### Record-High Carbon Dioxide Levels Highlight Climate Crisis

The Earth's atmosphere contains a higher concentration of carbon dioxide (CO₂) than it has in millions of years, according to recent data released by the National Oceanic and Atmospheric Administration (NOAA) and scientists at the University of California San Diego. This alarming milestone was surpassed in May, with global average concentrations of CO₂ exceeding 430 parts per million (ppm) for the first time.

These new measurements represent an increase of over 3 ppm from the previous year, setting a record high and signaling that global efforts to curtail greenhouse gas emissions are falling short. Ralph Keeling, a professor at UC San Diego's Scripps Institution of Oceanography, described the situation as "sad," reflecting the grim reality of another record year in the fight against global warming.

Carbon dioxide, which results from burning fossil fuels, is a potent greenhouse gas capable of trapping heat from the sun. This leads to higher global temperatures and numerous other consequences, including rising sea levels, melting polar ice, and more frequent and severe extreme weather events. Because CO₂ can remain in the atmosphere for centuries, high concentrations are particularly troubling.

Historically, atmospheric CO₂ levels have been on a sharp upward trajectory since preindustrial times due to human activity. Crossing the 400 ppm mark was once an unfathomable concept, yet that threshold was crossed in 2013. Now, scientists warn that CO₂ levels could reach 500 ppm within the next three decades.

According to Keeling, the current levels of CO₂ were last seen more than 30 million years ago, a time when Earth's climate was vastly different and humans had not yet emerged. The rapid pace at which these levels have increased is especially worrisome, as it challenges humanity's ability to adapt. "If humans had evolved in such a high-CO₂ world, there would probably be places where we wouldn't be living now," Keeling told NBC News.

These CO₂ levels have been carefully tracked since 1958, when Charles David Keeling, Ralph Keeling’s father, began daily measurements at the Mauna Loa Observatory in Hawaii. The resulting data, represented on the Keeling Curve, has shown a steep climb since the Industrial Revolution, highlighting the impact of human-caused climate change.

In May, Ralph Keeling and his team at the Scripps Institution of Oceanography recorded an average CO₂ concentration of 430.2 ppm. NOAA's Global Monitoring Laboratory, which has been conducting daily readings since 1974, reported an average of 430.5 ppm for the same month. Both sets of measurements underscore how much human activity is influencing Earth's climate and serve as a stark indicator of the planet's overall health.

"We're getting a holistic measurement of the atmosphere from really a kind of simple set of measurements," Keeling said. This data continues to be a critical tool in understanding and reacting to the broader implications of climate change.