Challenges in using land use and land cover data for global change studies

Land use and land cover data play a central role in climate change assessments. These data originate from different sources and inventory techniques. Each source of land use/cover data has its own domain of applicability and quality standards. Often data are selected without explicitly considering the suitability of the data for the specific application, the bias originating from data inventory and aggregation, and the effects of the uncertainty in the data on the results of the assessment. Uncertainties due to data selection and handling can be in the same order of magnitude as uncertainties related to the representation of the processes under investigation. While acknowledging the differences in data sources and the causes of inconsistencies, several methods have been developed to optimally extract information from the data and document the uncertainties. These methods include data integration, improved validation techniques and harmonization of classification systems. Based on the data needs of global change studies and the data availability, recommendations are formulated aimed at optimal use of current data and focused efforts for additional data collection. These include: improved documentation using classification systems for land use/cover data; careful selection of data given the specific application and the use of appropriate scaling and aggregation methods. In addition, the data availability may be improved by the combination of different data sources to optimize information content while collection of additional data must focus on validation of available data sets and improved coverage of regions and land cover types with a high level of uncertainty. Specific attention in data collection should be given to the representation of land management (systems) and mosaic landscape

Introducing carbon structural adjustment: Energy productivity and decarbonization of the global economy

In the 21st century, much of the world will experience untold wealth and prosperity that could not be conceived only some three centuries before. However as with most, if not all, of the human civilizations, increases in prosperity have accumulated significant environmental impacts that threaten to result in environmentally induced economic decline. A key part of the world's response to this challenge is to rapidly decarbonise economies, with options to achieve 60–80% improvements (i.e., in the order of Factor 5) in energy and water productivity now available and proven in every sector. Drawing upon the 2009 publication ‘Factor 5’, in this article we discuss how to realize such large-scale improvements, involving complexity beyond technical and process innovation. We begin by considering the concept of greenhouse gas stabilization trajectories that include reducing current greenhouse gas emissions to achieve a ‘peaking’ of global emissions, and subsequent ‘tailing’ of emissions to the desired endpoint in ‘decarbonising’ the economy. Temporal priorities given to peaking and tailing have significant implications for the mix of decarbonising solutions and the need for government and market assistance in causing them to be implemented, requiring careful consideration upfront. Within this context, we refer to a number of examples of Factor 5 style opportunities for energy productivity and decarbonization, and then discuss the need for critical economic contributions to take such success from examples to central mechanisms in decarbonizing the global economy