Carbon dioxide - the main greenhouse gas - is now in the earth's atmosphere as much as it was millions of years ago, when the Earth was a greenhouse flooded by the ocean, American scientists reported on Friday, quoted by AP NEWS.

The US National Oceanic and Atmospheric Administration reported that its monitoring station in Hawaii recorded an average of 421 parts per million of carbon dioxide in the month of May, which is the period when the most important greenhouse gas reaches its annual maximum..

Before the Industrial Revolution at the end of the 19th century, carbon dioxide levels were 280 parts per million, scientists say, so humans have changed the atmosphere significantly.. Some activists and scientists want carbon dioxide levels to be 350 parts per million.

However, the level of carbon dioxide in the atmosphere continues to rise, while it is necessary to fight for its reduction, scientists say.. Carbon dioxide levels are almost 1.9 ppm more this year than they were a year ago, slightly more than the jump from May 2020 to May 2021.

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" Our measurements show no improvement,"