Global warming and complexity: is there a strong but subtle solar signature behind global climate change?

Nicola Scafetta, Physics, Duke

Understanding global warming and global climate change is a major scientific issue of our days. Modern theoretical climate models are used to describe past climate and predict future scenarios. Anthropogenic added greenhouse forcing is blamed for the warming of the last decades and new policies are being proposed for its reduction. However, not all scientists agree on the correct interpretation of the findings and several controversies are rising about how to determine the natural vs. anthropogenic contribution to climate change. Part of these controversies regards the data themselves, other the mathematical methodologies adopted. We discuss some of these controversies and argue that the inherent complexity of climate rules out traditional geophysical analysis methodologies, such as multilinear regression analysis, and might requires novel computational and phenomenological analysis methodologies that carefully evaluate the complex patterns observed in the data. We suggest, by analyzing solar and temperature data that climate might likely present a strong but subtle solar signature that during the last century might have been responsible of approximately 50% of the observed warming, this value is significantly larger than what current climate models would predict.