I am sure you are all well aware of the UAH satellite data set from Spencer and Christy. Every month they report on the global warming of earth. They also give the long-term warming trend each month; e.g. the results for April 2024 included the statement: ‘The linear warming trend since January,1979 remains at +0.15 C/decade (+0.13 C/decade over the global-averaged oceans, and +0.20 C/decade over global-averaged land).’ To the casual observer this would suggest that the warming on land (SAT) is in a ratio of 3:2 to the warming of the seas and oceans (SST), thereby creating an impression that it is the change in atmosphere causing the extra warming of the earth.

I decided to check this by looking at a number of studies where SST was measured and evaluated manually, and then comparing the results with the nearest SAT results of adjacent land for which I found good data. The results of my investigations are reported below. 

It appears from my results that the idea of land always warming more than the seas holds reasonably well up until where we arrive in the NH subtropics. In the southern hemisphere (SH) the ratio appears to be going the other way around. I knew this already from previous investigations (See Footnote j). Note that I am not blaming Spencer and Christy for giving a wrong impression. What they are doing is completely correct, if you look at it linearly. They are simply averaging and averaging of what is inherently a very unequal warming of the earth going by same UAH data:

So, now what? By my results, there is definitely a significant correlation between SAT and SST: 

DISCUSSION

The highest rate of warming is observed in the Arctic, above the 70 degree latitude. Strangely enough, the warming rate in Barrow (Alaska) of 0.83K/decade compares to a warming rate of only 0.20K/decade in Nome (Alaska) over the same period 1982-2017 (See sheet 10, footnote a). Nome lies just south of Barrow, at 65 degrees, also on the coast of Alaska. The only explanation I can find for these results is that the Arctic is or was strongly affected by underground volcanic eruptions, as reported in a previous study: It is the earth itself, stupid!? | Bread on the water

especially on the Gakkel Ridge,

Volcanoes Erupt Beneath Arctic Ice | Live Science

Looking at the results, it would appear that the extra heat following these eruptions, is – or has been – flowing more towards the south via the corridor between Greenland and Norway. See also: Increasing amount of Arctic Ocean deep waters in the Greenland Sea – Somavilla – 2013 – Geophysical Research Letters – Wiley Online Library

There is also considerably more volcanic activity in Iceland…

A similar argument as the one above can be made for the extra volcanic activity noted in the Black Sea,

Black Sea mud volcanoes and their relation to the search for methane gas hydrates and environmental security – NASA/ADS (harvard.edu)

seemingly causing much warming and greening in northern Turkey.

As far as the Netherlands are concerned, I rely on the investigation done by Ap Cloosterman. See footnote e). He determined that the water of the major European rivers that end up in the North Sea, have warmed considerably due to the water being extensively used for cooling by many factories and energy companies nestled along the way from London, Holland, France, Germany and Switzerland. Warmer water has a higher vapor pressure obviously also bringing more warm water vapor in the atmosphere.

That brings me back to the correlation noted between SAT and SST. Which is causing what? If it were the extra CO2 from man in the air causing the extra warming of all the water and land, there are three points to make. (1) The extra CO2 is distributing itself equally into all directions of the atmosphere by diffusion, so the rate of increase is more or less the same wherever we measure it. So how come is there a complete unequal distribution of the warming of earth? (2) The mass of the increase in CO2 in the atmosphere over the past 50 years compares to next to nothing with the mass of all the seas and oceans of 1.4 x 10^21 kg. The increase in volume of CO2 in the atmosphere over the past 50 years is about 0,01% which compares to about 1% water vapour for the first 3 km of the atmosphere where the greenhouse effect is relevant. (3) A number of people, including myself, have carefully looked at the chemistry and optics and according to their evaluations they concluded that there is no or only a negligible net warming effect caused by more CO2 in the air (See footnote k) and subsequent footnotes in that report).

Assuming the extra heat comes from the oceans and the seas rather than from the atmosphere, how can it be that at some places there is more warming in the air than inside the adjacent sea?  The answer is simple, really. When the Hunga Tonga-Hunga Ha’apai volcano erupted on Jan. 15, it sent a tsunami racing around the world and set off a sonic boom that circled the globe twice. The underwater eruption in the South Pacific Ocean also blasted an enormous plume of water vapor into Earth’s stratosphere – enough to fill more than 58,000 Olympic-size swimming pools. The sheer amount of water vapor was enough to temporarily affect Earth’s global average temperature. 

Tonga Eruption Sent Ripples Through Earth’s Ionosphere (nasa.gov)

What do you think was the temperature of all that water vapor? Think of all those eruptions that we saw in Iceland. Suppose they were taking place underneath hundreds of meters of water. What do you think would happen? Large amounts of very warm water vapor would enter the atmosphere.

CONCLUSION

In my opinion, the extra ‘global’ warming of earth in the last 50 years, is coming from a change in sea surface temperature (SST). SST appears to be affected by combination of factors, including, amongst others,

1) UV/IR from the sun

2) Volcanic activity from the earth

3) Activities by man using the water from oceans, seas and rivers for irrigation and cooling

RECOMMENDATION

To avoid confusion, it would be better to rather look at reporting on the warming of the northern- and southern hemispheres separately instead of reporting on the warming of land and water separately.

Footnotes (links  to the reference reports)

a)

airtemperaturesBarrowMalmoSchipholEeldeBursaTangerMarionGough.xlsx

b)

(PDF) Exceptional warming over the Barents area (researchgate.net)

c)

Sea Surface Temperature – NOAA Arctic

d)

Copernicus Marine Data Store | Copernicus Marine Service

e)

‘Luctor et non emergo’ – Ik worstel en kom niet meer boven – Climategate Klimaat

f)

(PDF) Potential Effects on Climate Change on Black Sea Water Temperatures (researchgate.net)

g)

Remote Sensing | Free Full-Text | A Warming Mediterranean: 38 Years of Increasing Sea Surface Temperature (mdpi.com)

h)

(PDF) Coastal sea surface temperature variability along the south coast of South Africa and the relationship to regional and global climate (researchgate.net)

i)

https://journals.co.za/doi/pdf/10.10520/EJC97664#:~:text=At%20Marion%20Island%2C%20the%20mean,6.4%C2%B0C%20in%20February.

j)

An Inconvenient Truth | Bread on the water

k) 

https://breadonthewater.co.za/2022/12/15/an-evaluation-of-the-greenhouse-effect-by-carbon-dioxide/