|Smoke from industries contains
Credit: 'Señor Codo'
What is climate change mitigation?
In the field of climate change, mitigation is the term we use to describe efforts to lessen the damaging impacts of climate change by reducing the amount of greenhouse gases we pump into the atmosphere from power stations, industries, motor vehicles and other sources.
What can we do to mitigate future climate change?
There is a wide variety of mitigation activities we can undertake in our personal lives, in businesses and government. In terms of lifestyles, behaviour, and management practices, the following items presented by the IPCC all have potential to help:
Sectoral mitigation activities are presented in the table below.
||Key mitigation technologies and practices currently commercially available|
|Energy supply||Improved supply and distribution efficiency; fuel switching from coal to gas; nuclear power; renewable heat and power (hydropower, solar, wind, geothermal and bioenergy); combined heat and power; early applications of capture and storage of carbon (e.g. CO2 from natural gas)|
|Transport||More fuel efficient vehicles; hybrid vehicles; cleaner diesel vehicles; biofuels; modal shifts from road transport to rail and public transport systems; non-motorised transport (cycling, walking); land-use and transport planning|
|Buildings||Efficient lighting and daylighting; more efficient electrical appliances and heating and cooling devices; improved cooking stoves, improved insulation; passive and active solar design for heating and cooling; alternative refrigeration fluids, recovery and recycling of fluorinated gases|
|Industry||More efficient end-use electrical equipment; heat and power recovery; material recycling and substitution; control of non-CO2 gas emissions; and a wide array of process-specific technologies|
|Agriculture||Improved crop and grazing land management to increase soil carbon storage; restoration of cultivated peaty soils and degraded lands; improved livestock and manure management to reduce CH4 emissions; improved nitrogen fertilizer application techniques to reduce N2O emissions; dedicated energy crops to replace fossil fuel use; improved energy efficiency|
|Forestry||Afforestation (planting new forests); reforestation (restoring deforested areas); forest management; reduced deforestation; harvested wood product management; use of forestry products for bioenergy to replace fossil fuel use|
|Waste||Landfill methane recovery; waste incineration with energy recovery; composting of organic waste; controlled waste water treatment; recycling and waste minimization|
|Adapted from IPCC Fourth Assessment Report (2007), Working Group 3, Summary for Policy Makers, page 14.|
What are the costs of these actions and how do they relate to the costs of inaction?
The Stern Review: The Economics of Climate Change, a 2006 publication by Sir Nicholas Stern and a team of economists, presents the results of a major study on this topic. The key conclusion of the report is this:
The benefits of strong, early action on climate change considerably outweigh the costs.
The Stern Review goes on to say:
"The evidence shows that ignoring climate change will eventually damage economic growth. Our actions over the coming few decades could create risks of major disruption to economic and social activity, later in this century and in the next, on a scale similar to those associated with the great wars and the economic depression of the first half of the 20th century. And it will be difficult or impossible to reverse these changes. Tackling climate change is the pro-growth strategy for the longer term, and it can be done in a way that does not cap the aspirations for growth of rich or poor countries. The earlier effective action is taken, the less costly it will be."
Stern estimates that the cost of mitigation actions required to keep global average temperature from rising above 3°C is about 1% of the global GDP by 2050. This is far less than the future costs of inaction now. Ultimately, we have to choose how much we are willing to pay now to mitigate climate change costs in the future. Take a look at the illustration below and decide what you think we should sacrifice now in order to avoid the impacts described.
|Eventual temperature increase above pre-industrial times|
|Adapted from the "Stern Review: The Economics of Climate Change" (2006), Executive Summary, page v.|
How much time is available to realise the drastic reductions needed to stabilise greenhouse gas concentrations in the atmosphere?
|Sources of renewable energy such as wind provide alternatives to burning fossil fuels. Credit: 'Synapse-'|
The answer to this question depends on two things:
The answer to the first question can be answered by the temperature increase that we aim for (see the diagram above). Current concentrations of atmospheric carbon dioxide and other greenhouse gases are already much higher than pre-industrial concentrations. In 1750, the carbon dioxide concentration was 0.0280% (or 280 parts of carbon dioxide per million parts of air: 280ppm). By 2005, the concentration of carbon dioxide had reached 0.0379% (379ppm). During the period 1995 to 2005, carbon dioxide concentrations were increasing at a rate of nearly 2ppm per year. The warming effect of other greenhouse gases can be converted "carbon dioxide equivalent" values, producing a "common currency" for calculating the net greenhouse gas global warming potential.
If we allow greenhouse gases to reach a carbon dioxide equivalent of 450ppm we will be committed to a 2°C rise in temperature. At 550ppm, we can expect 3°C rise, and at 700ppm a 4°C rise in temperature. (Refer again to the illustration above.) The current (2008) carbon dioxide equivalent is about 440ppm and the rate of temperature increase is 0.2°C per decade.
The answer to the second question is really one of economics - should we start paying now and balance the cost over time, or try to pay it all later? Scientists can only make recommendations in this regard; it is up to the governments, businesses and civil society to decide. This is one of the things that the UNFCCC conference in Copenhagen, Denmark, at the end of 2009 will aim to do.
|An example of deforestation
occurring in Madagascar by ruby miners.
What are the policy actions that can overcome the barriers to implementation?
There is a wide variety of "policies and instruments" which governments can use as incentives for mitigation actions, though each has its costs and benefits. They should be evaluated using the following criteria: environmental effectiveness; cost effectiveness; distributional effects (including equity); and institutional feasibility. Climate-related policies are more likely to succeed if integrated into broader development policies (see the next question). The Fourth Assessment Report of IPCC Working Group 3 presents findings on the effectiveness of various policy approaches (such as regulations, taxes, tradable permits, voluntary agreements etc.)
It is important for governments to stimulate an economy that provides incentives for low greenhouse gas products, technologies and processes. This will require an effective "price of carbon", i.e. a financial value associated with greenhouse gas emissions and the prevention thereof. Government support for effective development, innovation and deployment of "climate-friendly" technology is important; this can be done through financial contributions, tax credits, setting standards and creating markets.
Some policies, measures and instruments which have been shown to be environmentally effective in various sectors are presented in Table SPM.7 (on pages 31 and 32) of the Summary for Policymakers, IPCC Fourth Assessment Report, Working Group 3 (2007). The sectors addressed are:
How can climate mitigation policy be aligned with sustainable development policies?
Climate change is not happening in an otherwise ideal world. The impacts of climate change are additional to existing stresses on the natural and social environment, such as unemployment and poverty, hunger, disease, loss of biodiversity and increasing desertification. Moreover, sustainable development is simply not possible without addressing climate change since humanity is entirely dependent on natural resources such as fresh air, clean water and fertile soils. Hence sound environmental management, of which climate change mitigation is part, is crucial to successful long-term development. "Mainstreaming" climate change mitigation into existing policies is likely to be more effective than establishing separate climate policies.
Mitigation practices often have "co-benefits" in other sectors, such as water- or electricity-saving. For example, recycling of consumer waste reduces greenhouse emissions from landfill sites, reduces the burden on landfill sites, and offers employment opportunities. These synergies should be identified and exploited.
Why should developing nations, such as those in southern Africa, spend resources on mitigation when most of the greenhouse gases to date have been produced by wealthy, developed countries?
The short answer to this question is that "we are all in this together". Moreover, since developing nations are most vulnerable to climate change impacts, it is in our interest to try to mitigate climate change - especially considering the conclusion of the Stern Review (see above). Also, there are substantial opportunities for synergy between climate mitigation and sustainable development, as explained in the answer to the question above.
In addition to these reasons, one should not overlook the power of a good example; in the recent UNFCCC Conference of Parties in Bali (December 2007), South Africa and other developing nations exerted substantial pressure on the United States was opposed to setting binding targets on greenhouse gas emissions. The trump card which South Africa presented was that developing countries were all willing to surpass the minimum obligations called for by developed nations.