CICERO - Center for International Climate Research

The NetBC project

Black carbon: A challenging piece of the climate puzzle

Few of our emissions connect to the climate in as many ways as soot, or black carbon. The NetBC project focuses on a number of such effects that are less well known. The result will be an improved, better constrained calculation of the total climate impact of black carbon.

Black carbon is emitted through incomplete combustion. Sources range from cars, industry and forest fires to wood-fuelled cooking stoves and single-use park grills. After emission, the tiny soot particles stay suspended in the air for a few days, and are transported by the prevailing winds.

Once in the air, soot absorbs solar radiation, thus heating the climate in much the same way as a greenhouse gas. In addition, it can influence the formation of clouds, how white they become and how long they last. Soot can land on snow and accelerate melting, and it can change how easily ice crystals form in cold air.

All of these effects have an impact on the total climate effect of black carbon emissions – but as of today none of them are sufficiently understood. Through the NetBC project, CICERO and its partners at institutions in Norway, England, Germany and the US will attempt to improve our knowledge of two key factors: The connection between soot and high altitude ice clouds, and the degree to which soot alters the stability of the atmosphere.

The NetBC project combines new measurements from airplanes and ground observation stations with the latest generation of climate models. Using this data, along with updated information on how and where black carbon is transported after emission, how long it stays airborne and how large global emissions are (see the AC/BC project), we will deliver estimates of the climate impact of soot that go beyond what has previously been available.

Results from the NetBC project will help us to answer a key question posed by policymakers: To what degree can reductions in black carbon emissions help to limit the harmful impacts of global warming?

The NetBC project is funded by the Research Council of Norway through the KLIMAFORSK programme. Partners include Yale University, the University of Leeds, NASA GISS, the UK Met Office, the University of Manchester, NOAA, LMU Munich and the Alfred Wegener Institute.