But Baby, It’s Cold Outside

It happens every winter. It is cold outside, there are kids to think about, our cars are old, and we need some way of looking out the windshield. All perfectly good excuses to go outside and warm our car up for a couple of minutes. While your car is warming up, it is spewing out carbon dioxide from its back end. A major greenhouse gas contributing to climate change.

The average car emits 411 grams of CO2 per mile (USEPA, 2014). But how much CO2 is coming out of your car in the several minutes it warms up in the driveway? Let’s say the average person warms their car up for 10 minutes (Motavalli, 2012). And on average, that person drives at a speed of 40 miles an hour. Hence it takes 1 and half minutes to drive 1 mile (If I did my math correctly). Leaving their car idling in the driveway in those ten minutes means they could have driven 15 miles! This is also assuming they are going at a constant speed the moment they start driving, with no stopping. So, the real amount of miles is probably 10-15 miles. 15 miles times 411 grams of CO2 emitted per mile gives you a total of 6165 grams of CO2 emitted from the car idling in the driveway in that 10 minutes. That is a good amount of CO2 spewed into the atmosphere and they haven’t even started driving yet!

The fuel used to warm up cars, could have been used to produce more food.

But if I, just one person, warm up my car for a couple minutes it is okay right? Well, if only a handful of people do this, it wouldn’t be too bad. However, if everyone thinks this and warm up their car anyways, then we have millions of people each emitting 6165 grams on CO2 into the atmosphere. This is called tragedy of the commons, when individuals neglect the well-being of society in the pursuit of personal gains (Investopedia, 2009). In this case, individuals are neglecting to think about our atmosphere in the hopes of having a slightly warmer car.

Is there a benefit to starting up your car a couple minutes early? People normally warm up their car to get the engine warmed before driving. Or if your car is like mine, the power steering stinks and warming up your car is supposed to help with that. But it doesn’t. Warming up your car only warms up the engine and the interior of the car. It does not warm up the steering, wheel bearings, or the tires (Natural Resources Canada, 2015). The only way to warm up these parts of the car is to drive it.

We all have been guilty of this at some point. Warming up the car to have it be a little warmer before actually driving it. But this small benefit has major consequences, especially if a lot of people do it. It causes over 6000 grams of CO2 into the atmosphere, contributing to climate change. Next time, it gets chilly outside (as it does every winter), put on some gloves or a hat instead of warming up your car. Try scrapping the ice of your windshield instead of waiting for it to defrost. If you need to warm up your car, try cutting down the amount of time you let it idle. This small change can make a huge impact on the amount of CO2 that goes into our atmosphere.



  1. Epa, U.s. Greenhouse Gas Emissions from a Typical Passenger Vehicle (EPA-420-F-14-040a, May 2014) (n.d.): n. pag. US Environmental Protection Agency. Office of Transportation and Air Quality, May 2014. Web. 7 Feb. 2016.
  2. “Tragedy Of The Commons Definition | Investopedia.”Investopedia. N.p., 22 Nov. 2009. Web. 07 Feb. 2016.
  3. Natural Resources Canada. “Vehicle Warm-Up.” Natural Resources Canada. Government of Canada, 1 Dec. 2015. Web. 07 Feb. 2016.
  4. Motavalli, Jim. “Better to Warm Up Your Car Or Not?” Esquire. N.p., 28 Jan. 2012. Web. 07 Feb. 2016.

2 thoughts on “But Baby, It’s Cold Outside

  1. I’ve been guilty of this offense many times in the past, and to be honest I’ve never given it much thought. Your post is a good reminder that anytime an engine’s running, it’s contributing to atmospheric CO2. Idling also forces the engine to operate inefficiently, wasting fuel and stressing the engine.

    I wonder, though: is idling really equivalent to driving at 40mph in terms of CO2 emission? I’m not entirely clear on the mechanics, but I would think that a car’s emission rate changes (either increasing or decreasing) when it’s idling relative to when it’s moving. What about when you accelerate repeatedly, slam on the brakes, drive at high speeds, or engage four-wheel drive?


  2. Super interesting. I remember growing up, having the task of starting the car in the morning – unfortunately 10 minutes before leaving is probably a fair estimate. Often my parents would be driving us only a few miles away. When you think about it this way, we emitted more CO2 warming the car then actually driving it. UGH.

    Fortunately I find that excessively warming our cars is not as common recently as it was in my childhood. It’s a rare occasion that I myself heat my car anymore then 1-2 minutes, if at all. To those out there that think heating you car is better/necessary for your car, I recently heard on Car-Talk (which I consider to be a pretty reliable source!) that heating your car is completely unnecessary. The most your car may need is 1 minute of idle time before driving.

    This is good news! We have a lot of potential to improve our car sourced CO2 emissions. There are numerous ways that we can reduce transportation based emissions – public transit, electric cars, reduced commute, carpooling, walking/biking, etc. – however, some of these alternatives aren’t available to all. Sometimes it’s the subtle changes (i.e. not excessively warming our cars) that can have valuable impacts.


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