Report: California Data Center Emissions Tripled From 2019 to 2023, Could Drive $266M in Annual Health Costs by 2028

Authors say guardrails and a cleaner grid can mitigate data center carbon emissions, diesel pollution and water use

SAN FRANCISCO--(BUSINESS WIRE)--A new report released today, An Assessment of California Data Centers’ Environmental and Public Health Impacts, authored by researchers from the University of California, Riverside and produced by the think tank Next 10 shows that from 2019 to 2023, health impacts from California’s data centers have tripled — and could rise by another 72% by 2028 unless strong mitigation policies are enacted.

“This report should be a wake-up call,” said F. Noel Perry, Founder of Next 10. “We’re witnessing the rapid buildout of the digital infrastructure that powers AI, cloud services, and the entire modern economy. But with that growth comes serious consequences — from worsening air quality and health impacts, to rising greenhouse gas emissions, and significant increases in water use, escalating health impacts in already overburdened communities. If we allow this industry to expand without smart policies and clear environmental standards, we risk not only undermining California’s hard-won climate progress, but also increasing the burden on the people least equipped to bear it. We have the tools to do better — but we need action now.”

Between 2019 and 2023, electricity use by California data centers increased by 95%, with projections showing demand could rise as much as 356% above 2019 levels by 2028. At the high end, data centers could consume 25.3 terawatt-hours of electricity annually, equivalent to the annual electricity consumption of 2.4 million average American households. Nationally, data centers could account for 12% of U.S. electricity demand by 2028, up from 4.4% in 2023, according to estimates from the Lawrence Berkeley National Lab.

“California can pioneer a sustainable model for data center growth,” said Shaolei Ren, associate professor at UC Riverside and author of the report. “But it requires continued commitment from California policymakers and regulators to keep lowering power grid emissions and other externalities such as water consumption. The state should also encourage data centers to replace existing diesel backup generators with cleaner, more reliable technology like long duration battery storage.”

In 2019, the average carbon intensity for electricity in California was just under half the national average. Yet even though California’s grid is among the cleanest in the country, the report finds that greenhouse gas emissions from data center operations are still climbing — primarily due to the grid’s continued reliance on natural gas plants as generating electricity from fossil fuels brings significant health impacts. Both the off-site natural gas plants and the onsite diesel generators — still the primary backup system for most data centers — emit nitrogen oxides (NOx) and fine particulate matter that worsen respiratory and cardiovascular disease.

Public health costs associated with electricity generation actually decreased by $14.07 million from 2023 to 2028 when modeled in a low data center growth scenario with a high gas generation plant retirement rate — even with a 49.4% increase in data center electricity consumption. Conversely, public health costs associated with on-site emissions continued to increase due to diesel backup generators.

“Data centers are making up an ever-larger share of the state’s emissions — and their local impacts are particularly concerning,” said Stephanie Leonard, Research Director at Next 10. “Some of these facilities are concentrated near vulnerable communities already overburdened by pollution. The state needs to act now to ensure this growing industry aligns with public health and climate goals.”

The environmental burden doesn’t stop at emissions. Data centers also require enormous volumes of fresh water for cooling and electricity generation. From 2019 to 2023, the total evaporated water—including both direct evaporation for cooling and indirect evaporation for electricity generation—used by California data centers increased by more than 96% to 49.9 billion liters, enough to fill 20,000 Olympic-sized swimming pools. By 2028, that number could rise to up to 116 billion liters annually, a concern in a state that regularly faces drought and water shortages.

The report recommends several key actions for policymakers and regulators, including phasing out diesel generators in favor of battery storage paired with renewables, improving data transparency, and setting siting and emissions standards that prioritize clean power and attention to all impacted communities.

More Key Findings:

• Total water consumption by data centers by 2028, including both on-site cooling and off-site electricity generation, could fill 30,000 to 47,000 Olympic sized swimming pools.
• On the high end, on-site water consumption by data centers in 2028 is estimated at 6.6 billion liters. Total water withdrawal by data centers is significantly higher. For comparison, San Francisco residents only use 5.1 billion liters per year.
• By 2028, negative health impacts from data center pollution could add approximately 3,900 cases of asthma and 490 lost workdays to California.
• Between 2019 and 2023, carbon emissions from data centers nearly doubled from 1.24 million short tons to 2.38 million. By 2028, that number could rise to 3.55 million short tons on the low end and 5.56 million short tons on the high end.
• As a result of the growing electricity demand, the data center share of statewide electricity-related emissions also grew steadily from 2.21% in 2019 to 4.52% in 2023.

Find the report here: https://www.next10.org/publications/ai-environmental-public-health-impacts