Archives par mot-clé : Mauna Loa

Is Mauna Loa Really The Best Location To Measure ‘Global’ CO2 Levels?

by K. Richard, Oct 19, 2020 in NoTricksZone


Highly anomalous terrain (an active volcano), 40 years of cooling temperatures, and a CO2 record that dramatically contrasts with fluctuating values from forests and meadows reaching 600-900 ppm all beg the question: Is Mauna Loa’s CO2 record globally representative?

Mauna Loa is the Earth’s largest land volcano. It has erupted over 3 dozen times since 1843, making this terrestrial landscape extremely unusual relative to the rest of the globe’s terrain. (Forests, in contrast, cover over 30% of the Earth’s  land surface.)

Mauna Loa has been thought to be the world’s best location to monitor global CO2 levels since 1958.

While Mauna Loa CO2 levels show a rise of 338 ppm to 415 ppm since 1980, Mauna Loa temperatures (HCN) show a cooling trend during this same time period. The only warming period in the last 65 years occurred between about 1975 and 1985.

Image Source: oz4caster

Forest CO2 fluctuations

As mentioned above, forests are orders of magnitude more terrestrially representative than the highly anomalous site of the Earth’s largest volcano.

In forests or tree-covered areas, CO2 rises from around 300 ppm in the warmth of the afternoon (~3 p.m.) to over 600 ppm before sunrise (~4 a.m.), when it is cooler (Fennici, 1986, Hamacher et al., 1994). This massive fluctuation occurs daily and CO2 values average out to be far higher than the Mauna Loa record suggests.