Six years ago, Google was confident that by 2030 it would power all operations with electricity generated from clean sources, including wind and solar power, and remove as much pollution as it produced. Today it calls those goals a “moonshot.” Microsoft says it’s still aiming to remove more carbon than it creates by 2030 but now describes the effort as “a marathon, not a sprint.” The race to deploy artificial intelligence is complicating tech companies’ commitments to reduce greenhouse gas