Protected areas (PAs) now shelter 54% of the remaining forests of the Brazilian Amazon and contain 56% of its forest carbon. However, the role of these PAs in reducing carbon fluxes to the atmosphere from deforestation and their associated costs are still uncertain. To fill this gap, we analyzed the effect of each of 595 Brazilian Amazon PAs on deforestation using a metric that accounts for differences in probability of deforestation in areas of pairwise comparison. We found that the three major categories of PA (indigenous land, strictly protected, and sustainable use) showed an inhibitory effect, on average, between 1997 and 2008. Of 206 PAs created after the year 1999, 115 showed increased effectiveness after their designation as protected. The recent expansion of PAs in the Brazilian Amazon was responsible for 37% of the region's total reduction in deforestation between 2004 and 2006 without provoking leakage. All PAs, if fully implemented, have the potential to avoid 8.0 ± 2.8 Pg of carbon emissions by 2050. Effectively implementing PAs in zones under high current or future anthropogenic threat offers high payoffs for reducing carbon emissions, and as a result should receive special attention in planning investments for regional conservation. Nevertheless, this strategy demands prompt and predictable resource streams. The Amazon PA network represents a cost of US$147 ± 53 billion (net present value) for Brazil in terms of forgone profits and investments needed for their consolidation. These costs could be partially compensated by an international climate accord that includes economic incentives for tropical countries that reduce their carbon emissions from deforestation and forest degradation.

Recent climate talks in Copenhagen reaffirmed the crucial role of reducing emissions from deforestation and degradation (REDD). Creating and strengthening indigenous lands and other protected areas represents an effective, practical, and immediate REDD strategy that addresses both biodiversity and climate crises at once.

Protected and conserved areas (PCAs) are increasingly recognized as essential tools for their effectiveness in conservation and the benefits they provide. However, their challenges are still significant. The concepts, legislation, and governance surrounding PCAs are the results of social contexts. Due to the evolution of scientific knowledge, human rights, and diversified demands, new approaches are necessary to fulfill their functions. To better understand the context and possibilities, a study group was established to evaluate the current research, exchange experiences, guide dialogues, and identify lessons from experiences. The core of the experiences and cases considered and the reflections developed focused on the Brazilian context. This article analyzes the collected information and reflections related to several themes associated with challenges. The results reinforce the importance of PCAs but warn about the limitations of current conservation strategies to respond to social actors’ expectations, the needs of the vulnerable social groups, and evolving demands. The complexity of PCA systems is evident in view of the multiplicity of interests, potential contributions, and possibilities for participatory arrangements. There is a need to improve management and governance conceptions to promote the reconnection between society and nature. Therefore, the concept of collaborative conservation is proposed as an instrumental approach to advance towards inclusive and effective conservation strategies.