The background This volume contains the proceedings of the first International symposium on "Non-C0 Greenhouse Gases: Why and How to 2 Control?" held in Maastricht, The Netherlands from 13-15 Decem ber 1993. Of the known greenhouse gases, political attention to date has been primarily focused on carbon dioxide (C0 ) and the 2 CFCs - the latter because of their interaction with stratospheric ozone. The other greenhouse gases, notably methane (CH ), nitrous 4 oxide (N 0), HCFCs, HFCs and tropospheric ozone and its precur 2 sors nitrogen oxides (NO), carbon monoxide (CO) and volatile organic compounds (VOCs), may appear collectively to be of equal importance for global warming but have attracted less attention. Nevertheless, a comprehensive approach to climate change respon se, taking into account all sources and sinks of all greenhouse gases, is explicitly allowed in the Framework Convention on Clima te Change. The Netherlands' policy on climate already addresses all greenhouse gases. In order to stimulate the development of international climate policy on this subject, the Dutch Ministry of Housing, Physical Planning and Environment supported the initative of organizing an international symposium on the science and policy of the non-C0 greenhouse gases. An important rationale behind 2 this initative was recognizing that for the non-C0 greenhouse 2 gases, abatement options are available that do not only address other environmental problems but that also do not require the major structural changes in society that an effective CO policy 2 may."

The background This volume contains the proceedings of the first International symposium on "Non-C0 Greenhouse Gases: Why and How to 2 Control?" held in Maastricht, The Netherlands from 13-15 Decem ber 1993. Of the known greenhouse gases, political attention to date has been primarily focused on carbon dioxide (C0 ) and the 2 CFCs - the latter because of their interaction with stratospheric ozone. The other greenhouse gases, notably methane (CH ), nitrous 4 oxide (N 0), HCFCs, HFCs and tropospheric ozone and its precur 2 sors nitrogen oxides (NO), carbon monoxide (CO) and volatile organic compounds (VOCs), may appear collectively to be of equal importance for global warming but have attracted less attention. Nevertheless, a comprehensive approach to climate change respon se, taking into account all sources and sinks of all greenhouse gases, is explicitly allowed in the Framework Convention on Clima te Change. The Netherlands' policy on climate already addresses all greenhouse gases. In order to stimulate the development of international climate policy on this subject, the Dutch Ministry of Housing, Physical Planning and Environment supported the initative of organizing an international symposium on the science and policy of the non-C0 greenhouse gases. An important rationale behind 2 this initative was recognizing that for the non-C0 greenhouse 2 gases, abatement options are available that do not only address other environmental problems but that also do not require the major structural changes in society that an effective CO policy 2 may."

Rapidly increasing concentrations of greenhouse gases in the atmosphere, emerging evidence of global warming and the threat of uncontrollable climate feedback mechan:i,sms are now triggering international action to reduce the emissions of greenhouse gases. In 1989 the Intergovernmental Panel on Climate Change (IPCC), established by the United Nations Environment Pro gramme and the World Meteorological Organization, started preparations for an international convention on climate. This convention is to be followed by protocols (agreements) on the reduction of the emissions of greenhouse gases and other measures and implementation mechanisms to preserve the global climate. After the CFC's, CO is the next in line, as the sources 2 and abatement measures for CH and N 0 are as yet insuffi 4 2 ciently understood. However, the abatement of CO . is a far 2 reaching issue. It will require major changes wi thin the most important sectors of the economy: energy (production and use) and agriculture (deforestations and land use pat terns). Given this situation it is not so surprising that national governments are hesitant to take action. One reason is the remaining uncertainty regarding the rat,e and the extent of climate change. However, further analysis will show that the uncertainties will be outweighed by the increasing risks when measures to reduce the emission of greenhouse gases are delayed.