We were surprised by a recent study claiming that humans emit approximately two tons of CO2 each year just from eating--a calculation that takes into account everything from food production and transportation to toilet paper and toilet water. It got us thinking: what other weird ways do we emit greenhouse gases in our daily lives?

A report from the U.K’s Institution of Engineering and Technology claimsthat working from home increases CO2 emissions for many workers. That's because telecommuting can increase home energy use by up to 30%--and many workers who telecommute a few days of the week tend to move further away from the office, increasing urban sprawl and upping travel time when they do head in to see the boss.

The same U.K Institution of Engineering and Technology report claims that online shopping often has a higher carbon footprint than traditional store-based shopping--emissions are simply shifted from the consumer to the delivery service. One exception: if 25 orders are delivered at the same time (replacing the equivalent of 3.5 shopping trips).

OK, so many of us don't buy CD's anymore. But just in case you needed even more incentive to download music instead of shelling out for discs, a studyfunded by Intel and Microsoft and performed by researchers at Carnegie Mellon University and Stanford University says buying digital music cuts carbon emissions by 40% to 80% compared to buying CDs. The study only looked at purchase-for-download services like iTunes--Bittorrent wasn't included--so the carbon footprint of bootlegging music is still up for debate.

A few years ago, a website called Blacklecaused a stir when it claimed that its black screen-backed Google Custom Search was more energy-efficient than Google's regular white screen. The reasoning: CRT and LCD computer monitors purportedly consume less energy when they display darker colors. The claim is disputed, however, and on some modern LCD screens the opposite may even be true, according to

Google

As evil as spammers may be, it's the people who read spam messages that generate significant carbon emissions. A recent study from ICF International and McAfee claims that the 62 trillion spam emails sent each year waste 33 billion kilowatt hours of power, or enough to power 2.4 million homes--and the majority of energy is wasted at the end user's computer while finding and delete spam. The solution is simple: install a spam filter.

Like every other product on the planet, purchasing books is responsible for energy use and carbon emissions (in production, transportation, marketing and so on). But there's a solution--a report from the Cleantech Group says that using an e-reader such as Amazon's Kindle displaces the purchase of 22.5 books each year, on average, for an estimated carbon savings of 168 kg of CO2. If the full storage capacity of the device is used, the Kindle stops the equivalent of almost 11,185 kg of CO2 from being released. The Cleantech Group only looked at the Kindle, but it's safe to say that other e-readers offer similar carbon savings.

Want to save carbon emissions when you fly? Pee before you board the plane. Japanese airline

ANA reasons that full bladders cause airplanes to be weighed down that little bit more, increasing carbon emissions and fuel use. If half of all travelers went to the bathroom before getting on the plane, it would cut CO2 emissions by 4.2 tons each month, the airline says. As an incentive to get passengers to pee, ANA has put up signs at airport gates asking passengers to go to the bathroom. Perhaps they should use a variation on what parents are used to saying on long car trips: Don't make me stop this plane!