What is ICT’s global carbon footprint?
In 2021, Freitag et al. estimated that that global emissions from Information Communication Technology (ICT) could be as high as 2.1%–3.9%. This figure was higher than previous studies, which suggested 1.8%–2.8%, as the authors summarise:
ICT is estimated at ca. 1.8%–2.8% of global GHG emissions in 2020. Estimates of ICT’s emissions in 2020 (see Figure 2) vary between 0.8 and 2.3 GtCO2e. The highest estimates (Andrae and Edler “worst case”) put ICT’s share of global GHG emissions around 6.3%, but Andrae now believes that the Andrae and Edler […] “best case” scenario of around 1.5% is more realistic for 2020 (personal communication). Belkhir and Elmeligi estimates are higher at 1.9%–2.3%, especially considering they omit TVs in their total estimate. Malmodin’s estimates sit in between the others at 1.9% of global emissions. When adjusting for differences in scope, these studies point toward a footprint of 1.0–1.7 GtCO2e for ICT, TVs, and other consumer electronics in 2020; this is 1.8%–2.8% of global GHG emissions. We stress that this estimate carries some uncertainty but gives us a reasonable idea of the impact of ICT.
We are now in 2024. Understandably, many digital sustainability commentators continue to lean on the three year old estimate, even while they recognise how rapidly the ICT landscape is evolving.
Either there are already more up-to-date estimates out there which I have not yet seen, or there soon will be. But consider Belkhir and Elmeligi (2018), who predicted ICT might contribute 14% of global emissions by 2040, based on 2016 emissions levels:
We have found that, if unchecked, ICT GHGE relative contribution could grow from roughly 1–1.6% in 2007 to exceed 14% of the 2016-level worldwide GHGE by 2040, accounting for more than half of the current relative contribution of the whole transportation sector.
With projections like this in mind, can’t we adjust Freitag et al.’s figures upward slightly? In 2021, explaining why they prefer the higher estimate, they mention rebound effects, a failure to fully account for blockchain and IoT to date, and the ongoing investment in blockchain, IoT and AI. Looking back at 2023, we’ve seen a year of intense interest and commercial rivalry around generative AI. The International Energy Agency’s 2024 report seems to confirm that this is driving rapid growth in electricity consumption:
Electricity consumption from data centres, artificial intelligence (AI) and the cryptocurrency sector could double by 2026. Data centres are significant drivers of growth in electricity demand in many regions.
A true analysis of the current carbon footprint of ICT needs to incorporate many other factors: we can’t really draw a line from 2.1% or 3.9% in 2021 to 14% or x% in 2040, for example, without at least considering how carbon emissions in other sectors are changing. Up-to-date figures on this aren’t easy to find (see here for total global emissions to 2022, and see here for a very coarse breakdown to 2020).
But until such a true analysis comes along, there is every reason to believe that the often quoted “2.1%–3.9” is low. I am favouring the estimate “perhaps around 5% and projected to grow.”
