Trapped Heat Is Like Trapped Animals (Somewhat Unpredictable)

Fig. 1 What comes in must equal what goes out (or else)

The peer reviewed paper which came out recently indicated that it was highly unlikely that a 2 degree C increase in average global surface temperature (atmospheric) could be achieved (Less than 2 °C warming by 2100 unlikely).

That is scary because, for one thing, another group wrote that a 2 deg. C increase in global mean average temperature was "highly dangerous" (New Study Says Even 2 Degrees of Warming 'Highly Dangerous').

The way this happens is that the planet's heat budget is unbalanced by greenhouse gases being injected into the atmosphere by a civilization that is recklessly using fossil fuels at an increasing rate; a rate that is keeping more and more of the Sun's heat trapped in the Earth's atmosphere and oceans (Fig. 1 oversimplified & not to scale).

Fig. 2a Ocean temperatures @ 7 depth layers

Fig. 2b Average Conservative Temperature

The bulk of this heat that is trapped here because it cannot flow back out into space, eventually enters the oceans (~93% ends up in the oceans).

The graph at Fig. 2a shows past, present, and future temperature changes in the oceans at seven depth layers.

The graph at Fig. 2b shows only the mean average of those temperature changes.

Notice how the same mean average values look quite different when graphed en masse (Fig. 2a) compared to being graphed alone (Fig. 2b).

That is something to keep in mind when viewing the same values being presented in different configurations that make them look different.

Fig. 3a Absolute Salinity @ 7 depth layers

Fig. 3b Mean average Absolute Salinity

The graphs at Fig. 3a and Fig. 3b present the same graph phenomenon while graphing Absolute Salinity in the same manner as Conservative Temperature is graphed in Fig. 2a and Fig. 2b.

Ocean salinity can be changed in several ways, such as by freshening (fresh melt water from ice sheets, ice shelves, and glaciers entering the ocean), currents, changes in temperature, and upwelling, to name a few.

The way to view the two presentations is to note the high and low shown at the left side of the graph.

For example, the mean average temperature begins at about 5.5 deg. C on both Fig. 2a and Fig. 2b, and stays within the 5.0 - 5.9 degree range as its temperature oscillates up and down by cooling and warming.

Nevertheless, that less than one degree of oscillation looks radical on Fig. 2b while looking quite tame on graph Fig. 2a.

Fig. 4a Thermal Expansion @ 7 depth layers

Fig. 4b Mean average Thermal Expansion

The same goes for the graphs of Thermal Expansion in graphs at Fig. 4a and Fig. 4b.

All of these graphs cover the years 1880 through 2100.

Actual in situ valid data contained in the WOD database (@ datasets CTD and PFL) only exists for the years 1968 - 2016.

So, the pre-1968 and post-2016 values are calculated using GISS temperature records from 1880 through 2016, then projected out to 2100 using the recent peer reviewed paper mentioned earlier (New Study Says Even 2 Degrees of Warming 'Highly Dangerous').

The scientists who produced the paper estimate a bit less that a 5 degree C temperature increase as the high end temperature likely to exist on Earth by the year 2100.

Fig. 5 GISS temperatures

I use their estimates to project the future ocean temperature by taking ~93 % of those values for computing temperature changes entering the oceans over that span of time (Fig. 5).

The past (pre-1968) is projected in the same manner, combined with PSMSL and WOD in situ measurements as a guide.

You may notice that some of the in situ WOD measurements are more volatile than the other measured values (PSMSL & GISS) during the about half a century of in place measurements we have.

We live in more volatile times now, which makes it difficult to guesstimate both the past (less radical) and the future (more radical), but remember that we are at a 1 deg C GISS anomaly now, and they project it to increase to about a 5 degree anomaly.

That is quite radical too.

The in situ measurements from 1880 - 2016 exist for PSMSL and GISS, meaning the projections are only future computations, but since the WOD measurements are not that robust, pre-1968 and post-2016 must be estimated by being informed by the other measurements.

At the end of the day, it is the trend line that will be the most accurate indicator.