The sun influences the patterns of climate change on Earth, but its influence is more pronounced during cooler periods, suggests a new study.
Professor Marit-Solveig Seidenkrantz from the Aarhus University in Denmark, one of the researchers of the study, believes that even though the sun affects the climate of the Earth, such impact is not constant and varies over time.
The last Ice Age on Earth ended about 12,000 years ago and since then the Earth has been relatively warmer than before. However, there have been variations to the planet's climate since the end of the Ice Age, but scientists suggest that the Earth has been cooler in the last 4,000 years. The North Atlantic ocean currents have also been weaker in the last 4,000 years.
Professor Seidenkrantz says that even though it is well known that the sun plays a very important role in the climate of the Earth, but the exact impact remains unclear. The changes to the climate are either weakened or strengthened by the sun's activity. However, the study found that the sun impacts the Earth's climate more during cooler times, at least in the North Atlantic regions.
"Our climate is enormously complex. By gathering knowledge piece by piece about the way the individual elements work together and influence each other to either strengthen an effect or mitigate or compensate for an impact, we can gradually get an overall picture of the mechanisms. This is also important for understanding how human-induced climate change can affect and be affected in this interaction," says Professor Seidenkrantz.
The study analyzed the North Atlantic region's sea surface temperatures during summers for the last 9,300 years. The researchers suggest that direct temperature measurements for the sea surface are available only for 140 years, which were recorded by the ships. However, the team examined diatoms, a group algae found in marine environment found in sediments that were deposited on the sea bed of North Atlantic Ocean.
The researchers say that examination of these marine algae helped them reconstruct the temperature of the sea surface back to thousands of years ago. Detailed study found a strong relation between solar activity and climate changes that occurred in the North Atlantic regions. The scientists are able to reconstruct the variations of climate changes in the last 10 to 20 years, as well as hundreds and thousands of years back.
The study was published in the journal Geology.
