Rich and developing countries alike have woken up to the reality that cheap and plentiful energy can no longer be taken for granted and that growing demand is harming the environment and quality of life.
Efforts to reduce energy consumption or increase the use of renewable sources are hampered by the fact that economic growth brings higher energy needs and it is still more expensive to produce power from the sun, wind and waves than from fossil fuels.
Yet governments do agree that using energy more efficiently will go some way towards ensuring that the climate isn't harmed by efforts to raise living standards worldwide.
Leaders of 16 major economies, including the United States, Japan, Germany, the U.K., China, Brazil, India and Russia, pledged in a joint statement at a meeting in Japan in July 2008 to "improve significantly energy efficiency, a low-cost way to reduce greenhouse gas emissions and enhance energy security."
The following is an overview of steps being taken in key countries and regions including the European Union, the United States, China and India to enhance energy efficiency.
European Union
The EU in 2007 adopted a target for greenhouse gas emissions and an action plan to achieve them. The 27-country group agreed to reduce emissions by 20 percent by 2020 and to meet 20 percent of its energy needs from renewable sources.
The EU pledged to deepen the cuts in emissions to 30 percent, provided other developed countries commit themselves to comparable reductions.
The United States
Through several programs, the U.S. is seeking to reduce its dependence on oil, and is promoting energy efficieny and the use of alternative resources.
Several states are taking action of their own. Ten north-eastern states are part of the Regional Greenhouse Gas Initiative that aims to reduce emissions from power stations by 10 percent by 2018.
California, the world's 12th-largest emitter of greenhouse gases, in August 2006 approved legislation requiring a 25 percent reduction in carbon dioxide emissions by 2020.
China
China accounts for more than 12 percent of global carbon dioxide emissions, making it the second-largest emitter after the U.S. The country's latest five-year development plan lists energy and environmental challenges among issues of priority.
The plan for the years 2006 to 2010 calls for a 20 percent reduction in the amount of energy used per unit of gross domestic product (GDP). It also aims to reduce emissions of major pollutants by 10 percent.
A Cleaner Production Promotion Law came into effect in China in 2003 and commits governments at all level to "give priority to purchase products conducive to energy and water conservation, waste reuse, environmental protection and resource conservation."
India
In 2001, India passed an energy conservation act as part of a strategy to make power available to all by 2012. The government identified efficiency and conservation as the cheapest option for narrowing the gap between supply and demand.
Other national policies
The International Energy Agency's (IEA) database of national policies on energy efficiency provides a comprehensive guide to the measures being taken by governments around the world.
Energy efficiency policies have been maturing over the years. A study commissioned by the IEA assesses the lessons to be learned from recent decades.
For additional links to government-related Web sites, please see the list in the right-hand column of this page.