Government revises July 2025 projections for AI-driven datacentre carbon footprint upwards by around 100x, but Carbon Brief suggests the numbers could be much higher stillThe UK government’s calculations for the projected carbon footprint of data centres have been found to be significantly off the mark. The revised figures for the carbon output, which is a result of electricity usage by data centres, have been adjusted upwards by a staggering 100 times for both the minimum and maximum projections.
In July of the previous year, the Department for Science, Innovation & Technology (DSIT) released its Compute evidence annex. This document outlined the future of AI, compute demand, and the implications for the carbon footprint. The DSIT has since removed the original report from its website, but it can still be accessed here.
The report initially stated, “We estimate that by 2035, the UK’s greenhouse gas emissions from AI compute could range from 0.025 to 0.142 MtCO₂ [millions of tonnes of CO₂] – this is below 0.05% of the UK’s projected total emissions.” However, a correction to the document was issued by the DSIT last week, stating, “The UK’s cumulative 10-year greenhouse gas emissions from AI compute could range from 34 to 123 MtCO₂ – this is around 0.9-3.4% of the UK’s projected total emissions over the 10-year period.”
The discrepancy in these figures is astounding. It appears that the initial numbers were annual estimates, while the revised figures represent a 10-year projection, resulting in an increase of around 100 times in the estimate.
Meanwhile, an analysis by the climate change science and policy research group, Carbon Brief, suggests that even these revised figures may be overly optimistic. The government’s target is to achieve 50gCO2/kWh by 2030, a figure that can be reached by utilising “clean” sources of energy such as wind, nuclear, hydro, and solar power. However, data from last month, researched by Carbon Brief and published in collaboration with environmental campaigners Foxglove, indicates that this estimate may be overly ambitious if any of the power generation needs to be gas-powered. Gas-powered electricity generation has a carbon intensity that is approximately 10 times that of clean sources.
Carbon Brief’s calculations suggest that emissions could actually range from 3.4 MtCO₂, assuming 5% of the electricity is gas-generated, to 68.1 MtCO₂ if 95% of the electricity is gas-generated. The higher figure, which is comparable to the annual carbon emissions of Sweden, is based on a recent projection by Ofgem of 20GW of future data centre electricity demand. This projection was illustrated by referencing the actual peak demand in February 2026, which was 45GW.
Ofgem’s 20GW projection is based on research conducted by the National Energy System Operator, which surveyed customers about their future grid connection requirements. Tim Squirrell, Foxglove’s head of strategy, commented on the situation, stating, “The government has a legally binding commitment to reach net zero by 2050. This already sat awkwardly alongside its hell-for-leather embrace of a hyperscale AI data centre buildout, which unchecked could double the electricity consumption of the entire country.”
The situation has now been revealed to be much more severe. The miscalculations in the carbon footprint projections for data centres highlight the urgent need for a more sustainable approach to power generation and consumption. The government’s commitment to achieving net zero emissions by 2050 is a step in the right direction, but it is clear that more needs to be done to ensure that this goal is met. The future of our planet depends on it.
