Why do you assume that building data centers is critical to begin with? You seem to start with an assumption you haven’t even questioned? Just 5 years ago very few Americans thought massive data center buildout was key to the economy.
Your comment about the size of the earth is confounding. How is that relevant? Raising temps 4 degrees locally is a serious issue. Yes it will be worse if it scales but it doesn’t have to in order for us to care.
The tech companies could be building green data centers. Using renewable energy they are paying to add to the grid ( ie building the solar plant along with the data centers) and then flowing half the power they make back to the grid to lower prices. They could similarly work with water, purifying non drinking sources and adding to supply overall.
Costs would balloon but the negative impacts would go and getting a data center would mean jobs, lower prices for energy, less carbon and clean water.
Doing it the way we are - based on subsidies and pollution - is a choice.
5 years ago was 2021. Covid was causing a lot of thoughts about the economy that I think, people who were thinking about it did actually include data centers in, given that shelter in place meant that Internet usage was up. As far as whether I think data centers are justified, the climate accords have failed to stop industrialization, so the only way forwards is through - meaning if data centers are how we get to fusion and advanced geothermal and solar and wind power because of the sheer power demands, so be it. I wish we could just get off coal and oil in the first place, but me wishing things has no effect on reality.
As far as what tech companies could be doing to be green, Google's investment into Fervo Energy gives them energy that runs 24/7 with no reliance on the weather or the sun. They've got an initial plant going, all that's left is to replicate it and find cheaper ways to do it.