For those hoping to save the planet by recycling and switching to ergonomic light bulbs, Swedish researchers are giving us a startling reality check.
They've analysed the carbon emissions of individuals across ten developed nations, including Australia, to find the most effective ways we can reduce our carbon footprint -- and they're not what our governments and education departments suggest.
The top-listed item? Having fewer kids.
In fact, reducing your family size by one person does far more to reduce pollution and tackle climate change than every other measure put together, saving 58.6 tonnes of carbon dioxide-equivalent emissions each year.
To put that into perspective, it's estimated that individuals must reduce their emissions to just 2.1 tonnes annually by 2050 to keep global warming to within two degrees Celsius.
But those of us not willing to give up our dreams of creating the Brady Bunch can still make a difference in other ways -- although you might not like those much either.
Giving up your car was the next most effective measure, saving an average of 2.4 tonnes of emissions annually across the ten nations (this figure was even higher in Australia and the U.S., at just over 3 tonnes annually).
Next on the list were aeroplane travel (giving up just one round-trip transatlantic flight saved 1.6 tonnes of carbon dioxide emissions) and investing in green energy (1.4 tonnes).
Going vegetarian (which saves 0.8 tonnes annually) reduces household emissions by eight times more than upgrading light bulbs and four times more than comprehensive recycling.
This graph shows just what that looks like in numbers:
The findings were published on Wednesday in Environmental Research letters.
While some of these measures sound drastic to say the least, there are some who have taken them on board.
Atmospheric scientist Peter Kalmus is one of them. He's reduced his carbon emissions by around 90 percent by doing many of the study's big-ticket items -- he refuses to get on a plane, he's gone vegetarian and his car runs on veggie fuel.
The authors of the report are calling for government guidelines and classroom textbooks to more accurately represent ways to reduce greenhouse gas emissions.
Australia was the only country studied whose government guidelines for cutting emissions advocate a car-free lifestyle, the EU was the only one to suggest eating less meat and no country mentioned the benefits of having fewer children.
"Some high-impact actions may be politically unpopular, but this does not justify a focus on moderate or low-impact actions at the expense of high-impact actions," the report authors write.
Using reusable shopping bags, for example, saves 5 kilograms of emissions a year -- less than one percent of the emissions saved by not eating meat.
But it's not all bad news -- just think of all the delicious vegetarian meals you can explore in the time that would otherwise have been spent changing nappies.
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