Core samples of rocks from several areas in the US have been collected by scientists to find out how the changes in the warming of the Earth has affected it. The samples show that the soil has become one of the biggest contributors of the greenhouse gases present in the atmosphere. The scientists also suggested that the modern climate models may have overestimated the Earth's ability to mitigate the warnings for the future conditions of the atmosphere.
The researchers found a drastic drop in the organic materials supposedly preserved in the core parts of the Earth. They got their samplers particularly from the Paleocene-Eocene Thermal Maximum (PETM), characterized by a global warming event that took place 55.5 million years ago. Scientists consider it as the best analogue to better understand the modern climate change.
The findings suggests that the ancient soil collected from the modern day Wyoming acted as a huge source of atmospheric carbon dioxide. It emitted greenhouse gases into the atmosphere and not into a sink, which basically trapped carbon underground. The researchers say that this reveals that the current climate models that show that the soil creates a sink where it can trap greenhouse gases may not be true at all. It may have overestimated the ability of the terrestrial ecosystem to help control the impacts of climate change.
"We can see that the amount of carbon drastically drops by orders of great magnitude, during the PETM event," said Allison Baczynski, lead author of the study. She is also a postdoctoral scholar in the geosciences at Penn University. " At least in Wyoming, the data reveals that the soil is the source of the greenhouse gas and not the sink particularly for carbon dioxide. This provides us with new information as we try to figure out what may eventually happen in the midst of this growing problem on climate change."
The team published their findings in the journal Paleoceanography and Paleoclimatology. Baczynski worked with Katherine Freeman, her adviser and professor at the Evan Pugh University, Geosciences Department.
The cores that were drilled from the Bighorn Basin in Wyoming is considered the first terrestrial core samples from a PETM site. It was collected in 2011, but the team, back then, did not have enough sensitivity to measure specific biomarkers.
"Prior to improving the sensitivity, we were focused on improving the gap in the study to further the results. It led to a better understanding of the role the soil plays in all these problems on greenhouse gases," Baczynski said.
