We used to call it "being thrifty" -- maximizing the benefits while reducing costs. Any of our older relatives who lived through tough times from wars or economic depressions can readily describe the many ways they were 'efficient' with the meagre resources available. Economists like to call it 'resource efficiency,' 'energy efficiency,' or even 'productivity.' Either way, it means doing more with less, and in the run-up to the Climate Summit at the United Nations on 23 September 2014, this approach could be a real game changer for climate protection.

Let us explain:

The Sustainable Energy for All Initiative is working with partners, such as the UN Environment Programme (UNEP), to give everyone on Planet Earth access to clean and modern forms of energy by improving the way we use energy and doubling the use of renewable sources of energy. But it is the improvement in the way we use energy -- energy efficiency -- that is the real goldmine. If we can double our energy efficiency by 2030, a major objective of the Initiative, we can greatly reduce the threat of severe climate change, improve our environment, and save a LOT of money.

How much? The International Energy Agency this week reported that our global economy could be $18 trillion better off by 2035 if we adopted energy efficiency as a "first choice" for new energy supplies. This could be a real game changer for the climate. Targeted energy efficiency measures could deliver close to 50 percent of the emissions reductions required to limit global warming to 2 degrees C by 2020 -- a threshold that climate scientists warn should not be breached if our societies and economies are to avoid serious harm from a rapidly changing climate.

How to do that? By accelerating energy efficiency. We looked at the different sectors shaping our daily lives and identified five of them -- buildings, lighting, appliances, district energy systems and transport -- to form a Global Energy Efficiency Accelerator Platform. Accelerating energy efficiency in these five sectors will harness multiple benefits. The platform is not only about cutting greenhouse gases, but also about reducing environmental pollution, promoting social and economic development, increasing productivity and improving health and well-being. Did you know for example that a shift to efficient refrigerators could reduce global electricity consumption by more than 275 Twh per year -- equivalent to the electricity needs of Australia -- and save us $40 billion on electricity bills? In Costa Rica, a household could save $230 by replacing an old refrigerator with a new efficient model.

Current and planned energy efficiency policies harness merely a third of the economically viable energy efficiency potential. Therefore we created the Global Energy Efficiency Accelerator Platform to promote a major scaling up of energy efficiency investment through technical assistance, mutual support and collaboration. The Accelerator platform brings together countries, cities, businesses, investors, civil society and individuals ready to do more with less, ready to work together to get more from our existing resources.

What if someone proposed that you could save $11 trillion in the next 15 years, reduce CO2 emissions by 5 gigatons, create a huge number of jobs -- and help make modern energy services available for all across the world. Would you do whatever you could to move towards energy efficiency? We bet you will.

This post is part of a month-long series produced by The Huffington Post in conjunction with a variety of events being held in September recognizing the threats posed by climate change. Those events include the UN's Climate Summit 2014 (to be held Sept. 23, 2014, at UN headquarters in New York) and Climate Week NYC (Sept. 22-28, 2014, throughout New York City). To see all the posts in the series, read here.