Some experts argue that a carbon tax should be considered among the range of instruments available to the South African government, economy and society as part of a broad portfolio of mitigation actions. A carbon tax was one of the most effective wedges of mitigation scenarios (LTMS - Long Term Mitigation Scenarios) for South Africa. The purpose of such a tax would be to reduce greenhouse gas (GHG) emissions. A carbon tax would achieve this through two broad effects - a demand effect, reducing energy demand due to higher prices, and a substitution effect, with switching from more or less carbon-intensive fuels. Experts further argue that there are other ways of achieving this end, but a carbon tax is a highly effective means of doing so - if experience of actual taxes in other countries and modelling of potential taxes in South Africa is any guide.