an explainer · grounding

Same question, two answers

Ask an AI whether something is safe, and its answer depends on what it's allowed to look at. This story follows one carbon credit purchase to show why. No AI or climate background needed.

Elena, her company, and the Cedar Hollow project are fictional. The wildfire and buffer pool facts are real and sourced.

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step 01 · the job

Elena has until year-end

Elena
Sustainability lead, outdoor-gear company

Her company can't cut all of its emissions this year, so it has promised to make up the gap by buying carbon credits. Her annual climate report is due in December. The purchase has to happen before then.

5,000credits to buy
Dec 31report deadline
1AI assistant to help
step 02 · what she's buying

A credit pays a forest to keep standing

The catch: if the forest burns, its carbon goes back into the air, and the credit no longer means what it says. To cover this, projects set aside spare credits in a shared reserve called the buffer pool, used to replace credits lost to fire.

step 03 · the shortlist

Cedar Hollow ticks every box

Elena finds a forest project in Northern California. It passes the checks her company uses for every purchase.

purchase checklist · Cedar Hollow
  • Certified by a major registryyes
  • Price within budget$18 / t
  • Enough credits available8,200
  • Long-term commitment100 yrs

Before signing, she wants a second opinion.

step 04 · the question

She asks an AI assistant

ElenaIs the Cedar Hollow forest project a safe carbon credit to buy?

What comes back depends on something Elena can't see from the chat box: whether the assistant answers from what it already knows, or from documents and data about this specific project. Let's look at both.

step 05 · answer one

From memory: reassuring

Looks safe to buy

Cedar Hollow is certified by a major carbon registry.

Forest projects are one of the most popular and trusted credit types.

If trees burn, an insurance reserve called the buffer pool replaces the lost credits.

No sources. The AI is answering from general knowledge.
concept · ungrounded answer

A language model learns general patterns from its training. Asked about something specific, it describes how things usually are. Nothing here is false. It's generic, and it can't know what happened to this forest.

step 06 · answer two

Grounded: the AI reads first

A better-designed assistant fetches evidence before it answers. Here's what happens behind the chat box.

  1. 1
    Elena asks the same question
    Nothing changes on her side.
  2. 2
    The product fetches sources
    It searches for documents and data about this project.
    project documentfire trackerbuffer pool status
  3. 3
    The AI reads the question and the sources together
    It's told to answer from what's in front of it.
  4. 4
    The answer comes back with citations
    Each claim points to the source that supports it.
concept · retrieval and grounding

Retrieval is step 2: finding the right documents. Grounding is steps 3 and 4: answering from them and showing where each claim came from.

step 07 · the difference

Watch the evidence change the answer

Looks safe to buy

Cedar Hollow is certified by a major carbon registry.1

Forest projects are one of the most popular and trusted credit types.no source

If trees burn, an insurance reserve called the buffer pool replaces the lost credits.3

38% of the project area sits inside a 2024 wildfire perimeter.2

Tap a sentence to see its source.
No sources. The AI is answering from general knowledge.
1 · project documentRegistry: certified
Commitment: 100 years
Location: Northern California
2 · fire tracker Green: project boundary. Red: 2024 burn area.
3 · buffer pool statusNearly 40% of California's forest buffer pool already lost to fire.

The 38% overlap is part of the fictional example. The buffer pool figure is real (CarbonPlan, 2025).

step 08 · what just happened

Grounding did four things

The AI didn't get smarter between the two answers. It got better information, and that changed each sentence differently.

ConfirmedThe registry claim now has a source behind it.
Removed"Forests are popular and trusted" has no source about this project, so it drops out.
CorrectedThe buffer pool exists, but the data shows it's already badly depleted.
AddedThe burn overlap is something no model could know from training.
step 09 · checklist vs risk

Passing every check isn't the same as being safe

Elena's checklist asks whether the credit is legitimate. It never asks what could go wrong.

what the checklist didn't ask
  • Has the project burned recently?yes, 38%
  • How fire-prone is the region?high
  • Is the backup reserve healthy?~40% lost
likelihoodHighDry, fire-prone region, and part of the project has already burned.
impactHighBurned credits stop offsetting anything, and the reserve meant to replace them is thin.
concept · risk analysis

A checklist asks yes or no questions. Risk analysis asks how likely a bad outcome is and how much it would hurt. A good grounded assistant surfaces both.

this part is real
step 10 · it keeps happening

Offset forests are burning now

Cedar Hollow is invented. The pattern isn't. Forests sold as carbon credits in the western US have burned in several recent fire seasons.

~45kacres of California offset forest burned in the 2024 Park Fire
97%of one project's listed area burned in that fire, per CarbonPlan's analysis at the time
~40%of California's forest buffer pool lost to fire by 2025

It isn't new either. In 2021, forests that had sold credits to Microsoft and BP burned in Oregon and Washington. Microsoft's carbon program manager said at the time that the company had bought forest offsets that were now burning.

The risk was visible in public data. That doesn't mean every loss was avoidable. Fires are hard to predict project by project.

step 11 · for the people who build it

The real decisions are product decisions

The model was the same in both answers. What changed was the product around it. Three choices made that difference.

what does it read?Include independent sourcesThe seller's project document said everything was fine. The fire tracker is what changed the verdict.
how does it show evidence?Cite every claim, flag the restElena can tap a sentence and check it. Claims with no source are marked or dropped.
who decides?A person, with the evidence in front of them"High risk, review before buying" hands the call back to Elena. The assistant informs the purchase. It doesn't make it.

It's the same principle as the agent in piece one: show your work.

step 12 · recap

Same question. Different evidence. Opposite answer.

An AI's answer can only be as good as what it's allowed to look at. Deciding what it looks at, and how it shows you, is part of designing the product.