Mean temperatures in the Arctic regions have risen nearly twice as rapidly as the global mean temperature during the past 100 years. Warming in the Arctic is accompanied by an earlier onset of the spring melt, which means a longer melt season and diminishing volumes of long-term summer ice, as well as faster melting of glaciers in Greenland.
A longer melt season accelerates global warming
A longer melt season reduces the Earth’s ability to reflect sunlight back into space, thereby accelerating global warming. Reducing the amount of carbon dioxide in the atmosphere is the only way to slow down climate change. But even if major reductions in carbon dioxide emissions were achieved quickly, they would not necessarily have time to affect melting in the Arctic, since carbon dioxide has a long life in the atmosphere. In contrast, the warming of the Arctic environment could probably be slowed down by reducing the atmospheric volumes of short-lived compounds affecting the climate, such as black carbon. This would shorten the melt season and more sunlight would be reflected back into space, cooling the climate. By reducing the emissions of these short-lived compounds into the atmosphere, more time can be won for the Arctic regions until the measures to cut carbon dioxide emissions lead to reduced concentrations in the atmosphere.
Black carbon as the object of study
The new project coordinated by the Finnish Meteorological Institute concentrates on one short-lived compound, black carbon, which has been shown to affect the Earth’s radiation balance markedly. It is thought that black carbon speeds up climate change regionally, for instance, in the Arctic and in the Himalayas. Black carbon is generated when the combustion process is incomplete. Its sources are mostly anthropogenic; the only natural sources are forest fires. Black carbon emissions from Europe are thought to have a major impact on black carbon concentrations and the climate in the Arctic regions. The main sources of black carbon are small-scale burning of wood and emissions from transport.
The principal objective of the project is to use the best methods available for demonstrating that climate change in the Arctic can be mitigated by reducing the emissions of black carbon at mid-latitudes and especially in Europe. At the same time, it is possible to assess how the current legislation on air quality and the climate affects black carbon emissions and the transportation of black carbon into the Arctic. In addition, the impact of black carbon on the Arctic climate and its links with warming caused by carbon dioxide will be studied.
The research findings will help assess the possibilities of reducing black carbon emissions. Another objective is to transmit scientific information, for instance on the impacts of wood burning, to decision-makers and the general public within the EU. Apart from the Finnish Meteorological Institute, the University of Helsinki, the Finnish Environment Institute, and the International Institute for Applied Systems Analysis of Austria are participating in the project.