Apart from manufactured chemicals, another culprit in the destruction of the Earth’s ozone layer is the gas ejected during massive volcanic eruptions, geoscientists have revealed.
Eruptive activity in Central America could have emitted enough ozone-depleting chemicals over the past 70,000 years, finds a new research.
“We have to be aware of this,” says study researcher Kirstin Krüger, a meteorologist at the Leibniz Institute of Marine Sciences at the University of Kiel (GEOMAR) in Germany. “Large-scale tropical eruptions have the potential to deplete ozone on a big scale.”
"As we have bromine and chlorine together, we believe that this can lead to substantial depletion. And this is from one single eruption."-- study researcher Kirstin Krüger.
Volcanic eruptions deliver ozone-damaging gases
The ozone layer is a thin, protective layer of the stratosphere, which shields the earth from the sun's ultraviolet rays.
Overexposure to these harmful rays can lead to skin cancer, cataracts, weakened immune systems, reduced crop yields and disruptions in plankton population.
Scientists found overwhelming evidence that volcanoes play a role in the destruction of ozone.
A recent discovery suggests that volcanic rocks in Nicaragua contain bromine, a reactive chemical known for accelerating ozone’s destruction in the upper atmosphere.
According to experts, when magma emitted to form those rocks it also released huge amounts of bromine into the air, large enough to cause local ozone depletion and affect stratospheric chemistry for several years.
Magma rocks studied
In a bid to determine whether volcanoes could damage the ozone layer, the researchers they studied rocks formed at 14 previous Nicaraguan eruptions.
They measured levels of halogens (the group of highly reactive elements that bromine and chlorine belong to) in the lava rocks before as well as post-eruption.
The difference along with existing data about the size of the eruption helped them to detect the amount of bromine and chlorine released.
Studies have established that in large volcanic eruptions up to 25 percent of the halogens ejected can penetrate the stratosphere.
The analysis revealed that each eruption pumped two or three times the levels of humanly produced bromine and chlorine currently in the stratosphere.
"As we have bromine and chlorine together, we believe that this can lead to substantial depletion," Krüger said. "And this is from one single eruption."
Krüger presented the study on June 12 at an American Geophysical Union conference on volcanism and the atmosphere.