Climate Change Shaped by Solar Activity in Cooler Periods

Scientists found that natural climate change was greatly influenced by solar activity especially in cooler periods. Although the research assessed the impact of the Sun on our climate over the past 4 millennia, researchers claim that their results are consistent over the decades.

Until now, research linked climate change to several other factors such as volcanic activity or oceanic temperature cycles. But more and more studies reveal that the amount of solar radiation that reach our planet may play an important role in how climate is shaped over time.

Researchers from Aarhus University in Denmark wrote in their recently published paper that over the past 4,000 years there is a tight connection between solar flares and the summer oceanic temperatures recorded in North Atlantic. However, authors noted that the link was not visible 4,000 years ago.

About 12,000 years ago, when the latest Ice Age ended, our planet had an overall warm climate with varying temperatures for prolonged periods of time. For instance, in the last 4,000 years, the climate was slightly cooler, and the oceanic currents were weaker.

“We know that the Sun is very important for our climate, but the impact is not clear. Climate change appears to be either strengthened or weakened by solar activity.”

wrote Marit-Solveig Seidenkrantz, co-author of the study and professor at the Department of Geoscience, Aarhus University, Denmark.

According to Ms. Seidenkrantz, solar influence upon planetary climate was not constant over time, but the greatest impact was recorded during cool periods, at least in the North Atlantic.

For their study, scientists analyzed the summer surface temperatures in the North Atlantic region over the last 9,300 years. Since the oldest global temperature records date back to 1850, researchers assessed climate variation over millennia by studying traces of marine algae found in seabed sediments in the North Atlantic.

Scientists liked the distribution of algae to fluctuations in sea surface levels and were able to create a model that can be applied on a larger time scale. Further analysis of the data revealed that climate change as it was reflected by sea surface temperatures was influenced by intense solar activity and bursts during the last 4,000 years.

Interestingly, scientists learned that the fluctuations in climate triggered by solar activity were recorded both on geological time scales and on smaller scales of 10 to 20 years. Prof Seidenkrantz argued that the new findings will help the scientific community expand its current knowledge on the mechanism of climate change and its triggering factors.

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