<p><em><strong>Heat capacity</strong></em> is the amount of thermal energy it requires to heat a gram of &quot;A substance&quot; one Kelvin degree.
Salt water of oceanic variant average salinity (3.5%) has specific heating of 3.993 J/(g K) or 3.993 Joules of energy per gram of water to raise it ONE degree kelvin.</p>
<p>using Metric; Water has a specific heat capacity of 4.186 J/g°C, meaning that it requires 4.186 J of energy (1 calorie) to heat a gram by one degree Celsius. With an Oceanic volume of 321 Million Cubic miles (1.338 Quintillion! cubic meters) with roughly one million grams of water per cubic meter it would take the removal of
nearly a Yottajoules worth of energy, 500 TIMES current human annual energy consumption.</p>

CC BY-SA 4.0
2022-12-10T21:20:10.030Z
≈ 1 yottajoule? Isn't it 4,183*1,338 ≈ 5,46 (* 10^18 * 10^6) -> 5,46 * 10^24 = 5 yotta joule
d-b
CC BY-SA 4.0
2021-12-18T07:17:49.097Z
2021-12-18T07:17:49.097Z
LazyReader
<p>Assuming a surface ocean temperature of 288 K and a deep ocean temperature of 277 K, let's assume a mean temperature around 282.5 K.</p>
<p>The specific heat capacity of seawater at constant pressure is 3,890 joules per kilogram per kelvin.</p>
<p>The mass of the ocean is 1.39 x 10<sup>21</sup> kg.</p>
<p>Therefore the &quot;thermal content,&quot; if I can call it that, of the ocean is 1.528 x 10<sup>27</sup> J.  At 281.5 K, it would be 1.522 x 10<sup>27</sup> J.  The difference is 5.407 x 10<sup>24</sup> J using all the significant figures Excel gives me.  That's a lot of energy!</p>

CC BY-SA 4.0
2021-12-16T21:38:12.037Z
Thank you the interesting answer
the4thv
CC BY-SA 4.0
2021-12-15T20:24:06.527Z
2021-12-15T21:36:49.030Z
2021-12-15T21:36:49.030Z
bpl1960
<p>The question is slightly confused, because reducing the temperature of the oceans, in a direct sense, doesn't require energy - it releases it. The amount that is released is simply related to the mass and specific heat capacity of seawater, as you suggest.</p>

<p>The missing question, though, is <em>why</em> the ocean is cooling. For it to happen naturally and simply release energy, it would need to be because its surroundings (e.g. the air) were cooler. If you want to actively cool the sea, then yes, that is going to consume energy. If the cooling has approximately the same level of performance as building-sized air conditioning, the power used by the cooling apparatus will be about 40% of the rate at which the energy is removed (and remember that this is not just the total energy divided by the time, because more heat will be leaking back in while you do it).</p>

<p>Leaving aside the, uh, engineering challenges of this scale of cooling, this leads to a question as to <em>why</em> one might want to do this. Remember that unless you devise some complex system to radiate this heat into space from above the atmosphere, you're going to be releasing the same heat into the same global climate system, plus the additional 40% that you've used to move it around.</p>

CC BY-SA 4.0
2019-05-23T03:58:25.587Z
this is how my closest city uses heat from a river for heating and cooling houses and industry https://www.bbc.com/news/business-31506073
trond hansen
CC BY-SA 4.0
2019-05-23T06:46:13.357Z
Thanks @semidiurnal-simon, I was hoping my question implied 'active', but I grant you it isn't explicit - I've corrected that.
the4thv
CC BY-SA 4.0
2019-05-23T06:51:58.627Z
OK, in response to your answer, thank you. Starting with the last paragraph first, as per my last comment above - the why is environmental; the oceans are a huge influencer of climate and have a _lot_ of heat energy stored, so as I see it, having the capability and system in place would be beneficial (that's not a topic for here though).
the4thv
CC BY-SA 4.0
2019-05-23T07:08:08.350Z
[Sorry, I hit return] ...Indeed, the idea would be reduce the addition of energy from fossil fuel stores, but it would definitely need to be done with a net reduction of overall energy release (compared to just using fossil fuels).

Re the 2nd paragraph: thanks for the formula, but do you happen to have these numbers for heat-pumps (as per @trondhansen's link) or could help me calculate the equivalent number? I can't imagine using normal air-conditioning methodology. I envisage solar powered heat-pumps at sea, storing the energy as salt storage, periodically returning with their store full.
the4thv
CC BY-SA 4.0
2019-05-23T15:27:16.407Z
@the4thv air conditioners *are* heat pumps. Same technology. The coefficient of performance (the 40% I mentioned) will vary, maybe a lot, but it's going to be more than zero and less than one.
Semidiurnal Simon
CC BY-SA 4.0
2019-05-23T15:30:33.597Z
@the4thv this is almost certainly counterproductive for combating climate change, because you have to answer more questions: 1. Where are you going to put this heat (I imagine the only useful answer is "radiate it into space" ) 2. How are you going to do that? 3. How much energy will it take to do that (what we've been talking about here may be the tip of the iceberg) and 4. Where is that additional energy going to end up?
Semidiurnal Simon
CC BY-SA 4.0
2019-05-22T22:24:01.940Z
2019-05-22T22:24:01.940Z
Semidiurnal Simon
<p>Is there a way to calculate the energy required to reduce the heat of oceans? </p>

<p>Am I wrong in thinking it is not as simple as reversing the calculation for specific heat of sea water?</p>

CC BY-SA 4.0
2019-04-19T15:35:28.800Z
it is literally as simple as calculating hte specific heat of seawater unless you are trying to coll it in some specific manor.
John
CC BY-SA 4.0
2019-04-19T15:54:57.457Z
Thanks - so the calculation would just be specific heat x mass of the oceans? I.e. the energy to raise by 1 degree is equal to the energy to reduce by 1 degree?
the4thv
CC BY-SA 4.0
2019-04-19T19:38:22.273Z
Note the very significant difference between the energy you need to extract from the ocean to cool it by 1°C and the energy required to extract that energy. In a similar way the energy used by a fridge to cool the food inside it is MUCH more than the energy actually extracted from the food,
Camilo Rada
CC BY-SA 4.0
2019-04-20T05:32:20.303Z
as your question is now it is a little theoretical so in real life you will need a plan for where you are going to dump the heat and that is the hard part of this(in the light of your tag climate-change)
trond hansen
CC BY-SA 4.0
2019-04-20T14:20:09.520Z
Thanks all for the points raised. I am trying to formulate a more practical question relating to this issue but I have a few steps I wish to take first. The first is the physics of this issue at a high level. @CamiloRada, I assume you say this because no system is 100% efficient (is this a reference to the second law of thermodynamics?).
the4thv
CC BY-SA 4.0
2019-04-20T14:32:54.047Z
@trondhansen, my thoughts exactly and this is where I'm going with this line of thought; we can store it in a manner that we can later utilize it, or somehow 'vent' it to outerspace. Two immediate ideas: 
1) Using a form of evaporation and salt storage (https://en.m.wikipedia.org/wiki/Thermal_energy_storage#Salt_hydrate_technology). 

2) Using the upper atmosphere to cool bodies of water by cooling something high up and then placing it in the ocean, kind of like a man made ice cube.

I currently can't see how either might work at scale or what that scale would need to be.
the4thv
CC BY-SA 4.0
2019-05-21T18:42:22.180Z
Unless you are simply asking for the heat content of sea water & efficiency of refrigeration, the question doesn't really have an answer.  For instance, you could do it with comparatively little energy just by placing thin (on the order of a few atoms thick) mirrors in orbit to reflect sunlight.
jamesqf
CC BY-SA 4.0
2021-12-17T01:02:45.370Z
@jamesqf - answer by calculating the energy required to build, launch and operate an orbital mirror system? But passive mirrors/shades won't stay where you put them - light pressure will move them and no orbit is 100% stable, so they need to be able to navigate and move. But putting the heat someplace else IS the fundamental issue here - so "indirectly" offers more options than ways to radiate energy to space or send to some kind of deep underground heat sink. 100% clean energy and time? (But may only stop further ocean warming, not make cooling.)
Ken Fabian
<climate-change><oceanography><water><geoengineering>
How much energy would be required to actively reduce the temperature of the oceans of Earth by 1℃?
the4thv
# How much energy would be required to actively reduce the temperature of the oceans of Earth by 1℃?

(Asked by: username_0 on 2019-04-19)

Is there a way to calculate the energy required to reduce the heat of oceans?

Am I wrong in thinking it is not as simple as reversing the calculation for specific heat of sea water?

**Tags:** climate-change, oceanography, water, geoengineering

> **Comments:**
> **username_1**: it is literally as simple as calculating hte specific heat of seawater unless you are trying to coll it in some specific manor.  
> **username_0**: Thanks - so the calculation would just be specific heat x mass of the oceans? I.e. the energy to raise by 1 degree is equal to the energy to reduce by 1 degree?  
> **username_2**: Note the very significant difference between the energy you need to extract from the ocean to cool it by 1°C and the energy required to extract that energy. In a similar way the energy used by a fridge to cool the food inside it is MUCH more than the energy actually extracted from the food,  
> **username_3**: as your question is now it is a little theoretical so in real life you will need a plan for where you are going to dump the heat and that is the hard part of this(in the light of your tag climate-change)  
> **username_0**: Thanks all for the points raised. I am trying to formulate a more practical question relating to this issue but I have a few steps I wish to take first. The first is the physics of this issue at a high level. @username_2, I assume you say this because no system is 100% efficient (is this a reference to the second law of thermodynamics?).  
> **username_0**: @username_3, my thoughts exactly and this is where I'm going with this line of thought; we can store it in a manner that we can later utilize it, or somehow 'vent' it to outerspace. Two immediate ideas:  1) Using a form of evaporation and salt storage (https://en.m.wikipedia.org/wiki/Thermal_energy_storage#Salt_hydrate_technology).   2) Using the upper atmosphere to cool bodies of water by cooling something high up and then placing it in the ocean, kind of like a man made ice cube.  I currently can't see how either might work at scale or what that scale would need to be.  
> **username_4**: Unless you are simply asking for the heat content of sea water & efficiency of refrigeration, the question doesn't really have an answer.  For instance, you could do it with comparatively little energy just by placing thin (on the order of a few atoms thick) mirrors in orbit to reflect sunlight.  
> **username_5**: @username_4 - answer by calculating the energy required to build, launch and operate an orbital mirror system? But passive mirrors/shades won't stay where you put them - light pressure will move them and no orbit is 100% stable, so they need to be able to navigate and move. But putting the heat someplace else IS the fundamental issue here - so "indirectly" offers more options than ways to radiate energy to space or send to some kind of deep underground heat sink. 100% clean energy and time? (But may only stop further ocean warming, not make cooling.)  

---

## 3 answers

### Answer by username_9 on 2019-05-22. Score: 6 | Accepted answer

The question is slightly confused, because reducing the temperature of the oceans, in a direct sense, doesn't require energy - it releases it. The amount that is released is simply related to the mass and specific heat capacity of seawater, as you suggest.

The missing question, though, is *why* the ocean is cooling. For it to happen naturally and simply release energy, it would need to be because its surroundings (e.g. the air) were cooler. If you want to actively cool the sea, then yes, that is going to consume energy. If the cooling has approximately the same level of performance as building-sized air conditioning, the power used by the cooling apparatus will be about 40% of the rate at which the energy is removed (and remember that this is not just the total energy divided by the time, because more heat will be leaking back in while you do it).

Leaving aside the, uh, engineering challenges of this scale of cooling, this leads to a question as to *why* one might want to do this. Remember that unless you devise some complex system to radiate this heat into space from above the atmosphere, you're going to be releasing the same heat into the same global climate system, plus the additional 40% that you've used to move it around.

> **Comments:**
> **username_3**: this is how my closest city uses heat from a river for heating and cooling houses and industry https://www.bbc.com/news/business-31506073  
> **username_0**: Thanks @username_9-username_9, I was hoping my question implied 'active', but I grant you it isn't explicit - I've corrected that.  
> **username_0**: OK, in response to your answer, thank you. Starting with the last paragraph first, as per my last comment above - the why is environmental; the oceans are a huge influencer of climate and have a _lot_ of heat energy stored, so as I see it, having the capability and system in place would be beneficial (that's not a topic for here though).  
> **username_0**: [Sorry, I hit return] ...Indeed, the idea would be reduce the addition of energy from fossil fuel stores, but it would definitely need to be done with a net reduction of overall energy release (compared to just using fossil fuels).  Re the 2nd paragraph: thanks for the formula, but do you happen to have these numbers for heat-pumps (as per @username_3's link) or could help me calculate the equivalent number? I can't imagine using normal air-conditioning methodology. I envisage solar powered heat-pumps at sea, storing the energy as salt storage, periodically returning with their store full.  
> **username_9**: @username_0 air conditioners *are* heat pumps. Same technology. The coefficient of performance (the 40% I mentioned) will vary, maybe a lot, but it's going to be more than zero and less than one.  
> **username_9**: @username_0 this is almost certainly counterproductive for combating climate change, because you have to answer more questions: 1. Where are you going to put this heat (I imagine the only useful answer is "radiate it into space" ) 2. How are you going to do that? 3. How much energy will it take to do that (what we've been talking about here may be the tip of the iceberg) and 4. Where is that additional energy going to end up?  

---

### Answer by username_6 on 2021-12-18. Score: 1

***Heat capacity*** is the amount of thermal energy it requires to heat a gram of "A substance" one Kelvin degree.
Salt water of oceanic variant average salinity (3.5%) has specific heating of 3.993 J/(g K) or 3.993 Joules of energy per gram of water to raise it ONE degree kelvin.

using Metric; Water has a specific heat capacity of 4.186 J/g°C, meaning that it requires 4.186 J of energy (1 calorie) to heat a gram by one degree Celsius. With an Oceanic volume of 321 Million Cubic miles (1.338 Quintillion! cubic meters) with roughly one million grams of water per cubic meter it would take the removal of
nearly a Yottajoules worth of energy, 500 TIMES current human annual energy consumption.

> **Comments:**
> **username_7**: ≈ 1 yottajoule? Isn't it 4,183*1,338 ≈ 5,46 (* 10^18 * 10^6) -> 5,46 * 10^24 = 5 yotta joule  

---

### Answer by username_8 on 2021-12-15. Score: 1

Assuming a surface ocean temperature of 288 K and a deep ocean temperature of 277 K, let's assume a mean temperature around 282.5 K.

The specific heat capacity of seawater at constant pressure is 3,890 joules per kilogram per kelvin.

The mass of the ocean is 1.39 x 1021 kg.

Therefore the "thermal content," if I can call it that, of the ocean is 1.528 x 1027 J. At 281.5 K, it would be 1.522 x 1027 J. The difference is 5.407 x 1024 J using all the significant figures Excel gives me. That's a lot of energy!

> **Comments:**
> **username_0**: Thank you the interesting answer  

---

