How can the Sun be blamed for the current global warming?

Question

Here is a graph from NASA showing solar irradiance from 1980-2005:

http://www.nasa.gov/centers/goddard/images/content/93617main_sun4m.jpg

And here is an average global temperature plot which includes that time period:

http://en.wikipedia.org/wiki/Image:Instrumental_Temperature_Record.png

There is little correlation between the two. For example, solar irradiance decreased dramatically from about 1980-1987, while the average global temperature increased by over a tenth of a degree. The current level of solar irradiance is roughly what it was 25 years ago, but the average global temperature is about 0.4°C higher.

How can anyone realistically blame the Sun for this warming?

Just in case someone decides to blame sunspots, here is a similar plot showing their lack of correlation to global temps as well:

http://solar-center.stanford.edu/sun-on-earth/600px-Temp-sunspot-co2.svg.png

Tomcat - stop trying to cherry pick the data and read the following:

http://answers.yahoo.com/question/index;_ylt=Ahj_9Ts6XCPlEPR8x0ZiSSPsy6IX;_ylv=3?qid=20070913123734AAgAWkc

jim z - I would suggest reading the whole page you link in the future.

"An often-cited 1980 study by Imbrie and Imbrie determined that 'Ignoring anthropogenic and other possible sources of variation acting at frequencies higher than one cycle per 19,000 years, this model predicts that the long-term cooling trend which began some 6,000 years ago will continue for the next 23,000 years.'"

Larry - compare your link's first 2 charts to mine provided by Stanford. Yours have been altered (sunspots shifted back in time) to make the correlation appear to exist.

Answer 1

Sheesh ... some of the stuff on Wiki is not bad. There was a great Q/A forum on c-span a while back I saw with the founder of Wikipedia discussing how things get vetted there. It made me feel a little better about citing stuff I find there. But I digress.

Here's the ACRIM/PMOD data straight from the horse's mouth:

http://www.pmodwrc.ch/pmod.php?topic=tsi/composite/SolarConstant

and here is the ACRIM link to the GRL paper that shows a 0.05% increase in solar irradiance from 1985 to 1995 (Figure 2, top panel):

http://www.acrim.com/Reference%20Files/Secular%20total%20solar%20irradiance%20trend%20during%20solar%20cycles%2021%9623.pdf

So, to get to the point, which is in support of Dana's contention changes in solar output cannot be sol-ly (heh heh, sol-ly, get it? I am *so* funny) responsible for the observed increase, the change in solar output has been tiny compared to the relative change in the greenhouse gas forcing, even if you use the ACRIM data from the PMOD website. There is no way to rationalize a smaller total forcing (0.6 W/m^2) from the ACRIM increase outweiging the 1.5 W/m^2 forcing from the increase in CO2. If you use the PMOD composite then you haven't got a hope.

If you want solar forcing to dominate, and even the ACRIM trend proponents only give the solar increase fraction to be 30% at most, then you have to explain using correct physics how that occurs.


Edit:

Solar forcing: Range of 0.06 to 0.3 W/m^2.

CO2 forcing: Range of 1.49 to 1.83 W/m^2

http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_SPM.pdf

Figure SPM.2

Again, explain using correct physics how something a factor of five smaller will dominate.


Edit 2:

Tomcat, the difference between the tropospheric and surface temperature records was largely reconciled several years ago. Both show an increase. Even John Christy agrees there is no real disagreement. I'm not sure this link will work for you, but the NAS report on the subject is pretty authoritative.

http://www.nap.edu/openbook.php?isbn=0309068916

Look, all you skeptics need to get it through your heads, the science behind global warming is by and large correct. There aren't huge unknowns in the system at this point. You are all going to have to start dealing in the subtleties of climate physics in its entirety if you want to make any progress. My suggestion is that you all learn about radiative transfer, atmospheric physics, weather patterns, physical and chemical oceanography, and biogeochemical cycling. It is essentially pointless discussing things with people raising these sorts of infantile objections. Face it, nearly all of the "contrarian" arguments are trash and anyone parroting them here is a gullible idiot. The devil in this case is deep in the details.

Edit 3:

Tomcat:

http://www.nature.com/nature/journal/v443/n7108/abs/nature05072.html

It ain't the sun. At least not in terms of luminosity. I know you want the sun to be responsible, but the recent research simply isn't in your favor. Look elsewhere.

Answer 2

I think the way some people look at it is that the sun is, for all intents and purposes, the only source of heat that warms the planet and therefore any variation in the global temperature has to be caused by the sun.

Stripped down to it's basics like this, it appears to make sense. Such a simplification fails to take account of how and why the sun keeps Earth at a habitable temperature and overlooks the many other factors that are involved.

Once you start digging deeper it soon becomes apparent that it's not so simple. People like yourself and others have done the digging and can identify the other factors and how we are able to influence our climate.

If people WANT to believe it's the sun they're unlikely to dig down, to do so could unearth facts that shatter their illusion. In this respect it's easier to remain ignorant rather than become educated with the facts, especially if those facts don't conform to a preconcieved notion.

There are undoubtedly some skeptics who are well aware that the sun can't be blamed for the current warming but to admit such would be tantamount to conceding that humans have a role to play as well. For some, this would never do. To do so would mean accepting being a part of the cause and problem, it would also mean loss of face at having to do a 'U-turn'.

Of course, it could all just be down to moose burps, cattle, termites, Al Gore, soda pop, volcanoes or anything else that comes to the mind of the skeptics. My money's on someone blaming little green men from Mars before the year's out.

Answer 3

I live within walking distance of the Pacific Ocean, and I have lived here when the alarmists/leftists were proclaiming global cooling. Over 30 years ago they started chanting global warming and predicted that where I live would have a serious rise in ocean levels, flooding lowlands, that would happen within twenty year or less. That was 25 years ago and I'm still waiting. Nothing has changed, not the ocean level, not the water temperature. The state climatologist, George Taylor, exposed the scam, and he is a real scientist, not a politician. The state governor read Taylor's report, and fired him, or tried to. Taylor wasn't politically correct. Also, I studied Earth Science in college as a minor. Also, I'm not new to science; I've spent my live working in Science and Technology. All my friends are scientists or technologists. So, don't repeat Al Gore's lies to me. This climate change hoax runs along leftist political lines, and it is fed by liars and morons. Believe it!

Answer 4

You can't blame global warming on solar irradiance because the data do not show an increase in irradiance. The data DO show a cyclical up and down that correlates pretty well with sunspots, but the long term average is not going up.

Answer 5

Romeomike:
Is that the new way of excusing your weight, blaming increased gravity? Sounds pretty convenient. :)

I do agree with Dana. If the Sun, or some other source, is claimed to be causing GW it shouldn't be claimed that it does so by referring to its potential, what it historically has done, but rather what it is doing right now. I don't think that anyone (hopefully) is doubting that changes in solar radiation can initiate temperature changes. The same goes for the Milankovich cycles. The question is: What are they doing right now? Is there increased solar radiation?
Does the Milankovich cycles currently constitute a GW factor?

Edit. And is any positive RF large enough to account for the seen changes?

Answer 6

A wikipedia article is mentioned...but so are Nasa and Stanford. The sun is not the only source of heat.
I read about the solar heat getting in b/c of a crack in our ozone layer (b/c of human activity) and the magnetic field (cause-?) and not out but I fail to see how that disproves human activity isn't contributing.

Answer 7

It is not (directly) the irradiation the sun projects on the Earth, it is the amount we feel on the surface that is important.

Cloud formation is key. Cosmic rays help form clouds. Heavy cloud cover causes cooling periods and ice ages.

The solar indicator you want to track is sun spot activity. With additional sun spots, you have more solar wind. With more solar wind, the 'current' deflects cosmic rays from reaching the Earth. Therefore, heavier sun spot activity causes fewer clouds to form and cause warmer weather. Fewer sun spots cause cooler temperatures as more cosmic rays reach the Earth and more clouds are formed.

Hope this helps.

Answer 8

It can be blamed because the suns radiation gets trapped in our atmosphere heating up the earth. But in most ways its our fault from overusing and polluting the Environment so you can't really blame anyone or anything but us as a human race.

And were at a LOW sun spot cycle so it should be better. Less radiation storms so the earth gets a rest from being battered. But i wouldn't blame it on the sunspots.

Answer 9

It is very simple Dana, stop looking at the surface temperature records when trying to evaluate a theory that involves forcing differences occurring in the atmosphere. The surface temperature record is contaminated by urbanization, and it is a mindless endeavor to keep showing the surface temperature graph if you really want to prove your point, when debating with people that understand long wavelength IR absorption spectra associated with trace gases in the atmosphere. What the ACRIM composite really shows, is that the solar minimum that occurred in 1997 was .5 watts/meter^2 higher than the previous minimum. The earth did not and could not cool down to it's level in which it did in the mid eighties. Have you ever stopped to consider the accumulative total of energy, that difference represents?

The Tropospheric temperature record tells a different story than the surface, that is what you should be looking at, not the temperature at your local airport.

http://hadobs.metoffice.com/hadat/images/update_images/global_upper_air.png


EDIT:

And gcnp58 compute the forcing difference of delta CO2 from 1978 to present, or compute delta TSI forcing from the start of industrial revolution please.

EDIT:

Dana? Mwaa... cherry picking data..?

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EDIT:

gcnp58

You are talking about the forcing since the industrial revolution with AGW forcing, but the solar since the same period is estimated at 3 watts.

Answer 10

It is pretty lame when at the bottom of your Wikipedia graph there is a foot note that says:

"This image is just an image. It shows how people can be fooled by man made global warming"

Heating of a planet can be caused by changes in gravity effecting the core of the planet that leads to heating the outer crust. An extreme case of this happens on the Jupiter's moon Io.