8.21 |
Interactions between climate change and
other environmental problems offer opportunities to capture synergies in
developing response options, enhancing benefits, and reducing costs (see
Figure 1-1).
|
|
8.22 |
By capturing synergies, some greenhouse gas mitigation
actions may yield extensive ancillary benefits for several other environmental
problems, but also trade-offs may occur. Examples include, inter
alia, reduction of negative environmental impacts such as air pollution
and acid deposition; protecting forests, soils, and watersheds; reducing
distortionary subsidies and taxes; and inducing more efficient technological
change and diffusion, contributing to wider goals of sustainable development.
However, dependent on the way climate change or other environmental problems
are addressed, and the degree to which interlinking issues are taken into
account, significant trade-offs may occur and unanticipated costs may
be incurred. For example, policy options to reduce greenhouse gas emissions
from the energy and land-use sectors can have both positive and negative
effects on other environmental problems:
- In the energy sector, greenhouse gas emissions as well as local and
regional pollutants could be reduced through more efficient and environmentally
sound use of energy and increasing the share of lower carbon emitting
fossil fuels, advanced fossil-fuel technologies (e.g., highly efficient
combined cycle gas turbines, fuel cells, and combined
heat and power), and renewable energy technologies (e.g., increased
use of environmentally sound biofuels, hydropower, solar, wind- and
wave-power). Increased use of biomass as a substitute for fossil fuel
could have positive or negative impacts on soils, biodiversity, and
water availability depending on the land use it replaces and the management
regime.
- In the land-use sector, conservation of biological carbon pools not
only prevents carbon from being emitted into the atmosphere, it also
can have a favorable effect on soil productivity, prevent biodiversity
loss, and reduce air pollution problems from biomass burning. Carbon
sequestration by plantation forestry can enhance carbon sinks and
protect soils and watersheds, but -- if developed improperly -- may
have negative effects on biodiversity and water availability. For example,
in some implementations, monoculture plantations could decrease local
biodiversity.
|
WGIII TAR Sections 3.6.4,
4.4, 8.2.4,
& 9.2.2-5 |
8.23 |
Conversely, addressing environmental problems other
than climate change can have ancillary climate benefits, but the linkages
between the various problems may also lead to trade-offs. Examples
include:
- There are likely to be substantial greenhouse gas benefits from policies
aimed at reducing air pollution. For example, increasing pollution is
often associated with the rapidly growing transportation sector in all
regions, involving emissions of particulate matter and precursors of
ozone pollution. Addressing these emissions to reduce the impacts on
human health, agriculture, and forestry through increasing energy efficiency
or penetration of non-fossil-fuel energy can also reduce greenhouse
gas emissions.
- Controlling sulfur emissions has positive impacts on human health
and vegetation, but sulfate aerosols partly offset the warming effect
of greenhouse gases and therefore control of sulfur emissions can amplify
possible climate change. If sulfur emissions are controlled through
desulfurization of flue gases at power plants, an energy penalty results,
with associated increase of greenhouse gas emissions.
|
WGIII TAR Sections 2.4,
9.2.8, & 10.3.2,
& SRES |
8.24 |
Adopting environmentally sound technologies
and practices offer particular opportunities for economically, environmentally,
and socially sound development while avoiding greenhouse gas-intensive activities.
For example, the application of supply- and demand-side energy-efficient
technologies simultaneously reduces various energy-related environmental
impacts and can lower the pressure on energy investments, reduce public
investments, improve export competitiveness, and enlarge energy reserves.
The adoption of more sustainable agricultural practices (e.g., in Africa)
illustrates the mutually reinforcing effects of climate change mitigation,
environmental protection, and long-term
economic benefits. The introduction or expansion of agroforestry and balanced
fertilizer agriculture can improve food security and at the same time reduce
greenhouse gas emissions. More decentralized development patterns based
on a stronger role for small- and medium-sized cities can decrease the
migration
of rural population into urban centers, reduce needs for transportation,
and allow the use of environmentally sound technologies (bio-fuel, solar
energy, wind, and small-scale hydropower) to tap the large reserves of
natural resources.
|
WGII TAR Section 7.5.4 &
WGIII TAR Section 10.3.2 |
8.25 |
Reducing vulnerability to climate change can often
reduce vulnerability to other environmental stresses and vice versa.
Examples include, inter alia:
- Protecting threatened ecosystems: Removing societal stresses
and managing resources in a sustainable manner may help unique and threatened
systems also to cope with the additional stress posed by climate change.
Accounting for potential climatic changes and integration with socio-economic
needs and development plans can make biodiversity
conservation strategies and climate change adaptation measures more
effective.
- Land-use management: Addressing or avoiding land degradation
also decreases vulnerability to climate change, especially when response
strategies consider the social and economic factors defining the land-use
practices together with the additional risks imposed by climate change.
In regions where deforestation is progressing and leading
to carbon loss and increased peak runoff, restoring vegetation by reforestation
(and when possible by afforestation) and revegetation can help to combat
desertification.
- Freshwater management: Problems with availability, abundance,
and pollution of freshwater, which are often caused by demographic and
development pressures, can be exacerbated by climate change. Reducing
vulnerability to water stress (e.g., by water conservation, water-demand
management, and more efficient water use) also reduces
vulnerability to additional stress by climate change.
|
WGII TAR Sections 4.1-2 &
7.5.4 |