In modern mines, there is measuring equipment that documents the orientation of 3D stresses over time and, combined with geological measurements, are used in the design of the direction of underground openings.

For me personally, there is great stress release when underground because of the beauty of the 3D geological world, the lack of mobile phone coverage and the camaraderie that those underground dirty people in danger enjoy.

REFRIGERATED

In the Western Deep Levels mine in South Africa, as in many other deep mines, ventilation is refrigerated so workers can survive the temperature at over 4000m depth.

In other mines, workers are in air-conditioned machinery cabins or wear ice suits. The high temperature and rock pressures at depth are one of the limitations on mining the eye-watering tonnages of metals required to have an EV or net-zero world.

In some mines, the rocks are so hot they burn ungloved hands and, if a precious sample is required, it is very common that a smack on an underground rock face with a hammer stimulates an explosion of sharp shards of rock as a result of instantaneous destressing.

Plumes of heat from the planet’s core are slowly convected through the Earth’s mantle with additional heat gained from the radioactive breakdown of small amounts of uranium, thorium and potassium.

The Earth’s continents are a 30-70km layer on hotter deeper denser rocks. High heat flow occurs where this continental crust is being pulled apart and thinned by thermal plumes (eg East African Rift, Red Sea), where uranium-, thorium- and potassium-rich rocks occur (eg granite rich areas) and where the wet sediment-covered oceanic crust is being pushed under the continental crust to produce volcanic chains and earthquakes (eg The Andes).

The denser oceanic crust is 6-12km thick and occupies 70 per cent of the Earth’s surface.

Oceans form by the pulling apart of continents resulting from thermal plumes rising from the lower mantle and spreading laterally underneath the crust.

Geothermal maps of the planet show that most of the planet’s heat is released along mid ocean ridges, off axis fracture-controlled volcanoes and oceanic hot spots such as Hawaii.

So, where does most of the heat from the cooling of the Earth end up? The oceans.

And where does heat from the oceans end up? In the atmosphere, where solar and some planetary heat drive weather and climate.

Water has a far higher heat capacity than air and most of the planet’s surface heat is held in the oceans. Weather is driven by ocean heat.

ERUPTIONS

There are more than 3.4 million known old basalt volcanoes on the ocean floor and 65,000km of active volcanic mid-ocean ridges where submarine volcanic eruptions, hot springs and huge volumes hot rocks all need to be cooled.

There are even pools of liquid carbon dioxide on the sea floor.

The mid-ocean ridges are a few thousand kilometres wide and rise up to 3km above the ocean floor.

The Ocean Drilling Program and field studies where old ocean floor has been pushed up to the surface (eg Cyprus), show that cold sea water does many laps through the top five kilometres of the oceanic crust as part of planetary cooling.

This process also removes carbon dioxide from seawater, adds heat to the oceans and involve chemical reactions that prevent the oceans from becoming acid.

Some of these chemical reactions also give out heat which is added to the oceans. When the planet stops cooling or is subsumed by a dying sun, the oceans will become acid. Don’t wait up.

Submarine basalt is molten at 1100°C and contains up to 15 per cent carbon dioxide in solution. As the lava ascends it releases most of the dissolved water, carbon dioxide, methane, helium and other gases.

The carbon dioxide then dissolves and mixes with cool saline bottom oceanic waters and much later is released to the air during upwelling.

The lava cools by exchanging heat with water. This warmer water is less dense and rises to the surface. The enigmatic ocean heat blobs and El Niño-La Niña cycles may derive from processes operating on the ocean floor rather than in the atmosphere.

There are millions of annual seismic events beneath the ocean floor and most are a proxy for rising mid-oceanic molten rocks and submarine eruptions.

There is a paucity of data because there is no array of submarine volcano monitoring centres. There is also an uncanny abundance of earthquakes and volcanoes at the time our planet is being kneaded by solar, planetary and lunar forces.

KNEADING

This is well known from Jupiter’s moon Europa where there are volcanic eruptions due to gravitational kneading.

At the recent 15^th International Heartland Climate Conference in Orlando, Florida, in March 2023, I rhetorically asked a prominent meteorologist why he looked to the skies for all the heat in the oceans and atmosphere rather than looking under his feet for additional heat from the continents and especially the ocean floor.

I don’t think those in the climate business have even thought that there are other heat sources besides the Sun that may transfer heat to the atmosphere. It is a process that has been taking place for billions of years yet has been ignored.

Another spanner in the works is plate tectonics. Moving continents open and close seaways thereby changing the carrying of heat by ocean currents.

The land around the Bering Strait is rising quickly. Forget tensions between Russia and the USA today. If Russia physically joins Alaska and the Bering Strait is completely closed, warm seawater cannot enter the Arctic and an ice age cometh.

Huge masses of lava erupting onto the sea floor cause sea levels to rise and deflect ocean currents thereby changing climate.

Changes in the shape of continents by plate tectonics also changes ocean current directions. Additions of sediment on the continental shelf and ocean depths pushes up sea level.