GHG Mitigation


Driver description
Interactions with the Environment Domain
Interactions within the Social Domain
Interactions with the Economy Domain
Interactions with the Technology Domain
Impacts on Mobility and Transport

Driver description

  • “GHGs are a number of different gases and aerosols that have climatic impacts. Scientists compare the climatic impact of these various gases in terms of what is called radiative forcing[1].” (Ref: CO_5046)
  • “As a consequence of the role played by fossil fuel combustion, CO2 is the predominant GHG emitted, accounting for 82 % of total GHG emissions (...). About 93 % of this CO2 originates from the combustion of fossil fuels, and the remaining 7 % from specific industrial processes.” (Ref: CO_0200)

[1]    Radiative forcing is a direct measure of the imbalance between the energy flowing into the earth’s atmosphere from the sun and the energy being reflected and radiated back out into space; if there is more energy coming into than leaving the atmosphere, the earth is going to heat up. The year 1750, before world industrialization began, is used by many scientists and the Intergovernmental Panel on Climate Change as the baseline or zero point in relation to which radiative forcing is computed

Figure 1‑59 GHG emissions in the EU-27 by gas and by sector (excerpt)

Source: A Roadmap for moving to a competitive low carbon economy in 2050 (Ref: CO_0194)

  • “In order to keep climate change below 2ºC, the European Council reconfirmed in February 2011 the EU objective of reducing greenhouse gas emissions by 80-95% by 2050 compared to 1990 (...). Taking into account necessary efforts from developing countries, this will allow a global reduction of 50% in emissions by 2050.” (Ref: CO_0194)
  • “The transport sector is a major contributor to CO2 emissions because of its dependency on fossil fuels in all modes. Statistics indicate that the transport sector contributes 23% of all CO2 emissions in the 27 EU Member States. Despite significant efforts to reduce emissions, transport has not achieved its decarbonising targets. If this trend continues, transport is expected to contribute 50% of all CO2 emissions in the EU by 2050, if not within the next two decades. An overview of historic development of CO2 emissions and estimates for various sectors is shown in figure below. It clearly indicates the expected continuing growth of emissions from transport.” (Ref: CO_0234)
Figure 1‑60 Change of CO2 emissions since 1990

Source: Towards low carbon transport in Europe (Ref: CO_0234)

  • “The largest share of these emissions is generated in industrialized countries. But with rising motorization in many developing countries, the world’s vehicle fleet will rapidly grow, and so will emissions. Most estimates of greenhouse gas emissions from transport are close to 13.5 percent of the total.” (Ref: CO_5028)
  • “Compared with 1990 levels, in no other sector has the growth rate of GHG emissions been as high as in transport. As the transport sector relies on fossil fuels for 97 % of its needs, the fight against climate change in this sector goes hand in hand with efforts to improve its energy security of supply.” (Ref: CO_0015)
  • “For passenger transport, urban transport is responsible for approximately a quarter of CO2 emissions.” (Ref: CO_0234)
  • “The intra-EU tourism transport alone contributes 11% of all greenhouse gas emissions in the EU (in 2000) which will rise to 18% (by 2020). The UN Intergovernmental panel on climate change estimates aviation causes 3.5% of man-made global warming and that figure could rise to 15% by 2050.” (Ref: CO_4010)
  • “Projections provided by sector indicate that with the existing measures currently in place, emissions will decrease between 2010 and 2020 in the main emitting sectors, except for the transport sector and emissions from industrial processes.” (Ref: CO_0131)
Figure 1‑61 Sectoral trends and projections of EU GHG emissions

Source: Greenhouse gas emission trends and projections in Europe 2011 (Ref: CO_0131)

  • “Projections from Member States indicate that total EU emissions will not be significantly reduced in the period up to 2020: with the current national domestic measures in place, EU emissions in 2020 will be 19 % below 1990 levels, which is just short of its 20 % reduction target. The gap of 1 percentage point could be filled and the target overachieved by 5 points if Member States implement all additional measures currently being planned, in particular in the transport and residential sectors.” (Ref: CO_0131)
  • “In order to do so, we need action on three fronts: targeted public policies, technological progress, and commitment from (...) consumers and citizens.” (Ref: CO_4013)
  • “Significant reductions in net greenhouse gas emissions are technically feasible due to an extensive array of technologies and practices in energy supply and demand, waste and land management, and industrial sectors - many at little or no cost to society. However, realizing this technical potential will involve the development and implementation of supporting policies to overcome barriers to the diffusion of these technologies into the marketplace, increased funding for R&D, and effective technology transfer.” (Ref: CO_2019)
  • “With the additional measures currently planned, the EU would remain far from a pathway enabling it to achieve the long-term objective of reducing emissions by 80 % to 95 % by 2050, as agreed by European Heads of State and governments. According to the 'Roadmap for moving to a competitive low-carbon economy in 2050', published in March 2011 by the European Commission, costeffective emission reductions consistent with the long-term target could result in domestic emission reductions of about 40 % by 2030.” (Ref: CO_0131)
  • “Reducing our GHG emissions means attempting climate change mitigation, trying to reduce the impact we must expect. This will include new policies, innovative technologies and a change in lifestyle for all of us, all of which will certainly come at a price.” (Ref: CO_0091)
  • “Given that the Earth’s climate has already changed and that further change is inevitable, future alterations need to be mitigated by reducing projected emissions of greenhouse emissions at the same time that countries adapt to climate change.” (Ref: CO_2019)
  • “Adaptation and mitigation can complement each other and together can significantly reduce the consequences of anthropogenic climate change – change caused by human activities.” (Ref: CO_0091)
  • “The exact nature of the trade-off between mitigation and adaptation is veiled by uncertainty on the actual impacts and on the potential progress of research and development on lower-cost cleaner technology.” (Ref: CO_2019)

Interactions within the Environment Domain

Climate change impacts

  • “Even if society substantially reduces its emissions of GHGs over the coming decades, the climate system is projected to continue to change over the coming centuries. In addition to taking mitigation measures, society will therefore have to adapt to the consequences of some inevitable climate change.” (Ref: CO_1027)
  • “Anthropogenic warming and sea level rise would continue for centuries even if GHG emissions were to be reduced sufficiently for GHG concentrations to stabilise, due to the time scales associated with climate processes and feedbacks.” (Ref: CO_1016)
  • “Unmitigated climate change beyond 2ºC will lead to unprecedented security scenarios as it is likely to trigger a number of tipping points that would lead to further accelerated, irreversible and largely unpredictable climate changes.” (Ref: CO_0120)

Emission Trading Schemes

  • “Average 2008–2010 emissions in EU-15 were 9.9 % lower than the base-year level, below the Kyoto target of -8 % for the period 2008–2012. In the sectors not covered by the EU ETS, emissions were lower than their respective target, by an amount equivalent to 1.2 % the country's base-year emissions. LULUCF activities are expected to decrease net emissions by an annual amount equivalent to 0.9 % of base-year level emissions. EU-15 intends to use the flexible mechanisms at government level by acquiring an amount of Kyoto units equivalent to 2.5 % of base-year emissions per year. Taking all these effects in to account, average emissions in the sectors not covered by the EU ETS in EU-15 were standing below their target level, by a gap representing 4.7 % of the baseyear emissions. The EU-15 was therefore on track towards its Kyoto target by the end of 2010. Projections also show that over the full commitment period 2008–2012, EU-15 aggregated emissions will stay well below its Kyoto target with the current policies in place. However, failure by any Member State to comply with its burden-sharing target by the end of the commitment period could actually result in the non-achievement of its target by the EU-15.” (Ref: CO_0131)

Pollution levels and emission standards

  • “There is also an emerging recognition of the important links between air pollution and climate change. Both issues share common sources of emissions — primarily from fuel combustion in industry and households, transport and agriculture — but also through cross-issue pollutant effects. This can be illustrated by the example of particulate black carbon (BC), formed through the incomplete combustion of fossil fuels, biofuels and biomass. BC is both an air pollutant harmful to health but also acts in a similar way as a greenhouse gas by increasing atmospheric radiative forcing.” (Ref: CO_0134)
  • “Most strategies to reduce transport GHG emission, also reduce emissions of local conventional pollutants and those that involve reduced vehicle use also reduce traffic congestion.” (Ref: CO_0148)
  • “Various scientific studies have identified that an important co‑benefit of climate policies that lead to lower fossil fuel combustion is the strong reduction in emissions of air pollutants such as SO2, NOx and particulate matter (PM).” (Ref: CO_0140)
  • “The combined effect of GHG reductions and air quality measures would bring about more than 65% lower levels of air pollution in 2030 compared to 2005.” (Ref: CO_0194)

Energy availability, production and consumption

  • “Without further action to tackle climate change, the baseline scenario shows global primary energy consumption increasing by more than 2½ times by 2050, and continuing to rise to 2100. These results are consistent with projections by IEA (IEA, 2004a), which show an increase of almost 60 % in global primary energy demand between 2002 and 2030.” (Ref: CO_1027)
  • “The energy sector produces the lion’s share of man-made greenhouse gas emissions. Therefore, reducing greenhouse gas emissions by 2050 by over 80 % will put particular pressure on energy systems.” (Ref: CO_0245)

Scarce resources of fossil fuels

  • “Most strategies to reduce transport GHG emissions also reduce petroleum use, thereby contributing to energy security.” (Ref: CO_0148)
Figure 1‑62 Global development in energy use (baseline)


Source: Climate change and a European low-carbon energy system (Ref: CO_1027)

Interactions with the Social Domain

Migration flows

  • “Yet, a failure by governments and international agencies to reduce global GHG emissions and to support rural and urban populations to adapt will bring crisis-driven population movements that make those forced to move very vulnerable.” (Ref: CO_0147)


  • “The confluence of a variety of interests and material circumstances in initiatives to mitigate climate change through urban design and development makes them complex and difficult to manage.” (Ref: CO_0147)
  • “The built environment provides low-cost and short-term opportunities to reduce emissions, first and foremost through improvement of the energy performance of buildings. The Commission's analysis shows that emissions in this area could be reduced by around 90% by 2050, a larger than average contribution over the long-term. This underlines the importance of achieving the objective of the recast Directive on energy performance of buildings that new buildings built from 2021 onwards will have to be nearly zero-energy buildings.” (Ref: CO_0194)


  • “Cities can be seen as part of the problem of climate change and therefore critical places for achieving mitigation. Reducing GHG emissions in cities is a key policy challenge. Municipal authorities are important actors in tackling the challenge of mitigation for three reasons. First, they have jurisdictional responsibility for key processes which shape emissions. Second, the concentration of people and business in urban areas means that mitigation solutions are feasible. Third, municipal governments provide a key interface for engagement with private-sector and civil society stakeholders that also have a significant role in addressing climate change at the urban level.” (Ref: CO_0147)
  • “Research has shown that a small number of distinct ‘modes of governing’ by municipalities are being employed to address climate change in the urban arena.” (Ref: CO_0147)
  • “(...) there are (...) principal means through which municipal authorities have sought to reduce their own GHG emissions. The first is through the management of municipal buildings, fleets and services. The second is through procurement policies, including purchasing renewable energy for the municipality, or in the transport sector, buying alternative low-carbon fuels. The effectiveness of self-governing measures in reducing urban GHG emissions is limited by the extent of the municipal estate and operations. Also, in the majority of cases, municipal GHG emissions constitute a small proportion of the total emissions in a city.” (Ref: CO_0147)
  • “Mitigating GHG emissions by designing communities that are conducive to shorter vehicle trips and non-motorized travel could achieve a 1 to 2 percent reduction in nationwide vehicle travel by 2035 and a 1.5 to 5 percent reduction by 2050. Further, individual communities with a commitment to creating a travel-efficient environment could do substantially more.” (Ref: CO_4013)
  • “The political success of the London and Stockholm systems indicate that, at least in cities with fairly high transit-mode share and high-income populations, congestion charging can be politically successful and also successful at controlling the growth of transport sector CO2 emissions.” (Ref: CO_0017)

Change of lifestyle and values

  • “Reaching the full greenhouse-gas mitigation potential of energy-efficient and low-carbon energy technologies will depend to a significant extent on influencing consumers’ technology choices and behavior.” (Ref: CO_0154)
  • “There are many policies that could reduce fuel consumption and GHG emissions at zero net cost for the simple reasons that consumers do not highly value, or are unaware of, efficiency considerations in their vehicle purchase decision and ignore many simple practices to reduce fuel use.” (Ref: CO_0148)


  • “Energy and CO2 emissions can (…) be reduced through interventions aimed at changing driving behavior, such as reductions in excessive vehicle acceleration and driving speeds, smoothing traffic flows and reducing congestion. Eco-driving represents a set of changes in driving habits that can be learned through training and information guides, including through real-time information being provided by the vehicle to its driver.” (Ref: CO_0154)

Interactions with the Economy Domain

GDP trends

  • “The implementation of policies to cut greenhouse emissions is acting as one of the key drivers for the modernization of the EU economy, directing investment and innovation to sectors with huge potential for growth and employment in the future. As set out in the Europe 2020 strategy, it is one of the core themes in any credible strategy to build sustainable prosperity for the future.” (Ref: CO_0201)
  • “In 2030 macro-economic costs for multi-gas mitigation, consistent with emissions trajectories towards stabilization between 445 and 710 ppm CO2-eq, are estimated at between a 3% decrease of global GDP (…). However, regional costs may differ significantly from global averages (high agreement, medium evidence).” (Ref: CO_0146)
  • “Various forms of low carbon energy sources, their supporting systems and infrastructure, including smart grids, passive housing, carbon capture and storage, advanced industrial processes and electrification of transport (including energy storage technologies) are key components which are starting to form the backbone of efficient, low carbon energy and transport systems after 2020. This will require major and sustained investment: on average over the coming 40 years, the increase in public and private investment is calculated to amount to around € 270 billion annually. This represents an additional investment of around 1.5% of EU GDP per annum on top of the overall current investment representing 19% of GDP in 2009. It would take us back to the investment levels before the economic crisis.” (Ref: CO_0194)


  • “It is important to note that mitigation policies can represent opportunities for cities and their development prospects in terms of creating jobs.” (Ref: CO_0147)
  • “On a more macro-economic level, economic opportunities arise from measures taken to reduce GHGs: insulating buildings for example will not only save energy costs, but also give the building sector an enormous boost and create employment.” (Ref: CO_0091)

Availability of public and private resources and investments in the transport sector

  • “It is important to note that mitigation policies can represent opportunities for cities and their development prospects in terms of saving money.” (Ref: CO_0147)

Energy availability and prices

  • “A second impact is that energy costs and prices are likely to increase in most parts of the world as energy systems shift from relatively low-cost fossil energy sources to somewhat more expensive alternative energy systems.” (Ref: CO_0147)

Fiscal policy

  • “It is important to note that mitigation policies can represent opportunities for cities and their development prospects in terms of generating new streams of tax revenues.” (Ref: CO_0147)
  • “To make sure deeper GHG cuts in future years are achieved, government tax incentives to industry and consumers will be needed to overcome initial cost, institutional and infrastructure concerns and barriers.” (Ref: CO_0148)
  • “Emissions from road, rail and inland waterways could (...) be brought back to below 1990 levels in 2030, in combination with measures such as pricing schemes to tackle congestion and air pollution, infrastructure charging, (...), whilst securing affordable mobility.” (Ref: CO_0194)

Interactions with the Technology Domain

Technology development in general and innovation diffusion

  • “To achieve deep reductions in GHG emissions and oil dependence, public policy must be multi-faceted, flexible, and adaptive. Policies are needed to pull technology that exists today into the marketplace, support technological development for the future, and correct market failures that have solidified our dependence on fossil fuels. This will require a combination of performance standards, pricing mechanisms, and research, development, demonstration, and deployment.” (Ref: CO_4013)
  • “To effectively reduce GHG emissions, energy efficiency, many types of renewable energy, carbon capture and storage (CCS), nuclear power and new transport technologies will all require widespread deployment.” (Ref: CO_5032)
  • “CCS[1] is on track to become one of the key technologies for combating climate change – within a portfolio of technologies, including greater energy efficiency and renewable energy.” (Ref: CO_2014)
  • “CCS can technically be applied to both coal- and natural gas-fired power plants.” (Ref: CO_2014)

[1] CO2 carbon Dioxide Capture and Storage

New vehicles design

  • “In the face of the challenges of global climate change, the question arises as to whether the concept of “the car” should itself be re-considered. (...) Are the current requirements of power, size and comfort appropriate in the long term, given the needs of climate protection?” (Ref: CO_0017)
  • “Aircraft fuel consumption and GHG emissions can be reduced by aerodynamic improvements to the airframe that increase its lift-to-drag ratio, material substitution and design changes that reduce the empty weight of the aircraft, and, increased engine efficiency, both in thermodynamics and propulsion.” (Ref: CO_4013)

Traction technologies

  • “The 2007 strategy aimed at reaching the Community objective of an equivalent of 120 gCO2/km by 2012 through a legislative framework addressing supply oriented measures. The package of measures listed the following elements:
    • to reach an objective of 130 gCO2/km for the average new car fleet by means of improvements in vehicle motor technology;
    • setting minimum efficiency requirements for air-conditioning systems;
    • the compulsory fitting of accurate tyre pressure monitoring systems;
    • setting maximum tyre rolling resistance limits in the EU for tyres fitted on passenger cars and light commercial vehicles;
    • the use of gear shift indicators, taking into account the extent to which such devices are used by consumers in real driving conditions;
    • fuel efficiency progress in light-commercial vehicles (vans) with the objective of reaching 175 gCO2/km by 2012 and 160 gCO2/km by 2015;
    • increased use of biofuels maximizing environmental performance.” (Ref: CO_0250)
  • “In the process of its implementation, the timeframe and the overall ambition of the Strategy have been amended. The main element of the Strategy, Regulation (EC) 443/2009, enters fully into force only in 2015. Also many of the additional implementing measures have different dates for entry into force, usually later than 2012. Furthermore, a new element of a long-term perspective, i.e. the 2020 target, was included in the CO2 from cars regulation and subsequently in the proposal for an equivalent regulation for light commercial vehicles. This longer-term vision should compensate for a delay of short-term reductions. Therefore, it is clear that despite the progress in implementing the Strategy (...), it is unlikely that the objective of an equivalent of 120 gCO2/km will be achieved in 2012.” (Ref: CO_0250)
  • “Policies and strategies for CO2 emission reduction have set targets for 2020 to increase the share of biofuels and of alternative hydrocarbon fuels. Targets have also been set for the development of hydrogen and fuel cell technology as economic, safe and reliable alternatives to fossil fuel.” (Ref: CO_0234)
  • “Low emission requirements and their maximum range favour the development of electric vehicles especially for urban use.” (Ref: CO_0234)
  • “One way to achieve substantial absolute emission reductions often suggested is to switch aviation to biofuels. However, there are doubts about the life cycle reductions to be achieved with alternative fuels and problems such as space use, conflicts with food production, and potential loss of biodiversity. It also appears that initially promising biofuels as Jatropha seeds, depend greatly on where the seeds are planted and may have serious environmental, social and economic problems associated with them. Some researchers recommend using caution when suggesting biofuels such as Jatropha will contribute to large scale greenhouse gas emission reductions.” (Ref: CO_0187)
  • “Governments have set targets to achieve 20 million electric vehicles (EVs) on the road by 2020, in line with levels required to achieve the 2DS[1] objectives. Achieving this goal, however, hinges on increasing vehicle production, lowering costs, developing infrastructure and boosting consumer choice and confidence.” (Ref: CO_0185)
  • “Up until 2025, the main driver for reversing the trend of increasing greenhouse gas emissions in transport sector is likely to remain improved fuel efficiency.” (Ref: CO_0194)

[1] Energy Technology Perspectives 2012 2OC Scenario (ETP 2DS) is a forthcoming publication that demonstrates how technologies can make a decisive difference in achieving the internationally agreed objective of limiting global temperature rise to 2°C above preindustrial levels.

Booking and payment systems

  • “In view of the growth of international road traffic, the objective to internalise road externalities has gained particular weight and a number of Member States actively consider introducing extensive electronic road toll systems.” (Ref: CO_0253)

Renewable energy production

  • “Reducing projected GHG emissions in the energy production and supply sector will require a broad portfolio of technologies, including increased use of renewable energy technologies (biomass, solar, wind, run-of-the-river and large hydropower, and so on), and nuclear power.” (Ref: CO_2019)

Energy efficiency

  • “Low tyre pressure can increase fuel consumption and CO2 emissions by 4%, reduce tyre lifespan by 45% and can cause accidents. Fitting tyre-pressure monitoring systems (TPMS) should contribute to both greater fuel efficiency and safety.” (Ref: CO_0250)
  • “With full implementation of current policies, the EU is on track to achieve a 20% domestic reduction in 2020 below 1990 levels, and 30% in 2030. However, with current policies, only half of the 20% energy efficiency target would be met by 2020.” (Ref: CO_0194)
  • “It is possible to cut GHG emissions from the transportation sector cost-effectively by up to 65 percent below 2010 levels by 2050 by improving vehicle efficiency, shifting to less carbon intensive fuels, changing travel behavior, and operating more efficiently.” (Ref: CO_4013)

Impacts on Mobility and Transport

Improvement in vehicles’ technologies (fuel and energy consumption)

  • “The main drivers of transportation GHG emissions are population, transport intensity (passenger or freight miles per person), energy intensity (vehicle fuel consumption), and fuel carbon intensity. Three of the four drivers of transportation GHG emissions (transport intensity, energy intensity, and carbon intensity) can also be thought of as levers that technologies and policies can use in order to reduce transport GHG emissions.” (Ref: CO_5046)
  • “Emission reductions have to be achieved by increasing efficiency in the transport sector, improving vehicle energy efficiency and extending the use of alternative fuels and propulsion technologies.” (Ref: CO_0234)
  • “(…) the decarbonisation of the transport sector is in essence reliant on two major assumptions: the availability of sustainable and very low GHG biofuels, and the use of almost carbon-neutral electricity (in line with the target set for the power sector) in electrified road transport.” (Ref: CO_5030)
  • “The European airline industry has set a target of 50% reduction in emissions per passenger kilometer by the year 2020, with 2000 as the benchmark year. Cleaner, more efficient engines will produce a 20% reduction but the remaining 30%—more than half the total figure—is uncertain (Millar, 2005).” (Ref: CO_4010)

But technologies will not be sufficient alone…

  • “Technical options alone cannot achieve the European Commission's target of a 60 % reduction in GHGs from transport by 2050. Demand optimization will form an essential part of meeting this target; it can be very cost effective and can also offer environmental co-benefits such as air quality improvements and noise reduction.” (Ref: CO_5030)

A shift to cleaner modes will be part of the solution

  • “The International Railway Organization UIC foresees a modal shift from road and air traffic to rail traffic over the next decade, partly because of environmental policy (greenhouse gas emission targets). This shift is also recognized in a position paper on railway noise by the European Commission.” (Ref: CO_0144)
  • “Research has shown — for example in the CIVITAS initiative — the potential for CO2 reduction by shifting car trips to collective transport or to cycling.” (Ref: CO_0234)

Together with measures for fostering public transport…

  • “A recent survey of climate change plans in 30 cities worldwide found that the most common climate change mitigation actions in transport were the development of public transport (including bus rapid transit systems), the implementation of cleaner technologies, promotion of non-motorized transport, public awareness campaigns and implementation of cleaner technologies.” (Ref: CO_0147)

Some users’ resistances are difficult to overcome

  • “Studies of cost effectiveness generally find transportation GHG reductions more expensive than reductions in most other sectors. The high cost is due to: low fuel price elasticity by passenger car owners (and light trucks); strong demand for personal travel, air travel, and goods transport; the difficulty of introducing new low carbon fuels and new fuel efficient propulsion technologies; deteriorating quality of public transport virtually everywhere; and the increasing share of goods carried by truck.” (Ref: CO_0148)