This month, humanity broke a record, and it’s not a good one.

March was the first month since modern records began that monthly global average concentrations of atmospheric carbon dioxide, a greenhouse gas, exceeded 400 parts per million (ppm), according to the National Oceanic and Atmospheric Administration (NOAA).

Related: Are Trees Making Climate Change Worse?

“It’s both disturbing and daunting,” NOAA chief greenhouse-gas scientist Pieter Tans told the Associated Press . “Daunting from the standpoint on how hard it is to slow this down.”

NOAA took samples from 40 sites around the world, including on cargo ships and the shores of remote islands. Those air samples were then shipped to NOAA laboratory in Boulder, Colorado, for testing.

While this is the first time the whole world went over the 400 ppm mark, it’s happened before in certain places. NOAA saw carbon dioxide levels rise past 400 ppm in the Arctic in 2012 and in Hawaii 2015.

The average CO2 level growth rate between 2012 and 2014 was 2.25 ppm per year, the highest ever recorded over three consecutive years, according to NOAA data.

Related: Pediatricians Call Climate Change a Rising Children's Health Threat

“This marks the fact that humans burning fossil fuels have caused global carbon dioxide concentrations to rise more than 120 parts per million since pre-industrial times,” Tans said in the NOAA news release. “Half of that rise has occurred since 1980.”

Researchers explained that even if we reduce current emissions by 80 percent, it would take time for the gases to clear out. “Concentrations of carbon dioxide would not start decreasing until even further reductions are made and then it would only do so slowly,” said James Butler, director of NOAA’s Global Monitoring Division.

Carbon dioxide levels are expected to remain above 400 ppm through May. After May, levels will decrease as plants and other blooms absorb the carbon dioxide, according to Tans.

Earlier this month, a study from the National Center for Atmospheric Research warned deadly heat waves could become an annual occurrence across 60 percent of the globe by 2075 if we don’t curb emissions of carbon dioxide and other greenhouse gases.

High concentration of carbon dioxide and other greenhouse gases also contribute to rising sea levels. One study showed sea levels rose more in the 20th century than in any of the previous 27 centuries due to higher temperatures.

Related: Make Your Own Car Greener: How to Reduce Carbon Emissions

Like this article? Share it with friends by clicking the Facebook or Twitter button below. And don't forget to visit our Facebook page!

Muriel Vega is a writer with a passion for budget travel and staying safe while abroad. A Georgia State University graduate, she has over 6 years of editorial experience and has written for The Guardian, The Atlantic, The Billfold, among other outlets. In her free time, you can find her baking pies, playing with her two dogs and cat, or planning her next vacation. She spends way too much time on Twitter, one of her favorite social media channels. Her favorite safety tip: Make sure you have all the necessary shots before you go abroad.