> For the complete documentation index, see [llms.txt](https://doc.duaer.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.duaer.com/getting-started/greenhouse-gases.md).

# Greenhouse gas levels in Duaer

In Duaer: NOAA GML: monthly CO2 at Mauna Loa and global CO2, methane, and nitrous oxide, with the change on a year earlier. One successful search uses 1 credit.
## What you get

Duaer Greenhouse gas levels reads the NOAA Global Monitoring Laboratory monthly series, newest month first, with the trend and the change on a year earlier.

Pick Duaer Data → Greenhouse gas levels in the node creator, or open the [data market](/getting-started/data-market.md). Related: [Climate projection](/getting-started/climate-projection.md), [GB grid carbon intensity](/getting-started/grid-carbon.md).

## When to use it

- Report the latest CO2 reading at Mauna Loa.
- Chart the rise of methane over a year.

## When not to use it

- Future climate projections. Use [Climate projection](/getting-started/climate-projection.md).
- Grid carbon intensity. Use [GB grid carbon intensity](/getting-started/grid-carbon.md).

## Search on the canvas

1. Open the node creator and pick Duaer Data → Greenhouse gas levels.
2. Fill Gas (co2, co2-global, ch4, or n2o).
3. Limit defaults to 10, max 20. Execute.

A search uses 1 credit only when it returns rows. No rows, wrong input, or an upstream failure uses 0.

## Call the API

- GET https://api.duaer.com/v1/data/greenhouse-gases?gas=co2
- Authorization: Bearer <Duaer key>

The call skill below matches Copy skill in the Duaer data market, with parameters, examples, and result fields.

## Call skill

Same text as Copy skill.

```
---
name: duaer-greenhouse-gases
description: >-
  Duaer Greenhouse gas levels. NOAA GML: monthly CO2 at Mauna Loa and global CO2, methane, and nitrous oxide, with the change on a year earlier.
  One successful search uses 1 Duaer credit.
---

# Duaer Greenhouse gas levels

Duaer Greenhouse gas levels reads the NOAA Global Monitoring Laboratory monthly series, newest month first, with the trend and the change on a year earlier.

## When to use

- Report the latest CO2 reading at Mauna Loa.
- Chart the rise of methane over a year.

## When not to use

- Future climate projections. Use https://skills.duaer.com/climate-projection.md.
- Grid carbon intensity. Use https://skills.duaer.com/grid-carbon.md.

## Call

`GET https://api.duaer.com/v1/data/greenhouse-gases?gas=co2`

Header: `Authorization: Bearer <Duaer key>`

Use an account key or a model API key.

Get a Duaer key: https://skills.duaer.com/keys.md

## Parameters

Provide `gas`.

- `gas` — `co2` (Mauna Loa), `co2-global`, `ch4`, or `n2o`. Default co2.
- `limit` — Optional. Rows to return, from 1 to 20. Default 10.

## Examples

- `GET https://api.duaer.com/v1/data/greenhouse-gases?gas=co2` — monthly CO2 at Mauna Loa.
- `GET https://api.duaer.com/v1/data/greenhouse-gases?gas=ch4` — global methane.

## Result

The response is `{ "items": [...] }`. Each item has `source`, `title`, `url`, and `summary`, plus:

- `gas`, `month` — series and YYYY-MM.
- `value`, `unit` — monthly mean, in ppm or ppb.
- `trend` — seasonally adjusted value.
- `changeOnYear` — change on the same month a year earlier.

Fields without a value are left out.

## Credits

A search that returns at least one row uses 1 credit.
An empty search, a search that finds nothing, or a failed search uses 0.
Wrong input returns 400 with a message and uses 0.
No remaining credits returns 402 and does not search.
A missing key returns 401.

## Related

- https://skills.duaer.com/climate-projection.md — Duaer Climate projection
- https://skills.duaer.com/grid-carbon.md — Duaer GB grid carbon intensity

```
## Questions

### How many credits does a Greenhouse gas levels search use in Duaer?

One credit when Duaer returns rows. A search with no rows or an error uses 0.

### What is trend in Duaer Greenhouse gas levels?

The value with the seasonal cycle removed, better for long-term change.

## Related

- [Climate projection in Duaer](https://doc.duaer.com/getting-started/climate-projection.md)
- [GB grid carbon intensity in Duaer](https://doc.duaer.com/getting-started/grid-carbon.md)