Carlos R.S. Milani and Guy Edwards, with contributions from Ricardo A. Gutiérrez, Ruth E. McKie, Lucas Christel and Janaína B. Pinto, review the prevalence and strategies of climate obstruction in Argentina and Brazil. The goal of this brief is to raise awareness about how and what climate obstruction techniques are used to affect policy. The audience is the Argentinian and Brazilian governments, national NGOs, think tanks, journalists and academics in these countries working on climate and energy- related issues, and their international partners.  These case studies are part of a special issue of the journal, Climate and Development, which is currently being developed.