Discounting refers to the practice of putting a present value on costs and benefits that will occur in the future. Economists generally value costs and benefits that are predicted to occur in the future less than those incurred in the present because it is assumed that economic growth will make people richer, on the whole, in the future than they are today. As such the value of a pound or dollar in the future will be worth relatively less. The lesser value economists assign to a future dollar also stems from the observation that because people are impatient and so they prefer income today over income tomorrow. There is much disagreement about how to set the discount rate and this disagreement has relevance for measures to address, for example, climate change. If the discount rate is set very high (i.e. the cost of a dollar tomorrow is much lower than it is today) then the upfront costs of tackling climate change will be judged to outweigh the future economic benefits of having avoided it. Some argue that discounting undermines the rights of future generations; turning fundamentally ethical issues into technical ones whilst wrongly assuming ecological crises will only marginally affect economic growth.