---
title: Seasonailty
url: 'https://oomeen.com/co2-2/seasonailty'
markdown: 'https://oomeen.com/co2-2/seasonailty.md'
date: '2026-07-30'
description: 'Seasonality The graph below compares the seasonality of CO2 and surface temperature (average 1991-2020) There are two causal explanations: (i) CO2 rise precedes temperature rise – i.e. rising CO2 causes warming or (ii) temperature rise precedes CO2 rise – i.e. rising temperatures cause CO2 to rise…'
---

# Seasonailty

## Seasonality

The graph below compares the seasonality of CO2 and surface temperature (average 1991-2020)

![NotCo2-03](https://oomeen.com/user/pages/08.co2-2/04.seasonailty/NotCo2-03.png "NotCo2-03")

There are two causal explanations: (i) CO2 rise precedes temperature rise – i.e. rising CO2 causes warming or (ii) temperature rise precedes CO2 rise – i.e. rising temperatures cause CO2 to rise.

That explanation one (i: CO2 causes warming) is the correct observation is difficult to argue. The Greenhouse effect is instantaneous to human observers, a 2.5-month delay in causation cannot be the explanation.

Explanation two (ii: Warming causes CO2 to rise): must be the causal explanation. There is a perfectly good causal explanation in the photosynthesis cycle which is dominated by the Northern hemisphere and gives rise to a 9.5 month delay.

Googe AI gives the following: • monthly changes in global temperature often precede seasonal fluctuations in CO2 by approximately 4 to 12 months. • 9 months: Lag between CO2 and lower troposphere temperature. • 10 months: Lag behind global surface air temperature. • 11–12 months: Lag behind global sea surface temperature.

---

## Navigation

- Parent: [CO2 is not the Villain](https://oomeen.com/co2-2.md)
- Previous: [Causality - which is cause and which is effect?](https://oomeen.com/co2-2/causality.md)
- Next: [Geographic Variability](https://oomeen.com/co2-2/geographic-variability.md)