Grand challenges in climate research

INTRODUCTION Climate change has been at the forefront of environmental concerns for over a quarter of a century. The sequence of reports published by the Intergovernmental Panel on Climate Change (IPCC, 1990, 1996, 2001, 2007, 2013) has been instrumental in bringing climate issues to the attention of the public and policy-makers alike. In 1992, the United Nations Conference on Environment and Development (UNCED-1992, Rio de Janeiro, Brazil) identified climate change as one of the major environmental challenges facing humankind and the Framework Convention on Climate Change (FCCC) was ratified on this occasion, thereby acknowledging the concerns of governments related to the impacts and risks to environmental resources, local to national economies, and society resulting from a changing climate. The two other major UN conventions drafted at UNCED-1992, namely the biodiversity and the desertification conventions, have never received the attention that the FCCC has, particularly since the Kyoto Protocol, aimed at reducing anthropogenic carbon emissions into the atmosphere, was signed in 1997. Despite much criticism as to the slow pace of negotiations and the limited success in the implementation of the Protocol, it remains to this day a unique attempt to address the greenhouse-gas problem at the global scale. The issues of climate change have led to heated debates, both within academia as well as between scientists and a large community of skeptics. While the sources of skepticism range from simple denial to organized “anti-global warming” lobbies, the opposition to what is considered to be a consensus view on anthropogenic climate change has had a beneficial side-effect in terms of encouraging improved research and communication. Large efforts have been deployed to improve the knowledge base on the functioning of the climate system, observations of the Earth system, numerical modeling techniques, and data handling and analysis. Despite large scientific progress in the last two decades, many domains of uncertainty still remain as to the functioning of the climate system. The reduction of these uncertainties would be unlikely to radically change the fairly robust conclusion that contemporary climate change is to a significant degree driven by anthropogenic emissions of greenhouse gases. However, furthering our understanding of climaterelevant processes would improve not only the predictive capability of climate models at space and time scales useful to decisionmaking, but also help reduce criticisms when communicating on climate issues. The outstanding issues that need continued scientific focus are today collectively termed as “grand challenges,” since many of these issues have been addressed over many years by many research teams, but still have large uncertainties associated with them. The World Climate Research Program (WCRP), one of the flagship domains of the World Meteorological Organization (WMO) has identified a number of these challenges that are currently receiving enhanced scientific attention that will be outlined in the next section. Indeed, the CLIVAR (Climate predictability and variability) program of the WCRP has proposed the definition that “A Grand Challenge is both highly specific and highly focused identifying a specific barrier preventing progress in a critical area of climate science.” In addition to the fundamental science issues identified by the WCRP, two further issues are identified as grand challenges in this paper, namely those associated improved communication of science, and those linked to access to environmental and socioeconomic data for research purposes.