SM5002 Chap.7 Carbon Footprint Scopes and Their Limits
Carbon Footprint Scopes and Their Limits
Why emissions are sorted into scopes
Every net zero pledge in healthcare eventually turns into an inventory, and an inventory needs rules about which emissions belong to whom. The GHG Protocol Corporate Standard supplies those rules by dividing an organisation's greenhouse gas emissions into three scopes.
The dividing question is not who paid for an activity or who benefited from it, but who owns or controls the source that actually releases the gas. That single test is what lets two organisations in the same supply chain report without claiming the same tonne twice in the same category.
Scope 1 covers direct emissions from sources the organisation owns or controls.
In a hospital this means the natural gas burned in its boilers, the diesel in backup generators, the fuel in an ambulance fleet it runs, and anaesthetic gases released in its theatres. Scope 2 covers the generation of electricity, steam, heat and cooling that the organisation buys and consumes.
The emissions physically occur at someone else's power plant, yet they are reported by the consumer because the consumer's demand caused them. Electricity for MRI scanners, lighting and air handling falls here, as does purchased steam for sterilisation.
Scope 3 is everything else in the value chain, upstream and downstream: the manufacture and transport of medical supplies and pharmaceuticals, staff and patient commuting, outsourced laundry and catering, construction, information technology services, and the incineration of clinical waste by a contractor.
Boundaries come before scopes
A scope cannot be assigned until the organisational boundary is fixed.
The Corporate Standard offers two consolidation approaches, equity share and control. Under equity share an organisation reports its proportional share of each operation it holds a stake in; under control it reports all of the operations it controls and none of the others. The choice matters because the same activity can move between scopes.
Transport carried out in vehicles the organisation owns or controls is scope 1, while the identical journey in a contractor's vans is scope 3. Once the organisational boundary is set, the operational boundary decides which scopes are covered, and the two together form the inventory boundary.
The standard requires scopes 1 and 2 to be reported separately at a minimum.
Scope 3 is optional in the corporate framework, and each company chooses which categories it covers. That freedom is useful for focusing effort on the activities that matter most, but it also means scope 3 totals from different organisations may cover different things and should not be compared as if they were like for like.
Electricity as the test case
Electricity shows how the rules hold together.
When power passes from a generator through a trader and a utility to a hospital, the generator reports the combustion as scope 1, the utility reports the share lost in its own wires as scope 2, and the hospital reports what it consumes as scope 2. Upstream losses and resold power appear only as scope 3 or as optional information.
Each tonne therefore lands exactly once on the producing side and once on the consuming side, which is the property that makes scopes 1 and 2 usable in programmes where double counting matters.
The gases that are counted
The Protocol requires accounting for six gases: carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, perfluorocarbons and hydrofluorocarbons.
Healthcare inventories often add others, notably the volatile anaesthetics isoflurane, desflurane and sevoflurane, which must be listed when included.
Each gas is converted to carbon dioxide equivalents with a global warming potential that reflects its radiative forcing and its lifetime in the atmosphere, most commonly over a 100-year horizon.
From the organisation to the product
Two companion standards extend the corporate view.
The Scope 3 Standard follows the full value chain at company level, and the Product Standard follows a single product through five life cycle stages: material acquisition and pre-processing, production, distribution and storage, use, and end-of-life. The two are designed to fit together.
If a company summed the life cycle emissions of all its products and added the remaining scope 3 categories such as business travel, the result should approximate its scope 1, 2 and 3 total. The Product Standard is built for tracking one product's performance over time.
It does not support comparative assertions, meaning claims that one product is environmentally better than a competitor, and it warns that a greenhouse gas only result can hide trade-offs with other environmental impacts.
What a footprint is good for
A commentary written for clinicians and procurement teams identifies four sound uses of carbon footprinting in healthcare: establishing a baseline and tracking progress with a consistent method, finding the products and processes that contribute most, comparing alternatives when the methods are consistent, and modelling scenarios to optimise a process.
It then sets out the questions any reader should ask. Where and when was the study done, given that grid electricity in different countries and years carries very different emission factors? What was included, given that leaving out part of a patient pathway can erase or reverse an apparent saving?
Is the comparison fair, given that functional equivalence must hold between the options compared?
The same authors add wider cautions. Carbon is only one environmental impact, and a full life cycle assessment may rank options differently across other categories.
Absolute numbers from separate studies differ with boundary choices, data granularity and conversion factors, so they should not drive contracts or financial decisions on their own. Studies may also omit better alternatives, such as redesigning a single-use device for multiple reuse.
Finally, footprinting every product is slow and expensive; reducing and reusing equipment first, then targeting the highest impact categories with a standard method, is usually the better use of effort.
What this chapter covers
- 01
Scope 1 direct emissions from owned or controlled sources
- 02
Scope 2 emissions from purchased electricity, steam, heat and cooling
- 03
Scope 3 value chain emissions and why they are optional and hard to compare
- 04
Equity share and control approaches to the organisational boundary
- 05
Assigning electricity emissions along a supply chain without double counting
- 06
Corporate, Scope 3 and Product Standards and the five product life cycle stages
- 07
Four uses and the main limitations of carbon footprints in healthcare
Worked example · free
Assigning emissions along an electricity chain
- 2Assign the generator's combustion and the trader's position.
- 2Assign the utility's own consumption and the electricity it resells.
- 2Assign the hospital's consumption and the upstream loss, then check the totals.
Key terms
- Scope 1 Emissions
- Direct greenhouse gas emissions from sources the reporting organisation owns or controls, such as its boilers, vehicles and released anaesthetic gases.
- Scope 2 Emissions
- Indirect emissions from generating the electricity, steam, heat or cooling an organisation purchases and consumes.
- Scope 3 Emissions
- All other indirect emissions in the value chain, upstream and downstream, reported at the organisation's discretion under the Corporate Standard.
- Consolidation Approach
- The equity share or control rule an organisation uses to decide which operations sit inside its organisational boundary.
- Inventory Boundary
- The organisational boundary combined with the operational boundary, which together fix what an inventory covers.
- Comparative Assertion
- A claim that one product is environmentally superior or equivalent to a competing product, which the Product Standard does not support.
- Global Warming Potential
- The warming caused by a unit mass of a gas over a chosen horizon relative to carbon dioxide, most often over 100 years.
Carbon Footprint Scopes and Their Limits FAQ
Why is purchased electricity reported by the hospital and not by the power station?
The power station does report the combustion, as its own scope 1. The hospital reports the same tonnes as scope 2 because its demand caused the generation, and keeping the two in different scopes prevents any one category from containing them twice.
Can an ambulance fleet appear in different scopes for different hospitals?
Yes. A hospital that owns or controls its vehicles reports their fuel combustion as scope 1, while a hospital that contracts the service out reports the same journeys as scope 3, so the consolidation approach and ownership arrangements must be stated.
Is it safe to compare the scope 3 totals of two health systems?
Only with great care. Each organisation selects which value chain categories it includes and which data sources it uses, so a smaller total may simply reflect a narrower selection rather than lower emissions in practice.
Does a lower product carbon footprint prove a product is greener overall?
No. A greenhouse gas only result can miss trade-offs in water use, toxicity, land use or resource depletion, and the Product Standard explicitly declines to support claims of overall environmental superiority over a competitor.
Assessment move
Build a three-column table for a hospital you know, placing at least three real activities under each scope, and mark which entries would move if the consolidation approach changed. Then rework the electricity chain arithmetic without notes until every tonne lands in the right place. Finish by writing the four cautions as questions you would ask of any published footprint.
