The issue with climate change was never with "heat production". It's always been the generation of heat trapping chemicals. The sun sends a stupid amount of energy our way. Generally the earth radiates almost the same amount back out into space, with a minor amount captured by various things, like photosynthesis.

Pollution alters that equation and causes more energy from the sun to get trapped in the atmosphere. That's the problem. We could never generate as much energy as the sun (even the tiny amount that hits the earth), but we can definitely alter the atmosphere to trap more and more of that heat.

Also, the ocean is a MASSIVE heat sink. I saw someone work out the calculations recently, I don't remember the numbers, but the conclusion was that we'd never measure a notable increase in ocean temps if we housed every datacentre in existence in the ocean. The sun hitting the ocean every day dumps more energy into the ocean directly than we'd ever be able to manage.

It all comes down to pollution.

This page says the ocean is about 352,670,000,000,000,000,000 gallons, which is about 1.3 x 10^21 liters, and each liter is a kg of water (yeah, yeah, the dissolved salt adds some mass but I don't think it adds sufficient thermal mass to make a difference). It takes 4.184 kilojoules to raise 1kg of liquid water 1°C, and 1 joule is 2.778 x 10^-4 wh.

So that's 1.55 x 10^18 watt hours, or 1,550,000 TWh.

Global electricity consumption is about 30,000 TWh per year, so if you use the entire world's electricity consumption for 51 years you'd raise the oceans' temperature by 1°C.

Or if you take global data center power capacity of about 125 GW, and ran them at full power 24/7, you'd be producing about 10.8 TWh per day or 3944 TWh per year. It'd take about 393 years of the world's data centers to raise the ocean by 1°C.

Just goes to show that much more of the energy heating up our world and our oceans is coming from the sun heating up the planet and the planet failing to radiate it out past our greenhouse blanket, not from the actual heating of our atmosphere from our own energy sources.