What do we do about the other kind of global warming?

Question

Suppose we've solved the greenhouse gas problem (deniers, that should make you happy, since you didn't believe it anyway), how do we solve the OTHER global warming problem? A new article in Eos, The Transactions of the American Geophysical Union, estimates that people on Earth have an average power usage of 2.5 kW per person, with the US leading the pack at about 12.5 kW per person. Since everything we do is less than 100% efficient (courtesy of the second law of thermodynamics), that means that there is a lot of waste heat generated, which will eventually heat up the planet. The time scale is longer than that caused by greenhouse emissions, but not that much longer. A 3C rise may take 280 years, while it would only take 350 years for a 10C rise.

Note that any non-renewable form of energy will necessarily contribute: oil, "clean" coal, nuclear, etc. To prevent this other form of global warming, we must switch to renewable energy sources. Any thoughts?

Answer 1

based off of your logic we are screwed no matter what, so what is the point in trying.

Answer 2

The good news is that to avoid catastrophic global warming, we necessarily have to switch to renewable energy sources.  So both problems are addressed simultaneously.  If we fail to switch to renewable energy, we'll face catastrophic consequences in less than the 280+ years you propose.  So I wouldn't worry about this particular problem.

Answer 3

Just view humanity as a natural process, let the Earth warm, stop building beach houses and enjoy life.

Answer 4

no, this "waste heat" is negligible compared to the amount of heat received from the sun, it is negligible compared to the amount of heat absorbed by gases in the atmosphere.

Answer 5

Courtesy of the Second Law of Thermodynamics.

Heat cannot spontaneously flow from a material at lower temperature to a material at higher temperature.

The second law states that there exists a useful state variable called entropy S. The change in entropy delta S is equal to the heat transfer delta Q divided by the temperature T.

delta S = delta Q / T

For a given physical process, the combined entropy of the system and the environment remains a constant if the process can be reversed. If we denote the initial and final states of the system by "i" and "f":

Sf = Si (reversible process)

An example of a reversible process is ideally forcing a flow through a constricted pipe. Ideal means no boundary layer losses. As the flow moves through the constriction, the pressure, temperature and velocity change, but these variables return to their original values downstream of the constriction. The state of the gas returns to its original conditions and the change of entropy of the system is zero. Engineers call such a process an isentropic process. Isentropic means constant entropy.

The second law states that if the physical process is irreversible, the combined entropy of the system and the environment must increase. The final entropy must be greater than the initial entropy for an irreversible process:

Sf > Si (irreversible process)

An example of an irreversible process is the problem discussed in the second paragraph. A hot object is put in contact with a cold object. Eventually, they both achieve the same equilibrium temperature. If we then separate the objects they remain at the equilibrium temperature and do not naturally return to their original temperatures. The process of bringing them to the same temperature is irreversible.

Answer 6

who cares about "global warming"lol

Answer 7

turn your lights off?

Answer 8

I wouldn't worry about the earth. Global wraming is most likely cause by natural occurances.  Also, since the Artic ocean is frozen over there is less water vapor escaping into the atmosphere. When there is less snow to replenish the Arctic ice cap, the cap may start to shrink. That could be the cause behind the retreat of the Arctic ice cap that scientists are documenting today.  With the cap shrinking as it is there is less snow and temperatures begin to rise. The higher temeratures open up more northern waters and the atmosphere can evaporate that water and let snow fall once again the the retreated caps. This replenishes the caps, cools the water and the Artic ocean freezes and the cycle starts overs again and again and again.

All we have to worry about is fixing our energy crysis.

Answer 9

Ok...I'm going to let you take me in that direction. First things first (Carnot heat engines) exist only on paper. To my knowledge no perfect engines exist in reality. If you consider 'Boltzmann Law' there can't be any net gain, just the principle of equilibrium. So now your talking retention of energy. (ie: selective absorbers, black bodies,latent, potential energy), "or to generalize...environmental regulatory processes." Some are man made(ie: dams,roads,buildings,airports...etc.)

The concept of wasted energy is confusing to say the least. But applying efficiency as a measuring stick, it becomes approachable. I'm curious how they came up the numbers though. One could also speculate on the US industrial power and it's energy demands in relationship to other countries.But as a conferment yes... America is lacking in energy efficiency standards. We're trapped in a political, social, economical, bubble, that leaves us with few choices.

Answer 10

mhh......to prevent global warming ........this blog tell you a lot check it out

http://www.smallstepsatatime.blogspot.co...

Answer 11

It's definitely something to be aware of.  I'm going to go back and read the article (it must be buried in the link below somewhere, and there are a few other articles that look interesting!).  Then I'll probably want to chew on this for a bit, find some alternative information to give me a broader perspective.

Renewable energy sources are a must for the future in any case.

Answer 12

That is certainly something to consider. As you note in the other thread on this subject, it will only take a few hundred years before waste heat's average global forcing will be 1 W/m2 (I calculated ~180 years, which is assuming that we carry on business-as-usual).

Renewables will still contribute, but we need to start heading in that direction, and place even more importance on energy efficiency and conservation.

Answer 13

"To prevent this other form of global warming, we must switch to renewable energy sources."

Wow...I didn't realize renewable energy sources are 100% efficient and/or don't abide by the second law of thermodynamics!  How does copper wiring know the difference?

The solution is to tweak whatever Magic 8 ball is coming up with these crazy figures until it more accurately mirrors the real world.

I'm going to go with:  The excess bleeds off into the cold vacuum of space.

Answer 14

My guess is that we'll become more heat-efficient as energy becomes more expensive.

Right now even the IPCC adjusts temperature estimates for the heat island effect.    And I'm not sure what assumptions you're making with respect to a 3 degree C rise in 280 years - that would seem excessive.

Lastly, ixnay on the use of the word "denier."      I don't say it can't be us - just that there's no affirmative proof that it is.

Answer 15

Changing every source of energy to renewable sources is a good thing. But let us not depend on it too much. We still need to save energy/heat.

It's like liposuction, low calorie snacks, etc. you think you've eaten less calories when in fact you've taken more.

Here's an example: a 30% less fat snac enticed a man to eat 2 packs of the sanck, instead of just one. In effect he took up more fat, 40% than if he just ate one.

So let's not waste the energy we will generate from renewable sources of energy.

Answer 16

You lost me at "Suppose we've".... besides Global warming is fake.