Forbush Effect

What the heck is a Forbush Effect? No, it doesn't mean you favor George W. Bush. It has to do with the reduction of clouds when there are strong solar flares. This effect could explain how the sun affects our weather in a surreptitious manner, and since cloud formation is important to climate, it could have ramifications for climate change.

The observation is that cloud formation is lessened when the sun is active. What happens here is that it's believed that cosmic rays, which are always hitting the Earth's upper atmosphere, help cause cloud formation by forming ions. Ions supposedly create aerosols, which help form clouds by seeding.

It turns out that when the sun erupts with flares, radiation sweeps the cosmic rays away, consequently lessening cloud formation for up to week. The reduction in ions is 20 percent, but this is only an estimate.

Of course there are problems with this theory. One is that the formation of aerosols by ions is only shown in the laboratory not in the atmosphere. The other problem is that strong solar activity occurrences are rare and detection of this effect is difficult to obtain. The reduction in cloud cover is only 2% but it represents a loss of a billion tons of water from the atmosphere. This may sound like a lot but it's not. The present data is based on studies form 1987 to 2007, where 26 of these Forbush events occurred and were ranked as to severity. The data comes from the National Space Institute at the Technical University of Denmark and the Racah Institute of Physics at the Hebrew University of Jerusalem and is based on 25 years of work.

Clouds are known to affect Earth's global temperature, and this is the reason that this effect could influence climate change. However, the sun's changes occur over a hundred years, so data takes time to obtain.

My take on this is that it's another interesting study of how space affects our weather over time. However, this has been occurring for as long as the Earth has been here, and there's nothing we can do about it.

Thanks for reading.