Another Kind of Global Warming
Posted by Jeff Id on January 26, 2009
Lately I have heard another theory of global warming. A seemingly more insidious form created not by gasses collected in the atmosphere or hot air from the politicians (yet) but direct heating from well… energy. Well the skeptic in me immediately has to question this new form of heating simply because it sounds like a massive amount of energy. Can you imagine generating so much power you compete with the sun?
Well here’s an article which claims we will do exactly that.
Even if we contain the greenhouse effect, says a Tufts astrophysicist, we’ll have another heat problem on our hands
Over the next 250 years, calculates Eric J. Chaisson in a recent paper, the earth’s population will start generating so much of its own heat – chiefly wasted from energy use – that it will warm the earth even without a rise in greenhouse gases. The only way to avoid it, he says, is to rethink how we generate energy.
His paper examines the planet’s growing pool of waste heat, a widespread phenomenon that nonetheless has been little studied as a cause of climate change. Nearly everything that uses or generates energy – chiefly power plants, but also cars, snowblowers, computers, and light bulbs – squanders some energy as wasted heat. And the larger and more energy-hungry the human population grows, the more waste heat remains in our atmosphere.
“What this means for humans is that this is the ultimate limit to growth,” said Dennis Bushnell, the chief scientist at NASA’s Langley Research Center, who urged Chaisson to publish his idea. “As we produce more kilowatts, we have to produce more waste heat.”
Chaisson’s prediction suggests we need to change our energy policy – not just by keeping emissions low, but by shifting toward power sources that don’t add new heat to the earth’s system
How did he come up with these numbers. I started doing the calculation myself to determine how much energy would be required to be input by humans just to achieve this goal. I used my numbers to verify his. It seems Eric Chaisson is basically right although he may have confused waste heat with energy generated. I mean, all the energy generated eventually turns to heat. The reason I say that is because of this quote from his paper.
Everyday appliances— including toasters, boilers, and lawn mowers— all generate heat while operating far from their theoretical effi ciency limits. Electricity production is currently about 37% efficient, automobile engines are roughly 25% efficient, and ordinary incandescent lightbulbs are only around 5% effi cient; the rest is immediately lost as heat.
This quote seems a bit slow to me because the stuff from your car that isn’t heat right away (velocity) is definitely becomes heat later on. I don’t have a clue why he doesn’t just say nearly 100% of all energy generated by man eventually turns into heat. The energy turned to velocity from your car certainly does. Well he’s only an astrophysicist and not an engineer so we’ll give him a break here.
Nature’s power budget on Earth is dominated by the Sun. Compared with our planet’s solar insolation of 120,000 terawatts (absorbed by the land, sea, and air, and accounting for Earth’s albedo of 31%), our global civilization currently produces an imperceptible approximately18 terawatts, about two thirds of which is wasted. But with humanity’s power usage on the rise (~2% annually as our species multiplies and becomes more complex, society’s energy demands by the close of the 21st century will likely exceed 100 terawatts—and much of that energy will heat our environment.
I checked out the 120000 terawatts number, it seems reasonable. Our current production of 18 terawatts is 0.015% of the input of the sun. He projects 2% annual growth to exceed 100 terawatts of heat power. This means that we continue to grow at two percent per year for another hundred years 1.02^100 = 7.2 times current production or 129 terawatts of power. Pretty hard to do on solar power but if we pull it off there is a net increase in heating of (120129/120000)^(0.25)* 280K = 280.07K. So if we do nothing and build one nuclear reactor after another and we have 7 times more power than today, by 2100 we will achieve 0.07 degrees C of temperature rise. This assumes no feedbacks!
Crazy stuff, just in case you’re not sure about my numbers check out what he says.
Estimates of how much heat and how quickly that heat will rise rely, once again, on thermodynamics. Because fl ux scales as σT 4, Earth’s surface temperature will rise about 3ºC (an IPCC “tipping point”) when (291/288)^4, namely, when about 4% more than the Sun’s daily dose (4800 terawatts) is additionally produced on Earth or delivered to Earth.
He said it, 4800 terawatts. Just so you understand the magnitude of that, if every person on earth (say 6 billion) had a personal average of about 8 hundred thousand watts of power we could achieve this heat level. Well the bulb over my head is 60W so that’s a good start. Dr. Chaisson says the US consumes about 12.5 kilowatts per person. If the world maintained the standard of living of today’s USA 4,800,000,000,000,000/12,500=384 billion people???? Does anyone think this is realistic in 300 years or um, ever! What would we do, farm the moon?
How can a scientist not realize this. Well of course he left a few clues. Here is a quote from the paper.
How much energy can all of our cultural devices—automobiles, stoves, factories, whatever—produce before Earth’s surface temperature increases enough to make our planet potentially hellishly uncomfortable?
Sounds pretty scientific eh. Hellishly uncomfortable?
If global nonrenewable energy use continues increasing at its current rate of about 2% annually and if all greenhouse gases are sequestered, then a 3ºC rise will still occur in roughly 8 doubling times, or about 280 years (or ~350 years for a 10ºC rise).
Yup just project the curve. How many people there be if I extend this calculation to 10C? Assuming the same power consumption as the US the temp^4 equation means there would be so many of us we would all need to hold hands so the ones on the shores didn’t fall in and drown.
Here’s another good one.
More realistically, if world population plateaus at 9 billion inhabitants by 2100, developed (Organisation for Economic Cooperation and Development, or OECD) countries increase nonrenewable energy use at 1% annually, and developing (non-OECD) countries do so at roughly 5% annually until east-west energy equity is achieved in the mid-22nd century after, which they too will continue generating more energy at 1% annually, then a 3ºC rise will occur in about 320 years (or 10ºC in ~450 years), even if carbon dioxide emissions end.
Wow, check out this idiocy. If we plateau at 9 billion inhabitants yet continue to increase energy usage ???? How much power is 10 C? It’s 18,000 trillion watts by his own numbers. Amongst a mere 9 billion people that’s 2 million watts a person. Two million f’n watts. Just to put it in perspective at 0.12 per kwh that is a 172,000 dollar per month energy bill per man woman an child — today’s dollars of course. Four person house, $700,000USD/month.
Here’s the genius’s final conclusion.
Less energy use, sometime in the relatively near future, seems vital for our continued well-being, lest Earth simply overheat.
Here’s some of his credentials and email at the end.
Eric J. Chaisson, Wright Center, Tufts University, Medford, Mass., and Harvard College Observatory, Cambridge, Mass.; E-mail: firstname.lastname@example.org
Oh yeah, for those who are big fans of peer review. This pig got published. I would love the names of the reviewers.
I’m not going to add much more to this, but I am madder than hell after reading it. What do you think – Politics or Science?