London, July 18: Global warming has finally been explained: the Earth is getting hotter because the Sun is burning more brightly than at any time during the past 1,000 years, according to new research.
A study by Swiss and German scientists suggests that increasing radiation from the Sun is responsible for recent global climate changes.
Sami Solanki, the director of the renowned Max Planck Institute for Solar System Research in Gottingen, Germany, who led the research, said: “The Sun has been at its strongest over the past 60 years and may now be affecting global temperatures.
“The Sun is in a changed state. It is brighter than it was a few hundred years ago and this brightening started relatively recently — in the last 100 to 150 years.”
Solanki said that the brighter Sun and higher levels of “greenhouse gases”, such as carbon dioxide, both contributed to the change in the Earth’s temperature but it was impossible to say which had the greater impact.
Average global temperatures have increased by about 0.2 degree Celsius over the past 20 years and are widely believed to be responsible for new extremes in weather patterns. After pressure from environmentalists, politicians agreed the Kyoto Protocol in 1997, promising to limit greenhouse gas emissions between 2008 and 2012.
Most scientists agree that greenhouse gases from fossil fuels have contributed to the warming of the planet in the past few decades but have questioned whether a brighter Sun is also responsible for rising temperatures.
To determine the Sun’s role in global warming, Solanki’s team measured magnetic zones on the Sun’s surface known as sunspots, which are believed to intensify the Sun’s energy output.
It studied sunspot data going back several hundred years. They found that a dearth of sunspots signalled a cold period — which could last up to 50 years — but that over the past century their numbers had increased as the Earth’s climate grew steadily warmer. The scientists also compared data from ice samples collected during an expedition to Greenland in 1991.
Solanki says that the increased solar brightness over the past 20 years has not been enough to cause the observed climate changes but believes that the impact of more intense sunshine on the ozone layer and on cloud cover could be affecting the climate more than the sunlight itself.
Gareth Jones, a climate researcher at the Met Office, said that Solanki’s findings were inconclusive because the study had not incorporated other potential climate change factors.
The research adds weight to the views of David Bellamy, the conservationist. “Global warming — at least the modern nightmare version — is a myth,” he said.
“I am sure of it and so are a growing number of scientists. But what is really worrying is that the world’s politicians and policy-makers are not.
“Instead, they have an unshakeable faith in what has, unfortunately, become one of the central credos of the environmental movement: humans burn fossil fuels, which release increased levels of carbon dioxide — the principal so-called greenhouse gas — into the atmosphere, causing the atmosphere to heat up. They say this is global warming: I say this is poppycock.”