Cosmic Rays too Wimpy to Influence Climate

[/caption]

People looking for new ways to explain climate change on Earth have sometimes turned to cosmic rays, showers of atomic nuclei that emanate from the Sun and other sources in the cosmos. 

But new research, in press in the journal Geophysical Research Letters, says cosmic rays are puny compared to other climatic influences, including greenhouse gases — and not likely to impact Earth’s climate much.

 

Jeffrey Pierce and Peter Adams of Carnegie Mellon University in Pittsburgh, Pennsylvania, point out that cycles in numerous climate phenomena, including tropospheric and stratospheric temperatures, sea-surface temperatures, sea-level pressure, and low level cloud cover have been observed to correlate with the 11-year solar cycle.

However, variation in the Sun’s brightness alone isn’t enough to explain the effects and scientists have speculated for years that cosmic rays could fill the gap.

For example, Henrick Svensmark, a solar researcher at the Danish Space Research Institute, has proposed numerous times, most recently in 2007, that solar cosmic rays can seed clouds on Earth – and he’s seen indications that periods of intense cosmic ray bombardment have yeilded stormy weather patterns in the past.

Others have disagreed.

“Dust and aerosols give us much quicker ways of producing clouds than cosmic rays,” said Mike Lockwood, a solar terrestrial physicist at Southampton University in the UK. “It could be real, but I think it will be very limited in scope.”

To address the debate, Pierce and Adams ran computer simulations using cosmic-ray fluctuations common over the 11-year solar cycle.

“In our simulations, changes in [cloud condensation nuclei concentrations] from changes in cosmic rays during a solar cycle are two orders of magnitude too small to account for the observed changes in cloud properties,” they write, “consequently, we conclude that the hypothesized effect is too small to play a significant role in current climate change.”

The results have met a mixed reception so far with other experts, according to an article in this week’s issue of the journal Science:  Jan Kazil of the University of Colorado at Boulder has reported results from a different set of models, confirming that cosmic rays’ influence is similarly weak. But at least one researcher — Fangqun Yu of the University at Albany in New York — has questioned the soundness of Pierce and Adams’ simulations.

And so, the debate isn’t over yet …

Sources: The original paper (available for registered AGU users here) and a news article in the May 1 issue of the journal Science. See links to some of Svensmark’s papers here.

Anne Minard

Anne Minard is a freelance science journalist with an academic background in biology and a fascination with outer space. Her first book, Pluto and Beyond, was published in 2007.

Recent Posts

Scientists Have Figured out why Martian Soil is so Crusty

On November 26th, 2018, NASA's Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight)…

8 hours ago

Another Way to Extract Energy From Black Holes?

Black holes are incredible powerhouses, but they might generate even more energy thanks to an…

14 hours ago

Plastic Waste on our Beaches Now Visible from Space, Says New Study

According to the United Nations, the world produces about 430 million metric tons (267 U.S.…

1 day ago

Future Space Telescopes Could be Made From Thin Membranes, Unrolled in Space to Enormous Size

As we saw with JWST, it's difficult and expensive to launch large telescope apertures, relying…

2 days ago

Voyager 1 is Forced to Rely on its Low Power Radio

Voyager 1 was launched waaaaaay back in 1977. I would have been 4 years old…

2 days ago

Webb Confirms a Longstanding Galaxy Model

The spectra of distant galaxies shows that dying sun-like stars, not supernovae, enrich galaxies the…

3 days ago