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donsutherland1

Paper: Record-Setting Ocean Warmth Continued in 2019

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Abstract:

uman-emitted greenhouse gases (GHGs) have resulted in a long-term and unequivocal warming of the planet (IPCC, 2019). More than 90% of the excess heat is stored within the world’s oceans, where it accumulates and causes increases in ocean temperature (Rhein et al., 2013; Abram et al., 2019). Because the oceans are the main repository of the Earth’s energy imbalance, measuring ocean heat content (OHC) is one of the best way to quantify the rate of global warming (Trenberth et al., 2016; Von Schuckmann et al., 2016; Cheng et al., 2018). Following reports released in the previous two years (Cheng and Zhu, 2018; Cheng et al., 2019c), this article presents new OHC data for the year 2019. These data reveal that the world’s oceans (especially at upper 2000 m) in 2019 were the warmest in recorded human history. Specifically, the ocean heat anomaly (0−2000 m) in 2019 was 228 Zetta Joules (ZJ, 1 ZJ=1021 Joules) above the 1981−2010 average and 25 ZJ above 2018 (Table 1).

The OHC values (for the upper 2000 m) were obtained from the Institute of Atmospheric Physics (IAP) ocean analysis (see "Data and methods" section, below), which uses a relatively new method to treat data sparseness and updates in the instruments that have been used to measure ocean temperature (Cheng et al., 2017). The evolution of OHC (Fig. 1) shows that the upper 2000 m OHC in 2019 was 228 ± 9 ZJ above the 1981–2010 average. The record-setting ocean warmth is also found in National Oceanic and Atmospheric Administration/National Center for Environmental Information (NOAA/NCEI) data, showing 217± 4 ZJ in 2019 above 1981−2010 average (21 ZJ above 2018) (Table 1) (updated from Levitus et al. 2012). With these newly available IAP data, a ranking of the warmest years since 1950s is now possible (Table 1). The past five years are the top five warmest years in the ocean historically with modern instruments, and the past ten years are also the top ten years on record. The same ranking also applies to NOAA/NCEI data (Table 1).

The full paper can be viewed here: https://link.springer.com/content/pdf/10.1007%2Fs00376-020-9283-7.pdf

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Powerful stuff! 

Can anyone help put the heat content change into perspective? The increase of roughly 300 Zetta Joules since the 1980s is what percentage of the annual global heat budget?

 

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So to put that in perspective the change from 1985 to 2019 is about 350e21 joules (eyeballing for now). The average uptake is thus...

350e21 (OHC-joules) / (31.56e6 (seconds in year) * 34 (years))  / 510e12 (Earth area-m^2) = 0.64 W/m^2.

The ocean takes up about 90% of the imbalance so we can probably estimate the average imbalance as 0.64 / 0.9 = +0.7 W/m^2.

That is a pretty large imbalance and is inline with expectations of the net radiative force from all agents subtracted off from what has already equilibriated to raise the global mean temperature.

Over the last 10 years this imbalance actually works out to about +1.0 W/m^2. The implication...even if GHG emissions were to cease instantly there is still a lot of warming waiting in the pipeline that needs to equilibriate.

 

 

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5 hours ago, etudiant said:

Powerful stuff! 

Can anyone help put the heat content change into perspective? The increase of roughly 300 Zetta Joules since the 1980s is what percentage of the annual global heat budget?

 

Using my +0.7 W/m^2 figure above and dividing by 240 W/m^2 yields = 0.7 / 240 = 0.3% of the surface budget. However, keep in mind that +0.7 W/m^2 is just the imbalance that still needs to equilibriate. The energy imbalance from the past that has caused 1.1C of warming has already equilibriated so is not included in my +0.7 W/m^2 value. This additional energy is probably in the 1.5-2.0 W/m^2 'ish range (just guessing right now). If you include that then we're probably close to 1% of the surface budget.

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7 hours ago, bdgwx said:

Using my +0.7 W/m^2 figure above and dividing by 240 W/m^2 yields = 0.7 / 240 = 0.3% of the surface budget. However, keep in mind that +0.7 W/m^2 is just the imbalance that still needs to equilibriate. The energy imbalance from the past that has caused 1.1C of warming has already equilibriated so is not included in my +0.7 W/m^2 value. This additional energy is probably in the 1.5-2.0 W/m^2 'ish range (just guessing right now). If you include that then we're probably close to 1% of the surface budget.

Thank you! That is both informative and very helpful.

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Trying to translate this measurement into actual temperature impact, I estimate as follows.

The increased heat content since 1990 of 300 or so zettajoules (300x10**21 joules) is spread over perhaps the top one third of the oceanic volume of roughly 1.3 billion cubic kilometers.

That is roughly 400 million cubic kilometers. (400x10**6 cubic kilometers).  A cubic kilometer contains 10**9 cubic meters, each of which contains 10**6 cubic centimeters of water, so the relevant ocean volume is about 400 zettacubic centimeters (10**21 cubic centimeters) of water. Rounding, it means the added heat content is about a joule per cubic centimeter.

It takes about 4 joules to raise the temperature of 1 cubic centimeter of water 1 degree C, so the added heat increases the temperature by about a quarter of a degree C.

At first glance, that does not seem much, but it really highlights how massively important the oceans are to our survival. They buffer the imbalances hugely.

 

 

 

 

 

 

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On 1/15/2020 at 8:24 AM, etudiant said:

Trying to translate this measurement into actual temperature impact, I estimate as follows.

The increased heat content since 1990 of 300 or so zettajoules (300x10**21 joules) is spread over perhaps the top one third of the oceanic volume of roughly 1.3 billion cubic kilometers.

That is roughly 400 million cubic kilometers. (400x10**6 cubic kilometers).  A cubic kilometer contains 10**9 cubic meters, each of which contains 10**6 cubic centimeters of water, so the relevant ocean volume is about 400 zettacubic centimeters (10**21 cubic centimeters) of water. Rounding, it means the added heat content is about a joule per cubic centimeter.

It takes about 4 joules to raise the temperature of 1 cubic centimeter of water 1 degree C, so the added heat increases the temperature by about a quarter of a degree C.

At first glance, that does not seem much, but it really highlights how massively important the oceans are to our survival. They buffer the imbalances hugely.

 

 

 

 

 

 

Here are 0 to 700m ocean temperatures. Your estimate is pretty good. The top 100m have warmed twice as fast.

inodc_temp700_0-360E_-90-90N_n.png

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I question the uncertainty range of this study. I seriously doubt that measurements going back to the 1960's regarding the top two kilometers of ocean temperature are accurate within plus or minus .003 degrees celsius. That seems highly problematic. The number of buoys that are currently in use versus the number it would take to truly measure enough of the ocean down to two kilometers is also quite problematic. As is the fact that this buoy system has only been in place since 2005.

 

Finally, even if one assumes their problematic findings are indeed accurate, it will take some 300+ years for the oceans to warn by a single degree. Not exactly alarming. And to say with certainty that the change in temperature is 100% due to human causes as opposed to cloud cover or El Nino frequency, or any number of other slight variances in a highly complex climate system seems to me very definition of arrogance.

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On 1/14/2020 at 9:51 AM, etudiant said:

Powerful stuff! 

Can anyone help put the heat content change into perspective? The increase of roughly 300 Zetta Joules since the 1980s is what percentage of the annual global heat budget?

 

the amount of heat being added to the oceans is the equivalent of 5 Hiroshima level atomic bombs EVERY SECOND!  Also read the paper on oceanic heatwaves that was posted earlier, pretty eyeopening....

 

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2 hours ago, bobjohnsonforthehall said:

I question the uncertainty range of this study. I seriously doubt that measurements going back to the 1960's regarding the top two kilometers of ocean temperature are accurate within plus or minus .003 degrees celsius. That seems highly problematic. The number of buoys that are currently in use versus the number it would take to truly measure enough of the ocean down to two kilometers is also quite problematic. As is the fact that this buoy system has only been in place since 2005.

 

Finally, even if one assumes their problematic findings are indeed accurate, it will take some 300+ years for the oceans to warn by a single degree. Not exactly alarming. And to say with certainty that the change in temperature is 100% due to human causes as opposed to cloud cover or El Nino frequency, or any number of other slight variances in a highly complex climate system seems to me very definition of arrogance.

increasing severity of el nino has also been connected to AGW.

 

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25 minutes ago, LibertyBell said:

the amount of heat being added to the oceans is the equivalent of 5 Hiroshima level atomic bombs EVERY SECOND!  Also read the paper on oceanic heatwaves that was posted earlier, pretty eyeopening....

 

And the amount of heat being added to the oceans BY THE SUN is what? A thousand times that? Every second? Yawn.

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