Black carbon (BC) has received increasing attention due to its importance in a wide range of biogeochemical processes. For example, BC storage in ocean sediments a represents long-term sink in the global carbon cycle, and BC aerosols in the atmosphere affect Earth's radiative heat balance. BC can be a useful tracer for Earth's fire history; it is a significant fraction of the carbon buried in soils and sediments; and it is an important carrier of organic pollutants. EGU meetings are very cross-disciplinary and thus attractive for scientists from diverse backgrounds, including those studying BC. One focus of the BC-meeting is to bring together the broad scientific community studying black carbon in the environment to discuss the latest research.

A second focus of the meeting is to discuss methodological aspects. Variations in BC chemistry, along a combustion continuum, create serious methodological problems, as every BC measurement method detects a unique window of the BC spectrum. To address methodological problems a ring trial was held (2004-6) on 12 BC-containing samples and materials potentially creating artifacts analyzed by 17 labs worldwide from soil, atmospheric, marine and water sciences (www.geo.unizh.ch/phys/bc). Implications and potential spin-off projects stemming from this ring trial will be presented and discussed during the meeting.