Rayonnements cosmiques & changement climat
CLIMAT - 16/09/2005
Pour la première fois, des scientifiques découvrent un lien entre rayonnements cosmiques et changement climatique.
Aujourd’hui, tout le monde pense que le changement climatique est lié à l’activité humaine, au travers notamment de la pollution.
Les scientifiques allemands qui sont à l’origine de cette découverte capitale assurent que bien au delà de l’activité humaine, c’est bien les rayonnements cosmiques, complètement sous-estimés dans les recherches traditionnelles, qui sont à l’origine du bouleversement climatique rapide que connaît le monde ces derniers temps. C’est bien ce qui est inquiétant.
English
German scientists have found a significant piece of evidence linking cosmic rays to climate change.
They have detected charged particle clusters in the lower atmosphere that were probably caused by the space radiation.
They say the clusters can lead to the condensed nuclei which form into dense clouds.
Clouds play a major, but as yet not fully understood, role in the dynamics of the climate, with some types acting to cool the planet and others warming it up.
The amount of cosmic rays reaching Earth is largely controlled by the Sun, and many solar scientists believe the star's indirect influence on Earth's global climate has been underestimated.
Some think a significant part of the global warming recorded in 20th Century may in fact have its origin in changes in solar activity - not just in the increase in fossil-fuel-produced greenhouse gases.
First evidence found
The German team, from the Max Planck Institute of Nuclear Physics in Heidelberg, used a large ion mass spectrometer mounted on an aircraft.
Cosmic rays and clouds
The Sun's magnetic field and solar wind shield the Solar System from cosmic rays (very energetic particles and radiation from outer space)
Changes in solar activity will affect the performance of the shield and how many cosmic rays get through to Earth
Theory suggests cosmic rays can "seed" clouds
Some satellite data have shown [...]
http://news.bbc.co.uk
