Pandora’s cradle-to‑gate carbon footprint study of its lab‑grown diamonds, verified by EY (formely Ernst & Young) under limited assurance, finds that one polished carat carries a footprint of 12.58 kg CO2 equivalent (e).
The growing stage (chemical vapour deposition) contributes 85% of total emissions, with electricity use accounting for 72% of the overall footprint.
All suppliers use 100% renewable electricity, backed by certificates; however, upstream emissions from renewable generation still dominate.
Sensitivity analysis shows that switching to local grid electricity would raise the footprint to approximately 180 kg CO2e per carat. Downstream activities (transport, retail, use, end‑of‑life) have a negligible impact.
The study follows ISO 14067:2018 and was prepared by Raison Consulting and Impact Business Modelling Systems.
Below are key questions and answers drawn directly from the report.
How much CO2 does a single carat of Pandora’s lab-grown diamond actually produce?
Using the highest supplier‑average result, the carbon footprint of one carat polished lab‑grown diamond cradle‑to‑gate is calculated to be: 12.58 kg CO2e/ct. This reported carbon footprint is based on the highest supplier‑average footprint across Pandora’s lab‑grown diamond suppliers. The reported 12.58kg CO2/ct is both a conservative and representative benchmark for Pandora’s lab‑grown diamond offering.
Which stage of production causes the most emissions – growing, cutting, or raw materials?
As depicted in Figure 5, the growing stage is the dominant contributor, accounting for approximately 85% of the total cradle‑to‑gate carbon footprint.
Cutting and polishing contribute a significant but smaller share (~13%), while raw material extraction represents a minor contribution of around 2%. Emissions from high-pressure, high-temperature (HPHT) annealing are negligible and do not materially affect the overall footprint. The exact distribution of carbon emissions across the primary life cycle stages varies to some extent for individual suppliers but not materially. The differences in individual suppliers’ carbon footprint are generally a result of production efficiency (how much electricity is used to produce one carat, also referred to as ‘yield’) and the renewable electricity mix (solar, hydro, wind, other).
What share of the footprint comes from electricity use (Scope 2)?
Figure 6. Estimated distribution of cradle‑to‑gate carbon footprint across primary sources of emissions.
Electricity use (Scope 2) is the dominant source, accounting for approximately 72% of total emissions. This is followed by Scope 3 purchased goods and services (~17%), Scope 1 material inputs (~10%), and other sources including upstream transport (~1%). Together, the various Scope 1 and Scope 3 sources make up the remaining portion (25% ‑ 30%) of the carbon footprint after accounting for electricity. They are secondary drivers in comparison to electricity use, but still important when considering the full cradle‑to‑gate impact (Figure 6).
What happens to the carbon footprint if the lab‑grown diamonds are made using local grid electricity instead of renewable power?
When applying the emission factor reflecting the local grid, the cradle‑to‑gate carbon footprint increases from 12.58kg CO2e/ct to approximately 180kg CO2e/ct. The sensitivity analysis shows that relying on the local grid electricity mix results in a substantial increase in the carbon footprint compared to market‑based renewable electricity sourcing. The magnitude of this effect varies depending on operational conditions, including local energy mix characteristics and potential use of onsite renewable electricity generation. However, across all suppliers: electricity use is the dominant driver of climate impact, and maintaining high‑quality renewable procurement is critical to achieving low emissions.
What technology is used to grow Pandora’s lab‑grown diamonds, and where does the growing take place?
The lab‑grown diamonds are produced using the Chemical Vapour Deposition (CVD) technology. The growing takes place in North America and South Asia. The growing process results in a diamond rough. All suppliers use the CVD technology. The growing process (synthesis) begins by placing tiny seeds of high‑quality lab‑grown diamonds in a vacuum chamber at a very high temperature. The chamber is filled with carbon‑rich gas, typically a methane gas, that is heated to the point where the gas molecules break apart.
Does the study include anything beyond the factory gate – like transport, shops, or the jewellery’s end‑of‑life?
It does not include downstream activities such as distribution, retail, use phase, or end‑of‑life stages. The analysis covers multiple global suppliers of lab‑grown diamonds using the CVD technology to produce the diamonds. The study adopts a cradle‑to‑gate system boundary that covers raw material extraction and processing (diamond seed and process gases), diamond growth (synthesis), and cutting, polishing and finishing as well as transportation between these processing steps. It excludes downstream stages like distribution to warehouses or jewellery manufacturers, retail, customer use, and end‑of‑life.
What is the functional unit used in this carbon footprint assessment?
The functional unit for this cradle‑to‑gate study is one polished carat (1 ct) lab‑grown diamond. It is expressed in kg CO2e/ct, i.e. kilogram carbon dioxides equivalent per one (1) carat lab‑grown diamond. The study applies one polished carat as the functional unit, as one carat (0.2 grams) is the standard measure of a diamond. All suppliers’ product carbon footprint (PCF) covers the cradle‑to‑gate footprint for one (1) carat of polished lab‑grown diamond, averaging across all cuts (shape) and colours, clarity and carat (design).
Do suppliers use renewable electricity, and how is that claim supported?
All suppliers report using 100% renewable electricity for diamond growth and for cutting and polishing. This 100% renewable electricity claim is supported through the purchase of renewable energy certificates (RECs) or equivalent contractual instruments, in line with the market‑based method of the GHG Protocol. In accordance with ISO 14067:2018, this study accounts for the full life cycle emissions of electricity generation by applying emission factors that reflect the characteristics of the renewable electricity production systems. This ensures that renewable electricity is not treated as zero emissions, when supported by RECs.
What happens to the carbon footprint if you include downstream activities like transport and retail?
The results show that the inclusion of downstream life‑cycle stages has a negligible impact on the carbon footprint. In the transport to store phase, the sensitivity analysis uses data from a third‑party carbon footprint study of the carbon footprint of the Pandora Infinite and Era collections, both of which feature lab‑grown diamonds. The study estimates the carbon footprint of several 1ct lab‑grown diamond bearing rings’ (and their boxes) transport from South‑East Asia to North America from 0.378 to 0.403 kg CO2e/ring; however, the weight of the lab‑grown diamond is likely to be less than a tenth of the total weight of the ring, excluding. the box.
How much do raw material extraction and HPHT annealing contribute to the overall carbon footprint?
As depicted in Figure 5, the growing stage is the dominant contributor, accounting for approximately 85% of the total cradle‑to‑gate carbon footprint. Cutting and polishing contribute a significant but smaller share (~13%), while raw material extraction represents a minor contribution of around 2%. Emissions from HPHT annealing are negligible (~0.4%) and do not materially affect the overall footprint, as outlined in Figure 5. When such a process step is undertaken, it is included in the relevant supplier’s product carbon footprint assessment.
Mathew Nyaungwa, Editor-In-Chief, Rough & Polished
