[Craig W. Thomson]

I don't think it will make any difference to Craig, but the rest of us will now accept that the direct effect from heating is small and the big change comes from something else.

What makes no difference to me is you arguing which part is small and which part is large. I don't care. I only said, they are both factors. They ARE both factors. agyejy proved my point.

The heat is a factor because the extra carbon dioxide helps keep it here. It doesn't just escape into space, so yes, it IS a factor, no matter how small you claim that factor is.

[Craig W. Thomson]

The word industry, today, refers to the organised use of labour to make stuff and to provide services.

Before the industrial revolution it was used to refer to working hard.

Industry and technology are separate ideas.

Can't hold your own in a scientific debate, so now you're nitpicking about etymology? Pathetic.

[Craig W. Thomson]

If you want to have a science forum you will have to be harsh with your allowance of idiocy. It's sort of OK to have a load of simple questions asked by those who have not done any science but this needs to be in it's own section otherwise more advanced discussions will be drowned out by the noise.

Have you even taken one college science course? You don't seem to recognize your own idiocy, hypocrite. Why don't you take your industry vs. technology argument to the kids table instead of drowning out our adult climate change discussion with nonsense?

[Craig W. Thomson]

The point is not that the CO2 traps the tiny little bit of heat generated directly by burning fossil fuels. The point is that it traps all heat- including a share of the 15000 times more heat that we get from the sun.

FALSE.

CO2 molecules absorb and re-emit heat, but not necessarily right back in the direction it came from. CO2 molecules aren't stationary, but rather tumble through space. Depending on the orientation of a CO2 molecule at the time of emission, that infrared photon might come back to earth, or it might escape into space. CO2 does NOT trap ALL the heat, just some. More CO2 traps more heat, but still not all of it.

You're a regular geyser of misinformation, aren't you?

[Bored chemist]

(Please stop talking about irrelevant stuff like logs- just answer the question I actually asked)

Burning logs is related to the thread topic. Your question is not. Answer it yourself.

Make up your mind.
You are the one who said entropy is important to the topic and you are the one who introduced the Feynman diagram.
If it's not relevant, why did you do that?
Anyway, since you claim to be such an expert on entropy, and it's a trivial calculation why don't you just answer the question and tell us what the entropy change for the reaction actually is?

Also, I already answered it twice.
I'm just checking if you have any idea what the answer is.

[Bored chemist]

I don't think it will make any difference to Craig, but the rest of us will now accept that the direct effect from heating is small and the big change comes from something else.

What makes no difference to me is you arguing which part is small and which part is large. I don't care. I only said, they are both factors. They ARE both factors. agyejy proved my point.

The heat is a factor because the extra carbon dioxide helps keep it here. It doesn't just escape into space, so yes, it IS a factor, no matter how small you claim that factor is.

You seem to have forgotten what you said in the first place that kicked off the debate.
It's the bit where Tim told you the difference between big an small and you pretended it wasn't.

No, the amount of heat produced directly by human activity is utterly tiny in comparison with the heat budget of nature.

FALSE. The earth's life forms spent hundreds of millions of years taking solar energy OUT of the system. That's what oil and coal are: dead plants and animals.

[Bored chemist]

The point is not that the CO2 traps the tiny little bit of heat generated directly by burning fossil fuels. The point is that it traps all heat- including a share of the 15000 times more heat that we get from the sun.

FALSE.

CO2 molecules absorb and re-emit heat, but not necessarily right back in the direction it came from. CO2 molecules aren't stationary, but rather tumble through space. Depending on the orientation of a CO2 molecule at the time of emission, that infrared photon might come back to earth, or it might escape into space. CO2 does NOT trap ALL the heat, just some. More CO2 traps more heat, but still not all of it.

You're a regular geyser of misinformation, aren't you?

Way to go on missing the point there.
it's as if you do it deliberately.
Anyway, the CO2 traps heat from all sources- not just the tiny bit produced by burning fuels.
So, yes it does trap all heat.
I didn't say it trap "all the heat" that's something you made up and pretended I said.
You really need to stop strawmanning or you will end up looking like this guy
http://dilbert.com/strip/2015-06-07

[agyejy]

What makes no difference to me is you arguing which part is small and which part is large. I don't care. I only said, they are both factors. They ARE both factors. agyejy proved my point.

The heat is a factor because the extra carbon dioxide helps keep it here. It doesn't just escape into space, so yes, it IS a factor, no matter how small you claim that factor is.

You've quite severely missed the point. The numbers I calculated were a very large overestimate. For starters only about 60% of the energy humans use ends up as waste heat. Therefore the numbers I gave are at least two times bigger than they actually are in reality. The real numbers are definitely closer to 0.025 K total and 0.0005 K per year or closer to a factor of 40 than a factor of 20. I purposefully overestimated so badly to conclusively demonstrate that the impact of direct heating is so small that it is literally not measurable. For example try and find a commercially available thermometer with a precision of 0.01 K (or °C as they are equivalent) that works above cryogenic temperature ranges. There are several very expensive units designed for cryogenic temperatures that are specifically marketed to scientists but no one would ever use these to measure ambient temperature and if you did they wouldn't be nearly as accurate as when measuring cryogenic temperatures. At best the thermometers used to measure ambient temperatures have an accuracy of 0.1 K (which again is the same as °C) so the impact of direct heating due to human energy use literally is not measurable which means scientifically speaking it is completely ignored in all climate models and calculations.

[Craig W. Thomson]

You seem to have forgotten what you said in the first place that kicked off the debate.
It's the bit where Tim told you the difference between big an small and you pretended it wasn't.

No, the amount of heat produced directly by human activity is utterly tiny in comparison with the heat budget of nature.

FALSE. The earth's life forms spent hundreds of millions of years taking solar energy OUT of the system. That's what oil and coal are: dead plants and animals.

I pretended it wasn't what? The difference between big and small? That statement makes no sense. Do you even think about what you are posting, or do you just rattle off any sort of nonsense you like?

You're wrong. Every lump of coal in the ground represents solar energy that did not enter the atmosphere or warm the ground under a tree, but rather was stored in plants via photosynthesis. After hundreds of millions of years, those dead trees add up to a lot of stored solar energy. Releasing it all at once adds up to something significant ENOUGH. To suggest otherwise is preposterous.

[Craig W. Thomson]

For starters only about 60% of the energy humans use ends up as waste heat.

The real numbers are definitely closer to 0.025 K total and 0.0005 K per year or closer to a factor of 40 than a factor of 20.

Citation, please.

Oh, never mind:

http://cleantechnica.com/2013/08/26/us-wastes-61-86-of-its-energy/

At any rate, Japanese car companies had several models that got more than 50 mpg, way back in the early 1980's. Now, after two and a half decades of technological development, we can barely squeeze 40 mpg out of a hybrid. Guess who's to blame for that? I'll give you a hint: highly profitable oil companies.

[Bored chemist]

You seem to have forgotten what you said in the first place that kicked off the debate.
It's the bit where Tim told you the difference between big an small and you pretended it wasn't.

No, the amount of heat produced directly by human activity is utterly tiny in comparison with the heat budget of nature.

FALSE. The earth's life forms spent hundreds of millions of years taking solar energy OUT of the system. That's what oil and coal are: dead plants and animals.

I pretended it wasn't what? The difference between big and small? That statement makes no sense. Do you even think about what you are posting, or do you just rattle off any sort of nonsense you like?

You're wrong. Every lump of coal in the ground represents solar energy that did not enter the atmosphere or warm the ground under a tree, but rather was stored in plants via photosynthesis. After hundreds of millions of years, those dead trees add up to a lot of stored solar energy. Releasing it all at once adds up to something significant ENOUGH. To suggest otherwise is preposterous.

Tim told you the difference between big and small.
The energy from the sun is big. The energy from fossil fuels is small.
You pretended that the direct heating effect wasn't small and you pretended that the heating from the sun wasn't big.

In particular, re "Releasing it all at once adds up to something significant ENOUGH. "
As I pointed out, even current rates of use (which means releasing as much of it "at once" as we ever have) ,mare small compared to the heat from the sun.


and you really ought to answer the question about the entropy change - otherwise it makes it look like you don't have a damned clue what you were on about and you can't do the simple calculation- even after someone has told you the answer.
Why are you so reluctant?
Is it because you can't?

[agyejy]

You're wrong. Every lump of coal in the ground represents solar energy that did not enter the atmosphere or warm the ground under a tree, but rather was stored in plants via photosynthesis. After hundreds of millions of years, those dead trees add up to a lot of stored solar energy. Releasing it all at once adds up to something significant ENOUGH. To suggest otherwise is preposterous.

Except that I just calculated the magnitude of the impact of releasing that energy at the rate humans are currently releasing it and found that it was literally not measurable and therefore cannot be considered significant by any acceptable definition of the word significant.

Citation, please.

Oh, never mind:

http://cleantechnica.com/2013/08/26/us-wastes-61-86-of-its-energy/

At any rate, Japanese car companies had several models that got more than 50 mpg, way back in the early 1980's. Now, after two and a half decades of technological development, we can barely squeeze 40 mpg out of a hybrid. Guess who's to blame for that? I'll give you a hint: highly profitable oil companies.

The best possible Carnot engine operating over a realistic temperature range would at best still reject about 40% of the energy fed to it as waste heat. This is the thermodynamic limit for any heat engine and real engines are always going to be significantly less efficient than this because they operate far from thermal equilibrium. Increasing the fuel efficiencies of cars would have reduced the overall amount of energy used by allowing people to drive further on less gas but the overall percentage of waste heat wouldn't have changed all that much. The efficiency of internal combustion engines has pretty much been maximized at this point and further gains in automotive fuel efficiency are mainly about reducing drag/weight and tricks like turning off the engine at stop lights.

[jeffreyH]

Our

If you want to have a science forum you will have to be harsh with your allowance of idiocy. It's sort of OK to have a load of simple questions asked by those who have not done any science but this needs to be in it's own section otherwise more advanced discussions will be drowned out by the noise.

Have you even taken one college science course? You don't seem to recognize your own idiocy, hypocrite. Why don't you take your industry vs. technology argument to the kids table instead of drowning out our adult climate change discussion with nonsense?

You are the furthest from an adult discussion that you could possibly be.

[alancalverd]

At any rate, Japanese car companies had several models that got more than 50 mpg, way back in the early 1980's. Now, after two and a half decades of technological development, we can barely squeeze 40 mpg out of a hybrid. Guess who's to blame for that? I'll give you a hint: highly profitable oil companies.

No, mostly Californian legislators. Battery hybrids are a lot heavier for a given power rating than simple internal combustion units, and the statutory reduction in particulate emissions, NOX emissions and lead content have produced significantly lower overall efficiency. Why do you think racing car manufacturers complain about noise limitation? Because everything you add to a car exhaust system makes the engine less efficient.

And of course your 1960s 50 mpg Jap rustbox didn't have airconditioning, power steering, antilock brakes, 4-wheel drive, airbags, auto gearbox, side impact protection, and all the other gubbins that makes its successors go slower.

[Bored chemist]

It doesn't matter what the MPG is - or anything like it.
All the energy ends up as heat, even if 40% of it started off moving a car; when the brakes go on that energy is dissipated as heat.
Some of the fossil fuel is used to generate electricity, but in the end, that too gets degraded to heat; that's why your TV sert gets warm

Ironically, this is the only bit where entropy gets involved, but it doesn't let Craig off the hook.
He should still be able to explain what the entropy change is for the reaction he cited.

I'm really looking forward to it.

[agyejy]

It doesn't matter what the MPG is - or anything like it.
All the energy ends up as heat, even if 40% of it started off moving a car; when the brakes go on that energy is dissipated as heat. Some of the fossil fuel is used to generate electricity, but in the end, that too gets degraded to heat; that's why your TV sert gets warm

Actually a significant amount of the energy not rejected as waste heat by the engine goes into sound, moving the air as the car passes through (some of which might end up as a slight increase in air temp), any net gain in altitude between where the car started and where it stopped (a decrease in altitude actually gives you energy), and any electrical needs the car might have (some of that electrical use becomes heat but you can also get sound both from the radio and other sources as well as chemical energy stored in the battery). Not even 100% of the energy dissipated by breaking ends up as thermal energy. At least some of it goes into the mechanical deformation and grinding of the brake pads and rotors.

As for TV sets certainly some of the input electrical energy becomes heat but not 100%. In a relatively efficient TV set a good portion comes out as visible light. Now some of that visible light will get absorbed and reemitted as infrared radiation but a not insignificant portion will simply be reflected away as ambient scattered light.

Yes thermodynamics says that you can't do anything without generating some amount of waste heat but that doesn't mean every joule of energy you use eventually becomes thermal energy.

[Bored chemist]

Sound doesn't carry indefinitely, it is degraded to heat by air viscosity.
The only energy that escapes from your car is if the lights shine up into the sky- and even that will eventually get degraded to heat when it hits something.
The light from the TV set is absorbed by the walls of the room within microseconds. (how long does it take for the room to get dark once you switch the lights off?)

Eventually you drive the car back home so the net change in gravitational energy is zero.

"Yes thermodynamics says that you can't do anything without generating some amount of waste heat but that doesn't mean every joule of energy you use eventually becomes thermal energy."
Oh yes it does.

[agyejy]

Sound doesn't carry indefinitely, it is degraded to heat by air viscosity.

That can actually take much longer than you'd think depending on the frequency of the sound. Most of the sound energy from cars is below 2 kHz and below that frequency dissipation via the viscosity of air can take many miles. Enough that a good portion of that energy ends up in the upper atmosphere before it is eventually converted to heat. I will concede that if you wait long enough it eventually becomes heat but that heat is very likely not to be anywhere near the surface of the planet.
 

The only energy that escapes from your car is if the lights shine up into the sky- and even that will eventually get degraded to heat when it hits something.

Some portion of it will but some portion of it will also get reflected away and there is generally a greater chance of going in a roughly upward direction.

The light from the TV set is absorbed by the walls of the room within microseconds. (how long does it take for the room to get dark once you switch the lights off?)

Unless you happen to really like black windowless rooms a good portion of the light is free to escape through the windows.

Eventually you drive the car back home so the net change in gravitational energy is zero.

I did address that fact actually.

"Yes thermodynamics says that you can't do anything without generating some amount of waste heat but that doesn't mean every joule of energy you use eventually becomes thermal energy."
Oh yes it does.

I was trying not to be overly pedantic and confuse the point more than than it already has been. Yes given enough time eventually everything degrades and turns to dust but generally speaking not on a time scale relevant to a typical human lifespan. A good portion of the human use of energy goes into constructing things. Things like buildings, cars, toys, and even increasingly complex molecules. Energy goes into making those things and is stored in those things. Eventually given time they will degrade and eventually that stored energy will become heat but generally speaking not on the time scale of a single human lifetime and certainly not on the scale of a single year. I was attempting to illustrate that in terms of the analysis I did above less than 100% of the energy we use in a year ends up as heat by the end of that year and generally speaking a decent percentage of our energy use is locked up in various things we build for decades or centuries.

[Bored chemist]

I tell you what, rather than carrying on this debate here, why don't we just wait?
https://en.wikipedia.org/wiki/Heat_death_of_the_universe

[alancalverd]

Let's be really pedantic for a while.

The car moves from A to B. If they are at the same height, there is no change in gravitational potential and as BC has said, you will probably return to A anyway. So where did all the energy go?

Most of it was dissipated as air turbulence and noise. Same as heat - a change in the mean energy of air molecules.

Some was dissipated by the flexing of the tyres - heat.

Some was dissipated by the brakes - heat

Some was dissipated by other frictional losses - heat.

So if you really care about heating the planet, use the phone instead of travelling.

Try telling that to people who attend "environmental" conferences.