Land-based Greenhouse Gas (GHG) emissions account for a significant portion of global GHG emissions, and the majority of these emissions come from the conversion of natural lands to cropland and other commercial use(Baumert, Herzog, and Pershing 2005). The pace of such conversion hinges critically on the speed with which crop yields can be raised. However, as the recent IPCC-WGII report on climate impacts makes clear, climate change is likely to slow such productivity growth, thereby speeding land conversion, adding to GHG emissions, and ultimately stimulating further climate change. Breaking this feedback loop requires effective agricultural adaptation to climate change. Global agricultural productivity growth has been extraordinarily high historically (Fuglie 2012). Indeed, this has allowed the world to triple crop production over the past fifty years, with only modest expansion in cropland area (Bruinsma 2009). This exceptional record of productivity growth has been knowledge driven, with public R&D leading the way. (The Green Revolution is one of the best known examples, having been fomented by the Consultative Group on International Agricultural Research.) However, in recent years, private agricultural R&D has grown faster than its public sector counterpart in the world's wealthiest countries (Beintema et al. 2012). Given the long lag from R&D investments to productivity outcomes (Alston, Pardey, and Ruttan 2008), the investments made over the next two decades will likely prove critical in determining mid-century yield growth. And, with climate change threatening to slow such productivity growth (David B. Lobell, Schlenker, and Costa-Roberts 2011), such R&D investments have become ever more important. Our research leverages historical data on private and public R&D investments and capital stocks, by region, worldwide, recently complied by Keith Fuglie. When combined with econometric estimates of the elasticity of total factor productivity (TFP) with respect to R&D stocks in each region, we are able to build future TFP scenarios based on projections of R&D spending and the efficiency of research dissemination. These allow us to estimate the cost of effective adaptation to climate change, including the benefits in terms of reduced GHG emissions as well as improved nutritional outcomes. In prior work, we demonstrated that such knowledge-based adaptation could indeed deliver cost-effective mitigation ($11-22/ton CO2e) (D. B Lobell, Baldos, and Hertel 2013). However, that work did not incorporate explicit estimates of the R&D capital stock, nor did it allow for differential rates of conversion of R&D capital into TFP by region.