Solar radiation study offers clues on 20th century global warming wobbles

Aug 26, 2013 by Merran Reed & Sunanda Creagh, The Conversation
The new paper shows that surface incident solar radiation (Rs) over land globally peaked in the 1930s, substantially decreased from the 1940s to the 1970s, and changed little after that. Credit: Jong Soo(Peter) Lee

The amount of solar radiation passing through Earth's atmosphere and reaching the ground globally peaked in the 1930s, substantially decreased from the 1940s to the 1970s, and changed little after that, a new study has found.

The study, published in the journal Proceedings of the National Academy of Sciences, found that "neither the rapid increase in temperature from the 1970s through the 1990s nor the slowdown of in the early 21st century appear to be significantly related to changes of Rs ( reaching the Earth's surface)".

The new finding may help explain variations in warming during the 20th century. The authors showed that, while aerosols and clouds did play some role in , they did not have a major effect on global mean land temperatures after 1985.

The authors, Kaicun Wang from Beijing Normal University and Robert E. Dickinson from the University of Texas at Austin, compiled a set of daily temperatures from the 1900s and through to 2010.

They analysed the relationship between the amount of solar radiation reaching the Earth and diurnal temperature range (the daily temperature variations that occur as day turns into night).

The authors of the study said that "the overall increase of global temperature over the last century has been largely attributable to the increase of . Less well understood are the reasons for the variability of this increase on a decadal time scale… However, do not appear to be significantly affected by changing Rs (solar radiation reaching the Earth's surface)."

Wobbles in warming

Steve Sherwood, Director of the Climate Change Research Centre at the University of New South Wales, said the new paper was not really about whether the sun drives climate change.

"We already know from direct observations of the power coming from the sun that it has contributed nothing to global warming since 1979, though it probably made a small contribution to warming early in the 20th century," said Professor Sherwood, who was not involved in the study.

"What this paper is really about is trying to explain the wobbles along the way in warming during the 20th century, and in particular the hiatus from about 1940 to 1970 in global warming, which was followed by strong warming thereafter. There has been a long debate as to whether such wobbles have been due to natural variations in ocean heat uptake, or to variations in aerosols (or clouds)," he said.

"This paper shows that aerosols and clouds did play some role but have never altered the global-mean land temperature by more than 0.1 to 0.2 degrees, while its overall warming has been over 1 degree."

John Cook, Climate Communication Research Fellow at the University of Queensland, said there was growing evidence that solar activity has made little to no contribution to over recent decades.

"In fact, several recent studies have found the sun and climate have been moving in opposite directions, with the sun having a slight cooling effect," said Cook, who was not involved in the new study.

Explore further: Mexico's Volcano of Fire blows huge ash cloud

More information: "Contribution of solar radiation to decadal temperature variability over land," www.pnas.org/cgi/doi/10.1073/pnas.1311433110

Related Stories

Detailed analysis shows clouds' effects on daily temperature

Aug 14, 2013

Clouds reflect some incoming sunlight, tending to cool Earth's surface, but they also trap some heat leaving Earth's surface, causing warming. These effects, known as cloud radiative forcing, play a key role in temperature ...

Dire outlook despite global warming 'pause': study

May 19, 2013

A global warming "pause" over the past decade may invalidate the harshest climate change predictions for the next 50 to 100 years, a study said Sunday—though levels remain in the danger zone.

Radio waves carry news of climate change

Jul 30, 2013

The ionosphere, one of the regions of the upper atmosphere, plays an important role in global communications. Ionized by solar radiation, this electricity-rich region is used for the transmission of long ...

Recommended for you

Erosion may trigger earthquakes

Nov 21, 2014

Researchers from laboratories at Géosciences Rennes (CNRS/Université de Rennes 1), Géosciences Montpellier (CNRS/Université de Montpellier 2) and Institut de Physique du Globe de Paris (CNRS/IPGP/Université Paris Diderot), ...

Strong undersea earthquake hits eastern Indonesia

Nov 21, 2014

A strong undersea earthquake hit off the coast of eastern Indonesia on Friday, but there were no immediate reports of injuries or serious damage and officials said it was unlikely to trigger a tsunami.

User comments : 29

Adjust slider to filter visible comments by rank

Display comments: newest first

VENDItardE
1.7 / 5 (30) Aug 26, 2013
what a crock of sh*t.....'nuff said.
runrig
3.8 / 5 (17) Aug 26, 2013
what a crock of sh*t.....'nuff said.


Now we would all be interested in your considered rebuttal of this, but I suspect there will be none coming, as you plainly have had your denialist nerve twitch - and of course that needs no such trivial thing as science to stop it.
djr
4.1 / 5 (17) Aug 26, 2013
"Now we would all be interested in your considered rebuttal of this.."

I would not be interested in anything VENDItardE had to say. VENDI has made it consistently clear that VENDI has nothing of any substance to offer to a discussion of a scientific issue - just another troll wasting everyone's time.
NikFromNYC
1.9 / 5 (23) Aug 26, 2013
Full text: www.pnas.org/cont...full.pdf
Supplement: http://www.pnas.o...33SI.pdf

This is an important paper that will now be possibly subjected to skeptical community analysis, especially by statistics wonks who delve into each data tweak with full access to command line program analysis software. None of the usual wild propaganda has been yet thrown into the mix above either that I might quickly debunk.

The study is a one trick pony which attempts to make up for the sad lack of solar brightness data by using the temperature record itself as a proxy for it, namely how much the daytime and thus sunlit temperature diverts from the nighttime and thus sun lacking one. Over the time and in areas where there does happen to be good brightness data they do establish a correlation to calibrate their proxy.
NikFromNYC
1.8 / 5 (25) Aug 26, 2013
Right in the middle of their claim that sunlight brightness reaching land no longer correlates with temperature and thus the greenhouse effect takes over, there is a massive dying off of the number of available temperature stations, shown in their Fig. 53:
http://s10.postim...Loss.png

This issue has been called "The Great Dying Of Thermometers" by skeptics and is pictured here on the EPA web site due to skeptical comments on their endangerment finding concerning carbon dioxide as a "pollutant":
http://www.epa.go...e006.gif

Reference: http://www.epa.go...me1.html

NikFromNYC
1.7 / 5 (24) Aug 26, 2013
Their data also suffers from an unprecedented major change in instrumentation exactly during their claimed divergence from sunlight brightness correlation:

"The unadjusted DTR (dashed lines) have a spurious stronger decreasing trend, resulting from changes in the time of observation from the mid–twentieth century onward (introduce spurious cooling to both maximum and minimum temperatures) and conversion from liquid in glass to electronic resistance thermometers, primarily during the mid 1980s (introduce spurious cooling in maximum and warming in minimum)."
NikFromNYC
1.7 / 5 (24) Aug 26, 2013
It's rather confusing that the actual temperature average that they use for their final claim, though only over land, forms a perfect hockey stick instead of the well known double bump, seen in Fig. 6B:
http://s21.postim...Land.png

This contrasts strongly with the NOAA's own plot of the global average temperature that shows near perfect precedent between former and contemporary variations, re-plotted here:
http://s22.postim...te_B.gif

They reference an earlier work which leads to NASA GISS and Gavin Schmidt, who is seen here in a hilarious two minute clip from Fox News, *literally* skirting around real debate as he offers a mere argument from ignorance to support AGW claims while *failing* to mention that the ocean currents that dominate climate heat dynamics and fluctuations is inherently chaotic and thus by its very nature unpredictable:
http://tinypic.co...&s=5

Maybe he was worried that Roy would bring that up?
gregor1
1 / 5 (19) Aug 27, 2013
Nik. I don't have time right now to help much now but this may be of use. There have been a number of papers recently documenting the decline in cloud cover ( and thus more sunlight being reflected out ) during the last 50 or so years of the 20th cent. It has been suggested that this decline explains the warming. Here's onehttp://www.ann-ge...12.html, and there are more on Hocky schtick http://hockeyscht...sed.html
VendicarE
2.7 / 5 (11) Aug 27, 2013
"what a crock of sh*t." - VendiTardE AKA ParkerTard

ParkerTard like virtually all of his fellow Republicans, see science as an enemy to their Conservative ideology.

He is right.

Truth is poison to Republicans.
VendicarE
2.9 / 5 (10) Aug 27, 2013
NikkieTard provides the link...

http://www.pnas.o...full.pdf

As evidence that changes in solar output alter the climate.

In fact the article he links to finds a correlation between daily temperatures and variations in solar output over the day.

Now, was NikkieTard trying to purposely misrepresent the result of the study, or is he just too stupid to understand the article?

Both perhaps.

VendicarE
2.9 / 5 (12) Aug 27, 2013
"This issue has been called "The Great Dying Of Thermometers" by skeptics" - NikkieTard

What NikkieTard doesn't want people to know is that the same 70's temperature increase shown in the graphic is even more pronounced when the number of thermometers is held constant.

Poor NikkieTard. He needs to stop eating at the Republican Diner of Ignorance.
aroc91
5 / 5 (4) Aug 27, 2013
what a crock of sh*t.....'nuff said.


I'm glad you censored yourself. I would have been extremely offended if that "i" weren't replaced by an asterisk.
runrig
4.2 / 5 (6) Aug 27, 2013
"Now we would all be interested in your considered rebuttal of this.."

I would not be interested in anything VENDItardE had to say. VENDI has made it consistently clear that VENDI has nothing of any substance to offer to a discussion of a scientific issue - just another troll wasting everyone's time.


djr: it's called irony.
runrig
4.2 / 5 (6) Aug 27, 2013
....as he offers a mere argument from ignorance to support AGW claims while *failing* to mention that the ocean currents that dominate climate heat dynamics and fluctuations is inherently chaotic and thus by its very nature unpredictable:


Two things. First have you heard the one about the speck of sawdust, the plank and the eye?
Ocean currents are not "inherently" chaotic anymore than weather or climate is ...... up to a certain point (note - I said up to a CERTAIN point ). And that point hasn't been found yet. Just as NWP in Meteorology has made a 5 day forecast as accurate as a 2 day one was 30 years ago.
Oh, and it would be on Fox News wouldn't it? That fount of rational, unbiased thinking/reporting.
djr
4.3 / 5 (7) Aug 27, 2013
djr: it's called irony.

I know - I know......
Jim Steele
1.5 / 5 (15) Aug 27, 2013
Seeking linear correlations with solar input fails to account for how oceans mediate the absorption and ventilation of solar heat. The upper 10 feet of the ocean surface contains more heat than the entire atmopshere. Dr Kevin Trenberth now argues that the reason increasing CO2 does not correlate with the 15 year halt in the global average temperature is because oceans are absorbing CO2's presumed contribution. The Pacific Decadal Ocillation alternates between 20 to 30 year periods of heat absorption & more la NIna then 20-30 year periods of more El Ninos & heat ventilation. However this mechanism also applies to solar input. The Pacific Ocean was absorbing heat between 1946 and 1976. Peak solar activity occured in the 40s and 50s. As the oceans ventilated that heat in the 80s and 90s temperatures rose despite lower solar activity. The oceans are now in a heat absorbing mode, but solar activity is even lower. If solar is driving warming, the next ventilation will not warm the earth.
runrig
3 / 5 (3) Aug 28, 2013
Jim:
Even though from a skeptic - I can buy that.
However...
"If solar is driving warming, the next ventilation will not warm the earth."
Would read better as...
If solar is not driving warming, then the next ventilation will warm the Earth.
It will. As It must do and has done historically. An El Nino significantly warms the global atmosphere, and the current hiatus will end.
Jim Steele
1.3 / 5 (14) Aug 28, 2013
@runrig "If solar is not driving warming, then the next ventilation will warm the Earth."

Either phrasing works as both posit the same testable hypothesis. These decadal oscillations are the only way to truly test the CO2 hypothesis. You and Jim Hansen are convinced of CO2's power. But a word of caution. Hansen believed he super El Nino of 1997-98 was ventilating stored heated derived from CO2 and so predicted an even bigger El Nino in 2006. That prediction failed to occur. According to Trenberth CO2 caused warming increases atmospheric warming that increased water vapor. He also noted the atmospheric water vapor correlated with El Nino. With the Pacific Decadal Oscillation in a cool phase and fewer El Ninos atmospheric water vapor has declined slightly, suggesting it is natural variation of the El Nino cycles that mediate solar heat absorption and ventilation that drive climate change. The next 20 years will tell. If the hiatus continues the political fallout will be unprecedented.
runrig
3 / 5 (3) Aug 28, 2013
With the Pacific Decadal Oscillation in a cool phase and fewer El Ninos atmospheric water vapor has declined slightly, suggesting it is natural variation of the El Nino cycles that mediate solar heat absorption and ventilation that drive climate change. The next 20 years will tell. If the hiatus continues the political fallout will be unprecedented.

Jim:
it's both. The natural cycle of ENSO/PDO and the overlying CO2 AGW driver. If otherwise we would have had a decline in global mean temperature, especially considering the recent low solar. What we have had is still (just) a continuing increase.
Jim Steele
1.5 / 5 (15) Aug 28, 2013
@runrig "What we have had is still (just) a continuing increase."

Actually if we use the global average there has been NO increase in 15 years by all accounts. If we use the upper 300 meters of the ocean measured by Argo, there has been a slight decrease since 2003 (read Xue 2012) . Only Trenberth and associates claim warming continues by suggesting at ocean depths of 700 meter and below there is a slight warming. However the data for those depths are the least reliable of all and the mechanism of heat transport is unknown.
ryggesogn2
1.3 / 5 (16) Aug 28, 2013
"This paper uses long comprehensive datasets for diurnal temperature range to establish what has been the contribution of Rs to decadal temperature variability. "
Nothing is said about dew points.
Diurnal temperature range depends upon could cover and relative humidity.
Diurnal temperature ranges greater than 20K occur in deserts and less than 5K in humid or cloud covered regions.
How was solar irradiance measured in the 30s?
runrig
4.5 / 5 (2) Aug 29, 2013
Actually if we use the global average there has been NO increase in 15 years by all accounts.


Jim: That depends on whether you count in 1998 with the BIG El Nino. If not then a small increase...
http://www.woodfo....5/trend

Let's agree a hiatus.
runrig
4.5 / 5 (2) Aug 29, 2013
"This paper uses long comprehensive datasets for diurnal temperature range to establish what has been the contribution of Rs to decadal temperature variability. "
Nothing is said about dew points.
Diurnal temperature range depends upon could cover and relative humidity.
Diurnal temperature ranges greater than 20K occur in deserts and less than 5K in humid or cloud covered regions.
How was solar irradiance measured in the 30s?


The methodology is all explained in the paper. DTR is used as a proxy for Solar irradiance.
ryggesogn2
1 / 5 (14) Aug 29, 2013
"This paper uses long comprehensive datasets for diurnal temperature range to establish what has been the contribution of Rs to decadal temperature variability. "
Nothing is said about dew points.
Diurnal temperature range depends upon could cover and relative humidity.
Diurnal temperature ranges greater than 20K occur in deserts and less than 5K in humid or cloud covered regions.
How was solar irradiance measured in the 30s?


The methodology is all explained in the paper. DTR is used as a proxy for Solar irradiance.

Of course it is.
runrig
4.5 / 5 (2) Aug 29, 2013
"This paper uses long comprehensive datasets for diurnal temperature range to establish what has been the contribution of Rs to decadal temperature variability. "
Nothing is said about dew points.
Diurnal temperature range depends upon could cover and relative humidity.
Diurnal temperature ranges greater than 20K occur in deserts and less than 5K in humid or cloud covered regions.
How was solar irradiance measured in the 30s?


The methodology is all explained in the paper. DTR is used as a proxy for Solar irradiance.

Of course it is.


Then why ask?
Jim Steele
1.3 / 5 (14) Aug 30, 2013
@runrig "The methodology is all explained in the paper. DTR is used as a proxy for Solar irradiance."

Using the DTR, Daily Temperature Range, is a huge flaw. Changes in surface conditions alter minimum temperatures far more than maximum. Minimum measures the air just before dawn when it is more often still and inversions are in place. Waste heat and materials that hold the heat longer skew the minimum 2 to 3 times more than maximum. The maximum temperature would be a better proxy. Maximum temperatures measure mid day heat when convection has mixed a tall column of air. Many maximum temperatures and tree ring temperatures match the change in sunspot activity peaking in the 40s and 50s.
ryggesogn2
1 / 5 (13) Aug 31, 2013
If the DTR data is readily available, I would like to see it plotted as a function of dew point over the time span.
If CO2 absorbs so much heat, then the DTR should decrease in low dew point climates as CO2 increases.
runrig
5 / 5 (1) Aug 31, 2013
Jim:
Yes, but they do say "use of DTR for estimates of variability of Rs and its impact on Ta should be confined to decadal timescale and regional space scale".
Averaged out, a signal of heat input (solar) would emerge. There is as much likelihood of an air-mass change to affect either max or min.. Actually in many instances Tmin occurs just after dawn (radiation conditions) and when read at 0900 local it would be recorded. If read at 6am it may well be missed (hence the local observation time is important). In winter-time, then use of Tmin would indeed be more subject to error, given longer nights and low insolation perhaps precluding breakdown of surface inversions - but I see no objection when using Boreal warm season data. The results show a more marked drop off of Rs then - perhaps showing better correlation because of this.
runrig
5 / 5 (1) Aug 31, 2013
If the DTR data is readily available, I would like to see it plotted as a function of dew point over the time span.
If CO2 absorbs so much heat, then the DTR should decrease in low dew point climates as CO2 increases.


A lower DP would generally mean a higher DTR - so yes, you would see a direct correlation. DP and therefor air-mass characteristics have to be overridden else a change in DTR would not reveal Rs (unless you zero-in to regional climates, which would introduce other errors) - that is what the large time/spacing does.
CO2 does not just "absorb" heat - it absorbs then re-emits, so a fraction of outgoing IR comes back to the surface - that would lead to a higher max ... but also a higher min - leading to a similar DTR. This study is global or at least hemispheric and seeks to average out such factors.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.