Why Bicycling to a BBQ is Bad for the Climate

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My brother had a barbeque this summer in a lovely house 35 kilometers from Stockholm city. One of the guests, the new rabbi of the community, came on her bicycle. Needless to say, my family was impressed with this feat, and I really hope my brother gave the hungry climate hero an extra good piece of meat. (Muslim and Jewish ritual slather has been banned in Sweden since WW II, so kosher meat is considered a special treat).

But I was left with a question: how much better is it for the climate to bicycle instead of taking the car?

A car emits about 130gCO₂ /km as it is burning fuel[1]. A small but significant amount of CO₂ is also emitted in the production of the car[2].

Exactly like there are CO₂emissions associated with the proposal of a car, there are also CO₂emissions coming from the bike, or more exact from the biker. The energy input for the bicycle comes from the food that the bicyclist eats, and food is a very greenhouse gas intensive product. An average person in Sweden consumes 1 200 000 kcal every year [3]and this contributes to about 2 ton of CO₂ equivalent[4]. To make a 35 km bike ride an average adult needs about 850 kcal[5]. This will cause about 1400g of CO₂ equivalent greenhouse gases to be emitted.

This means that a car ride emits about 3.4 times more greenhouse gases compared to a bicycle ride. So if four friends are going to a BBQ it is better, from a greenhouse gas perspective, to be sharing a car compared than each one riding a bicycle.

Does this sound counterintuitive? There is a large focus on media on greenhouse gas emissions from cars and the importance of finding alternatives for today’s transportation system. Meanwhile, our food consumption contributes as much to climate change as our transportation[6]^,[7]. According to one study published in Nature, the global food system is responsible for a third for all greenhouse gas emissions[8].

Climate conscious consumers are asked to eat local and organic foods to decrease their CO₂footprints but it is uncertain if this tactic is effective. Organic farming do emit, on average, less greenhouse gases compared to conventional farms[9], but they are also less land efficient[10]. When farming requires more land it means that forests has to be cut down, and deforestation alone contributes to about a 10% – 20% of greenhouse gas emissions [11]^,[12].

Local food is also a tricky issue. In cold countries local food production is usually very energy intensive and therefore it could often be better, from a climate perspective, to import food from a warmer country[13].

If one wishes to be climate conscious about food consumption there is really just one thing to do – eat less meat. For example, one hamburger is equal to about 20 km of driving[14]. There are two reasons for the large climate footprint of meat. I) animals fart, especially animals that ruminate. This contributes to a large release of methane, a very potent greenhouse gas[15]. II) An animal need 10 kilos of feed to gain one kilo. This feed is often an agriculture product, such as soya or hay, and as such causes large greenhouse gas emissions.

In conclusion: if four friends are going to a BBQ they should they should take a car, but if they are going to a vegetarian restaurant it is better if they bicycle.

Rank	Food	CO2 Kilos Equivalent
1	Lamb	39.2
2	Beef	27.0
3	Cheese	13.5
4	Pork	12.1
5	Turkey	10.9
6	Chicken	6.9
7	Tuna	6.1
8	Eggs	4.8
9	Potatoes	2.9
10	Rice	2.7
11	Nuts	2.3
12	Beans/tofu	2.0
13	Vegetables	2.0
14	Milk	1.9
15	Fruit	1.1
16	Lentils	0.9