In 2024, datancenter have consumed 1% of the total worldwide electricity production and are responsible for 0.5% of the co2 emissions.¹
1- https://www.carbonbrief.org/ai-five-charts-that-put-data-cen...
The buried ledes here are firstly that a concrete building is a one-time thing, where once it's built it is built and that's that. (The 8% of pollution is a yearly recurring thing from the production of concrete, but an individual concrete building is done polluting once construction is finished.) On the other hand, an AI data center contributes its pollution every year continuously forever.
Secondly, the matter of scale. Concrete took billions of buildings to get to its share of the pollution done. You will be hard pressed to find anything in the world period that can be produced at that scale without causing significant pollution. It's almost miraculous that it's only at 8% globally, especially when compared to AI data centers, of which there are only 12,000. You could build a dozen buildings out of concrete every day for the next 40 years and on a global scale you would not move the needle on how much pollution concrete is responsible for. Do the same with data centers and while the math is a bit harder you will wind up being responsible for ~30% of the pollution on Earth.