Foreword

Fine particles have come to be recognized as being much more significant air pollutants than particles larger than several microns diameter. The removal of fine particles from an effluent gas stream is, unfortunately, more difficult than that of large particles. Because wet scrubbers are one of the major types of air pollution control equipment which can collect fine particles, it is important to define and exploit their potentialities.     

Foreword

We provide an introduction to the volume The Arctic in the Earth System perspective: the role of tipping points. The terms tipping point and tipping element are described and their role in current science, general debates, and the Arctic are elucidated. From a wider perspective, the volume focuses upon the role of humans in the Arctic component of the Earth system and in particular the envelope for human existence, the Arctic ecosystems. The Arctic climate tipping elements, the tipping elements in Arctic ecosystems and societies, and the challenges of governance and anticipation are illuminated through short summaries of eight publications that derive from the Arctic Frontiers conference in 2011 and the EU FP7 project Arctic Tipping Points. Then some ideas based upon resilience thinking are developed to show how wise system management could ease pressures on Arctic systems in order to keep them away from tipping points.