Working Group III is concerned with how to stabilize greenhouse gases and reduce future impacts from climate change.
Key Findings
For more information on mitigation options in Canada see Climate Solutions.
Stabilization of greenhouse gas concentrations is possible
As shown by WG I and II, climate change is a global problem which will have long-term effects on both human societies and the natural world. Yet the future is undetermined: the choices we and our governments make regarding development paths over the coming decades will determine the extent to which the climate will change, and the consequent severity of the impacts.
This figure shows one possible set of futures. The grey area represents increasing emissions over the 21st century given a fossil-fuel-intensive development path. Each coloured area represents a different mitigation scenario, diverging from the grey "baseline" towards stabilization targets (450 to 750ppmv CO2). Clearly the mitigation paths which diverge soonest are the smoothest - these would require the least amount of economic and social disruption.
A goal for the stabilization level of CO2 has not yet been accepted, but it is generally regarded as between 450ppmv and 750ppmv by 2100.
Mitigation is linked to broader issues
Climate change mitigation is linked strongly to broader socio-economic policies and trends such as those relating to development, sustainability and equity. Many steps to mitigate climate change could also:
improve public health
increase employment
improve local environments
enhance forests and watersheds
eliminate subsidies to the fossil fuel sector
stimulate technological advances
In this sense, climate change mitigation presents many possibilities for synergistic projects with benefits across a range of issues.
The resources required to mitigate emissions are dominantly held by developed nations - therefore it is amongst them that mitigation must begin. Given that these countries are the most intensive producers of greenhouse gases, they also have the greatest number of options for reductions.
Technological Mitigation Options
Technological advances are providing low-emission alternatives such as:
wind turbines
efficient hybrid engine cars
fuel cells
low carbon and renewable-biomass fuels
zero-emissions technologies
reduction of industrial by-product and gas emissions
Greenhouse gas emission reductions by 2020 could be substantial using existing technologies, many of which would involve no net implementation cost. In fact, substantial reductions of greenhouse gas emissions could be made in North America by increasing the efficiency of buildings, transportation and industry - while providing overall profit to everyone involved and creating new economic opportunities.
Government action and policies are needed to remove both barriers to emission reducing technologies entering the market and subsidies to fossil fuels.
Biological Mitigation Options
Biological mitigation relies on forests, agricultural lands and other terrestrial ecosystems to remove carbon from the atmosphere. These are referred to as "carbon pools", and a process which moves carbon from the atmosphere to a pool is termed a "sink" (e.g. reforestation).
Although not usually permanent, biological mitigation provides a useful stop-gap measure. In general, strategies involve:
the conservation of existing carbon pools,
increasing the size of carbon pools, and
substituting sustainably produced biological products for energy intensive products (eg. building with wood instead of steel).
It is important to note that these strategies must be implemented correctly in order to achieve reductions in atmospheric greenhouse gases. Without carefully considered rules they may cause loss of biodiversity, ground-water pollution, and negligeable emissions reductions.
There are many possible paths to mitigation
There is no single path to a low emission future - countries and regions will have to choose their own strategies. There are many institutional and practical barriers to implementing mitigation schemes which need to be overcome.
Social learning and changes in institutional structure could contribute to climate change mitigation, particularly if preferences and cultural norms shift towards lower emitting and sustainable behaviours. Greater public participation in the decision-making process could reduce resistance to innovation and contribute toward sustainability and equity.
National responses should involve a balanced portfolio of policy instruments, integrated with broader non-climate objectives. Policy instruments may include:
emissions/carbon/energy taxes
tradable or non-tradable permits
provision and/or removal of subsidies
energy mix requirements
product bans
voluntary agreements
government spending and investment
support for research and development.
Early action promises large benefits at low cost
Economic models show that a gradual, early transition from the world's current energy system towards a low emission economy minimizes cost and maximizes opportunities for technology and profit. For example, estimated costs of meeting the Kyoto Protocol, ignoring beneficial spinoffs, are at most $125 US per capita per year in the OECD (including most developed nations).
Delay will encourage locking in carbon-intensive technologies, reducing future flexibility and possibly requiring rapid shifts in capital.
Of course, near-term action has the further benefit of minimizing the risks to human and natural systems (outlined by WG II) and avoiding the costs thereof, which are not taken into account.
Greenhouse Gases
TAR
WGI
