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PUBLIC RELEASE DATE: 7-Nov-2013
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ShareContact: Michael Bishop
michael.bishop@iop.org
01-179-301-032
Institute of Physics
Changes in solar activity have contributed no more than 10 per cent to global warming in the twentieth century, a new study has found.
The findings, made by Professor Terry Sloan at the University of Lancaster and Professor Sir Arnold Wolfendale at the University of Durham, find that neither changes in the activity of the Sun, nor its impact in blocking cosmic rays, can be a significant contributor to global warming.
The results have been published today, 8 November, in IOP Publishing's journal Environmental Research Letters.
Changes in the amount of energy from the Sun reaching the Earth have previously been proposed as a driver of increasing global temperatures, as has the Sun's ability to block cosmic rays. It has been proposed that cosmic rays may have a role in cooling the Earth by encouraging clouds to form, which subsequently reflect the Sun's rays back into space.
According to this proposal, in periods of high activity the Sun blocks some of the cosmic rays from entering the Earth's atmosphere, so that fewer clouds form and the Earth's surface temperatures rise.
In an attempt to quantify the effect that solar activitywhether directly or through cosmic raysmay have had on global temperatures in the twentieth century, Sloan and Wolfendale compared data on the rate of cosmic rays entering the atmosphere, which can be used as a proxy for solar activity, with the record of global temperatures going back to 1955.
They found a small correlation between cosmic rays and global temperatures occurring every 22 years; however, the changing cosmic ray rate lagged behind the change in temperatures by between one and two years, suggesting that the cause may not be down to cosmic rays and cloud formation, but may be due to the direct effects of the Sun.
By comparing the small oscillations in cosmic ray rate, which was taken from data from two neutron monitors, and temperature with the overall trends in both since 1955, Sloan and Wolfendale found that less than 14 per cent of the global warming seen during this period could be attributable to solar activity.
Furthermore, the researchers reviewed their own previous studies and surveyed the relevant literature to find other evidence of a link between solar activity and increasing global temperatures existing. Their findings indicated that overall, the contribution of changing solar activity, either directly or through cosmic rays, was even less cannot have contributed more than 10 per cent to global warming in the twentieth century.
They concluded that the paleontological evidence, derived from carbon and oxygen isotopes, was "weak and confused" and that a more-up-to-date study linking cosmic rays with low-level cloud cover was flawed because the correlation only occurred in certain regions rather than the entire globe.
Sloan and Wolfendale also discussed the results from the CLOUD experiment at CERN, where researchers are looking at ways in which cosmic rays can ionize, or charge, aerosols in the atmosphere, which can then influence how clouds are formed. They also examined instances where real-world events produced large-scale ionization in the atmosphere.
Events such as the Chernobyl nuclear disaster and nuclear weapons testing would have been expected to have affected aerosol production in the atmosphere, but no such effects could be seen.
Professor Sloan said: "Our paper reviews our work to try and find a connection between cosmic rays and cloud formation with changes in global temperature.
"We conclude that the level of contribution of changing solar activity is less than 10 per cent of the measured global warming observed in the twentieth century. As a result of this and other work, the IPCC state that no robust association between changes in cosmic rays and cloudiness has been identified."
From Friday 8 November, this paper can be downloaded from http://iopscience.iop.org/1748-9326/8/4/045022/article
###
Notes to Editors
Contact
1. For further information, a full draft of the journal paper or contact with one of the researchers, contact IOP Press Officer, Michael Bishop:
Tel: 0117 930 1032
E-mail: michael.bishop@iop.org
For more information on how to use the embargoed material above, please refer to our embargo policy.
IOP Publishing Journalist Area
2. The IOP Publishing Journalist Area gives journalists access to embargoed press releases, advanced copies of papers, supplementary images and videos. In addition to this, a weekly news digest is uploaded into the Journalist Area every Friday, highlighting a selection of newsworthy papers set to be published in the following week.
Login details also give free access to IOPscience, IOP Publishing's journal platform.
To apply for a free subscription to this service, please email Michael Bishop, IOP Press Officer, michael.bishop@iop.org, with your name, organisation, address and a preferred username.
Cosmic rays, solar activity and the climate
3. The published version of the paper 'Cosmic rays, solar activity and the climate' (T Sloan and A W Wolfendale 2013 Environ. Res. Lett. 8 045022) will be freely available online from Friday 8 November. It will be available at http://iopscience.iop.org/1748-9326/8/4/045022/article
Environmental Research Letters
4. Environmental Research Letters is an open access journal that covers all of environmental science, providing a coherent and integrated approach including research articles, perspectives and editorials.
IOP Publishing
5. IOP Publishing provides a range of journals, magazines, websites and services that enable researchers and research organisations to reach the widest possible audience for their research.
We combine the culture of a learned society with global reach and highly efficient and effective publishing systems and processes. With offices in the UK, US, Germany, China and Japan, and staff in many other locations including Mexico and Russia, we serve researchers in the physical and related sciences in all parts of the world.
IOP Publishing is a wholly owned subsidiary of the Institute of Physics. The Institute is a leading scientific society promoting physics and bringing physicists together for the benefit of all. Any profits generated by IOP Publishing are used by the Institute to support science and scientists in both the developed and developing world. Go to ioppublishing.org.
The Institute of Physics
6. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application. We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications. Go to http://www.iop.org.
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Share]
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
PUBLIC RELEASE DATE: 7-Nov-2013
[
]
ShareContact: Michael Bishop
michael.bishop@iop.org
01-179-301-032
Institute of Physics
Changes in solar activity have contributed no more than 10 per cent to global warming in the twentieth century, a new study has found.
The findings, made by Professor Terry Sloan at the University of Lancaster and Professor Sir Arnold Wolfendale at the University of Durham, find that neither changes in the activity of the Sun, nor its impact in blocking cosmic rays, can be a significant contributor to global warming.
The results have been published today, 8 November, in IOP Publishing's journal Environmental Research Letters.
Changes in the amount of energy from the Sun reaching the Earth have previously been proposed as a driver of increasing global temperatures, as has the Sun's ability to block cosmic rays. It has been proposed that cosmic rays may have a role in cooling the Earth by encouraging clouds to form, which subsequently reflect the Sun's rays back into space.
According to this proposal, in periods of high activity the Sun blocks some of the cosmic rays from entering the Earth's atmosphere, so that fewer clouds form and the Earth's surface temperatures rise.
In an attempt to quantify the effect that solar activitywhether directly or through cosmic raysmay have had on global temperatures in the twentieth century, Sloan and Wolfendale compared data on the rate of cosmic rays entering the atmosphere, which can be used as a proxy for solar activity, with the record of global temperatures going back to 1955.
They found a small correlation between cosmic rays and global temperatures occurring every 22 years; however, the changing cosmic ray rate lagged behind the change in temperatures by between one and two years, suggesting that the cause may not be down to cosmic rays and cloud formation, but may be due to the direct effects of the Sun.
By comparing the small oscillations in cosmic ray rate, which was taken from data from two neutron monitors, and temperature with the overall trends in both since 1955, Sloan and Wolfendale found that less than 14 per cent of the global warming seen during this period could be attributable to solar activity.
Furthermore, the researchers reviewed their own previous studies and surveyed the relevant literature to find other evidence of a link between solar activity and increasing global temperatures existing. Their findings indicated that overall, the contribution of changing solar activity, either directly or through cosmic rays, was even less cannot have contributed more than 10 per cent to global warming in the twentieth century.
They concluded that the paleontological evidence, derived from carbon and oxygen isotopes, was "weak and confused" and that a more-up-to-date study linking cosmic rays with low-level cloud cover was flawed because the correlation only occurred in certain regions rather than the entire globe.
Sloan and Wolfendale also discussed the results from the CLOUD experiment at CERN, where researchers are looking at ways in which cosmic rays can ionize, or charge, aerosols in the atmosphere, which can then influence how clouds are formed. They also examined instances where real-world events produced large-scale ionization in the atmosphere.
Events such as the Chernobyl nuclear disaster and nuclear weapons testing would have been expected to have affected aerosol production in the atmosphere, but no such effects could be seen.
Professor Sloan said: "Our paper reviews our work to try and find a connection between cosmic rays and cloud formation with changes in global temperature.
"We conclude that the level of contribution of changing solar activity is less than 10 per cent of the measured global warming observed in the twentieth century. As a result of this and other work, the IPCC state that no robust association between changes in cosmic rays and cloudiness has been identified."
From Friday 8 November, this paper can be downloaded from http://iopscience.iop.org/1748-9326/8/4/045022/article
###
Notes to Editors
Contact
1. For further information, a full draft of the journal paper or contact with one of the researchers, contact IOP Press Officer, Michael Bishop:
Tel: 0117 930 1032
E-mail: michael.bishop@iop.org
For more information on how to use the embargoed material above, please refer to our embargo policy.
IOP Publishing Journalist Area
2. The IOP Publishing Journalist Area gives journalists access to embargoed press releases, advanced copies of papers, supplementary images and videos. In addition to this, a weekly news digest is uploaded into the Journalist Area every Friday, highlighting a selection of newsworthy papers set to be published in the following week.
Login details also give free access to IOPscience, IOP Publishing's journal platform.
To apply for a free subscription to this service, please email Michael Bishop, IOP Press Officer, michael.bishop@iop.org, with your name, organisation, address and a preferred username.
Cosmic rays, solar activity and the climate
3. The published version of the paper 'Cosmic rays, solar activity and the climate' (T Sloan and A W Wolfendale 2013 Environ. Res. Lett. 8 045022) will be freely available online from Friday 8 November. It will be available at http://iopscience.iop.org/1748-9326/8/4/045022/article
Environmental Research Letters
4. Environmental Research Letters is an open access journal that covers all of environmental science, providing a coherent and integrated approach including research articles, perspectives and editorials.
IOP Publishing
5. IOP Publishing provides a range of journals, magazines, websites and services that enable researchers and research organisations to reach the widest possible audience for their research.
We combine the culture of a learned society with global reach and highly efficient and effective publishing systems and processes. With offices in the UK, US, Germany, China and Japan, and staff in many other locations including Mexico and Russia, we serve researchers in the physical and related sciences in all parts of the world.
IOP Publishing is a wholly owned subsidiary of the Institute of Physics. The Institute is a leading scientific society promoting physics and bringing physicists together for the benefit of all. Any profits generated by IOP Publishing are used by the Institute to support science and scientists in both the developed and developing world. Go to ioppublishing.org.
The Institute of Physics
6. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application. We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications. Go to http://www.iop.org.
[
Share]
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Source: http://www.eurekalert.org/pub_releases/2013-11/iop-sap110613.php
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