Et pour finir, le point #concentration en #co2 : On s'approche du minimum saisonnier à Mauna Loa.
Les dernières mesures quotidiennes témoignent de cette fin de descente.

Dernière mise à jour:

Weekly average CO2 at Mauna Loa

Week beginning on
October 05, 2025:  424.39 ppm
Weekly value from
1 year ago:  422.05 ppm
Weekly value from
10 years ago:  398.62 ppm

+2,34ppm sur cette première semaine d'octobre

Les chaînes d'information ont peut-être sorti un bandeau, une dépêche....
Ah non... j'ai rien vu 😄🤣

"" the total emissions from human activities during
the 2014–2023 period, about 53% accumulated in the
atmosphere, 26% in the ocean and 21% on land, with no
unattributed imbalance [4]. The portion of CO2 emitted
by fossil fuel combustion that remains in the atmosphere
(the airborne fraction, (AF)), varies inter-annually due
to the high natural variability of (mainly terrestrial) CO2
sinks, although there is little evidence for a long-term
AF trend (see the cover story in WMO Greenhouse Gas
Bulletin No. 17). ""

Globalement, tous les indicateurs sont au rouge vif !!!

"" The pre-industrial level of 278.3 ppm represented a
balance of fluxes among the atmosphere, the oceans
and the land biosphere. The globally averaged CO2
concentration in 2024 was 423.9±0.2 ppm (Figure 5a),
152% of the pre-industrial level. The increase in the
annual mean from 2023 to 2024, 3.5 ppm (Figure 5b),
was the highest in the recent history of observations,
higher than the 2.4 ppm increase from 2022 to 2023 by
large margin and higher than the average growth rate
for the past decade (2.57 ppm yr–1) ""

Un moyenne 2024, que l'on sait déjà battu en 2025.