While you were sitting in the dark, let's shine a light on how much of the planet's resources you've been using up.
At 8:30 on the evening of March 28, city streets faded to black as thousands of communities took part in the global rallying cry for the environment casting the City of Light into shadow and swathing the Acropolis in blackness.
"We want to make visible what is so often invisible, which is people's desire to do something to halt climate change,"said Keith Stewart, manager of climate change for the World Wild-life Fund (WWF) Canada, which co-ordinated the event.
Turning off lights and appliances is an environmentally friendly way to call for action on climate change.
But even when the lights go out, your impact on the environment continues. From the refrigerator humming in the kitchen to the furnace in the basement and the car parked in your driveway, your ecological footprint is taking a toll on the planet.
The ecological footprint represents your impact on the environment. It calculates how much land would be needed to produce all the resources you consume and absorb all the waste you dump back into the environment.
Canadians are among the world's greediest resource-gobblers. Canada has the world's seventh-largest ecological footprint per capita, after the United Arab Emirates, United States, Kuwait, Denmark, Australia and New Zealand.
According to the World Wildlife Fund's 2008 Living Planet Report, Canadians' average footprint is 7.1 global hectares.
The Earth's carrying capacity is 1.8 hectares per person, meaning we are in "overshoot"spending the Earth's natural capital at a pace that threatens our very survival. The average global footprint is 2.7 hectares.
The footprints of Canadian cities range from a high of 9.9 for Calgary to a low of 6.9 for Sudbury, according to a 2004 survey by the Federation of Canadian Municipalities.
Calgary's footprint is highest because of C02 emissions from Alberta's oil and gas industry, dependence on coal for electricity, higher disposable income and car-centred transportation, according to Hans Messinger, a research adviser at Statistics Canada.
About 70 per cent of your footprint is determined by factors over which you have little control, such as availability of public transit, said Meredith Stechbart, a project manager with the Global Footprint Network in Oakland, Calif.
"If you're in L. A. and you have to drive everywhere, that locks you into a certain category of footprint," she said. Government and local services like water supply, mail delivery and financial services together account for 26 per cent of your footprint.
However, lifestyle choices regarding transportation, diet and housing can make a significant difference, according to Bill Rees, the University of British Columbia professor who originated the concept of the ecological footprint.
Do you commute by car or walk and cycle everywhere, for instance? Do you eat a lot of red meat or eat mostly vegetables, preferably organic? Do you live in a sprawling house or a compact, energy-efficient condo or row house?
"There's no question the biggest thing people can do is to reduce their carbon output and the biggest contributor to that is the car," Rees says.
Transportation represents 17 per cent of the average Canadian's footprint, said Stechbart.
Car travel makes up 80 per cent of the typical footprint. Twenty per cent is from the manufacture of your vehicle and 60 per cent from driving it.
Food makes up 24 per cent of our footprint. Environmentalists have long urged us to choose organic, local products. But Canadians have no choice but to eat imported food in winter. And recent studies suggest foods shipped by sea have a lower footprint than produce trucked from closer to home, because trucking has a higher carbon footprint.
Our homes are better insulated than 20 years ago, but Rees said we still have a long way to go.
Home heating accounts for 60 per cent of residential energy use, according to Statistics Canada, and represents 15 per cent of our total footprint. Choose a smaller dwelling in a dense neighbourhood and make it as airtight as possible, Rees counseled. And buy the most energy-efficient appliances you can find.
"We're discounters. We want to save $100, so we don't buy the most efficient model. The point is it would pay for itself."