For nearly 70 years, scientists have used an outpost near the top of Mauna Loa on the Big Island to record the rising levels of carbon dioxide in the atmosphere — one of the top indicators of human-caused climate change.

However, future collections of that data atop one of Hawaiʻi’s tallest volcanic peaks remain uncertain amid efforts by President Donald Trump and his special advisor, Elon Musk, to slash federal programs and agencies.

The Hilo-based office supporting that Mauna Loa Observatory is one of at least 34 National Oceanic and Atmospheric Administration facilities flagged for possible closure, according to a list circulated by Congressional Democrats.

Those Democrats asked U.S. Commerce Secretary Howard Lutnick for more details this week on the potential lease cancelations in Hilo and around the nation. In addition to climate research, NOAA provides critical weather information.

Mauna Loa’s peak offers an ideal spot to collect air samples on the planet’s growing carbon dioxide levels, researchers say, due to its thin air and remote location in the middle of the Pacific Ocean, away from major urban centers.

Sample collections began there in 1958 under Charles Keeling, a scientist studying seasonal carbon dioxide patterns in the atmosphere. The rise in carbon dioxide levels detected at Mauna Loa in subsequent decades became known as the Keeling Curve. His research further linked that increase to the growing use of fossil fuels.

The data collected on Mauna Loa in recent years shows that atmospheric carbon dioxide levels have reached their highest levels in human history, at over 420 parts per million. That’s far more than the 315 parts per million that Keeling recorded in the 1960s and also more than 50% higher than pre-industrial levels.

Civil Beat Editor Nathan Eagle contributed to this report.

CORRECTION: The total increase of carbon dioxide levels compared to pre-industrial levels was misstated and has been corrected.

Civil Beat’s coverage of climate change is supported by The Healy Foundation, Marisla Fund of the Hawai‘i Community Foundation and the Frost Family Foundation.