Beam Measurements of a CLOUD (Cosmics Leaving OUtdoor Droplets) Chamber

TL;DR

This paper proposes an experimental study at CERN to measure how cosmic rays influence cloud formation, aiming to clarify their potential impact on Earth's climate and improve long-term climate predictions.

Contribution

It introduces a novel experimental setup to directly measure cosmic ray effects on cloud droplets under controlled conditions, providing data previously unavailable.

Findings

Establishes a method to simulate tropospheric conditions in a CLOUD chamber.

Aims to quantify the influence of cosmic rays on cloud formation.

Supports the potential link between cosmic rays and climate variability.

Abstract

A striking correlation has recently been observed between global cloud cover and the flux of incident cosmic rays. The effect of natural variations in the cosmic ray flux is large, causing estimated changes in the Earth's energy radiation balance that are comparable to those attributed to greenhouse gases from the burning of fossil fuels since the Industrial Revolution. However a direct link between cosmic rays and cloud formation has not been unambiguously established. We therefore propose to experimentally measure cloud (water droplet) formation under controlled conditions in a test beam at CERN with a CLOUD chamber, duplicating the conditions prevailing in the troposphere. These data, which have never been previously obtained, will allow a detailed understanding of the possible effects of cosmic rays on clouds and confirm, or otherwise, a direct link between cosmic rays, global cloud cover and the Earth's climate. The measurements will, in turn, allow more reliable calculations to be made of the residual effect on global temperatures of the burning of fossil fuels, an issue of profound importance to society. Furthermore, light radio-isotope records indicate a correlation has existed between global climate and the cosmic ray flux extending back over the present inter-glacial and perhaps earlier. This suggests it may eventually become possible to make long-term (10-1,000 year) predictions of changes in the Earth's climate, provided a deeper understanding can be achieved of the ``geomagnetic climate'' of the Sun and Earth that modulates the cosmic-ray flux.