Of the six sectors needing transformation to increase efficiency and reduce oil use -- cars, trucks, planes, fuels, finance and military -- three or four are near or past their tipping point and starting to get easier.

CNN: Freeing America from its addiction to oil

Existing techniques and technologies in energy efficiency retrofitting can reduce energy use by up to 40 percent per home and lower total associated greenhouse gas emissions by up to 160 million metric tons annually.

WHITEHOUSE: THE WHITE HOUSE

It says the way to reduce paper use lies in cutting consumption in industrialised countries, improving papermaking efficiency, and using more recycled paper and materials other than wood in manufacture.

BBC: Half paper waste 'could be saved'

To date, 64 European airports have signed up to the Airport Carbon Accreditation Scheme, a voluntary initiative launched in 2009 that aims to reduce emissions from ground transport, boost the use of renewable energy and increase the energy efficiency of airport terminals.

BBC: Airports doing more to go green

We funded and awarded more than 1, 800 of the Energy Efficiency and Conservation Block Grants that you conceived -- flexible products that reduce energy use, put people back to work and save taxpayers' money.

WHITEHOUSE: Talking Jobs with America��s Mayors

The first kinds are those who use it for corporate sustainability reporting, and the others are for those that want to reduce cost through building energy efficiency.

FORBES: What sustainability reporting software is the right one for you?