Understanding the impact of political and institutional factors on the fight against climate change has become increasingly important in the global debate on sustainability. From a political science perspective, it is crucial to research how different democratic institutions affect the development of climate policies. To contribute to this agenda, we discuss the role of participatory institutions in this policy sector. We offer a global literature review of cases where participatory mechanisms have helped improve the tools used to combat global warming. Next, we discuss the concept of climate denialism and examine the environmental policy of the Jair Bolsonaro administration in Brazil (2019-2022) and the dismantling of participatory bodies. This neoconservative government is an example of how limiting civil society's ability to oversee and regulate government policies helps to promote a climate denialist agenda. Finally, we conclude that enhancing participatory democracy is essential to improving climate change policies. However, this relationship also operates in reverse. Disrupting participatory mechanisms can be highly damaging to good environmental governance, paving the way for denialist projects.