3. Climate Change
3. Climate Change
3.1 The Issue
Climate change, resulting from global warming, is a global environmental issue identified by the EU as one of the key environmental themes to be tackled under the 5EAP. Global warming is expected to take place as a result of increasing amounts of anthropogenic emissions of gases that affect the absorption and emission of radiation in the atmosphere. These gases, in particular carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and chlorofluorocarbons (CFCs) and their substitutes are referred to collectively as greenhouse gases (GHGs). The contribution to the overall global warming effect of these pollutants is shown in Table 3.1. Tropospheric ozone (O3) also contributes to global warming. CFCs and HCFCs (less damaging substitutes for CFCs) furthermore cause depletion of the ozone layer.
Greenhouses Gases - Sources and Contribution to Global Impact
Source: IPCC (1994, 1995)
Note: Bases on 1994 source emission data adjusted using 100 year Global Warming Potentials (RIVM, 1996)
The continued emission and accumulation of these gases is expected to result in an enhanced greenhouse effect and an attendant rise in the global mean temperature, which might affect the overall climatic conditions on the planet. This is expected to affect sea level, run-off patterns of watercourses, frequency of droughts and flooding, agriculture, forests, precipitation levels and biodiversity.
The severity of these impacts is extremely uncertain, though in recent years the international scientific community has made considerable progress in understanding the relationships between, for example: GHG emissions, atmospheric concentration, temperature, and economic costs.
The Second Assessment Report of IPCC (1995) concluded inter alia that :
- "the balance of evidence suggests a discernible human influence on global climate";
- changes in greenhouse gases and aerosols, taken together, are projected to change regional and global climate-related parameters such as temperature, precipitation, soil moisture and sea level. Potentially serious changes have been identified, including an increase in some regions in the incidence of high-temperature events, floods and droughts, with resultant consequences for fires, pest outbreaks, and ecosystem composition, structure and functioning, including primary production";
- "if CO2 emissions were maintained at near current levels, they would lead to a nearly constant rate of increase in atmospheric concentrations for at least two centuries reaching almost twice the pre-industrial concentration level of 280 ppmv by the end of the 21st century";
- "for the mid-range IPCC scenarios of future emissions, and assuming the best estimate value of climate sensitivity, models project an increase in global mean temperature, relative to 1990, of about 2° C by the year 2100 (the uncertainty range is 1-3.5° C) and an associated increase in sea level of about 50 cm from 1990 to 2100 (the uncertainty range is 15 to 95 cm)";
- "the global average annual per capita emissions of CO2 due to the combustion of fossil fuels is at present about 4 tonnes, in developed and transitional economy countries about 10 tonnes and in developing countries about 1.8 tonnes".
While the findings vary (a range of 1 - 3.5 degrees Celcius by 2100), the overall conclusions generally support the view that policy action is essential to curb global GHG emissions to control global warming.
Timing is a key issue in climate change. There is a considerable time delay between a reduction of the emissions of these gases and stabilisation of atmospheric concentrations. Once climate change has become manifest, it will show an irreversible character or, when actions are undertaken, a long recovery time. Furthermore, there are the societal time-lags inherent in, for example: raising public awareness, development and timing of policy actions, and fully implementing these measures (taking into account the relatively small annual turnover of capital goods).
Environmental policies and EU targets
In an international context, governments responded to the concerns about climate change at the 1992 UN Conference on Environment and Development (Rio de Janeiro). At the Conference, the Framework Convention on Climate Change (UNFCCC) was opened for signatures and individual countries or groups of countries made commitments to control their emissions of CO2 and other greenhouse gases. Annex-1 Parties (i.e. industrialised countries) made commitments to aim at returning individually or jointly their emissions of greenhouse gases not controlled by the Montreal Protocol to their 1990 levels and to communicate detailed information on its policies and measures on the mitigation of climate change. The European Community and all Member States have ratified the UNFCCC.
The European Union has set two overall environmental climate change objectives: to not allow the natural absorbing capacity of the Earth to be exceeded, and to follow the activities set out in the Framework Convention on Climate Change. The Fifth Environmental Action Programme (5EAP) Towards Sustainability mentions a target for the EU, as a whole, to stabilise CO2 emissions at the 1990 level by the year 2000. The document also identified the need for a monitoring mechanism, which was established under Council Decision 93/389. In the recently presented Review of the 5EAP, the Commission proposes as one of the key strategies to identify reduction objectives for CO2 and other greenhouse gases for 2005 and 2010, and to define policies and measures for their achievement (EC, 1996f).
The first Conference of the Parties to the Convention was held in March/April 1995. This Conference agreed "to begin a process to enable it to take appropriate action for the period beyond 2000, including the strengthening of the commitments of Annex-1 Parties, through the adoption of a protocol or another legal instrument" (the so-called Berlin Mandate).
At the Ministerial segment of the second session of the Conference of the Parties to the Convention the 1995 IPCC Second Assessment Report was endorsed (July 1996) "as currently the most comprehensive and authoritative assessment of the science of climate change, its impacts and response options now available". The Ministers further stated that the Report "should provide a scientific basis for urgently strengthening action at the global, regional and national levels, particularly action by Annex-1 Parties to limit and reduce emissions of GHGs". It was agreed to accelerate negotiations on the text of a legally-binding protocol or another legal instrument to be completed in due time for adoption at the third session of the conference (Kyoto, Japan, December 1997).
The EU Member States individually and the Commission on behalf of the European Community have submitted their communications, as required under the UNFCCC. These Communications contain inventories of GHG emissions and removals by sinks and describe programmes, policies and measures which are taken or will be taken to address climate change. The commitments of the Community are to be reached with complementary Community and National Programmes (EC, 1996b). A monitoring mechanism has been established under which the National Programmes and the details of measures which Member States are putting in place are assessed. Likely emission profiles for each Member State and the Community as a whole up to the year 2000 are described by the Commission (EC, 1996a).
Furthermore the EU has presented a separate communication on a "community strategy on climate change" after the meeting of the Council of Ministers in June 1996 (EC, 1996c), which concludes inter alia :
- "a protocol or another legal instrument should be set up in a combined approach, including commitments for Annex-1 Parties regarding policies and measures as well as quantified emission limitation and reduction objectives within specified time-frames";
- " .the Council believes that global average temperatures should not exceed 2 degrees Celcius above pre-industrial level and that therefore concentration levels lower than 550 ppm CO2 should guide global limitation and reduction efforts. This means that the concentrations of all GHGs should also be stabilised. This is likely to require a reduction of emissions of GHGs other than CO2, in particular CH4 and N2O";
- " it is essential that each of the Annex-1 Parties - it is being understood that the Community is treated as one Party - agrees to set quantified objectives for significant overall reductions of GHG emissions after the year 2000 below 1990 levels, within specified timeframes, not simply to limit growth of total emissions";
- " it is feasible for the Community as a whole to reach reduction of CO2 emissions by the year 2010 compared to 1990 level, through the implementation of policies and measures identified by Member States and the Commission, at national and Community level".
Apart from National Programmes EU has also taken action on a Community level, such as energy efficiency programmes (see Chapter 2) and, recently, its strategy to reduce CO2 emissions from passenger cars (EC, 1996d). The aim of the latter is to achieve a substantial emission reduction for new cars in 2005 (at the latest in 2010). Binding CO2 emission limit values and fiscal measures are not foreseen at the moment.
The proposal for one of the key measures at the Community level (the energy/carbon tax) has not been adopted, but some Member States (Denmark, Finland, the Netherlands, Austria and Sweden) have already introduced such taxes to date. However the contribution of these countries to the total EUR 15 emissions of CO2 is not large.
The climate change policy has concentrated on the control of CO2 and its stabilisation at 1990 levels by the year 2000, since CO2 is the largest contributor to the problem. No EU policy measures and targets have yet been developed for N2O and CH4, although the Commission intends to present a communication on methane during 1996. Some Member States have taken action to reduce these emissions. Actions to achieve these reductions include the introduction of a landfill levy and regulations, agricultural policies to reduce fertiliser use and livestock numbers, as well as measures to reduce leakage from gas pipes.
On CFCs and HCFCs international negotiations to tighten existing limitations (eg, of CFC production as proposed in the Montreal protocol) have accelerated and the European Union is playing a pioneering role in this.
A summary of EU policy measures aimed at achieving the targets set out in the 5EAP is presented in Box 3.1.
Box 3.1: - EU state of action in the Climate Change theme since 1992
3.2 State of the Environment
Past trends and current status
Given the difficulties in measuring climate change and its environmental effects, the most common indicators used are the pressure indicators of emissions of the individual gases. An examination of changes in key stress indicators (CO2, CH4, N2O) over the last 30 years shows a steady increase in emissions.
Recent trends in GHG emissions are now monitored more regularly due to the commitments of the EU and individual Member States under the UNFCCC. There are a number of different databases for CO2 emissions including National Programmes, Corinair, Eurostat and the UNECE Convention on Long Range Transboundary Air Pollution (LRTAP), although each is based on national data. There are difficulties in selecting a data set which meets all the criteria of reliability, consistency, completeness and multiple years. Corinair is the emission inventory developed in collaboration with Member States and maintained by the EEA. Provisional results of the 1994 inventory are available. The Corinair emission inventory includes fossil fuel related and other emission sources and is in line with the IPCC Guidelines. However only emission data for 1990 and 1994 are presently available. Therefore for the following trend analysis emission data from Eurostat are also used. Up-to-date data from Eurostat for CO2 emissions from fossil fuel combustion indicates 3100 million tonnes (Mt) in 1994 for the EUR 15 (2.7 % reduction compared to 1990 level). Figure 3.1 shows the trend in total CO2 emissions in EUR 15 from 1980 to 1994 (excludes final non-energy consumption and bunkers). The latest provisional Corinair emission data for EUR 15 (EEA-ETC/AEM, 1996) are in line with these figures (reduction of 3290 Mt in 1990 to 3230 Mt in 1994), showing that fossil fuel related emissions account for 95 % of the total emissions.
Development of CO2 emissions in EUR 15 from fossil fuel
non-energy consumption and bunkers) (1985-1994). Source: Eurostat (data includes
emissions from former East Germany)
Emissions from fossil fuel combustion in the EUR 15 increased by about 1% overall in the period 1985-90. Emission reductions were achieved by Germany, Denmark and France during 1985-90. From 1990 to 1994 emissions of several countries (Germany, France, United Kingdom) decreased, resulting for the EUR 15 in an emission reduction of approximately 2 %, mainly due to short-term factors like the temporary decrease of industrial and economic growth rates, the restructuring of industry in Germany, the closing of coal mines in the UK and the conversion of power plants to natural gas.
Source apportionment of CO2 emissions from
fuel combustion. Source: Eurostat (data includes emissions
from the former East Germany)
Figure 3.2 shows the sectors responsible for CO2 emissions from fuel combustion in 1985 and 1994. Although emissions from industry have reduced, emissions from the transport sector show an increase. The average EUR 15 annual per capita CO2 emissions from fuel combustion only in 1990 is 8.8 tonnes, of which around 2.1 tonnes (24 %) is originating from transport. CO2 emissions per capita from transport can be further divided in respectively 1.2 tonnes from passenger cars, 600 kg from heavy duty vehicles and buses and 300 kg from other mobile sources (including air transport) (see also Appendix I).
Source apportionment of N2O emissions
in 1994. Source: EEA-ETC/AEM, 1996
Figures 3.3 and 3.4 show emissions of N2O and CH4 in the EUR 15 in 1994 by source. The main sources of N2O emissions are agriculture and industry, with a total of 0.9 million tonnes and the main sources of CH4 emissions are agriculture and waste treatment, with a total of 22.8 million tonnes in 1994, both excluding natural emissions (provisional results, EEA-ETC/AEM, 1996). Natural sources of both these gases are also significant.
Source apportionment of CH4 emissions
in 1994. Source: EEA-ETC/AEM, 1996
The production and consumption of CFCs show a decreasing trend: an 80% reduction between 1986 and 1994 (Figure 3.5). The 1994 target for halons (phase out) has been reached. The production of HCFCs (targeted for complete phase out by 2015) has increased during the period 1986-1994 as a result of the substitution for previous uses of CFCs.
Figure 3.5: Production and consumption of CFCs in the EUR 12. Source: EC-DGXI
To compare the effect of different GHGs the Global Warming Potential is usually expressed in CO2-equivalents. On a global scale the contribution of CO2 emissions to the total GHG emissions (CO2-eq.) is approximately 65 %, of CH4 20 %, of N2O 5 % and of CFCs 10 % (see Table 3.1). The share of the total GHG emissions (CO2-eq.) originating from OECD countries is 40 %, from Central and Eastern European countries and the CIS (former Soviet Union) countries 10 % and from other countries 50 %. In the period 1980 to 1990 total global GHG emissions (CO2-eq.) increased 15 %, mainly due to growth of CO2 emissions in the less industrialised countries. From 1990 to 1994 global CO2 emissions did not grow, mainly due to the economic recession/restructuring in the CEE and CIS countries. The emissions of CFC have decreased in this period, resulting in a decrease of global GHG emissions (CO2-eq) of 5 % from 1990 to 1994 (RIVM, 1996). However, GHG emissions (CO2-eq) in OECD countries have increased over the period 1990 to 1994, whereas the UNFCCC target is to stabilise the emissions between 1990 and 2000 (WEC, 1996).
Development of CO2 concentration (1950-1994)
(at Mauna Loa, Hawaii). Source: CDIAC, 1994
Figure 3.6 illustrates the trend towards increasing concentration of CO2 in the atmosphere since the 1950s as recorded at one of the monitoring stations existing at that time (located in Hawaii). According to the IPCC the atmospheric concentrations of GHGs, inter alia CO2, CH4 and N2O have grown significantly since pre-industrial times: by about 30 %, 145 % and 15 % respectively (values for 1992) (IPCC, 1995). Since 1950 the concentration of CO2 has increased 16 %.
Figure 3.7 shows the global mean temperature since 1900. Global mean surface air temperature has increased by between about 0.3 and 0.6 °C since the late 19th century (IPCC, 1995). For the year 1995 the global mean surface temperature was 0.40 degrees Celcius above the 1961-1990 average (CRU, 1996). The EU objective of a maximum of 2 degrees Celcius increase above pre-industrial temperature in 2100 is also shown. Taking into account the present increase of approximately 0.5 degrees Celcius this means a maximum additional 1.5 degrees Celcius temperature increase until 2100 relative to 1990.
Figure 3.7: Changes in global mean temperature since 1900. Source: CRU (1996)
Underlying factors and new insights
The main driving force for GHG emissions is fuel combustion, which is driven by activity in the energy, industry and transport sectors (see Chapter 2). The principal objective of policy instruments is to decouple the link between energy consumption and GHG emissions from growth in these sectors.
In the current context it is important to consider a number of key issues:
- Penetration of energy efficient technologies. The rate of penetration of more efficient technologies depends on economic decisions, which are based on the increased capital cost of the technology and the future benefits in terms of energy cost savings. Incentives (including price incentives via taxes) and information dissemination are required to counteract the expected impact of decreasing energy prices and to encourage the uptake of efficient technologies.
- Increasing natural gas use could increase CH4 emissions. Natural gas is expected to increase its share of primary energy in the EU due to the efficiency of gas technologies and the low emissions (CO2, SO2, NOx and particulates) characteristics of the fuel. It is important to ensure that this increase in use is not accompanied by an increase in emissions of CH4 resulting from leakage in the distribution system.
- Member States economic structure. The ability of a Member State to stabilise CO2 emissions depends on its economic and energy structure in the base year (1990) as the scope for improving energy efficiency and reducing emissions is greater in the energy intensive sectors (metals, building materials, paper, etc) than the knowledge intensive sectors (eg, electronics, services).
- The transport sector is critical. The transport sector (road and air) is currently the fastest growing sector in the majority of EU economies and therefore the fastest growing contributor to GHG emissions.
- CO2 emissions will remain the largest contributor. CO2 contributes around 65% to total GHG emissions, mainly from the use of fossil fuels, which is most easily monitored. It is, therefore, the gas for which the policy initiatives are best developed. However, there are also opportunities to reduce emissions of other GHGs such as methane from agriculture and waste; measures to phase out CFCs are in place. HCFCs, which have greater global warming potentials than CFCs, are targeted for complete phase out by 2015.
In order to fully integrate environmental objectives (such as eliminating climate change) into economic and sectoral policies in an efficient way, it is essential that the external costs of activities (such as those concerning the combustion of fossil fuels) be incorporated into the prices that consumers pay for their energy.
Effect of removal by sinks
The enhancement of removal of CO2 by sinks, generally through the encouragement of forestry, is currently not counted as part of achieving the EU target, which is presently based only on emissions, since the UNFCCC target only relates to emissions. Afforestation can remove CO2 from the atmosphere. However it does not halt the gross growth in emissions or affect the main cause of rising CO2 emissions, namely the combustion of fossil fuels.
3.3 Progress and Outlook
The target of stabilisation of EU CO2 emissions at 1990 levels by 2000 is being monitored by the European Commission. All Member States have submitted Annual Inventories for at least 1990 and National Programmes in which they make projections for the future and describe the measures that are proposed to bring about reductions. However transport and mobility patterns have not been addressed in most National Programmes.
Although Member States intend to stabilise emissions overall, targets for every Member State have not been established. It is recognised that the overall stabilisation will be achieved through burden sharing of emissions and that some Member States (e.g Spain, Portugal, Ireland), will increase, while others intend to make reductions (e.g. Germany, Netherlands, Denmark). Approaches to limiting emissions and measures implemented by Member States are discussed in Chapter 2: Energy.
Progress towards target
There have been several studies that have attempted to estimate whether the EU will comply with the CO2 stabilisation target. Studies include DRI (1994), DG XVII, DGXI. The EU has evaluated the National Programmes (EC, 1996a). The report concluded that there is still considerable uncertainty regarding the expected emission level in 2000. A compilation of an EU trajectory for 2000, by adding up the individual Member States trajectories could only give indicative results, due to difference in methodology and assumptions used by the Member States.1 Therefore separately for the EU, projections of emissions in 2000, 2010 and 2020 have been calculated using different scenarios, based on the Member States trajectories but using common assumptions (EC, 1996b). The Conventional Wisdom scenario, which denotes the "business as usual" world representing a conventional wisdom view of the most likely evaluation of events (see also Chapter 2), resulted in an expected increase (compared to 1990 levels) of 5 % in 2000, 13 % in 2010 and 16 % in 2020. Stabilisation would only be within reach if the maximum potential of the estimated effects of measures, reported by the Member States in their National Programmes, is actually realised 2. If energy prices remain low and GDP growth is faster than expected the increase could be 5 % or even higher.
In summary, there is great uncertainty about whether the EU will meet the target for 2000 and there is a wide range of estimates from an increase of 10% above the stabilisation level (DG XVII) to a 5% reduction by 2000 (DRI et al., 1994), which assumes the introduction of a carbon/energy tax. The outcome is highly dependent on the reduction achieved by Germany, which contributed about 30% of EUR15 emissions in 1990 and has not yet set a target for 2000, although a target for 2005 is set . A preliminary forecast based on the German National Programme predicts that the interpolated target for 2000 will be overshot by 1%. These ranges and the key driving factors are illustrated in Figure 3.8.
Figure 3.8: Progress towards CO2 stabilisation in the EUR15
In consideration of the specific measures which have contributed to the reduction of emissions to date and which will affect the likelihood of meeting the targets, a number of key issues are worth highlighting:
- Short-term factors have been a major cause of the reduction of emissions between 1990 and 1994.
- The EC programmes, SAVE, THERMIE, ALTENER and JOULE have had some impact, but full evaluations of these programmes have not yet been carried out. However, only half of the target of 20% improvement in energy efficiency is expected to be achieved under the SAVE programme.
- Only 3 of the 12 intended Directives on household appliance efficiency have been adopted, although there has been a switch in domestic fuel consumption from coal to an increased use of gas.
- In the transport sector there has been limited progress in fuel substitution towards less CO2 emitting sources, such as non-fossil fuels (bioethanol, electricity from renewables or gas).
- A number of Member States have introduced policies which are likely to have a positive impact; these are mainly fiscal measures (see Chapter 2).
After 2000, CO2 emissions in the EU are likely to rise further by about 1% per year as a result of the continuing growth of production, assuming that no additional policy measures are taken to tackle emissions (DRI et al.,1994; RIVM, 1992; EC, 1996b).
Methane emissions are also expected to increase from the 1990 level. The emission reduction in agriculture (due to the decrease in livestock population as a result of the CAP reform) might be offset by the increased use of natural gas as a primary energy source. It is uncertain how N2O emissions will develop: reductions of emissions from agriculture, by limiting the use of artificial fertilisers, might be counterbalanced by industry and transport. Community policy for both gases is (still) absent, although some individual Member States are developing programmes.
Sustainable Pathways Towards 2010
Setting of EU emission reduction targets for 2010 appears the key for future climate change policy. Although the Berlin Mandate also mentions 2005 and 2020 as target years, the EU Council of Ministers and the Review of the 5EAP explicitly refer to 2010 (EC, 1996c; EC, 1996f). As stated above the EU has declared, based on present knowledge, that global average temperatures should not exceed 2 degrees Celcius above pre-industrial level in 2100 (which in practice means a maximum 1.5 degrees temperature increase from 1990) by 2100. Reaching this objective is dependant on the following key issues.
Distribution of emissions
Climate change is a global issue. Discussions on strategies to reduce the risks of an enhanced greenhouse effect involve agreement on the distribution of the environmental space among countries, especially between industrialised (the so-called Annex-1 Parties of the UNFCCC ) and the non-Annex-1 countries. Current (1990) anthropogenic CO2 , CH4 and N2O emissions for these two groups are 5.8 and 4.4 Gt C ( CO2 equivalent) respectively, or 55 and 45% of total global emissions.
IPCC has developed a range of scenarios, without specific mitigation policies, but including assumptions concerning population growth, land-use, technological changes, energy availability and fuel mix. These IPCC scenarios, which are described here as "baseline emission scenarios" give for the year 2010 for non-Annex-1 countries results within the range of 5.3-7.0 Gt C (as there are no commitments for these countries to limit their emissions). The upper value represents (a relatively) high economic growth and growth of emissions in non-industrialised countries. The lower value marks low population growth, favourable economic development and halting deforestation. However, the achievability of the lower value can be supported by industrialised countries through "Activities implemented jointly" and technology transfer to developing countries.
Timing of actions
Another debate is on the question when actions aimed at mitigating climate change effects should be started in Annex-1 countries. This is motivated by the argument that waiting for actions gives more time in order to attain firmer scientific ground. Another argument is that costs of measures might be reduced by developing improved (cheaper) technology. However, due to the long atmospheric lifetime of greenhouse gases, delays in introducing reduction policies will certainly lead to the requirement for substantial additional actions at a later stage. According to the IPCC, global emissions of greenhouse gases should be reduced immediately by 50 to 70 % and further thereafter to achieve stabilisation of the concentration of CO2 at the present level by 2100 (IPCC, 1995).
What are the possible scenarios for the EU after 2000 or, in other words, how can long term objectives be translated in short term targets? Assuming that the EU maximum temperature objective refers to the year 2100, allowable emissions can be computed for the year 2010 (see Table 3.2). The results are depending on the allowable temperature increase per decade. Scientists have proposed to use a provisional limit for sustainability of 0.1°C temperature rise per decade (Krause et al., 1990) and a provisional limit of a 2 cm rise in sea level per decade to prevent damage to coastal zones, wetlands and coral reefs caused by too rapid climatological changes (AGGG, 1990). Increases above this limit will cause major risks for ecosystems, food production and sensitive coastal areas.
Table 3.2 shows that if the sustainable limit of 0.1 oC temperature increase per decade up to 2100 is added as a climate target, emissions in industrialised countries (Annex-1 countries, including EU) should be reduced by at least 30-55 % in 2010 compared to 1990 levels, depending on the baseline emissions in the non-industrialised countries.
Table 3.2: Maximum allowable CO2 equivalent emissions scenarios and associated minimum emission reductions for Annex-1 Parties in 2010 (based on EU objective of 1.5 degrees Celcius temperature increase between 1990 and 2100)
a) Including (unavoidable)
violations of the temperature increase concerned in two decades.
A temperature increase of 0.1 degrees Celcius per decade could be
regarded as a limit for sustainability. An increase of 0.15
degrees Celcius per decade is substantially above this level
b) Range presents non-Annex-1 Parties baseline emissions of 5.3 - 7 Gt C equivalent CO2 in 2010 and only includes the upper limit of the emission corridor
c) The lowest baseline emission value for non-Annex-1 Parties means that in this case (upper limit of emission corridor) that no emission reduction by Annex-1 Parties is required
Source: IMAGE computations by RIVM
using the so-called safe landing method (Alcamo and Kreileman,
This would for example mean for CO2 emissions from fossil fuel a reduction of the annual average per capita emission (EUR15) of 8.8 tonnes in 1990 to 5.8 and 3.7 tonnes respectively in 2010 (accounting for some increase in population). The present global average per capita CO2 emission from fossil fuel is 4 tonnes and in developing countries 1.8 tonnes.
The ranges of allowable global emissions in 2010 (the so-called emission corridors) include the minimum and maximum reductions according to the timing of policy measures. Following the upper limit of the emission corridor maximum actions are required after 2010 (i.e. global reductions of emissions of 2% per year). Only the maximal allowable emissions in 2010, according to the upper limit of the corridor, are presented in Table 3.2. If the lower limit of the corridor is followed, alternative strategies (including lower emission reductions) are still open after 2010. Table 3.2 also shows the emissions corridors for a considerably higher rate of temperature increase per decade.
Apart from the above-mentioned issues and trade-offs which have to be dealt with, strategies have to be developed regarding the reduction schemes for the separate greenhouse gases CO2, CH4 and N2O. CFCs should already be phased out by 2010, but its substitutes will require further attention. Although CO2 is the most important greenhouse gas, scientists argue that high priority should also be given to methane. Based on 100 year Global Warming Potentials reduction of methane emissions would be 25 times more effective in reducing the enhanced greenhouse effect than CO2 (IPPC, 1995). It will provide additional benefits of reducing the potential for increasing tropospheric ozone (summer smog). Furthermore, reduction measures for CH4 might be more feasible (technical and economic) than CO2 reductions.
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