutions. (shrink)