According to the National Oceanic and Atmospheric Administration, worldwide levels of carbon dioxide have achieved a significant feat in the month of March. The scientists said that the gas is highly accountable for global warming.

The scientists said the global monthly average for carbon dioxide hit 400.83 parts per million in March. According to NOAA, it is the first time that the average surpassed 400 ppm for a whole month since such measurements started in the late 1950s.

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

According to the scientists, the burning of the oil, gas and coal for energy releases greenhouse gases like carbon dioxide and methane. These gases led the Earth's temperature to increase over the past century to levels that cannot be explained by natural variability.

As per the journal Nature Geoscience, the last time carbon dioxide reached 400 ppm was millions of years ago. According to a 2009 report in the journal, evidence has been found of CO2 levels of 365 ppm to 415 ppm about 4.5 million years ago.

In the late 1800s, CO2 levels were around 280 ppm previous to the Industrial Revolution. At that time large amounts of greenhouse gases started to be released by the burning of fossil fuels.

According to the scientists, carbon dioxide is invisible, odorless, and colorless and it is yet accountable for 63% of the warming attributable to all greenhouse gases. Levels of carbon dioxide increase and decrease every year and reached their highest levels in May and then going back down as plants absorb the gas.