Sierra Club: gas plants for data centers could lift US power emissions 42% by 2030

New gas-fired power plants built to serve data center electricity demand could push US power sector carbon dioxide emissions 42 percent higher in 2030 than they were in 2025, according to a Sierra Club analysis reported by The Verge. The group estimates that such an increase would effectively cancel out 15 years' worth of greenhouse gas reductions in the United States.

A 618-million-ton swing

The Sierra Club projects that carbon dioxide from electricity generation will grow by 618 million tons by the end of the decade if planned AI infrastructure projects move ahead. As The Verge notes, that is roughly equivalent to the annual electricity-related carbon pollution of more than 128 million homes. The projection stands out because the power sector had been one of the country's clearest climate success stories, with national emissions falling steadily for well over a decade.

Higher than earlier forecasts

The Sierra Club's number is more pessimistic than previous work in this area. An academic study published in June estimated that electricity demand from data centers and crypto mining could raise power sector emissions 28 percent by 2030 compared with a hypothetical scenario in which data center growth does not occur — a different baseline than the Sierra Club's comparison against 2025 levels. According to The Verge, the spread between the two forecasts reflects genuine uncertainty: how many planned data centers are actually completed, and what kind of generation ends up serving them, will determine the real-world outcome.

A long decline is already reversing

US net greenhouse gas emissions dropped from a peak of about 6.58 billion metric tons in 2007 to roughly 5.35 billion metric tons in 2025. But that downward trend stalled and began moving in the wrong direction last year as data centers drove up electricity demand, The Verge reports. A separate report from the Environmental Defense Fund published this month found that the US is now planning to add more fossil fuel capacity than at any point in the past decade.

Policy is pulling in the same direction

The Verge also points to the policy environment behind the buildout. The current administration is encouraging new fossil fuel projects aimed at data centers while simultaneously unwinding pollution regulations and holding up renewable energy development, which makes gas the path of least resistance for new capacity.

Why it matters

Electricity supply has become a binding constraint on AI infrastructure growth, and the Sierra Club analysis puts a number on the environmental cost of meeting that demand with gas. A 42 percent jump in power sector CO2 would not merely slow US decarbonization; it would reverse it, erasing gains that took a decade and a half to accumulate. For cloud providers and AI developers, the findings raise uncomfortable questions about whether clean energy procurement can keep pace with accelerating demand, and how much of the resulting pollution will ultimately land in their own carbon accounting. The wide gap between the Sierra Club's 42 percent projection and the academic study's 28 percent estimate also shows how unsettled the picture remains: which projects get built, and what powers them, has yet to be decided. That decision will shape both the grid's emissions trajectory and the feasibility of the AI buildout itself.