Or ride a unicycle. It still needs some effort to balance, but the big problem is that it isn't really steerable.

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huh??

How is exercise........bad for the environment?? You know what, I don't really care. Most of us are just interested in reducing the impact of pollution that results from our daily lifestyle, not necessarily achieving a ZERO carbon footprint, as thats impossible as long as we're living (note: dead bodies emit methane gas, which according to your extremist views would be *VERY* not green).

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I think our health is a bit more important to us than the environment.

Besides, healthy people eat less than obese people.

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"Besides, healthy people eat less than obese people."

When doing the same amount of exercise, yes. But people who are not exercising burn fewer calories than people who are, even when the people not exercising are more out of shape.

But yes, weigh your health and the environment as you see fit. All I care is that people not try and act like exercise helps the environment. Anything that makes you burn more calories is horrible to the environment. Electric drivetrains have far lower environmental effects.

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> Electric drivetrains have far lower environmental effects.

How are you figuring this? Which environmental effects, and how much lower?

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Oh, come on, this is trivially easy. A kilogram of beef (~2600 calories) takes as much energy to produce as your *average* European *CAR* uses in *250 kilometers*. Now beef is one of the worst, but food in general takes a huge amount of energy to produce, process, and transport. And then, on top of that, the human body is at best 20% efficient at turning food energy into kinetic energy, and only in optimal conditions (legs, at a specific torque in a specific direction and at a specific burn rate). And depending on how you harness that kinetic energy, a large chunk of even that can be wasted.

By comparison, thermal power plants are ~30-40% efficient (and rising), transmission is 92.8% efficient, charging is ~92% efficient, li-ion batteries 96-99.9% efficient, and electric drivetrains 85-90% efficient under typical operating conditions (they can peak at over 95%).

But hey, that's just energy (and, correspondingly, GHGs). It gets far worse when you look at things other than GHGs. Food crops rarely put more than a couple percent of the sun's energy into their edible components. Sugarcane is a rare exception at around 10%, but most foods are in the 0.1 to 3% range. If you assume that it *merely* takes as much energy on average to produce your food as it contains, which generally isn't even close to true for the American diet, your average person is at under 1% solar efficiency. Factor in the huge losses in the human body, and you're lucky if your average solar efficiency is over 0.1%. On the other hand, solar thermal plants are about 30% efficient, and then you have the (minor) additional losses of an EV drivetrain. It's well over two orders magnitude difference in terms of land area being taken up. Ever looked at a satellite image of our planet? We've destroyed most of the world's wildlife habitat because of agriculture and livestock raising taking up something like 4/5ths of the planet's non-ice-covered surface.

Oh, but it gets worse. Farming requires utterly ridiculous amounts of freshwater to produce food -- often thousands of gallons per pound of food. Agriculture is responsible for the Colorado literally not reaching the Gulf of California anymore, for example. And where the wastewater does make it to the sea, look out. Agriculture is responsible, for example, for the massive Gulf of Mexico dead zone, and similar dead zones around the world. It even affects climate on its own. The decline of the glaciers of Kilimanjaro is generally credited by the scientific community not to be due to global warming, but due to the expansion of livestock raising in the area altering weather patterns.

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Well, we could always commit mass suicide so we can stop tormenting mother earth for the selfish sake of survival.

We'll just make sure we don't do it with environmentally-damaging poison-spiked punch.

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Right on.

"human power" is still using a machine to do work. They are using the human body as the machine instead of a small engine. The problem with this is the human body ALSO requires fuel, and the human body is incredibly inefficient.

Just as the environmental movement derides the amount of land and environmental destruction that is caused by raising animals, they forget that if we replace motors with human power, we'll just be adding more land and produce needed to provide those extra calories to humans doing that work. That means extra land needed to feed the same people. Which WILL have an impact on the environment, it's not "no impact" and may not even be "net positive" though maybe it is.

But the big lesson is that by removing a machine, the work being done is STILL being done, you are just using a different machine, and that machine requires fuel.

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First off, since when do Americans get any reasonable percentage of their calories from cane sugar? Most American diets are dominated by meat, and in particular, beef. And even our sweeteners are primarily corn syrup, and corn is *not* a very efficient crop to produce (unlike sugar). And even where you do use cane sugar, it's essentially never eaten plain; it's almost always fixed into a food, which wastes energy. But hey, if you want plain sugarcane sugar, I hope you don't like rainforest, because that's what sugarcane competes against for land.

"Bio-mechanical expenditure of energy is incredibly efficient"

I'm sorry, buy bulls***. Biomechanical expenditure of energy is incredibly *inefficient*. In an optimal regime (legs at a specific torque at a specific power at a specific altitude, and so forth), it's approximately 35% blood-sugar-to-work/20% food-calories-to-work efficiency. And it falls off fast outside of an optimal range. And that's ignoring any inefficiencies in the device you're riding (or simply standing) -- balance often being a prime example.

http://books.google.com/books?id=ayISAAAAYAAJ&pg=PA539&lpg=PA539&dq=digestion+efficiency+percent+calories&source=bl&ots=xpOaPxL3Nn&sig=Cu4mX4es3NR1KfTIg6rLaEKkLwk&hl=en&ei=T53qSd7vLYbKM_3QmdkF&sa=X&oi=book_result&ct=result&resnum=4

The comparisons that try to show people exercising as being efficient almost always involve comparing a person on a vegan diet who's going at under 5mph versus a full-sized car going at 60, or something of that nature. But that's obviously a ridiculous comparison; it's not a difference in powertrains that's causing the efficiency difference, but a huge difference in weight and drag between the two. Electric bicycles at low speed are about the most efficient way a person can travel (apart from an eco-racer at similar speeds).

"If you can engineer something to move in a bi-pedal fashion for 20kms on a single meal"

Actually, thank you for reinforcing my point! Bipedal travel is *inefficient* because energy has to be wasted to retain balance and you have a high cross-sectional area. And since when is a "single meal" enough to walk 20 kilometers? 20kms on, say, 800 calories? Give me a break; that's 930 watt-hours. Walking slowly (the most efficient manner) -- 3.5mph -- takes about 125 minutes to burn 800 calories -- 11.75 kilometers. The segway uses 50Wh/mi at its *maximum speed*, i.e., 30 kilometers. At *many times the speed* (and the faster you go, the more energy you waste). Even if you count them as literally producing that meal and then burning it, with 2/3rds of the energy as being wasted in a power plant, charging, and transmission, and the heat not being used for anything, they merely come on par, despite the segway operating so much faster and the person walking at their optimal pace. Now consider that on the average American diet, far more energy went into producing that food than it contained. And that the energy amount is just the least of the environmental problems when it comes to food -- the massive, massive amounts of water waste, dead zones, habitat destruction on an almost unfathomable scale, etc. Food is a *horrible* way to create propulsion.

"I'm super sick and tired of the "Everything hurts the Earth, we should all just give up and die cause it's the 'green' thing to do" ideology."

Which is exactly *NOT* what I said. I said precisely the opposite: that we should use electric drivetrains *rather* than food for propulsion. But thanks for showing how much you're paying attention.

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My thoughts exactly. This "art" is a spoof and to trigger such a debate is really strange. It doesn't coast pete's sake. "This isn't expected to be a real form of transportation". ...should be "This isn't anything. Don't waste a moment of your time". And yet I did.

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