Reduction of greenhouse gases: mitigation
The IPCC suggests a portfolio of measures to further
reduce greenhouse gases. This includes changes in
lifestyle towards reducing individual and collective
ecologic footprints; upgrading energy infrastructure;
investment into energy security; energy efficiency
measures for vehicles, buildings and the electricity
sector; renewable energy; biofuels; and a model shift in
transport and carbon storage. Not all of them have the
same potential for greenhouse gas reduction or growth.
Some of them also have possible health impacts
(nuclear energy and carbon storage) – but most of
them combined in the long term would have multiple
benefits for health.
Lifestyle changes can reduce greenhouse gas emissions.
Changes in lifestyle and consumption patterns that
emphasize resource conservation can contribute to
developing a low-carbon economy that is both equitable
and sustainable. Education and training programmes
can help overcome barriers to the market acceptance of
energy efficiency, particularly in combination with other
measures. Changes in occupant behaviour, cultural
patterns and consumer choice and use of technologies
can result in considerable reduction in CO2 emissions
related to energy use in buildings. Transport Demand
Management, which includes urban planning (that can reduce the demand for travel) and provision
of information and educational techniques (that can reduce car usage and lead to an efficient
driving style) can support greenhouse gas mitigation. In industry, management tools that include
staff training, reward systems, regular feedback and documentation of existing practices can help
overcome industrial organization barriers and reduce energy use and greenhouse gas emissions.
Upgrades of energy infrastructure in industrialized countries and policies that promote energy
security can, in many cases, create opportunities to achieve greenhouse gas emission reductions
compared to baseline scenarios. Additional co-benefits are country-specific but often include air
pollution abatement, balance of trade improvement, provision of modern energy services to rural
areas and employment. The widespread diffusion of low-carbon technologies may take many
decades, even if early investments in these technologies are made attractive. Initial estimates
Key messages
• The measures taken to reduce
greenhouse gas emissions in Italy
are not adequate.
• If human health were included in
policy planning, the costs of
greehouse gas mitigation could be
offset by the benefits it will have for
human health through the reduction
of air pollution.
• Integrating air pollution abatement
and climate change mitigation
policies offers potentially large cost
reductions compared to treating
those policies in isolation.
• Lessons learned in other countries
showed that combined examples of
measures to reduce greenhouse gas
emissions and air pollution are also
reducing the use of resources
through energy conservation,
increasing energy efficiency, fuel
switching, demand management and
behavioural change.
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show that returning global energy-related CO2 missions to 2005 levels by 2030 would require a
large shift in the pattern of investment, although the net additional investment required ranges
from negligible to 5–10%. It is often more cost-effective to invest in end-use energy efficiency
improvement than in increasing energy supply to satisfy demand for energy services. Efficiency
improvement has a positive effect on energy security, local and regional air pollution abatement
and employment.
Renewable energy generally has a positive effect on energy security, employment and on air
quality. Given costs relative to other supply options, renewable electricity, which accounted for
18% of the electricity supply in 2005, can have a 30–35% share of the total electricity supply in
2030 at carbon prices up to US$ 50 per (metric) ton of CO2 equivalent (US$ 50/tCO2-eq). The
higher the market prices of fossil fuels, the more low-carbon alternatives will be competitive,
although price volatility will be a disincentive for investors. Higher priced conventional oil
resources, on the other hand, may be replaced by high carbon alternatives such as from oil sands,
oil shales, heavy oils and synthetic fuels from coal and gas, leading to increasing greenhouse gas
emissions, unless production plants are equipped with carbon dioxide capture and storage (CCS).
Given costs relative to other supply options, nuclear power, which accounted for 16% of the
electricity supply in 2005, can have an 18% share of the total electricity supply in 2030 at carbon
prices up to US$ 50/tCO2-eq, but safety, weapons proliferation and waste remain a high
constraint, in particular for human health. Carbon storage in underground geological formations is
a new technology with the potential to make an important contribution to mitigation by 2030.
Technical, economic and regulatory developments will affect the actual contribution. Carbon
storage is not free of health effects – such as the effects of accidental release of CO2 through
leakages.
There are multiple mitigation options in the transport sector, but their effect may be counteracted
by growth in the sector. Mitigation options are faced with many barriers, such as consumer
preferences and lack of policy frameworks. Improved vehicle efficiency measures leading to fuel
savings in many cases have net benefits (at least for light-duty vehicles), but the market potential
is much lower than the economic potential due to the influence of other consumer considerations,
such as performance and size. There is not enough information to assess the mitigation potential
for heavy-duty vehicles. Market forces alone, including rising fuel costs, are therefore not expected
to lead to significant emission reductions.
Biofuels might play an important role in addressing greenhouse gas emissions in the transport
sector, depending on their production pathway. Biofuels used as gasoline and diesel fuel
additives/substitutes are projected to grow to 3% of the baseline of total transport energy demand
in 2030. This could increase to about 5-10%, depending on future oil and carbon prices,
improvements in vehicle efficiency and the success of technologies to utilize cellulose biomass.
Modal shifts from road to rail and inland waterway shipping and from low-occupancy to highoccupancy
passenger transportation, as well as land use, urban planning and non-motorized
transport, offer opportunities for greenhouse gas mitigation, depending on local conditions and
policies. Medium-term mitigation potential for CO2 emissions from the aviation sector can come
from improved fuel efficiency, which can be achieved through a variety of means, including
technology, operations and air traffic management. However, such improvements are expected to
only partially offset the growth of aviation emissions. Total mitigation potential in the sector would
also need to account for non-CO2 climate impacts of aviation emissions. Realizing emissions
reductions in the transport sector is often a co-benefit of addressing traffic congestion, air quality
and energy security.
Energy efficiency options for new and existing buildings could considerably reduce CO2 emissions
with net economic benefit. Many barriers exist against tapping this potential, but there are also
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large co-benefits (high agreement, much evidence). By 2030, about 30% of the projected
greenhouse gas emissions in the building sector can be avoided, with net economic benefit.
Energy efficient buildings, while limiting the growth of CO2 emissions, can also improve indoor and
outdoor air quality, improve social welfare and enhance energy security. Opportunities for realizing
greenhouse gas reductions in the building sector exist worldwide. However, multiple barriers make
it difficult to realize this potential. These barriers include availability of technology, financing,
poverty, higher costs of reliable information, limitations inherent in building designs and an
appropriate portfolio of policies and programmes. The magnitude of the above barriers is higher in
the developing countries and this makes it more difficult for them to achieve the greenhouse gas
reduction potential of the building sector.
The economic potential in the industrial sector is predominantly located in energy intensive
industries. Full use of available mitigation options is not being made in either industrialized or
developing nations (high agreement, much evidence). Many industrial facilities in developing
countries are new and include the latest technology with the lowest specific emissions. However,
many older, inefficient facilities remain in both industrialized and developing countries. Upgrading
these facilities can deliver significant emission reductions. The slow rate of capital stock turnover,
lack of financial and technical resources and limitations in the ability of firms, particularly small and
medium-sized enterprises, to access and absorb technological information are key barriers to the
full use of available mitigation options.