ground- water, geo- statistics, environmental- engineering, earth- science

Heat Stored in the Oceans

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Here is an interesting chart, that I saw yesterday at the IPCC session at EGU.

It shows the energy stored in different compartments. There is more heat stored in water than say in the air, due to the larger heat capacity of water. The exchange of heat, I think, must occur via temperature. So this must have an affect on the oceans, the living beings within the oceans, and on climate.

As Steve Easterbrook points out at azimuth:

The oceans act as a huge storage heater, and will continue to warm up the lower atmosphere (no matter what changes we make to the atmosphere in the future).

IPCC AR5 WG1 Box 3 1 Fig 1

Description of this figure from IPCC

(Box 3.1 Fig 1) Plot of energy accumulation in zettajoules within distinct components of Earth’s climate system relative to 1971 and from 1971–2010 unless otherwise indicated. Ocean warming (heat content change) dominates, with the upper ocean (light blue, above 700 m) contributing more than the deep ocean (dark blue, below 700 m; including below 2000 m estimates starting from 1992). Ice melt (light grey; for glaciers and ice caps, Greenland and Antarctic ice sheet estimates starting from 1992, and Arctic sea ice estimate from 1979–2008); continental (land) warming (orange); and atmospheric warming (purple; estimate starting from 1979) make smaller contributions. Uncertainty in the ocean estimate also dominates the total uncertainty (dot-dashed lines about the error from all five components at 90% confidence intervals).

A good discussion about this topic, also related to the uncertainties in the predictions related to stored heat can be found at Climate Etc.

Written by Claus

May 1st, 2014 at 2:49 pm

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2 Responses to 'Heat Stored in the Oceans'

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  1. According to Wikipedia the atmosphere has a mass of 5.15×E18 kg All the earth’s water is about 1,338,000,000 cubic kilometers (according to here which would be 1.338E24 kg. With water having a heat capacity roughly 4 times higher than that of air (at sea level pressure and room temperature, which is of course a strong simplification), you can put roughly 1 million times more energy into the global water body to get the same increase in temperature.

    So, does that mean that it is indeed irrelevant what we do to the atmosphere?


    10 May 14 at 10:19 pm

  2. Dommy, thanks for your comments. I think I fully understand your argumentation. This also occupies my mind a bit. Here are a few further comments:

    • the heat stored in the oceans got there via exchange of temperature from the atmosphere. What role does relatively warm precipitation versus relative cold input (glacial meltwater) play?
    • so whatever we do to the atmosphere will not all migrate into the oceans, some (I assume the larger part) stays in the atmosphere
    • heat exchange is a diffusive process (in both directions). So we will see the effects for some time.
    • so if it’s a diffusive process, how does the heat get into the deep ocean? Currents? There seems to be some time lag in the blue curves, but only about a decade
    • my guess is also that a 1-2 orders of magnitude increase of heat stored in the (deep) oceans, must have some impact on the flora and fauna that lives down there
    • how much of this stuff (like heat stored in the deep ocean) have we actually measured (in a meaningful spatio-temporal resolution)?

    I am wondering, why the uncertainty about the amount of energy stored over all decreases with time.

    This is directly from the IPCC report and might help

    It is virtually certain that the Earth has gained substantial energy from 1971 to 2010 — the estimated increase in energy inventory between 1971 and 2010 is 274 [196 to 351] ZJ (1 ZJ = 1021 J), with a rate of 213 TW from a linear fit to the annual values over that time period (Box 3.1, Figure 1). An energy gain of 274 ZJ is equivalent to a heating rate of 0.42 W m-2 applied continuously over the surface area of the earth (5.10 × 1014 m2). Ocean warming dominates the total energy change inventory, accounting for roughly 93% on average from 1971 to 2010 (high confidence). The upper ocean (0-700 m) accounts for about 64% of the total energy change inventory. Melting ice (including Arctic sea ice, ice sheets and glaciers) accounts for 3% of the total, and warming of the continents 3%. Warming of the atmosphere makes up the remaining 1%. The 1971–2010 estimated rate of oceanic energy gain is 199 TW from a linear fit to data over that time period, implying a mean heat flux of 0.55 W m–2 across the global ocean surface area (3.60 × 1014 m2). The Earth’s net estimated energy increase from 1993 to 2010 is 163 [127 to 201] ZJ with a trend estimate of 275 TW. The ocean portion of the trend for 1993–2010 is 257 TW, equivalent to a mean heat flux into the ocean of 0.71 W m–2 over the global ocean surface area.


    12 May 14 at 8:31 am

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