If you polled sustainability teams across Europe on which ESRS standard causes them the most grief, E1 would win by a wide margin. It's the climate change standard, and it's both the most detailed and the most consequential of the topical standards, which is saying something given there are ten of them.

What You're Actually Required to Disclose

GHG emissions, all three scopes. Scope 1 and Scope 2 are relatively contained, though Scope 2 does require dual reporting (both location-based and market-based). Scope 3 is where it gets heavy: emissions need to be broken down across all 15 relevant categories, everything expressed in tonnes of CO₂ equivalent.

A real transition plan. Not a slide with good intentions, but a detailed account of how the company's strategy lines up with keeping warming under 1.5°C, including the specific decarbonization levers being pulled, the investment behind them, and interim targets to check progress along the way.

Risk assessment, both directions. Physical risks like extreme weather and sea-level rise, alongside transition risks: policy shifts, market changes, and technology disruption that could upend a business model.

Targets you can actually track. Absolute and intensity-based reduction targets, each with a defined baseline, a timeline, and a way to measure progress against it.

The Assurance Bar Is High

Every disclosure under E1 requires independent third-party assurance, with no exceptions. That means data provenance actually matters: an auditor needs to be able to trace a number back to its source. There's a subtlety here that trips a lot of companies up: the temporal accuracy rule. Emission factors have to reflect the values that were current during the reporting year itself, not whatever the latest published figures happen to be by the time the report is filed.

That last point alone causes more rework than almost anything else in E1 reporting: companies recalculate an entire year's emissions because they used this year's factors instead of last year's. It's a small detail with outsized consequences, and it's exactly the kind of thing automation handles better than a spreadsheet. At BUME, factors get locked to the correct reporting period automatically, so temporal accuracy isn't something your team has to remember to check manually.