Cosmic Rays and Global Warming

TL;DR

This paper investigates the claimed link between cosmic rays and global warming, finding no substantial evidence to support a causal relationship and attributing observed correlations mainly to solar irradiance variations.

Contribution

The study critically examines the cosmic ray-global warming hypothesis and provides quantitative estimates showing minimal influence of cosmic rays on recent climate change.

Findings

Less than 15% of 11-year cycle warming variations are due to cosmic rays.

Less than 2% of recent warming over 35 years is attributable to cosmic rays.

Observed correlations are more likely caused by solar irradiance variations.

Abstract

It has been claimed by others that observed temporal correlations of terrestrial cloud cover with `the cosmic ray intensity' are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim to look for evidence to corroborate it. So far we have not found any and so our tentative conclusions are to doubt it. Such correlations as appear are more likely to be due to the small variations in solar irradiance, which, of course, correlate with cosmic rays. We estimate that less than 15% of the 11-year cycle warming variations are due to cosmic rays and less than 2% of the warming over the last 35 years is due to this cause.