Spider-Man

His carbon footprint depends on how crafty he is at hiding the enormous amount of energy required to make his webs.

Spider-Man is a hero in the Marvel Comics universe, and the alter ego of mild-mannered student Peter Parker. He swings around New York on his webbing, which is a pretty incredible invention. It’s super strong, flexible, and likely requires a ton of energy to produce. But let’s begin by looking at that fancy suit.

The Spider-Man Suit
Unlike Batman or Ironman, it doesn’t seem like Spider-Man’s outfit has any real protective padding or armor or anything like that. The natural conclusion is that he’s just really into spandex.

I asked my friend Emily Grubert to use something called Life Cycle Analysis to figure out the carbon footprint of a spandex suit. In one of the best emails I’ve ever received, she wrote,

“Spandex is apparently known for being a problem with respect to reuse and recycling. I messed around with a few carbon footprinting standards focused on textiles and came up with about 35 kg CO2e per kg Spandex (a mixture of polyurethane and polyester).

Turns out, it’s pretty easy to figure out how much material you’d need by looking at various CosPlay websites. They have pretty… thorough… documentation. According to several sites, you need around 3 m2 to make a full body suit. So there you go.”

I love the internet.

The carbon footprint of a single bodysuit would come out to 50.7 lb CO2e. But spandex isn’t the toughest material, so let’s say it rips from time to time and Peter has to remake his suit around 5 times per year. That brings the carbon footprint of all his suits to:

Emissions = 50.7 lb CO2e * 5 = 254 lb CO2e

Not too bad, Spidey!

Spider-Man’s webs
Spider-Man’s webs are probably the most investigated comic book ability I’ve been able to find. The general consensus is that they are some kind of woven carbon nano-fiber strong enough to support his weight while remaining flexible enough for him to swing around. Here’s the crazy thing: woven carbon nano-fiber really exists!

All we have to do now is determine the carbon footprint of producing carbon nano-fiber.

Scientists all over the world have been working on various techniques to produce carbon nano-fiber. The hope is to build something much lighter and much stronger to construct everything from cables to space stations. There are many different methods and each requires a different amount of energy. A magnificent review study published at MIT found that the general energy requirements for carbon nano-fiber range from 211 – 148,329 kWh per kilogram produced.

Now that we know how much energy it takes to make carbon nano-fiber, we need to figure out how much webbing Spider-Man carries with him on a typical day swinging around New York City. Luckily for us, Rhett Allain at WIRED has already done the heavy lifting. The most important assumptions shake out like this:

Number of web shots per hand = 50
Average length of a web shot = 20 m (~66 feet)
Average web radius = 1 mm
Density of carbon nano-fiber = 0.55 g/cm3 (0.02 lb/in3)

Which means that Spider-Man needs 3,454 g (~7.5 lbs) of webbing per outing. Spider-Man’s a pretty active teenager, but he still needs some time for school, so let’s say he makes 3-4 outings per week. This means he’ll need around 629 kg (1,387 lb) of webbing per year. That’s a — not-quite-an-actual-ton of carbon nano-fiber.

What about the energy? After all, this is where his carbon footprint is coming from. Well, we know that Peter Parker is brilliant, and we’ll assume that he’s trying to optimize his energy use at whatever university lab he’s using. Based on the numbers above, it will take somewhere between 133 – 93,240 MWh per year. For reference, the average American household uses 11 MWh per year.

Our final step is to figure out the carbon emissions coefficient for the energy he’s using This number goes up if the power comes from something dirty, like coal. It goes down if the power comes from something cleaner, like solar. From the comics, we know that Parker attends Empire State University — which doesn’t exist, but it’s pretty close to Columbia University ZIP: 10025/10027. According to the EPA, the carbon emissions coefficient for Columbia’s ZIP code is 623.78 lb CO2e / MWh. We can use this to calculate Spider-Man’s carbon emissions from creating his webbing:

Emissions (min) = 132.98 MWh * 623.78 lb CO2e/MWh = 82,894 lb CO2e
Emissions (max) = 93,239.74 MWh * 623.78 lb CO2e/MWh = 58,161,085 lb CO2e

While these numbers look pretty bad, that MIT study I mentioned above points out that making carbon nano-fibers is becoming less energy intensive, so the smaller value is probably closer to Spider-Man’s carbon footprint.

It’s also important to note that mild-mannered student Peter Parker might be able to hide that energy footprint within his school at Empire State University. The Columbia Medical Center alone accounted for 79,200 MWh in 2010. Peter Parker’s web-making could be just 0.2% of the Medical Center’s energy use, if he’s using the most efficient carbon nano-fiber production method. If he’s using the most-intensive production method, then Parker’s energy bill would come out to 118% of the Columbia Medical Center’s. That’d be pretty tough to hide.

The Final Analysis
Compared to other superheroes, Spider-Man is making a relatively minor contribution to global carbon emissions. His carbon footprint is likely around:

Spider-Man = 82,894(webs) + 254(suit) = 83,148 lb CO2e

BONUS ROUND TIME

While woven carbon nano-fibers do exist, they’re not nearly long enough for anyone to try swinging around New York City. They also require a long time to make. That got me thinking, how long would it take Parker to make all of this spider-rope?

The most efficient method for producing carbon nano-fibers can make them at a rate of 0.052 kg/hr. If Spider-Man makes an outing 3-4 times per week, that means he has around 2 days to make his webbing for each outing. Can he do it?

3,454 g webbing per outing = 3.454 kg
Time required = 3.454 kg / 0.052 kg/hr = 66.4 hr = ~ 2 days, 18 hr

No. No, he cannot.

“But wait!” I can hear you saying. “What if he’s using multiple machines?” Yes, you’re very clever. But let’s play that scenario out here.

If we assume that Empire State University is trying to corner the carbon nano-fiber market, that means they might have as many as 5 different labs producing carbon nano-fibers non-stop around the clock. And we know that Parker needs to take the fiber being produced by at least two of those labs. That leaves us with the following possibilities:

Previous character: Oracle/Barbara Gordon

Next character: Superman

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