Start year: 2011
End year: 2013
Coordinating beneficiary: Finnish Meteorological Institute (FMI)
Contact at FMI: Heikki Lihavainen
Funding: EU LIFE+
Partners: Finnish Meteorological Institute (FMI, coordinator), University of Helsinki (UHEL), Finnish Environment Institute (SYKE), International Institute for Applied Systems Analysis (IIASA)
Arctic temperatures have increased at almost twice the global average rate over the past 100 years. Warming in the arctic has been accompanied by an earlier onset of spring melt, lengthening of the melt season and changes in the mass balance of Greenland ice sheet. The lengthening of the melt season changes the Earth's albedo, a positive feedback effect which leads to further warming. Arctic warming is primarily a manifestation of global warming. Reductions in the atmospheric burden of CO2 are the backbone of any meaningful effort to mitigate climate forcing. But even if swift and deep reductions were made, the reductions may not delay the rapid melting of the Arctic. This is because the long life time of CO2 in the atmosphere. Reductions in the concentration levels of short-lived climate forcing agents, such as black carbon (BC), might be used to slow down the warming of the Arctic environment, to constrain the length of the melting season and thereby to reduce the feedback effects. These short- lived species have the advantage that emission reduction will quickly affect radiative balance of the atmosphere as opposed to reduction of long-lived greenhouse gases. By such reductions, one may potentially buy time for the Arctic environment until CO2 reduction efforts will decrease its atmospheric concentration.
Several studies have been made to link emissions from different areas and abundance of BC in the Arctic areas. Europe was found to be significant source to surface concentration of BC whereas East Asia dominated the sources at higher troposphere. There are still large uncertainties associated with modelling the forcing and temperature response due to BC. This prevents us from providing definitive answers regarding impacts and mitigation strategies. We can, however, use the best available tools to develop a system, by which we can demonstrate where the major gaps in the knowledge are. With the tool developed in this project we can estimate BC concentrations and corresponding radiative forcing over the Arctic areas and link them with the emissions from various areas and sources. This toolbox can be used to analyse different mitigation strategies and to find out the relative contribution of different areas (USA, China, Europe) and countries in Europe to Arctic warming by BC.
The project has three main objectives:
Aerosol emissions from the European countries cause currently a negative top-of-the-atmosphere direct aerosol forcing (cooling effect). The forcing is largest in central Europe and extends to over Arctic.
Compared with the present-day situation, currently agreed policies affecting air pollutant emissions will reduce the aerosol cooling effect (i.e. enhance warming) over both Europe and Arctic areas during the next couple of decades. Less future warming will be expected if emission reductions target emission sources with high share of black carbon. However, the warming will be enhanced even more if maximum technically feasible reductions of air pollutant emissions, especially sulfur dioxide, will be implemented.
There is a significant reduction potential for black carbon emissions with technologies that are currently available. To reach the reductions, technology switch is required that is not substantially promoted by current emission legislation.
It is not possible to reduce the emissions of black carbon alone. From the impact standpoint it is important to analyze the effects of emission reduction technologies and policies to multiple pollutants, i.e., organic carbon and sulfur emissions.
Residential wood combustion is a major source of black carbon emissions in many countries, both in Europe and developing world. In addition to stove technology, user's behavior in the form of stove operation and fuel quality has substantial impact on residential wood combustion emissions. Information campaigns about proper stove operation can be used to influence user's behavior.
Black carbon emissions are at highest in winter and thus their effect on melting of snow and ice is pronounced. This was shown by the ground-based black carbon monitoring at background sites in Finland. The probable reason for this is residential wood combustion.
The largest uncertainties in estimating the climatic effects of black carbon in Arctic areas arise from the difficulties in modeling the efficiency by which black carbon particles are transported from their source areas to the Arctic atmosphere, and in understanding how these particles interact with Arctic clouds.
The web portal www.maceb.fi
MACEB project leaflet:
Dr. Heikki Lihavainen
senior research scientist, project coordinator
Finnish Meteorological Institute (FMI)
phone +358 29 539 5492
The project is coordinated by Finnish Meteorological Institute (FMI).