How bad are bananas?

I have to admit, I don't actually like bananas. But I've just bought a book called "How bad are bananas? (the carbon footprint of everything)". And it contains far more than just musings on bendy-shaped yellow fruit.

Bananas galore!
Image: Martin Wiesheu

The author, Mike Berners-Lee, meausres carbon footprints for a living. While it's not an exact science, he does at least explain how he arrived at his figures, and is very careful with some of his results that contradict popular wisdom.

I even found the answers to the hand drier versus paper towel debate and the fruit juice dilemma :

• Using two paper towels is equivalent to using an electric hand drier. Surprisingly, there is no difference in the energy used, even though the paper towels are usually transported by truck. So if you can get away with using a single paper towel, that's the more environmentally friendly option. However, even this is trumped by a cyclonic hand drier, like the Dyson Airblade, which wins hands down.

• Fresh juice seems to beat concentrated juice. Oranges are usually transported by boat, which is fairly efficient. However, creating fruit juice concentrate uses lots of energy. So despite the fact that concentrates are made to reduce the volume and weight of the juice, so it can be transported more easily, it doesn't translate into less energy being used overall. It just means that a single boat can carry more.

I found some other surprising facts about transportation that I hadn't considered. For example, a bottle of wine imported from New Zealand to the UK could have a lower carbon footprint than one from Italy. Products from within Europe tend to be transported by road, whereas the New Zealand wine will arrive on a boat. So even though Italy is closer to the UK, it's the mode of transport that makes the biggest difference. The concept of "food miles" is beginning to look a bit suspect to me now.

By the way, the same logic applies to bananas too. They may come from far away, but they usually arrive by boat.

Which begs the question, why don't we ship more freight by sea and waterway?

Photo by Martin Wiesheu, CC-BY-SA licence, obtained via http://www.flickr.com/photos/49325640@N00/3768818

Which is greener: hand driers or paper towels?

In the toilets at work, we have both electric hand driers and paper towels. I'm always surprised by the amount of people that use the paper towels, as I've never seen them as good for the environment. On the other hand, some people can't believe I use the hand drier, and ask if I'm aware how dirty they can be.

I looked into this, and they do have a point.

Hand driers usually have filters that need regular cleaning to remove dust and grime. If this isn't done, then bacteria can breed inside the machine, and then get blown onto your freshly washed hands. However, I do wonder if this is any worse than the bacteria that's always on toilet door handles, from people who haven't washed their hands. I'm still alive, so I guess it's not a major issue.

The argument for paper towels is that they're greener because they can be recycled and they don't use electricity. I've looked into this.

Dirty paper towels are often unsuitable for recycling, because they are made from low-grade paper, and are contaminated with bacteria (and worse) from people's hands. There's also a vast amount of energy used to fell trees, cut them, ship them to the paper plant, grind them into pulp, dry them (using hot air!), cut them into sheets, and drive them to the office. So I reckon using a hand drier eliminates a lot of unnecessary energy use.

Unfortunately, the information I have is from sources connected with either the paper industry or the hand drier manufacturers. I don't have concrete figures or independent evidence, so it's difficult to prove either argument. At the moment, I'm sticking with the hand drier.

So what's your preference - paper towels or hand drier?