This article is from the source 'bbc' and was first published or seen on . It will not be checked again for changes.
You can find the current article at its original source at http://news.bbc.co.uk/go/rss/-/1/hi/sci/tech/7327393.stm
The article has changed 3 times. There is an RSS feed of changes available.
| Version 1 | Version 2 |
|---|---|
| 'No Sun link' to climate change | 'No Sun link' to climate change |
| (4 days later) | |
| Scientists have produced further compelling evidence showing that modern-day climate change is not caused by changes in the Sun's activity. | Scientists have produced further compelling evidence showing that modern-day climate change is not caused by changes in the Sun's activity. |
| The research contradicts a favoured theory of climate "sceptics", that changes in cosmic rays coming to Earth determine cloudiness and temperature. | The research contradicts a favoured theory of climate "sceptics", that changes in cosmic rays coming to Earth determine cloudiness and temperature. |
| The idea is that variations in solar activity affect cosmic ray intensity. | The idea is that variations in solar activity affect cosmic ray intensity. |
| But UK scientists found there has been no significant link between cosmic rays and cloudiness in the last 20 years. | |
| Presenting their findings in the Institute of Physics journal, Environmental Research Letters, the University of Lancaster team explain that they used three different ways to search for a correlation, and found virtually none. | |
| The IPCC has got it right, so we had better carry on trying to cut carbon emissions Terry Sloan | The IPCC has got it right, so we had better carry on trying to cut carbon emissions Terry Sloan |
| This is the latest piece of evidence which at the very least puts the cosmic ray theory, developed by Danish scientist Henrik Svensmark at the Danish National Space Center (DNSC), under very heavy pressure. | This is the latest piece of evidence which at the very least puts the cosmic ray theory, developed by Danish scientist Henrik Svensmark at the Danish National Space Center (DNSC), under very heavy pressure. |
| Dr Svensmark's idea formed a centrepiece of the controversial documentary The Great Global Warming Swindle. | Dr Svensmark's idea formed a centrepiece of the controversial documentary The Great Global Warming Swindle. |
| Wrong path | Wrong path |
| "We started on this game because of Svensmark's work," said Terry Sloan from Lancaster University. | "We started on this game because of Svensmark's work," said Terry Sloan from Lancaster University. |
| Terry Sloan has simply failed to understand how cosmic rays work on clouds Henrik Svensmark | Terry Sloan has simply failed to understand how cosmic rays work on clouds Henrik Svensmark |
| "If he is right, then we are going down the wrong path of taking all these expensive measures to cut carbon emissions; if he is right, we could carry on with carbon emissions as normal." | "If he is right, then we are going down the wrong path of taking all these expensive measures to cut carbon emissions; if he is right, we could carry on with carbon emissions as normal." |
| Cosmic rays are deflected away from Earth by our planet's magnetic field, and by the solar wind - streams of electrically charged particles coming from the Sun. | Cosmic rays are deflected away from Earth by our planet's magnetic field, and by the solar wind - streams of electrically charged particles coming from the Sun. |
| The Svensmark hypothesis is that when the solar wind is weak, more cosmic rays penetrate to Earth. | The Svensmark hypothesis is that when the solar wind is weak, more cosmic rays penetrate to Earth. |
| That creates more charged particles in the atmosphere, which in turn induces more clouds to form, cooling the climate. | That creates more charged particles in the atmosphere, which in turn induces more clouds to form, cooling the climate. |
| The planet warms up when the Sun's output is strong. | The planet warms up when the Sun's output is strong. |
| Professor Sloan's team investigated the link by looking for periods in time and for places on the Earth which had documented weak or strong cosmic ray arrivals, and seeing if that affected the cloudiness observed in those locations or at those times. | Professor Sloan's team investigated the link by looking for periods in time and for places on the Earth which had documented weak or strong cosmic ray arrivals, and seeing if that affected the cloudiness observed in those locations or at those times. |
| FEELING THE HEATThree theories on how the Sun could be causing climate changeIn graphics | FEELING THE HEATThree theories on how the Sun could be causing climate changeIn graphics |
| "For example; sometimes the Sun 'burps' - it throws out a huge burst of charged particles," he explained to BBC News. | "For example; sometimes the Sun 'burps' - it throws out a huge burst of charged particles," he explained to BBC News. |
| "So we looked to see whether cloud cover increased after one of these bursts of rays from the Sun; we saw nothing." | "So we looked to see whether cloud cover increased after one of these bursts of rays from the Sun; we saw nothing." |
| Over the course of one of the Sun's natural 11-year cycles, there was a weak correlation between cosmic ray intensity and cloud cover - but cosmic ray variability could at the very most explain only a quarter of the changes in cloudiness. | Over the course of one of the Sun's natural 11-year cycles, there was a weak correlation between cosmic ray intensity and cloud cover - but cosmic ray variability could at the very most explain only a quarter of the changes in cloudiness. |
| And for the following cycle, no correlation was found. | And for the following cycle, no correlation was found. |
| Limited effect | Limited effect |
| Dr Svensmark himself was unimpressed by the findings. | Dr Svensmark himself was unimpressed by the findings. |
| "Terry Sloan has simply failed to understand how cosmic rays work on clouds," he told BBC News. | "Terry Sloan has simply failed to understand how cosmic rays work on clouds," he told BBC News. |
| "He predicts much bigger effects than we would do, as between the equator and the poles, and after solar eruptions; then, because he doesn't see those big effects, he says our story is wrong, when in fact we have plenty of evidence to support it." | "He predicts much bigger effects than we would do, as between the equator and the poles, and after solar eruptions; then, because he doesn't see those big effects, he says our story is wrong, when in fact we have plenty of evidence to support it." |
| But another researcher who has worked on the issue, Giles Harrison from Reading University, said the work was important "as it provides an upper limit on the cosmic ray-cloud effect in global satellite cloud data". | But another researcher who has worked on the issue, Giles Harrison from Reading University, said the work was important "as it provides an upper limit on the cosmic ray-cloud effect in global satellite cloud data". |
| Climate change: No Sun link A cosmic climate connection? | Climate change: No Sun link A cosmic climate connection? |
| Dr Harrison's own research, looking at the UK only, has also suggested that cosmic rays make only a very weak contribution to cloud formation. | Dr Harrison's own research, looking at the UK only, has also suggested that cosmic rays make only a very weak contribution to cloud formation. |
| The Svensmark hypothesis has also been attacked in recent months by Mike Lockwood from the UK's Rutherford-Appleton Laboratory. | The Svensmark hypothesis has also been attacked in recent months by Mike Lockwood from the UK's Rutherford-Appleton Laboratory. |
| He showed that over the last 20 years, solar activity has been slowly declining, which should have led to a drop in global temperatures if the theory was correct. | He showed that over the last 20 years, solar activity has been slowly declining, which should have led to a drop in global temperatures if the theory was correct. |
| The Intergovernmental Panel on Climate Change (IPCC), in its vast assessment of climate science last year, concluded that since temperatures began rising rapidly in the 1970s, the contribution of humankind's greenhouse gas emissions has outweighed that of solar variability by a factor of about 13 to one. | The Intergovernmental Panel on Climate Change (IPCC), in its vast assessment of climate science last year, concluded that since temperatures began rising rapidly in the 1970s, the contribution of humankind's greenhouse gas emissions has outweighed that of solar variability by a factor of about 13 to one. |
| According to Terry Sloan, the message coming from his research is simple. | According to Terry Sloan, the message coming from his research is simple. |
| "We tried to corroborate Svensmark's hypothesis, but we could not; as far as we can see, he has no reason to challenge the IPCC - the IPCC has got it right. | "We tried to corroborate Svensmark's hypothesis, but we could not; as far as we can see, he has no reason to challenge the IPCC - the IPCC has got it right. |
| "So we had better carry on trying to cut carbon emissions." | "So we had better carry on trying to cut carbon emissions." |
| Richard.Black-INTERNET@bbc.co.uk | Richard.Black-INTERNET@bbc.co.uk |