By Richard Black
Environment correspondent, BBC News website
Cloud cover affects temperature - but what determines cloud cover?
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 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 Ins ute 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.
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 do entary The Great Global Warming Swindle.
Wrong path
"We started on this game because of Svensmark's work," said Terry Sloan from Lancaster University.
"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.
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.
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 do ented weak or strong cosmic ray arrivals, and seeing if that affected the cloudiness observed in those locations or at those times.
FEELING THE HEAT
Three theories on how the Sun could be causing climate change
In graphics
"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."
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.
Limited effect
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.
"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".
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.
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.
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.
"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."
I find it strange that the hottest year on record was 1934 (was 1998 before NASA fixed their mistake) and only four of the top 10 warmest years occurred since 1953.
Also, the years 2000, 2002, 2003, and 2004 were cooler than the year 1900.
What's up with that?
Is that in the U.S. or globally?
I believe they are U.S. temps, but I still find it interesting.
So, if you have a theory as a skeptic, ACTUAL data is going to be gathered and measured to see if your theory holds water. Otherwise, man made global warming is gospel, and measurements are irrelevant - it's happening.
Got it.
IPCC exists why? (To study man made climate change)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.
If they find out that Manmade global warming is NOT significant what happens to them and their funding?
Definitely non-partisan and unbiased THAT group.
These ing scientist and experts get on my nerves. The History Channel just had a show on called A Global Warning which was all about how sun spot activity on the sun affects our weather. They had all kinds of scientists and data which proved up their thesis. Most of it was centered on the lack of sunspots from circa 1600 to early 1715 which caused the Little Ice Age in Europe. Apparently if there few or no sunspots the sun gets cooler and so do we. Converesly, the more sunspots the hotter the sun and the Earth.
So who to beleive?
Hey guys, get this argument right...
COSMIC RAYS!
Dammit... Get the le right too...
Cosmic rays probably make up well under 1% of the energy the sun puts out too.
Those of us who know the sun is the driving force of the Earths temperature agree. The cosmic ray theory has been argued years ago, and we do not argue that cosmic rays have any effect of concern on the greenhouse effect. Cosmic rays are only one narrow bandwidth of the suns spectra. They do very little to global warming if anything.
We are talking about the lower fequency spectras of the sun that make it through the atmosphere!
Pointless article.
VERY old news!
Now the only way that normal increases in cosmic radiation *MIGHT* have an effect is the fact that more C14 is created in the atmosphere when the cosmic radiation changes a neutron to a proton in nitrogen. Carbon dioxide has about a 6 C greenhouse effect on the atmosphere. This is at the current mix of isotopes making up CO2. The carbon can have 12(98.9%), 13(1.1%), or 14(trace) neutrons in nature. The Oxygen can have 16(99.76%), 17(0.039%), or 18(.201%). This makes several combinations of CO2, each of which has it's own vibration characteristics, each trapping IR at different frequencies.
Now Carbon 14 at trace levels seems meaningless. However, this is the amount that is estimated in all of the earth. Of the six isotopes above, it is the only radioactive one, It was a half-life of 5730 years. Anything on the earth for any historical time is at rediced levels. Since it is created in the atmosphere, the levels are far higher. I have not found reference to the amounts, only relative changes with the sun. If carbon 14 levels are at least a permille of the CO2, then the changes would be noteworthy for the effect of the greenhouse effect. If it were up to 1% of the carbon in CO2, I think it would make up to a 1 C change!. I simply do not know if the levels are high enough to matter. The other isotopes are pretty stable in the atmosphere. Carbon 14 is the only one that changes dramatically with the suns' changes.
I believe the above scientists you mention. We have meaningful data from satellites that see and measure the sun 24/7 for a few decades now. We have known patterns. One of them is that the suns total luminance increases slightly with increased sunspot activity. This is about +/1 0.08% from average for the short 11 years sunspot cycle. We really don't experience much change with that because the lag time for full effect far exceeds a quarter cycle. Various proxy isotopes show greater changes have occurred in conjunction with long term events. If I recall, the increase from before 1900 to after 1950 was just over 0.2% for the sun's 11 year period average. This is definitely noteworthy. If you consider a 0.2% change from the average temperature from absolute zero, then that 0.2% makes a 0.574 C change in the global temperature from before 1900 to after 1950. Since the earth generates some of it's own feat through radioactivity and pressure in the core, the effect isn't that great. Still, 100 K (-173 C) would be the warmest we can expect the earth to be with no sun. That still gives a 0.374 C change from before 1900 to after 1950. We could have easily peaked in 1996 or so because of the lag time it takes for the heat to stabilize. Even if the earth would be 200 K with no external heat, that equates to a 0.174 C change.
Anyone know the accepted temperature the earth would be with no sun? The best I was able to find isn't earth specific, but it was 55 K. If that is the value, then the 0.2% change amounts to a 0.464 C change. This is a number that makes perfect sense to me.
scientists and reports are not truth givers, they are observation givers.
RandomGuy, are you saying the sun has no affect on climate?
There are some observations that are undeniable. The sun does not maintain a perfect temperature. The hotter the sun, the hotter the earth. Period.
----added----
Tell you what Phil, Random, and others. Do a simple experiment for yourself. Take something like a lamp with a shade. Place a thermometer right inside the shade. See what the temperature reads with a 60 watt lamp vs. a 40 watt lamp, or any change in size you wish. Then tell me changed in the sun's thermal output doesn't change the effect of how it's light heats a distant surface. Make sure you are keeping the room temperature the same.
Last edited by Wild Cobra; 04-10-2008 at 11:40 PM.
Maybe you just need better sources? Or how about just 1 source....please!
2007 Was Tied as Earth's Second-Warmest Year
01.16.08
The Partisan Group Known as NASAClimatologists at the NASA Goddard Ins ute for Space Studies (GISS) in New York City have found that 2007 tied with 1998 for Earth’s second warmest year in a century.
"It is unlikely that 2008 will be a year with truly exceptional global mean temperature," said Hansen. "Barring a large volcanic eruption, a record global temperature clearly exceeding that of 2005 can be expected within the next few years, at the time of the next El Nino, because of the background warming trend attributable to continuing increases of greenhouse gases."
The eight warmest years in the GISS record have all occurred since 1998, and the 14 warmest years in the record have all occurred since 1990.
The International Panel on Climate Control (IPCC) certainly does have a vested interest in proving anthropogenic climate change. As a body within the UN, they are committed to the same goal of their parent organization; killing capitalism and redistributing the wealth of the United States.
How would that work any better than supporting a theory that has led to no pain windfalls such as "carbon credits?"
The prevailing theory in the IPCC was shot down a few years ago. That hasn't stopped them from continuing to try and make current data fit their wrong-headed theory.
Pass a law that we (United States) will never approve any law
taxing us on the basis of climate change and we will no longer have
global warming. I promise. Actually, not a law but a cons utional
amendment that that effect.
I think you should move to higher ground before the giant 20 foot tidal wave crashes the mainland and the marauding, maneating polar bears are driven south.
By the way, the Rockies-Braves game was just called off due to snowfall.
But what does Wikipedia say?
Having trouble finding the link?
Or you can just:
No. We don't need carbon credits. Because it isn't
a problem.
A 2.8 increase in the avg. temp in the last 10 years is a problem, especially since in the previous 100 years it was only a 1/2 degree increase...
0.6 degree Celcius increase over the last CENTURY.
Ooooh, I'm soooo scared.
Baseball game called off recently because of snowfall.
Dan, I suggest you read the following before making such
a broad statement as you did above.
Check it out
The relevant paragraph in the article is quoted below:
Since 1979, satellites have been measuring lower atmospheric temperatures around the globe. In the past 12 months, they show the Earth's mean temperature has dropped by 1.13º F. Thus, in one year, the natural variability in temperature is four times greater than the amount of warming that would be prevented if the entire industrialized world adopted the original Kansas statute.
Infamous (and typical) neocon tactic: One isolated data point trumps decades of trends.
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