It's not a telescope[0]; it's a spectrometer that takes in local air samples. It's far more useful if it's at high elevation (else you're drowning in local/regional effects as noise), which is why it happens to be colocated with several astronomy experiments—but they are not the same equipment.
> "We have other ways to measure atmospheric CO2"
It's destroying the continuity of the world's highest-quality and longest-running dataset.
edit: Also, this CO2 observatory closure reflects the entire NOAA climate observation budget being zero'd out[1], so I don't know what where else you'd like us to look instead.
[1] https://www.nytimes.com/2025/07/17/climate/budget-cuts-clima... ("But President Trump’s proposed 2026 budget would put an end to Mauna Loa, along with three other key observatories and almost all the climate research being done by the National Oceanic and Atmospheric Administration.")
I think you are just fundamentally confused. There are two separate entities with similar names. There's the Mauna Loa Observatory, which is what's being discussed here, and there are the Mauna Kea Observatories. The latter one has the telescopes. The Mauna Loa Observatory monitors the atmosphere. It has other types of sensors that are useful for atmospheric science. It isn't an astronomical observatory that just happens to have a CO2 sensor. It was specifically set up in the 1950s to study the atmosphere because of the advantages of being at that specific location. It just happens to have a name that's similar to an institution that does have telescopes.
I think you’re thinking of the complex on Mauna Kea (which has several individual sites and has funding from several countries).
Mauna Loa has a telescope that studies the Sun in order to help understand better how that contributes to changing weather patterns on Earth. It is a relatively small site but very important.
The reason that telescopes are often in high up, hard to reach places is because that is the most efficient, cost-effective place for them to be.
> "We have other ways to measure atmospheric CO2"
It's destroying the continuity of the world's highest-quality and longest-running dataset.
edit: Also, this CO2 observatory closure reflects the entire NOAA climate observation budget being zero'd out[1], so I don't know what where else you'd like us to look instead.
[0] https://gml.noaa.gov/ccgg/about/co2_measurements.html
[1] https://www.nytimes.com/2025/07/17/climate/budget-cuts-clima... ("But President Trump’s proposed 2026 budget would put an end to Mauna Loa, along with three other key observatories and almost all the climate research being done by the National Oceanic and Atmospheric Administration.")