June 4 (UPI) -- The highest carbon dioxide concentration levels in human history have been recorded at Mauna Loa Observatory in Hawaii.
During the month of May, CO2 levels averaged 414.8 parts per million -- levels not present on Earth in millions of years.
CO2 levels typically peak on Mauna Loa around this time of year, but carbon dioxide levels have increased consistently during the past few decades. This year's peak was 3.5 parts per million higher than last year's apex of 411.3 parts per million.
Climate scientists agree that increases in atmospheric CO2, the result of the burning of oil, gas and other fossil fuels, is to blame for rising global temperatures.
"Many proposals have been made to mitigate global warming, but without a rapid decrease of CO2 emissions from fossil fuels they are pretty much futile," Pieter Tans, senior scientist with NOAA's global monitoring division, told USA Today.
Carbon dioxide is the most abundant greenhouse gas, but the levels of other planet-warming gases like methane are also rising. NOAA tracks many of them.
Earlier this year, NOAA announced that the Annual Greenhouse Gas Index -- a measure of greenhouse gas emissions and their impact on the the atmosphere's heat-trapping capacity -- rose to a value of 1.43.
"Greenhouse gas pollution traps heat in the atmosphere, which has consequences," James Butler, director of NOAA's Global Monitoring Division, said in a news release. "There's no getting around it -- burning fossil fuels is changing the course of our planet's future. How society deals with that will be a major challenge in coming decades."
The agency also announced that CO2 levels increased at a record rate in 2018, echoing the findings of other studies that showed carbon emissions increased around the world after a few years of minimal growth.