CO2 IMPACT: Cars, bikes, electricity, volcanoes, and recycling

CO2 emissions comparison: Car vs Bicycle

If you are interested in reducing your carbon footprint, one of the things you have undoubtedly heard is that cycling instead of driving is a great way to lower your CO2 emissions. While this is certainly true, especially at face value, there are a lot of factors to consider when trying to find out just how much CO2 you’re actually saving.

Let’s start by taking out the CO2 associated with production of bikes and cars, since this is a one-time manufacturing measurement – we will only focus on how much carbon is emitted from directly using these modes of transportation.

Measuring CO2 emissions from bicycles is easy: the amount is zero. Therefore, switching to biking will be less than driving, no matter which type of vehicle you drive.

Measuring CO2 emissions from vehicles, on the other hand, is much more complicated. The EU average for internal combustion engine vehicles is a little over 122 g CO2/km (2019 EEA data), meaning 1kg of CO2 is emitted for every eight kilometers driven, more or less. In real life, emissions vary based on driving habits, such as city vs highway driving, how much the driver starts and stops, vehicle tire pressure, and many other tiny factors that all add up to differences in real emissions.

But what about electric vehicles? EVs emit no direct emissions – the true carbon footprint of driving them depends on your local electricity source. Charging EVs on coal-powered electricity in somewhere such as Germany will have a much different footprint than charging on hydro-powered electricity in somewhere such as Norway. Regardless, even if charging from a grid powered solely from fossil fuels, it is still cleaner to drive an electric vehicle than an ICE vehicle – by about 10kg per 100km, rounding it out slightly to make it a nice clean number.

Offsetting the average home’s electricity usage – How does this really work?

The average North American home uses around ~900 kWh of electricity per month. You can offset this by planting 10 seedlings that will grow for 10 years!  But what does this really mean?

First off all, it depends which sources you get your electricity from. If you are connected to a grid run mainly on hydro (which is used extensively in Canada, Norway, and many other water-rich countries), planting seedlings will do more than offset your electric emissions – you’ll be below net-zero in this respect, meaning you’re offsetting more emissions than you are responsible for using, since renewables produce no emissions during operation (there are emissions associated with their production and maintenance, but over their lifespans this ends up being much less than the same timeframe for coal). This is true for nuclear energy; even though there are perceived issues with radioactive waste disposal, when it comes to carbon-free electricity it is one of the most reliable sources.

However, if you are connected to a grid that is powered by coal, oil, or even natural gas, there are carbon emissions associated with your electricity usage. And since electricity is ubiquitous in almost all areas of modern life – with coal still being the most utilized form of electricity production worldwide – there are many people around the world that could offset their electric emissions through the best method we currently have: planting trees.

With regard to tree planting, it is both straightforward and complicated. The straightforward part is how trees offset carbon: by absorbing it from the atmosphere during photosynthesis and storing it in trunks and branches. The complicated part is how to accurately measure this to determine how many trees are needed to offset any particular amount of emissions. Different trees absorb different amounts of carbon; some begin to absorb a lot of carbon right away (such as cecropia trees, which are ideal for replating in tropical rainforests), while some take years before they sequester any meaningful amount (such as mahogany). Some trees are not very good at all, such as some northern conifers – but planting trees is still a good idea no matter how much carbon they take in. There are three main keys you need to know: 1) Where is your electricity coming from, 2) How much electricity do you use (by knowing the answer to both of these you can determine your emissions from electricity), and 3) Which trees are you planning to plant? All you need to do is find out what your average emissions are from 1) + 2) and then find which tree would sequester enough carbon to offset this amount if you planted ten of them.

Or you could plant several dozen of any type of tree – this would more than offset your electricity emissions and make up for some other CO2 you emit.

What emissions come from a volcanic explosion?

Published scientific estimates of the global CO2 emission rates for all volcanoes are between 0.13 gigatons to 0.44 gigatons per year. This may seem like a lot – and it is – but it pales in comparison to what human activity emits over the same time period. Average anthropogenic CO2 emissions (aka from humans) is about 100 times greater at around 33 gigatons per year.

How many trees does recycling paper save?

Recycling 1 ton of paper saves 17 mature trees – but that’s not all. Every ton of paper recycled can save the energy equivalent of 642 liters of gasoline, which emits 1,476 kg of CO2. If that same ton of paper were burned it would create 6,818 kg of carbon dioxide. Furthermore, those 17 trees that are saved can absorb a total of 113 kg of carbon dioxide from the air each year.