Reducing atmospheric carbon dioxide concentrations

Using a combination of policy, financial, technical and behavioural means to reduce the rate of increase of carbon dioxide (CO2) emissions to the atmosphere. For example, it is estimated that to stabilize global CO2 at twice that of today (1994), current emissions would need to be cut immediately by a factor of 25. It is very desirable to stabilize the level at no more than 550 ppm.

CO2 is not the only greenhouse gas produced by human activity, but it is the main one, accounting for about half of all human sources of global warming – the equivalent of more than 6,000 million tonnes of carbon a year. CO2 had a pre-industrial level of 280 parts per million (ppm), the 1986 level was 346 ppm, and the 1992 level 357 ppm. The current annual increase is 1.5 ppm. Historically the level has fluctuated, but at no time in the previous 100,000 years did concentrations reach 300 ppm. Anthropogenic emissions, particularly those from fossil fuel combustion for energy, are the primary cause for the more than 25% increase in the concentration of CO2 during the past two centuries. The top 20 CO2 emitters in 1989 were: USA, former Soviet Union, China, Japan, India, Germany (both GDR and DDR), UK, Canada, Poland, Italy, France, Mexico, South Africa, Australia, Czechoslovakia, Korea, Romania, Brazil and Spain, accounting for nearly 80% of CO2 emissions. Overall, about one-half of potential global warming will be caused by the presence of CO2 in the atmosphere.

The Intergovernmental Panel on Climate Change (IPCC), on the basis of a combination of business as usual and efficiency policies, estimated that the global energy consumption level of 270,000 pica joules (PJ) in 1986 will increase to 500,000 PJ by the year 2025. This is based on an annual increase of 0.7% in Western Europe, 1.3% in Northern America and the OECD countries in the Pacific and 3.6% in developing countries. The developing world will go from emitting 27% of the world's CO2 in 1990 to 46% in the year 2050. Based on these predictions, rich countries will use six times as much fossil energy per person than poor countries. The IPCC recommended an annual worldwide decrease in CO2 emissions of 1 to 2%. Integrated climate-economic modelling studies suggest that meeting this objective might also be possible for a carbon tax of US$126/tonne.

Among the most attractive options for reducing or offsetting CO2 emissions are energy efficiency, better municipal planning, technology transfer to less developed countries (LDCs), carbon sequestration in agro-forest ecosystems and use of biomass and alternative fuels.

Through the United Nations Framework Convention on Climate Change and the Kyoto Protocol, efforts are under way to start controlling and reducing greenhouse gas emissions. During the Third Conference of the Parties in Buenos Aires in 1998, a plan of action was developed on how to use the new international policy instruments such as emission trading and the Clean Development Mechanism. However, the Kyoto Protocol alone will be insufficient to stabilize carbon dioxide levels in the atmosphere.

The Action Plan Sustainable Netherlands takes as its starting point that IPCC recommendations should be followed up on the basis of an equal global redistribution of CO2 emissions by the year 2030. For the Netherlands, this means a 60% reduction in CO2 emissions by the year 2010 and an 85% reduction by the year 2030. It is suggested that the first 60% can be easily achieved by efficiency measures, while the reduction targets for the year 2030 will have to be achieved with the help of additional policies aimed at introducing solar power.

The Enquête-Kommission of the German Bundestag Protection of the Earth's Atmosphere recommends a 20-30% reduction in CO2 emissions by the year 2005, 50% by 2020 and 80% by the year 2050. This decreases, proposes the Kommission, is possible by making good use of the enormous potential for energy saving which have not yet been utilized.

Using the IPPC methodology, UK carbon dioxide emissions fell by 7 per cent between 1990 and 1995 (from 168 to 157 million tonnes), mainly because of greater use of gas and reduced use of coal in electricity generation and increased use of nuclear-generated electricity. However, emissions rose by 3 per cent in 1996 (to 162 million tonnes), mainly because of the colder winter in 1996/97. 1997 emissions of carbon dioxide are provisionally estimated at 155 million tonnes.