Daily chart answer for Sunday, October 18, 2026
How did monthly CO₂ at Mauna Loa change from 1985 to 1987 (ppm)? Climate · 36 observations · NOAA Global Monitoring Laboratory.
Solid line = the part players could see · dashed violet = the daily chart’s hidden stretch, revealed here.
What happened
After the visible part ended on Mar 1986, it advanced 0.3% to finish at 349.28 ppm. Players saw the first 15 of 36 observations before drawing. From 345.48 ppm to 349.28 ppm, the full span nets out up 1.1%. The period high of 352.15 ppm came in May 1987; the low of 343.35 ppm, in Oct 1985. The biggest one-step move was a 0.6% downward in Aug 1986. Data: NOAA Global Monitoring Laboratory.
The hidden values
After the cutoff (Mar 1986), the series printed:
| Date | Actual value |
|---|---|
| Apr 1986 | 349.86 |
| May 1986 | 350.52 |
| Jun 1986 | 349.98 |
| Jul 1986 | 348.25 |
| Aug 1986 | 346.17 |
| Sep 1986 | 345.48 |
| Oct 1986 | 344.82 |
| Nov 1986 | 346.22 |
| Dec 1986 | 347.48 |
| Jan 1987 | 348.73 |
| Feb 1987 | 348.92 |
| Mar 1987 | 349.81 |
| Apr 1987 | 351.4 |
| May 1987 | 352.15 |
| Jun 1987 | 351.58 |
| Jul 1987 | 350.21 |
| Aug 1987 | 348.2 |
| Sep 1987 | 346.66 |
| Oct 1987 | 346.72 |
| Nov 1987 | 348.08 |
| Dec 1987 | 349.28 |
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