> ## Documentation Index
> Fetch the complete documentation index at: https://code.dcycle.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Update Historical Emission

> Update an existing historical emission entry

# Update Historical Emission

Update one or more fields of an existing historical emission entry. Only send the fields you want to change — all fields are optional.

## Request

### Headers

<ParamField header="x-api-key" type="string" required>
  Your API key for authentication

  **Example:** `sk_live_1234567890abcdef`
</ParamField>

<ParamField header="x-organization-id" type="string" required>
  Your organization UUID

  **Example:** `a8315ef3-dd50-43f8-b7ce-d839e68d51fa`
</ParamField>

### Path Parameters

<ParamField path="historical_emission_id" type="string" required>
  UUID of the historical emission entry

  **Example:** `"a1b2c3d4-e5f6-7890-abcd-ef1234567890"`
</ParamField>

### Body Parameters

All fields are optional — only send what you want to change.

<ParamField body="start_date" type="string">
  Start date (ISO 8601)
</ParamField>

<ParamField body="end_date" type="string">
  End date. Must be >= `start_date` when both are provided.
</ParamField>

<ParamField body="category" type="string">
  Emission category (see [Create](/api-reference/historical-emissions/create) for full list)
</ParamField>

<ParamField body="total_co2e" type="number">
  Total CO2e in kilograms (must be > 0)
</ParamField>

<ParamField body="description" type="string">
  Free text description
</ParamField>

<ParamField body="file_id" type="string">
  UUID of evidence file
</ParamField>

<ParamField body="file_url" type="string">
  URL of evidence file
</ParamField>

<ParamField body="file_name" type="string">
  Name of evidence file (max 255 chars)
</ParamField>

## Response

Returns the updated historical emission object with HTTP 200.

<ResponseField name="id" type="string">
  Historical emission UUID
</ResponseField>

<ResponseField name="organization_id" type="string">
  Organization UUID
</ResponseField>

<ResponseField name="start_date" type="date">
  Start date of the emission period (ISO 8601)
</ResponseField>

<ResponseField name="end_date" type="date">
  End date of the emission period (ISO 8601)
</ResponseField>

<ResponseField name="scope" type="integer">
  GHG scope automatically derived from category (1, 2, or 3)
</ResponseField>

<ResponseField name="category" type="string">
  Emission category (e.g. `electricity`, `transport`, `purchases`)
</ResponseField>

<ResponseField name="total_co2e" type="number">
  Total CO2e emissions in kilograms
</ResponseField>

<ResponseField name="description" type="string | null">
  Free text description of the emission entry
</ResponseField>

<ResponseField name="ghg_gas" type="string">
  GHG gas type (e.g. `co2e`)
</ResponseField>

<ResponseField name="ghg_type" type="integer">
  GHG type: `0` = fossil, `1` = biomass
</ResponseField>

<ResponseField name="enabled" type="boolean">
  Whether this emission entry is enabled and included in totals
</ResponseField>

<ResponseField name="file_id" type="string | null">
  UUID of the attached evidence file
</ResponseField>

<ResponseField name="file_url" type="string | null">
  URL of the attached evidence file
</ResponseField>

<ResponseField name="file_name" type="string | null">
  Name of the attached evidence file
</ResponseField>

<ResponseField name="created_at" type="datetime">
  Creation timestamp (ISO 8601)
</ResponseField>

<ResponseField name="updated_at" type="string | null">
  Last update timestamp (ISO 8601)
</ResponseField>

## Example

<CodeGroup>
  ```bash cURL theme={"theme":{"light":"github-light","dark":"github-dark"}}
  curl -X PATCH "https://api.dcycle.io/v1/historical-emissions/a1b2c3d4-e5f6-7890-abcd-ef1234567890" \
    -H "x-api-key: ${DCYCLE_API_KEY}" \
    -H "x-organization-id: ${DCYCLE_ORG_ID}" \
    -H "Content-Type: application/json" \
    -d '{"total_co2e": 48500.0, "description": "Updated with verified utility data"}'
  ```

  ```python Python theme={"theme":{"light":"github-light","dark":"github-dark"}}
  import requests
  import os

  headers = {
      "x-api-key": os.getenv("DCYCLE_API_KEY"),
      "x-organization-id": os.getenv("DCYCLE_ORG_ID"),
      "Content-Type": "application/json",
  }

  emission_id = "a1b2c3d4-e5f6-7890-abcd-ef1234567890"

  response = requests.patch(
      f"https://api.dcycle.io/v1/historical-emissions/{emission_id}",
      headers=headers,
      json={"total_co2e": 48500.0, "description": "Updated with verified utility data"},
  )

  entry = response.json()
  print(f"Updated: {entry['total_co2e']} kg CO2e")
  ```

  ```javascript JavaScript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  const axios = require('axios');

  const headers = {
    'x-api-key': process.env.DCYCLE_API_KEY,
    'x-organization-id': process.env.DCYCLE_ORG_ID,
    'Content-Type': 'application/json',
  };

  const id = 'a1b2c3d4-e5f6-7890-abcd-ef1234567890';

  axios.patch(`https://api.dcycle.io/v1/historical-emissions/${id}`, {
    total_co2e: 48500.0,
    description: 'Updated with verified utility data',
  }, { headers })
  .then(response => console.log(`Updated: ${response.data.total_co2e} kg`));
  ```
</CodeGroup>

### Successful Response

```json theme={"theme":{"light":"github-light","dark":"github-dark"}}
{
  "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "organization_id": "a8315ef3-dd50-43f8-b7ce-d839e68d51fa",
  "start_date": "2023-01-01",
  "end_date": "2023-12-31",
  "scope": 2,
  "category": "electricity",
  "total_co2e": 48500.0,
  "description": "Updated with verified utility data",
  "file_id": "b2c3d4e5-f6a7-8901-bcde-f12345678901",
  "file_url": "https://storage.dcycle.io/historical/electricity-2023.pdf",
  "file_name": "electricity-2023.pdf",
  "ghg_gas": "co2e",
  "ghg_type": 0,
  "enabled": true,
  "created_at": "2024-02-15T10:00:00Z",
  "updated_at": "2024-03-10T14:22:00Z"
}
```

## Common Errors

### 401 Unauthorized

**Cause:** Missing or invalid API key

```json theme={"theme":{"light":"github-light","dark":"github-dark"}}
{"detail": "Invalid API key for organization", "code": "INVALID_API_KEY"}
```

### 403 Forbidden

**Cause:** The authenticated user is not a member of the organization

```json theme={"theme":{"light":"github-light","dark":"github-dark"}}
{"detail": "Logged User is not Member of Organization", "code": "LOGGED_USER_NOT_MEMBER"}
```

### 404 Not Found

**Cause:** Historical emission not found

```json theme={"theme":{"light":"github-light","dark":"github-dark"}}
{
  "detail": "Historical emission not found"
}
```

## Related Endpoints

<CardGroup cols={2}>
  <Card title="Get" icon="magnifying-glass" href="/api-reference/historical-emissions/get">
    View the current entry
  </Card>

  <Card title="List" icon="list" href="/api-reference/historical-emissions/list">
    View all entries
  </Card>
</CardGroup>