COPENHAGEN: In a controversial study, Danish researchers claim a major part of global warming could be the result of cosmic rays hitting the atmosphere rather that carbon emissions.
Dr Henrik Svensmark, a weather scientist at the Danish National Space Center, and his colleagues have contended in the study that impact of human activity may be less to cause the global warming than previously thought and the culprit could be cosmic rays impacting the cloud cover.
They build their theory on the premise that cosmic rays help ionize the outer atmosphere, the ions attract water molecules leading to nucleation of small water clusters and the water clusters leads to cloud formation. Fewer that normal cosmic rays lead to fewer than normal clouds and less reflection of sunlight from the Earth. This naturally causes global warming.
The study comes just a week after the U.N. Panel on Climate Change released a report that said human contribution to higher levels of carbon dioxide emissions was responsible for much of global warming.
The scientists are publishing a book outlining the theory and emphasizing that fluctuations in the quantity of cosmic rays hitting the atmosphere directly alter the amount of cloud covering the planet.
Svensmark says Earth is experiencing a natural period of low cloud cover due to fewer cosmic rays entering the atmosphere. This is responsible for much of the global warming that is being experienced.
Scientists say the quantum of cosmic rays reaching the Earth is controlled by magnetic activity of the Sun. This to certain extent clarifies the correlation between sunspots and Earth's climate.
Svensmark says it was long believed that clouds were the results of climate change, but it is now seen that climate change is driven by clouds.
He predicts that researchers will come with analyses showing CO2 is responsible for much less warming than thought and if this is the case the predictions of warming due to human activity will need to be relooked.
Scientists under an international effort are about to carry out an experiment in Geneva to replicate the effect of cosmic rays hitting the atmosphere. This will throw light on the issue whether deep space radiation is causing changes in cloud cover. If this contention is proved correct, climate scientists will have to re-evaluate their favored arguments on the causes of global warming.
