Earth's Climate History May be a Bit Different, According to the Global Carbon Cycle

It turns out that we may need to rework our view of Earth's climate history. Scientists have taken a closer look at the global carbon cycle, which offers a new perspective of Earth's climate records through time.

The global carbon cycle is when carbon is cycled through the different components of Earth, including the mantle, atmosphere, plants, the ocean and sediments. Because carbon is cycled, scientists can take cores of marine sediments that can show them a bit more about our planet's past climate. In this case, the scientists measured the abundance of carbon-12 and carbon13 isotopes in both the organic matter and carbon sediments found in cores.

"Without geological context, classical interpretations of this dataset would suggest that there was a significant change in global carbon cycling, or a very large change in the concentration of atmospheric CO2 during the past five-million years," said Amanda Oehlert, lead author of the new study, in a news release. "These findings show how important it is to understand the geological context of carbon isotope records."

In this case, the researchers found that post-depositional changes in sediments could cause carbonate and organic values to co-vary through time; this is a process that has never been witnessed before and has actually been considered impossible. This finding suggests that similar trends in carbon isotopes values through time do not always provide conclusive information about the amount of CO2 in the atmosphere or how carbon was cycled through the atmospheres and oceans.

So what does this mean? It's likely we may need to take another look at what our climate was like in the past. The findings highlight the importance of understanding how the sediments and organic matter were originally produced in order to create an accurate record.

The findings are published in the journal Nature Communications.