How did monthly atmospheric methane worldwide change from 1998 to 2000 (ppb)?
This is a real historical chart. Extraplot shows you the beginning and asks you to draw what happens next, then reveals the actual line. Below is the full series with the reveal point marked.
Solid line = visible part you would draw from · dashed violet = the actual revealed data after the cutoff.
The reveal
After the cutoff (Mar 1999), the actual values were:
| Date | Actual value |
|---|---|
| Apr 1999 | 1,774.96 |
| May 1999 | 1,772.66 |
| Jun 1999 | 1,767.35 |
| Jul 1999 | 1,762.93 |
| Aug 1999 | 1,764.61 |
| Sep 1999 | 1,771.02 |
| Oct 1999 | 1,776.61 |
| Nov 1999 | 1,778.53 |
| Dec 1999 | 1,777.24 |
| Jan 2000 | 1,775.53 |
| Feb 2000 | 1,775.44 |
| Mar 2000 | 1,776.5 |
| Apr 2000 | 1,777.21 |
| May 2000 | 1,774.57 |
| Jun 2000 | 1,768.14 |
| Jul 2000 | 1,763.45 |
| Aug 2000 | 1,765.44 |
| Sep 2000 | 1,772.05 |
| Oct 2000 | 1,777.09 |
| Nov 2000 | 1,777.71 |
| Dec 2000 | 1,775.32 |
About this dataset
- Category: Climate
- Source: NOAA Global Monitoring Laboratory
- Date range: Jan 1998 – Dec 2000
- Data points: 36
- Source fetched: Nov 10, 2026
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