Is something ailing The Register’s Lewis Page ? Despite having access to the text of a recent research paper about the Sun’s recent output, and its short-term impact on surface temperatures on Earth, and having had plenty of time to read plain English reviews of the paper’s findings in everyday language, he still writes it up poorly (in my humble opinion). Could this be due to internal bias, I ask myself ? Or is Lewis Page being wilfully contrarian ? Who can say ?
“Much of recent global warming actually caused by Sun : By Lewis Page : 7th October 2010 : New data indicates that changes in the Sun’s output of energy were a major factor in the global temperature increases seen in recent years. The research will be unwelcome among hardcore green activists, as it downplays the influence of human-driven carbon emissions. As the Sun has shown decreased levels of activity during the past decade, it had been generally thought that it was warming the Earth less, not more. Thus, scientists considered that temperature rises seen in global databases must mean that human-caused greenhouse gas emissions – in particular of CO2 – must be exerting a powerful warming effect. Now, however, boffins working at Imperial College in London (and one in Boulder, Colorado) have analysed detailed sunlight readings taken from 2004 to 2007 by NASA’s Solar Radiation and Climate Experiment (SORCE) satellite. They found that although the Sun was putting out less energy overall than usual, in line with observations showing decreased sunspot activity, it actually emitted more in the key visible-light and near-infrared wavelengths. These shorter wavelength forms of radiated heat penetrate the atmosphere particularly well to heat up the Earth’s surface – just as the same frequencies get in through car windows to heat up its interior. The hot seats and dashboard – in this case the seas, landmasses etc – then radiate their own increased warmth via conduction, convection and longer-wave infrared, which can’t escape the way the shortwave energy came in. This is why the car, and the planet, become so hot. Thus the Sun, though it was unusually calm in the back half of the last decade, was actually warming the planet much more strongly than before…”
Lewis Page is playing up the warming influence of the solar minimum, in my view.
Let’s take a short look at the Abstract of the paper :-
Letter : Nature 467, 696-699 (7 October 2010)
doi:10.1038/nature09426; Published online 6 October 2010
“An influence of solar spectral variations on radiative forcing of climate”
Joanna D. Haigh, Ann R. Winning, Ralf Toumi & Jerald W. Harder
“Abstract : The thermal structure and composition of the atmosphere is determined fundamentally by the incoming solar irradiance. Radiation at ultraviolet wavelengths dissociates atmospheric molecules, initiating chains of chemical reactions—specifically those producing stratospheric ozone—and providing the major source of heating for the middle atmosphere, while radiation at visible and near-infrared wavelengths mainly reaches and warms the lower atmosphere and the Earth’s surface. Thus the spectral composition of solar radiation is crucial in determining atmospheric structure, as well as surface temperature, and it follows that the response of the atmosphere to variations in solar irradiance depends on the spectrum. Daily measurements of the solar spectrum between 0.2 micrometres and 2.4 micrometres, made by the Spectral Irradiance Monitor (SIM) instrument on the Solar Radiation and Climate Experiment (SORCE) satellite since April 2004, have revealed that over this declining phase of the solar cycle there was a four to six times larger decline in ultraviolet than would have been predicted on the basis of our previous understanding. This reduction was partially compensated in the total solar output by an increase in radiation at visible wavelengths. Here we show that these spectral changes appear to have led to a significant decline from 2004 to 2007 in stratospheric ozone below an altitude of 45 km, with an increase above this altitude. Our results, simulated with a radiative-photochemical model, are consistent with contemporaneous measurements of ozone from the Aura-MLS satellite, although the short time period makes precise attribution to solar effects difficult. We also show, using the SIM data, that solar radiative forcing of surface climate is out of phase with solar activity. Currently there is insufficient observational evidence to validate the spectral variations observed by SIM, or to fully characterize other solar cycles, but our findings raise the possibility that the effects of solar variability on temperature throughout the atmosphere may be contrary to current expectations.”
It just doesn’t say what Lewis Page is saying.
Fiona Harvey at the Financial Times seems slightly confused, as she doesn’t appear to have realised about the difference between longer wave and shorter wave radiation, and their different impacts on the different layers of the atmosphere :-
“Sun throws new light on global warming : By Fiona Harvey, Environment Correspondent : Published: October 7 2010 : The sun has been behaving more curiously in the last few years than previously thought, scientists have found, in research that throws new light on global warming. Data from new satellites show that although the sun’s activity – which can be measured in part by observing sunspots – has been at an unusual low, the effect of this has not been to cool the earth, as might have been expected, but to warm it. The research challenges some accepted opinions on the effect of the sun’s activities on the climate, as it suggests that climate models may have slightly over-estimated the sun’s role in warming the earth. Scientists from Imperial College London and the University of Colorado monitored the sun’s activity from 2004-07, a period when its activity was declining. Activity on the sun waxes and wanes over an 11-year cycle, and in the declining phase the overall amount of radiation reaching the earth also declines. That should have meant that the earth would become slightly cooler. But instead, the amount of energy reaching the earth increased. This has led the scientists involved to theorise that, conversely, decreasing solar activity could slightly warm the earth. Joannah Haigh, professor at Imperial and lead author of the study, said: “These results are challenging what we thought we knew about the sun’s effect on our climate. If further studies find the same pattern over a longer period, this could suggest we may have overestimated the sun’s role in warming the planet, rather than underestimating it.” However, the amount of warming involved either way is very small. The research, published on Thursday in the peer-review journal Nature, is complex, and the authors cautioned that there were several potential explanations for their observations. They also warned that as the research had been carried out over a relatively short period, it would be wrong to extrapolate too much from it, and that more study was needed. However, the research is likely to spark further debates in climate circles. The role of the sun has been hotly disputed, with some sceptics claiming that solar activity, measured by sunspots, was the real culprit behind warming temperatures. Prof Haigh said: “This [new research] does not give comfort to climate change sceptics at all – it may suggest we do not know enough about the sun but casts no aspersions on climate models [which] would still be producing the same results without these solar effects.”
Agence France-Presse does better than Fiona :-
“…The amount of energy in the ultraviolet part of the energy spectrum fell, the researchers found…”These results are challenging what we thought we knew about the Sun’s effect on our climate,” said lead author Joanna Haigh, a professor at Imperial College London where she is also a member of the Grantham Institute for Climate change. “However, they only show us a snapshot of the Sun’s activity and its behaviour over the three years of our study could be an anomaly.” Insisting on caution, Haigh said that if the Sun turned out to have a warming effect during the “waning” part of the cycle, it might also turn out to have a cooling effect during the “waxing” part of the cycle. In that case, greenhouse gases would be more to blame than thought for the perceptible rise in global temperatures over the past century. “We cannot jump to any conclusions based on what we have found during this comparatively short period,” Haigh said. “We need to carry out further studies to explore the Sun’s activity, and the patterns that we have uncovered, on longer timescales.”… ”
The situation has not been helped by the write-up in Nature itself, sadly :-
“Published online 6 October 2010 : Nature : doi:10.1038/news.2010.519 : News : Declining solar activity linked to recent warming : The Sun may have caused as much warming as carbon dioxide over three years : Quirin Schiermeier : Waning solar activity between 2004 and 2007 has unexpectedly been linked to a warmer Earth. : An analysis of satellite data challenges the intuitive idea that decreasing solar activity cools Earth, and vice versa. In fact, solar forcing of Earth’s surface climate seems to work the opposite way around — at least during the current Sun cycle…Over the three-year study period, the observed variations in the solar spectrum have caused roughly as much warming of Earth’s surface as have increases in carbon dioxide emissions, says Haigh. But because solar activity is cyclic it should have no long-term impact on climate, regardless of whether similar spectral changes have occurred during previous solar cycles. “If the climate were affected in the long term, the Sun should have produced a notable cooling in the first half of the twentieth century, which we know it didn’t,” she says…”
RealClimate dig their teeth into this and commence chewing :-
“Solar spectral stumper : gavin @ 7 October 2010 : It’s again time for one of those puzzling results that if they turn out to be true, would have some very important implications and upset a lot of relatively established science. The big issue of course is the “if”. The case in question relates to some results published this week in Nature by Joanna Haigh and colleagues. They took some ‘hot off the presses’ satellite data from the SORCE mission (which has been in operation since 2003) and ran it through a relatively complex chemistry/radiation model. These data are measurements of how the solar output varies as a function of wavelength from an instrument called “SIM” (the Spectral Irradiance Monitor). It has been known for some time that over a solar cycle, different wavelengths vary with different amplitudes. For instance, Lean (2000) showed that the UV component varied by about 10 times as much as the total solar irradiance (TSI) did over a cycle. This information (and subsequent analyses) have lent a lot of support to the idea that solar variability changes have an important amplification via changes in stratospheric ozone (Shindell et al (2001), for instance). So it is not a novel finding that the SIM results in the UV don’t look exactly like the TSI. What is a surprise is that for the visible wavelengths, SIM seems to suggest that the irradiance changes are opposite in sign to the changes in the TSI. To be clear, while the TSI has decreased since 2003 (as part of the descent into the current solar minimum), SIM seems to indicate that the UV decreases are much larger than expected, while irradiance in visible bands has actually increased! This is counter to any current understanding of what controls irradiance on solar cycle timescales. What are the implications of such a phenomena? Well, since the UV portion of the solar input is mostly absorbed in stratosphere, it is the visible and near-IR portions of the irradiance change that directly influence the lower atmosphere. Bigger changes in the UV also imply bigger changes in stratospheric ozone and temperature, and this influences the tropospheric radiative forcing too. Indeed, according to Haigh’s calculations, the combination of the two effects means that the net radiative forcing at the tropopause is opposite in sign to the TSI change. So during a solar minimum you would expect a warmer surface!…”
The Guardian has it about right – a gold star and a bonus pint goes to Damian Carrington (and there was I thinking that his only role was to write fluff) :-
“Sun’s role in warming the planet may be overestimated, study finds : The discovery could help explain why Europe can have cold winters while the world as a whole is heating up : Damian Carrington : Wednesday 6 October 2010…Some climate change sceptics have suggested the changes in the sun’s brightness can explain the global warming seen over the past century. But Haigh said: “It does not give comfort to climate sceptics at all.” If the sun warmed the Earth less when it was at the solar maximum, then the reverse was also true, she said: “You can’t have it one way and not the other.” In addition, she said, the warming influence of rising greenhouse gases in the atmosphere, emitted by human activities, was at least 10 times greater than changes in the strength of the sun. Prof Mike Lockwood, a solar physicist at the University of Reading said: “We don’t have any reason at the moment to change our overall view of the contributions of changing solar radiation to climate change, not on a global scale, but there is quite a lot of evidence coming forward that these changes do matter on a regional scale and particularly to us here in Europe.” That is because the sun’s intensity plays a crucial role at mid-latitudes, where the UK sits, by controlling the jet stream winds, which in turn govern weather, he said. Changes to the jet stream are responsible for extremely cold European winters, such as the last one, and also the conditions which caused the volcanic ash cloud from the Eyjafjallajökull volcano to blow southwards and ground flights in April and May…”
The trouble with science communication, is that sometimes scientists don’t communicate very well :-
It appears that in this case, the scientists have communicated exceptionally well and the journalists have been “neutral” about the results.
I have to give Richard Black at the BBC his dues – his write-up is very reasonable and balanced :-
“6 October 2010 : Solar surprise for climate issue : By Richard Black : Environment correspondent, BBC News : The view that the Sun may be driving modern-day climate change has clouded policy discussions
The Sun’s influence on modern-day global warming may have been overestimated, a study suggests…”
I think we should give New Scientist the last word :-
“The sun joins the climate club : Updated 13:05 29 September 2010 by Michael Marshall : Editorial: The sun’s activity has a place in climate science : THE idea that changes in the sun’s activity can influence the climate is making a comeback, after years of scientific vilification, thanks to major advances in our understanding of the atmosphere. The findings do not suggest – as climate sceptics frequently do – that we can blame the rise of global temperatures since the early 20th century on the sun. “There are extravagant claims for the effects of the sun on global climate,” says Giles Harrison, an atmospheric physicist at the University of Reading, UK. “They are not supported.”…”