Estimating the Value of Near-real-time Satellite Information for Monitoring Deforestation in the Brazilian Amazon Katrina Mullan1, Thales A. P. West2, Jill Caviglia-Harris3, Erin Sills4, Thaís Ottoni Santiago1, Jime Rodrigues Ribeiro4, Trent Biggs5 Affiliations: 1 Department of Economics, University of Montana 2 Environmental Geography Group, Institute for Environmental Studies (IVM), Vrije University Amsterdam 3 Economics and Finance Department, Environmental Studies Department, Salisbury University 4 Department of Forestry and Environmental Resources, North Carolina State University 5 Department of Geography, San Diego State University Abstract We estimate the amount of avoided deforestation due to the use of near-real-time satellite imagery (DETER) to support the Action Plan for the Prevention and Control of Deforestation in the Legal Amazon (PPCDAm), the conservation of indigenous and other protected areas, and compliance with the Brazilian Forest Code (FC). We develop a Directed Acyclical Graph (DAG) that outlines some of the econometric challenges that arise from the role of policy in the estimation of satellite data on deforestation and consider that policy could be a mediator and/or a moderator along this causal chain. We control for policies that were introduced simultaneously with DETER, and allow for changes in the influences of prices, agricultural settlement, and forest conservation policies on deforestation after near-real-time monitoring was introduced. We find both direct impacts of DETER on deforestation, and indirect impacts via changes in the influences of commodity prices on deforestation. In total we estimate the amount of avoided deforestation is approximately 467-471 thousand km2 between 2001-2015, an area that is larger than the state of California, more than twice the amount of deforestation recorded in that region in the same time period, and translates to approximately 12 billion tons of avoided CO2. The net benefits of satellite monitoring range from US$1-5.4 billion per year when estimated using the WTP to preserve Amazon rainforest and between US$54 US$197 billion per year when estimating using the social cost of carbon. Keywords value of information; satellite monitoring; mediators; moderators; directed acyclical graph (DAG); deforestation; Brazilian Amazon 1. Introduction Remotely sensed data provides enormous societal benefits when mobilized to address global issues such as climate change, natural disasters, and disease outbreak; national challenges related to land cover and land use change; and regional emergencies such as dangerously impaired air quality (Kansakar and Hossain 2016). However, the value of satellite data is largely invisible because the benefits are not communicated to the general public, the data are used by many private and public agencies and governments in unknown ways, and because the quantification of these non-market benefits is challenging. Remote sensing data from satellites have been used to monitor deforestation in the Brazilian Amazon beginning in 1988 with the launch of the PRODES (Portuguese acronym) monitoring system, which publishes annual deforestation rates for use by policy makers, government agencies, and the broader public. These data have been crucial to the enforcement of environmental policy because the Earth's largest contiguous tropical rainforest is too vast to otherwise monitor. The Brazilian Amazon is home to a third of the world’s rainforests (FAO 2011), contains one of the most biologically diverse biomes, (Dirzo and Raven 2003; Mittermeier et al. 2003) and significantly influences global climate (Cao and Woodward 1998; Foley et al. 2007; D. C. Nepstad et al. 2008). Approximately 47% of the existing native forests in this region are protected within conservation units and indigenous territories. The remainder of the Brazilian Amazon (with the exception of a few contested public land areas) includes private properties that fall under the protection of the Forest Code (FC), the central piece of legislation designed to protect the public good aspects of forests (Sparovek et al. 2010). The DETER satellite system, launched in 2004 as part of the Action Plan for the Prevention and Control of Deforestation in the Legal Amazon (PPCDAm), changed the deforestation policy landscape in Brazil. The DETER system enables near real-time detection of deforestation and has served as an effective way to monitor ongoing land cover change (Har