# air-conditioning and global warming **URL:** \ **Category:** Factual Questions\ **Created:** [May 10, 2016, 4:02am UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464 "2016-05-10T04:02:19Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Vicsage](https://avatars.discourse-cdn.com/v4/letter/v/e68b1a/32.png) [@Vicsage](https://boards.straightdope.com/u/Vicsage)\ **Post date:** [May 10, 2016, 4:02am UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/1 "2016-05-10T04:02:19Z")
How much does air-conditioning contribute to global warming? I don’t just mean the energy needed to run the units. When an air-conditioner cools a space, it heats up an equal space even more than it cools. That’s why you cannot run an A/C unit in a room without blowing the hot air outside. Think of all the buildings in the summer, cooling the inside by as much as 20 to 30 degrees. They’re heating the outside even more. Would this make the summer outside hotter and how much? And during the winter, most electric heating units just heat coils. There is no compensating cool air created. So winters are made hotter too. I’ve never heard anything about what this contributes to warming. Is it significant or not? ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [May 10, 2016, 4:27am UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/2 "2016-05-10T04:27:23Z")
It is actually transferring the heat from inside to outside, which would sort of equal out without the air conditioning. The heat was originally outside. The energy expended to make the transfer is adding to global warming in it’s creation and the heat of it’s use in the motor and pump mechanisms. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [May 10, 2016, 4:30am UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/3 "2016-05-10T04:30:42Z")
No, it’s not significant. The total energy usage worldwide is something like 5.67 x 10^20 joules/year (from [here](https://en.wikipedia.org/wiki/World_energy_consumption)). The total energy received from the sun is around 3.85 x 10^24 joules/year (from [here](https://en.wikipedia.org/wiki/Solar_energy)). So, all of mankind’s energy consumption only amounts to around .01% of the amount of energy that the sun provides. ---
**Author:** ![Carl\_Pham](https://avatars.discourse-cdn.com/v4/letter/c/e9a140/32.png) [@Carl\_Pham](https://boards.straightdope.com/u/Carl_Pham)\ **Post date:** [May 10, 2016, 4:37am UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/4 "2016-05-10T04:37:02Z")
This is what the backs of envelopes are for. E = World total annual electricity production = 90 EJ, roughly. m = Mass of the atmosphere = 5 x 10^18 kg c = Heat capacity of air = 1 kJ/(kg\*K), roughly. Maximum conceivable annual rise in temperature dT, if all the world’s electricity is converted to heat, and absolutely none escapes to space: dT = E/(m \* c) = 0.018 K = 0.018 degrees C. By the way, the Sun delivers about 4 million EJ of energy every year to the Earth, or about 11,000 EJ per day. Since the Earth isn’t continuously heating up, that means 11,000 EJ of energy leave the Earth every night. It’s radiated away into space, largely as infrared light. You can think of the night sky as a gigantic refrigerating unit with the dial set to almost absolute zero. While the transfer of heat to it is not early as efficient as it would be if there was some working fluid between Earth and deep space (like there is in an ordinary refrigerator), it’s enormous size and incredibly low temperature are more than enough to pull that staggering amount of energy out of the Earth’s night side in 12 hours. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [May 10, 2016, 5:13am UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/5 "2016-05-10T05:13:39Z")
It isn’t just the energy converted to heat that contributes to the warming. It is the greenhouse gases produced to make the energy, that more effectively trap solar energy and earth bound energy as heat. The rise in temperature also helps release more greenhouse gases that are mostly trapped in a cooler temperature system. The Earth has warmed and cooled many times for various reasons. The processes of billions of people are a cause of a present warming trend. I see no reason that is so unbelievable to so many people. ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [May 10, 2016, 5:33am UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/6 "2016-05-10T05:33:37Z")
To summarize: the actual heat produced by A/C or other human activities is negligible and very quickly radiates to space. But any GHGs produced by those activities are very significant because they cause increasing percentages of the enormous amount of incoming solar radiation to be effectively trapped due to absorption and retransmission of lower-frequency thermal radiation. CO2 in particular stays in the atmosphere for an average of about 100 years and creates additional feedback effects like polar ice melt. What it does essentially is move the whole planet to a long-term higher temperature equilibrium. So running your A/C causes no real problems in terms of the obvious heat that it emits, but depending on your electricity source it may contribute to global warming by corresponding increases in emissions at the power plant. Where I live most of the power is either nuclear or hydro-electric, so if the weather is hot I run the A/C without any qualms about adding to global warming. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 10, 2016, 11:06am UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/7 "2016-05-10T11:06:39Z")
It all comes down to the power consumed by the air conditioners. That’s all you need to know. ---
**Author:** ![joema](https://avatars.discourse-cdn.com/v4/letter/j/a9adbd/32.png) [@joema](https://boards.straightdope.com/u/joema)\ **Post date:** [May 10, 2016, 2:16pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/8 "2016-05-10T14:16:09Z")
> [@Vicsage](#): > > How much does air-conditioning contribute to global warming?.. Air conditioning has two main contributors to global warming. The first is energy consumption itself, since that energy comes mostly from hydrocarbon sources – about 85% globally. The other contributor of air conditioners to global warming is refrigerant leakage. It may not seem like much but according to some research, leakage of refrigerant is responsible for a sizeable fraction of global warming. IOW if every other possible source of green house gasses on earth were eliminated – no cars, no trucks, no jet planes, no hydrocarbon power plants – significant climate-altering effects would still happen from air conditioner refrigerant leakage (even if they were powered by totally clean energy). Ironically the phaseout of HCFC refrigerants to save ozone may result in higher usage of HFC refrigerants which have greater global warming potential. [http://www.nytimes.com/2012/06/21/world/asia/global-demand-for-air-conditioning-forces-tough-environmental-choices.html](http://www.nytimes.com/2012/06/21/world/asia/global-demand-for-air-conditioning-forces-tough-environmental-choices.html) _“The leading scientists in the field have just calculated that if all the equipment entering the world market uses the newest gases currently employed in air-conditioners, up to 27 percent of all global warming will be attributable to those gases by 2050.”_ ---
**Author:** ![Me\_Billy](https://avatars.discourse-cdn.com/v4/letter/m/e480ec/32.png) [@Me\_Billy](https://boards.straightdope.com/u/Me_Billy)\ **Post date:** [May 10, 2016, 2:20pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/9 "2016-05-10T14:20:51Z")
I’ve noticed that when I drive into a large city from the country, the temperature rises about 5 degrees. That increased temperature is also due to automobiles, so I don’t know how much of that is due to A/C. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [May 10, 2016, 2:27pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/10 "2016-05-10T14:27:15Z")
> [@Me\_Billy](#): > > I’ve noticed that when I drive into a large city from the country, the temperature rises about 5 degrees. That increased temperature is also due to automobiles, so I don’t know how much of that is due to A/C. The increased temperatures of cities is known as the urban heat island effect. Very little of that is attributed to cars or A/C. It is mostly the effect of covering over soil with heat-absorbing materials. A primer can be found [here](http://usatoday30.usatoday.com/weather/wurbheat.htm). ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [May 10, 2016, 5:57pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/11 "2016-05-10T17:57:46Z")
> [@joema](#): > > Air conditioning has two main contributors to global warming. The first is energy consumption itself, since that energy comes mostly from hydrocarbon sources – about 85% globally. > > The other contributor of air conditioners to global warming is refrigerant leakage. It may not seem like much but according to some research, leakage of refrigerant is responsible for a sizeable fraction of global warming. IOW if every other possible source of green house gasses on earth were eliminated – no cars, no trucks, no jet planes, no hydrocarbon power plants – significant climate-altering effects would still happen from air conditioner refrigerant leakage (even if they were powered by totally clean energy). > > Ironically the phaseout of HCFC refrigerants to save ozone may result in higher usage of HFC refrigerants which have greater global warming potential. > > [http://www.nytimes.com/2012/06/21/world/asia/global-demand-for-air-conditioning-forces-tough-environmental-choices.html](http://www.nytimes.com/2012/06/21/world/asia/global-demand-for-air-conditioning-forces-tough-environmental-choices.html) > > _“The leading scientists in the field have just calculated that if all the equipment entering the world market uses the newest gases currently employed in air-conditioners, up to 27 percent of all global warming will be attributable to those gases by 2050.”_ The point about refrigerant leakage is an interesting one and I want to make a few comments about some of those statements, not all of which are quite accurate. First of all, obviously, refrigerant emissions are unrelated to the actual operation of an air conditioner, which is what the OP was asking about. But leaks do happen, and sometimes refrigerant is released during maintenance even though by law in most places it’s supposed to be recovered and recycled. The picture in the NYT of those dozens of portable air conditioners in some hovel in India doesn’t inspire confidence that their refrigerant contents will be responsibly treated. So, given that some releases are inevitable, what’s the scoop on global warming? It’s a bit misleading to say that if all other sources of GHGs were eliminated, refrigerants would still cause “significant” global warming. The IPCC recently assessed halocarbons (CFCs and HCFCs) as contributing 0.18 W/m[sup]2[/sup] to climate forcing and HFCs and PFCs 0.03 W/m[sup]2[/sup]. This is a very tiny fraction of the 1.68 W/m[sup]2[/sup] that incremental CO2 forcing alone contributes, not to mention other GHGs like methane. They further assess that “atmospheric burdens of major CFCs and halons have decreased since 2005. HCFCs, which are transitional substitutes for CFCs, continue to increase”, but presumably not for much longer. Meanwhile, “HFCs, PFCs, and SF6 all continue to increase relatively rapidly, but their contributions to radiative forcing are less than 1% of the total by well-mixed greenhouse gases.” It’s true that some HFCs have somewhat greater global warming potential than HCFCs, but it’s only marginal and it depends on which ones you’re comparing. HFC-134a which is commonly used in automotive air conditioning and in foam blowing actually has significantly lower GWP than either HCFC-22 or HCFC-142b, and as a bonus it also has one of the shortest atmospheric lifetimes of any of the halocarbons or HFCs. Where one sees truly big differences is looking at the traditional old CFCs. They typically have the highest global warming potentials of any of these substances combined with the longest atmospheric lifetimes, _ **and** _ they deplete the ozone layer! A triple-whammy! What could possibly go wrong? So we’re moving in the right direction in getting rid of them and moving to HFCs. We just need to enact and enforce laws globally around recovery and recycling. ---
**Author:** ![joema](https://avatars.discourse-cdn.com/v4/letter/j/a9adbd/32.png) [@joema](https://boards.straightdope.com/u/joema)\ **Post date:** [May 10, 2016, 6:52pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/12 "2016-05-10T18:52:59Z")
> [@wolfpup](#): > > …It’s a bit misleading to say that if all other sources of GHGs were eliminated, refrigerants would still cause “significant” global warming. The IPCC recently assessed halocarbons (CFCs and HCFCs) as contributing 0.18 W/m[sup]2[/sup] to climate forcing and HFCs and PFCs 0.03 W/m[sup]2[/sup]. This is a very tiny fraction of the 1.68 W/m[sup]2[/sup] that incremental CO2 forcing alone contributes, not to mention other GHGs like methane… That is not what this 2012 paper published in Science says: [www.igsd.org/documents/Science-2012-Velders-922-3.pdf](http://www.igsd.org/documents/Science-2012-Velders-922-3.pdf) Graph from paper: [Projected Radiative Forcings - joema](https://joema.smugmug.com/Other/Projected-Radiative-Forcings/n-sS7HQj/i-Psv9zkS/O) ---
**Author:** ![doorhinge](https://avatars.discourse-cdn.com/v4/letter/d/a5b964/32.png) [@doorhinge](https://boards.straightdope.com/u/doorhinge)\ **Post date:** [May 10, 2016, 7:14pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/13 "2016-05-10T19:14:31Z")
> [@Vicsage](#): > > …When an air-conditioner cools a space, it heats up an equal space even more than it cools. That’s why you cannot run an A/C unit in a room without blowing the hot air outside. Think of all the buildings in the summer, cooling the inside by as much as 20 to 30 degrees. They’re heating the outside even more. (post shortened) You are correct. Your use of AC creates heat which is then dispersed into the atmosphere. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [May 10, 2016, 7:37pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/14 "2016-05-10T19:37:32Z")
> [@doorhinge](#): > > (post shortened) > > You are correct. Your use of AC creates heat which is then dispersed into the atmosphere. Ummmm … no heat is created … the AC unit is just moving the heat from inside to the outside. Just this in of itself doesn’t add to Global Warming. ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [May 10, 2016, 7:53pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/15 "2016-05-10T19:53:25Z")
> [@joema](#): > > That is not what this 2012 paper published in Science says: [www.igsd.org/documents/Science-2012-Velders-922-3.pdf](http://www.igsd.org/documents/Science-2012-Velders-922-3.pdf) > > Graph from paper: [Projected Radiative Forcings - joema](https://joema.smugmug.com/Other/Projected-Radiative-Forcings/n-sS7HQj/i-Psv9zkS/O) Actually, that’s _ **exactly** _ what your cited paper says, though it may not be immediately obvious. First of all they lump all the halocarbons and the HFCs together in that graph, so you’re just seeing a grand total. If you break it down, the HFC contribution to radiative forcing is still negligibly small, so almost all of the combined forcings in 2011 (the reference year for the IPCC stats) were from halocarbons, which they assess at around 0.3 W/m[sup]2[/sup]. What the IPCC correctly accounts for, however, and they don’t, is that halocarbons also intrinsically create a negative forcing due to ozone depletion, which for the reference year is around -0.12 W/m[sup]2[/sup], and which leaves the net halocarbon forcing of 0.18 W/m[sup]2[/sup] that I stated. The rest of it is just future projections which seems to be intended to make a case for inclusion of HFCs under the Montreal Protocol. I support the principle but I can’t attest to the accuracy of their projections, nor should anyone rely on just one paper for such. What can be said with certainty is that right now, the net effects of all halocarbons and HFCs on radiative climate forcing are relatively minor, but looking to the future, all of them including HFCs need to be regulated. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 10, 2016, 8:09pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/16 "2016-05-10T20:09:02Z")
> [@](#): > > Quoth **watchwolf49** : > > Ummmm … no heat is created … the AC unit is just moving the heat from inside to the outside. Just this in of itself doesn’t add to Global Warming. In this house, we obey the laws of thermodynamics. So long as the inside is cooler than the outside, the heat dumped outside must always be greater than the amount removed from the inside. Or to look at it another way: Your air conditioner has a power rating, somewhere near the cord, that says how much electrical energy it uses per time. That’s the amount of extra heat it’s producing. ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [May 10, 2016, 8:16pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/17 "2016-05-10T20:16:32Z")
> [@Chronos](#): > > In this house, we obey the laws of thermodynamics. It’s always good to obey the law! 🙂 > [@Chronos](#): > > So long as the inside is cooler than the outside, the heat dumped outside must always be greater than the amount removed from the inside. Of course. And as already said, it matters not a bean to the global climate. What matters is any associated GHG emissions. ---
**Author:** ![Orwell](https://avatars.discourse-cdn.com/v4/letter/o/dfb087/32.png) [@Orwell](https://boards.straightdope.com/u/Orwell)\ **Post date:** [May 10, 2016, 8:49pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/18 "2016-05-10T20:49:08Z")
> [@Kedikat](#): > > The Earth has warmed and cooled many times for various reasons. The processes of billions of people are a cause of a present warming trend. I see no reason that is so unbelievable to so many people. Why is this time different than all of the other times the earth has warmed and cooled? Your first and second sentences are not supportive of each other. If anything, they are contradictory. I see no reason that it is believable to so many people that changes in climate are now caused by people, but were not decades and centuries ago. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [May 10, 2016, 9:02pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/19 "2016-05-10T21:02:16Z")
> [@Chronos](#): > > In this house, we obey the laws of thermodynamics. So long as the inside is cooler than the outside, the heat dumped outside must always be greater than the amount removed from the inside. Or to look at it another way: Your air conditioner has a power rating, somewhere near the cord, that says how much electrical energy it uses per time. That’s the amount of extra heat it’s producing. I disagree, assuming perfect efficiency, that power rating is the power required to maintain our thermodynamic imbalance. The heat outside will naturally migrate inside, our AC unit is constantly taking the heat inside and sending it outside. We have to constantly add energy to the system in order to “violate” the laws of thermodynamics. Referg-a-tators work the same way, except we vent the excess heat into our living spaces so our AC can pump that out too. In reality, these processes are very very _in_efficient … a lot of the electrical energy is indeed converted to heat … ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [May 10, 2016, 9:07pm UTC](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464/20 "2016-05-10T21:07:22Z")
> [@watchwolf49](#): > > I disagree, assuming perfect efficiency, that power rating is the power required to maintain our thermodynamic imbalance. The heat outside will naturally migrate inside, our AC unit is constantly taking the heat inside and sending it outside. We have to constantly add energy to the system in order to “violate” the laws of thermodynamics. I believe that’s what **Chronos** was saying: in real life, ACs are not perfectly efficient (because nothing is.) Therefore there is a net production of heat. It’s just negligible as far as global warming goes. [Next page](https://boards.straightdope.com/t/air-conditioning-and-global-warming/754464.md?page=2)