Rocks emit as much carbon dioxide as volcanoes – study
[ad_1]
A new study shows that rock weathering may be a major source of carbon dioxide (CO2) emissions. The amount of these emissions can be compared with volcanic emissions.
Sci Tech Daily writes about it.
The data obtained from the study showed that rocks can act not only as an absorber of CO2, but also as a source. The results are important, because currently this fact is not taken into account in climate models.
The experiment was conducted under the guidance of Oxford University. The full report was published in the journal Nature on October 4.
| Photo: James O’Neil/Gettyimages.com |
Scientists know that rocks contain huge reserves of carbon in the ancient remains of plants and animals. This indicates that its circulation acts like a thermostat, helping to regulate the Earth’s temperature.
As an example, during chemical weathering, rocks can absorb carbon dioxide when certain minerals are exposed to weak acids from rainwater. This process helps counteract unprecedented CO2 emissions by volcanoes. In addition, this circulation is able to maintain the Earth’s temperature suitable for life.
However, the new study measured for the first time an additional process of releasing CO2 from rocks into the atmosphere. It appears when rocks formed on the ancient seabed are pushed back to the Earth’s surface.
This could be during the formation of mountains like the Andes or the Himalayas. During the process, the organic carbon in the rocks is exposed to oxygen in the air and water, which can react to release CO2.
In the past, it was difficult to quantify the release of CO2 from organic carbon. However, the trace element rhenium was used in the study – it is released in water when the carbon of rocks reacts with oxygen.
Sampling of river water to measure the level of rhenium makes it possible to quantitatively assess CO2 release. However, it is quite difficult to take samples from all the river water in the world. Therefore, to scale to the Earth’s surface, researchers did 2 things.
First, they found out how much organic carbon is in the rocks near the surface, and then found out where it is destroyed most quickly due to erosion in steep mountain areas.
Dr. Jesse Zondervan, who led the study, said the challenge was combining global maps with river data, given the uncertainties. All the data were loaded into a supercomputer that modeled the complex interaction of physical, chemical and hydrological processes.
Having put everything together, the scientists obtained the total amount of carbon dioxide, which is released during the weathering of rocks. The researchers realized that the hot spots of CO2 release were concentrated in mountain ranges with high rates of uplift, resulting in the exposure of sedimentary rocks such as the Eastern Himalayas, the Rocky Mountains and the Andes.
Scientists have determined that the global emission of CO2 as a result of the weathering of organic carbon in rocks amounts to 68 megatons of carbon per year. At the same time, it is approximately 100 times less than human emissions from burning fossil fuels.
Future work will focus on how human influence may increase this natural outflow over the next century.
“Although carbon dioxide emissions from rock weathering are small compared to modern human emissions, a better understanding of these natural fluxes will help us better predict our carbon budget.” said Zondervan.
Previously, NASA showed how the world is suffocating with carbon dioxide.
Read also: The Webb Space Telescope recorded carbon dioxide on an exoplanet for the first time in history
[ad_2]
Original Source Link
