The sea ice surrounding Antarctica has increased in extent and concentration from the late 1970s, when satellite-based measurements began, until 2015. Although this increasing trend is modest, it is surprising given the overall warming of the global climate and the region. Indeed, climate models, which incorporate our best understanding of the processes affecting the region, generally simulate a decrease in sea ice. Moreover, sea ice in the Arctic has exhibited pronounced declines over the same period, consistent with global climate model simulations. For these reasons, the behavior of Antarctic sea ice has presented a conundrum for global climate change science. The National Academies of Sciences, Engineering, and Medicine held a workshop in January 2016, to bring together scientists with different sets of expertise and perspectives to further explore potential mechanisms driving the evolution of recent Antarctic sea ice variability and to discuss ways to advance understanding of Antarctic sea ice and its relationship to the broader ocean-climate system. This publication summarizes the presentations and discussions from the workshop.

This book provides in-depth information about the sea ice in the Arctic at scales from paleoenvironmental variability to more contemporary changes during the past and present centuries. The book is based on several decades of research related to sea ice in the Arctic and its variability, sea ice process studies as well as implications of the sea ice variability on human activities. The chapters provide an extensive overview of the research results related to sea ice in the Arctic at paleo-scales to more resent scales of variations as well as projections for changes during the 21st century. The authors have pioneered the satellite remote sensing monitoring of sea ice and used other monitoring data in order to study, monitor and model sea ice and its processes.

The proceedings of this workshop provide a valuable review of the methodologies of climate observations during the past 150 years, together with a summary of their findings, and a description of the difficulties inherent in their interpretation. In addition the volume reviews the use of climate model simulations of greenhouse-gas-induced equilibrium and nonequilibrium change. Finally, the contributed papers consider the methodologies of climate change detection by comparison of model simulations and climate observations, a summary of findings, and a description of what should be done to detect GHG-induced climate change. The volume will be of particular interest to researchers and students in the fields of meteorology, atmospheric science, oceanography, global change and climate impact assessement. Scientists in related fields will find much of value also.