A more useful comparison would be the share of new emissions that data centers represent, and a comparison of the growth rates of various sources of marginal new emissions (eg, from cement, or ammonia). Besides their visibility, the reason that people focus on AI data centers is that they are a new source, on top of whatever organic growth there is in existing industries. And marginal growth in CO2 emissions is important because climate models bake in certain assumptions about growth. If a wildcard source suddenly appears with exponential growth, the projections on which public policy is based can be affected non-linearly. This article uses data only up to 2024; 18 months of exponential growth can change the picture quite a bit.