What Are Scope 3 Emissions in Real Estate and Why Do They Matter

A landlord can run the most efficient building services in their entire portfolio and still be responsible on paper for more emissions than a neighbouring building with mediocre plant purely because of what happens inside the tenants own space. That gap is Scope 3 and understanding what are Scope 3 emissions properly rather than treating them as a vague catch all category is where most real estate sustainability conversations actually need to start since for the majority of portfolios this single category outweighs everything a landlord directly controls combined.

This guide explains what Scope 3 actually means in plain terms where it shows up specifically inside a real estate portfolio and why it matters even for landlords who are not yet formally required to report it.

The three scopes in plain terms

Emissions reporting splits a businesss carbon footprint into three categories. Scope 1 covers direct emissions from sources a business owns or controls outright a gas boiler a company vehicle a refrigerant leak from equipment on site. Scope 2 covers indirect emissions from purchased energy mainly electricity that a business consumes but does not generate itself. Scope 3 covers everything else every emission connected to a businesss activity that happens somewhere else entirely in someone elses control upstream in a supply chain or downstream in how a product or space actually gets used. For most industries Scope 3 is broad but manageable. For real estate specifically it is often enormous because the single biggest thing a landlords business enables a tenant occupying and running their own operations inside a building sits almost entirely within this category.

Why Scope 3 is different and why it is harder

Scope 1 and 2 are measured from data a landlord already largely controls meters on plant a landlord owns invoices for electricity a landlord buys directly. Scope 3 is measured from data that belongs to someone else a tenants own energy consumption a construction suppliers material emissions a contractors fuel use none of which a landlord can simply read off their own meter. This is why Scope 3 has a reputation for being difficult. It genuinely is not because the concept is complicated but because collecting reliable data about activity happening in someone elses operational control requires cooperation infrastructure and process that most portfolios never had to build for Scope 1 and 2.

What Scope 3 actually looks like inside a real estate portfolio

Rather than staying abstract it helps to see where this category actually shows up building by building.

Tenants running their own operations inside your buildings

This is for most landlords the single largest Scope 3 category by far. Every kilowatt hour a tenant consumes running their own lighting equipment and air conditioning within their leased space counts as the landlords downstream Scope 3 emissions even though the landlord has no direct control over how that tenant chooses to operate. Getting a reliable handle on this depends entirely on proper tenant carbon allocation since without it this category is usually estimated rather than measured.

What went into the building before it was ever occupied

Every tonne of concrete every steel beam every piece of glazing used to construct or substantially refurbish a building carried its own emissions before it ever arrived on site. This embodied carbon sits within Scope 3 as purchased goods and capital goods and it can represent a genuinely significant one time contribution to a buildings total lifetime footprint particularly for recent developments.

Everything a portfolio buys to keep running

Beyond construction the ongoing goods and services a real estate business purchases facilities contracts professional services waste collection all carry their own upstream emissions contributing to Scope 3 in smaller more distributed ways across a huge range of supplier relationships.

Why Scope 3 matters even where it is not yet mandatory

SECR does not currently require comprehensive Scope 3 disclosure which leads some portfolios to treat the category as optional until a regulation forces the issue. That reasoning misses two things. First other frameworks a portfolio likely already engages with GRESB scoring and CSRD where material already expect it. Second and more fundamentally a net zero pathway that only addresses Scope 1 and 2 is for most real estate portfolios addressing a genuine minority of the total footprint which makes any net zero claim built purely on landlord controlled emissions considerably less credible to an investor or lender actually checking the maths.

Where portfolios usually start when they take this seriously

Given the scale of the category prioritisation matters more than attempting everything at once. Tenant energy use is almost always the right starting point given how large a share of total Scope 3 it typically represents built on the same governed carbon calculation process already used for Scope 1 and 2. Embodied carbon from active development and major refurbishment projects is the next priority since decisions made at design stage lock in a significant one time impact that later reporting cannot meaningfully change. The long tail of supplier related emissions while genuinely part of the category is generally the lowest priority to tackle first since its individual contribution per supplier relationship tends to be far smaller than the concentrated impact sitting in tenant energy and construction.

A test for how well you actually understand your own Scope 3

Ask yourself three honest questions about your own portfolio. Do you know even roughly what proportion of your total footprint sits in Scope 3 versus Scope 1 and 2 combined or have you never actually calculated that split. If asked could you say which specific category tenant energy embodied carbon or supplier emissions represents the largest share of your Scope 3 total. And is any of your current Scope 3 figure genuinely measured or is all of it currently a rough undocumented estimate. If any answer leaves you uncertain Scope 3 is currently a category you know exists rather than one you actually understand inside your own portfolio.

Teams starting this work often find it useful to review practical Scope 3 fundamentals guides and sector specific sustainability insights and to compare approaches with peers through a partner programme where relevant. If you are weighing up tools to support this reviewing pricing and learning more about the team behind the platform is a sensible next step before you start measuring.