02/25/2011 09:40 am ET | Updated May 25, 2011

The New Face of an Old Enemy

Unexpected threats to the health of global systems keep emerging. Twenty years ago we didn't recognize global warming. Ten years ago we didn't know about ocean acidification. This might be the landmark week in which a broad public recognized a new threat to the global climate -- black carbon.

The United Nations Environment Programme (UNEP) has just published a science-based analysis of the climate forcing effects of black carbon. The findings are that cutting black carbon and troposperhic ozone now could halve regional warming for 30 to 60 years and reduce global warming by half a degree. It turns out that reducing black carbon emissions needs to become a priority. According to the United Nations Economic Commission for Europe (UNECE), greenhouse gas reductions alone will not avert further destruction of the arctic; black carbon and ozone reductions are needed.

Black carbon is made up of fine particles. It is colloquially known as soot. It comes from diesel engines as well as burning wood, waste and gas. The health effects of black carbon are well known. In London, for example, the soot from our beloved taxis and other sources leads to the early death of 4,500 people a year according to the government.

But black carbon's effects on the climate are just beginning to gain prominence. Recently, black carbon appeared in proposed climate legislation in the US (the Waxman-Markley Bill and the Kerry-Boxer Bill). In January the European Parliament called for the European Commission to acknowledge black carbon as a threat and include it in laws that protect against climate change. No action, however, has yet been taken on either side of the Atlantic.

I established ClientEarth as Europe's first public interest environmental law organization to provide the legal expertise needed to drive such action forward, and our team have been investigating what needs to be done. The EU could act now and impose black carbon specific monitoring and reporting obligations; move to retrofit or scrap old diesel engines; move away from diesel as a fuel source for engines in cars; create black carbon obligations for ships calling at EU ports; and it could seriously examine measures to reduce the emissions from residential burning of wood and implement better controls for open land burning.

Estimates are that black carbon may be the second or third biggest contributor to global warming after CO2. It is a short term "climate forcer" which means that we could make an instant impact on global warming -- this is crucial, the arctic is a key 'tipping point' for global warming.

It's a good thing that black carbon is increasingly being talked about in environmental and policy circles. Here in Europe ClientEarth and others will be working to ensure that talk becomes action as quickly as possible.