A carbon offset is a reduction or removal of emissions of carbon dioxide or other greenhouse gases made in order to compensate for emissions made elsewhere. Offsets are measured in tonnes of carbon dioxide-equivalent (CO2e). One ton of carbon offset represents the reduction or removal of one ton of carbon dioxide or its equivalent in other greenhouse gases. Offsets are viewed as an important policy tool to maintain stable economies and to improve sustainability. One of the hidden dangers of climate change policy is unequal prices of carbon in the economy, which can cause economic collateral damage if production flows to regions or industries that have a lower price of carbon—unless carbon can be purchased from that area, which offsets effectively permit, equalizing the price.