# Atmospheric CO₂ — WATCH (worsening)
id co2 · Climate · horizon chronic · checked 2026-11-01T11:52Z · at this level since 2026-11-01T11:52Z · stale after 2026-11-02T23:52Z
Assessed by an AI model (Anthropic Claude) against published rubrics; not a forecast or advice · CC BY 4.0 · https://canary.danleech.com/s/co2

Value: 427.2 ppm, +2.00/yr
Rated on: 2.0–3.0 ppm.
Situation: Super El Niño [super-el-nino]

CO₂ growth reaches 2 ppm a year as El Niño weakens carbon sinks

Why it's at this level: Mauna Loa recorded 427.2 ppm in the week of 25 Oct, 2.00 ppm higher than a year earlier, reaching the 2 ppm/yr Watch line from 1.59 ppm the previous week. Strong El Niño years usually speed up CO₂ growth as land carbon sinks weaken.

What this means for you: Faster CO₂ growth means more warming locked in. There is no immediate personal risk; this is a long-run indicator.

Why it matters: CO₂ concentration is the main long-run driver of warming; the growth rate shows whether emissions cuts are biting.
What moves it: Fossil emissions, land sinks, El Niño (weakens sinks), wildfires.

Rubric — Alert: > 3.0 ppm. | Watch: 2.0–3.0 ppm. | Normal: Year-on-year growth < 2.0 ppm.

Sources:
- NOAA GML — Trends in atmospheric CO₂ (Mauna Loa) (2026-10-18) https://gml.noaa.gov/ccgg/trends/