Copenhagen consensus on climate: an analysis of black carbon mitigation as a response to climate change.

pREfacE COPENHAGEN CONSENSUS ON CLIMATE copenhAgen consensus on climAte The Copenhagen Consensus Center has commissioned 21 papers to examine the costs and benefits of different solutions to global warming. The project’s goal is to answer the question: “If the global community wants to spend up to, say $250 billion per year over the next 10 years to diminish the adverse effects of climate changes, and to do most good for the world, which solutions would yield the greatest net benefits?” The series of papers is divided into Assessment Papers and Perspective Papers. Each Assessment Paper outlines the costs and benefits of one way to respond to global warming. Each Perspective Paper reviews the assumptions and analyses made within an Assessment Paper. It is hoped that, as a body of work, this research will provide a foundation for an informed debate about the best way to respond to this threat. Much attention has been given to mitigation policies designed to limit the emissions of carbon dioxide (CO2) and other greenhouse gases (GHGs) that contribute to atmospheric warming. However, it is generally agreed that as much as 40% of current net warming (10-20% of gross warming) is attributable to black carbon. Because of its large effect on radiative forcing and relatively short residence time in the atmosphere, black carbon presents some unique opportunities for postponing the effects of climate change. Whereas CO2 has a life of up to about 40 years, black carbon remains in the atmosphere for as little as several weeks. As such, reducing emissions of black carbon can have an immediate near term impact on atmospheric warming. Furthermore, since black carbon is considered responsible for about 30% of the arctic melting, black carbon emission reductions can rapidly reduce the rate at which arctic ice is melting and avert associated consequences. Black carbon reduction policies can also result in large health benefits especially to citizens of developing countries. Black carbon emissions originate in both industrial countries (mostly from diesel emissions) and developing countries (from residential activities, crop management, and diesel emissions). Over the past century, technological advances have significantly mitigated black carbon emissions in industrial countries. Developing countries, on the other hand, often have been unable to afford the same technological advances, and, in turn, as their populations have grown, so have black carbon emissions. Moreover, the extensive practice of closed-area cooking and heating has exacerbated the black carbon problem in these developing countries. This practice can result in negative health effects on those living in close quarters, often women and children. This paper argues that controlling black carbon emissions in developing countries is a potentially cost-effective means of postponing the effects of global warming, while at the same time improving the health and quality of life of those living in those countries. Black carbon can be controlled in developing countries through the implementation of cleaner fuels, new cooking technologies, and changing crop management practices. This paper also presents potential ways to implement these policies.