The contribution of cosmic rays to global warming

TL;DR

This paper investigates whether variations in cosmic ray intensity have significantly contributed to global warming over the last century, concluding that their impact is likely less than 8%.

Contribution

It provides a quantitative analysis of the potential link between cosmic rays and global warming, which has not been definitively established before.

Findings

Cosmic ray intensity decreased since 1900.

The potential contribution of cosmic rays to warming is less than 8%.

No strong evidence found for a major cosmic ray influence on global temperature increase.

Abstract

A search has been made for a contribution of the changing cosmic ray intensity to the global warming observed in the last century. The cosmic ray intensity shows a strong 11 year cycle due to solar modulation and the overall rate has decreased since 1900. These changes in cosmic ray intensity are compared to those of the mean global surface temperature to attempt to quantify any link between the two. It is shown that, if such a link exists, the changing cosmic ray intensity contributes less than 8% to the increase in the mean global surface temperature observed since 1900.