A new study has revealed that levels of molecular hydrogen (H2) in the atmosphere have risen in the modern era due to human activity.

Molecular hydrogen is a natural component of the atmosphere due to the breakdown of formaldehyde, but it is also a by-product of fossil fuel combustion, particularly from automobile exhaust and biomass burning.

According to the study, published in the journal "Pance", scientists from the University of California analyzed air samples trapped in the Antarctic ice core, and found that atmospheric hydrogen has increased by 70% over the course of the 20th century.

The current study is the first to provide a strong figure, between 1852 and 2003; Air samples near Antarctica indicate that atmospheric hydrogen jumped from 330 parts per billion to 550 parts per billion.

According to the researchers; This data is not the only one, as previous research has also shown a steady rise in hydrogen between 2000 and 2015.

Regarding human-caused emissions; Hydrogen emissions may come mostly from automobile exhaust.

Hydrogen leakage from industrial processes is rarely considered; No one has directly measured the amount of hydrogen released from these processes; But preliminary estimates suggest it may be important.

Researchers say the dropout rate increased by 10% between 1985 and 2005; It will account for nearly half of the increase in recent hydrogen emissions.

Scientists say hydrogen does not trap heat in the atmosphere; However, it can indirectly affect the distribution of methane and ozone, which are responsible for global warming.

Hydrogen comes after carbon dioxide, in affecting the two most important greenhouse gases; Which means global hydrogen levels could disturb the climate as well.

A previous study, published in the scientific journal "Science" in 2003, had predicted that hydrogen gas levels would increase to four times its proportion in the air, which amounted to - at that time - half a part per million; It will increase the amount of water vapor in the stratosphere; Hydrogen combines with oxygen, which increases the amount of clouds.

In addition, the temperature of the stratosphere may drop by half a degree Celsius; This slows down the arrival of spring in the north and south polar regions, and expands the size, depth and survival of the holes in the ozone layer.

As a result of the decrease in the proportion of ozone gas in the upper atmosphere, a greater amount of dangerous sunlight reaches the earth; This increases the chances of developing skin cancer.