Solar Activity is Not Key to Climate Change: Sun Doesn't Impact Temperature

Solar activity was once thought to influence climate. In fact, some scientists have speculated that it might have helped impact current changing temperatures. Now, though, researchers have shown that this isn't the case; climate change has not been strongly influenced by variations in heat from the sun.

In order to better understand past drivers of climate change, the researchers looked at the causes of temperature differences in the northern hemisphere over the past 1,000 years. More specifically, they used records of past temperatures constructed with data from tree rings and other historical sources. They then compared this data record with computer-based models of past climate, featuring both significant and   minor changes in the sun.

In the end, they found that until the year 1800, the key driver of periodic changes in climate was volcanic eruptions. These eruptions prevented sunlight from reaching the Earth which, in turn, caused cool, drier weather. Since 1900, they found that the greenhouse gas has been the primary cause of climate change.

"Until now, the influence of the sun on past climate has been poorly understood," said Andrew Schurer, one of the researchers, in a news release. "We hope that our new discoveries will help improve our understanding of how temperatures have changed over the past few centuries, and improve predictions for how they might develop in future. Links between the sun and anomalously cold winters in the UK are still being explored."

The findings reveal that the sun isn't to blame when it comes to climate change. This could impact future models which should take into account the fact that solar activity has a minimal impact on temperature. In addition, the new study reveals that periods of low sun activity should not be expected to have an impact; this, in turn, could improve scientists' understanding and help climate forecasting.

The findings are published in the journal Nature GeoScience.