Manufacturing
Manufacturing covers the production of digital equipment, from extraction of raw materials to assembly of the finished device. For most equipment it is the stage that dominates the environmental balance.
According to the work of Frédéric Bordage (GreenIT, 2019), manufacturing accounts across the whole life cycle for the entire impact on abiotic resources, 79 % of the impact on freshwater stocks, 44 % of greenhouse gas emissions and 35 % of primary energy consumption.
The share varies by device. For a smartphone, the French environment agency ADEME puts manufacturing at roughly three quarters of the carbon footprint over its lifetime. For a laptop the figure is lower but still dominant. For a server used intensively for years, electricity in use eventually catches up, though it rarely overtakes manufacturing before the machine is replaced.
These figures come from different studies with different scopes and should be read as orders of magnitude, not as constants.
The carbon debt is paid up front
Manufacturing emissions occur before the device is switched on for the first time. From then on, every additional year of use divides that debt by a larger number.
Doubling the working life of a laptop roughly halves its annual carbon footprint. No efficiency gain in use produces a comparable result, which is why how long a device stays in service matters more than its energy rating.
What a smartphone is made of
A smartphone weighing around 150 grams mobilises on the order of 70 kilograms of raw materials, most of it rock moved and discarded during mining.
The device contains between 50 and 60 different metals, drawn from most of the periodic table:
- structure and casing: aluminium, magnesium, titanium;
- electronics: copper, gold, silver, palladium, tantalum in capacitors;
- battery: lithium, cobalt, nickel, graphite, manganese;
- screen: indium in the transparent conductive layer, plus several rare earths for colour;
- magnets, vibration motor and speakers: neodymium, praseodymium, dysprosium.
Many of these are present in fractions of a gram. That is precisely what makes them hard to recover.
Scarcity and dependency
Scarcity here is rarely geological. It is economic, technical and geopolitical:
- Concentration of supply
- the European Union lists 34 critical raw materials, of which 17 are considered strategic. For several of them a single country supplies most of the world's output, and the refining stage is more concentrated still than the mining stage.
- Extraction conditions
- cobalt from the Democratic Republic of the Congo and tantalum from coltan carry documented social and environmental costs, including artisanal mining and armed conflict financing.
- Recovery that does not happen
- the United Nations Environment Programme found that of 60 metals studied, 34 have an end-of-life recycling rate below 1 %. Metals present in milligrams and alloyed with others are technically recoverable but economically not worth recovering.
The consequence for practice: recycling will not solve the supply problem for these metals. Only keeping devices in service longer, and reusing them, delays the next extraction.
