Can someone explain to me what sunspots have to do with global warming?

Question

Seriously, we all know that heat from the sun does not reach earth. Only the light.

So if someone told me that the sun was getting dimmer, I woudl conclude that the earth would get cooler.

Explain the sunspot theory to me? I just don't get it.

Answer 1

One theory is that sunspot activity indicates the sun's magnetic field is stronger than when there are few sunspots. The sun's field is far stronger than the Earth's and it sweeps away most of the incoming cosmic rays from elsewhere in the universe, primarily from our own galaxy. When it is inactive, as it is now and as it was during the Little Ice Age, more cosmic (gamma) rays flood in, interact with our atmosphere and form clouds. The clouds then block sunlight from reaching the Earth's surface and that causes cooling.

A good book on the subject is The Chilling Stars by Henrik Svensmark but he bases the book on the work of other scientists as well as his own. There may be other reasons for this but the fact is that the sunspot cycle matches the temperature record much more closely than CO2 does.

There are claims that the sun was very active over the last few decades, now that the cycle has almost stopped, it was much cooler than usual last year. Others claim the sun's brightness hasn't increased since the 1970s, but that has no bearing on this sunspot theory since it doesn't depend on the sun's overall brightness, just it's magnetic field. If the current cycle doesn't get more active, we're likely to see a steep cooling trend that will make today's temp seem ideal.

Answer 2

sunspots play a minor roll, if any, in global warming.

they indicate locations where there are disruptions in the sun's magnetic field.

you might keep in mind that the hotter something is, the higher the radiation, and the shorter the wavelength.

SO, it can happen that something is so hot that it puts out all, or most, of it's energy in the ultraviolet portion of the spectrum, which we cannot see, and which, to our eyes, would look black.

like a sunspot.

so, when there are more sunspots, the sun is more active, and puts out slightly more energy.

however, there's an 11 year cycle to sunspots, and if you look at temperature graphs of the earth, you cannot see any reflection of that 11 year cycle, so it would appear that they have little impact, if any, on earth's temperature.

Answer 3

I SEE YOU'VE NEVER BEEN OUTSIDE AND FELT THE HEAT FROM THE SUN. SUN SPOTS DOES'NT HAVE A THING TO DO WITH GLOBAL WARMING. I SUGGEST YOU GO OUTSIDE WHEN THE SUN IS OUT AND PERSONNALLY FEEL THE HEAT FROM THE SUN.

Answer 4

The variation in the total amount of energy reaching Earth from the Sun is one of the main factors determining our planet's climate (see Climate myths: Global warming is down to the Sun, not humans).

However, this factor alone cannot explain the recent warming nor, indeed, can it fully explain many past changes such as Earth's ice ages. But what if changes in the Sun's activity have larger-than-expected effects on the climate?

There are plenty of ideas about how this could happen. For instance, one as-yet-unproven idea is that changes in the relative amount of ultraviolet light emitted by the Sun might affect the ozone layer, heating the stratosphere and altering circulation patterns in the lower atmosphere.

In the late 1990s, some Danish scientists revived another idea, proposed decades earlier, that cosmic rays might be able to amplify small changes in solar activity by ionising the atmosphere and triggering cloud formation.

Chilling idea

Increased sunspot activity is known to strengthen the Sun's magnetic field, which deflects more of the galactic cosmic rays entering the solar system and thus reducing the number hitting Earth. The argument championed by Henrik Svensmark is that this would reduce cloud formation in the atmosphere – warming the Earth – and that this effect explains the recent global warming.

The case has been made at greater length in a book Svensmark wrote with science journalist Nigel Calder (who edited New Scientist from 1962 to 1966), called The Chilling Stars.

There are at least three separate issues here. First, do cosmic rays really trigger cloud formation? If so, how do the resulting changes in cloud cover affect temperature? Finally, does this explain the warming trend of the past few decades?

Answer 5

The sun does indeed heat the Earth but not in the normal sense. Instead of heating directly, infrared rays are emitted and "converted" into heat when they hit the Earth.

Anyway, regarding sunspots, sunspots are cooler areas that appear on the sun surface. It may then seem strange then that more sunspots means hotter Earth, but this is because the area around a sunspot is much hotter than the sun's surface. This results in an overall heating of the sun's surface when there are more sunspots.

Sunspots are in a way a determination for the total solar irradience (irradience = infrared rays) of the sun at any one time. So that is why it heats the Earth.

A possible positive feedback has been postulated which is when solar activity is high, it "blocks off" galactic cosmic rays, which causes fewer low-level clouds to form, causing warming (I think that's how it goes anyway).

As solar activity has increased rapidly to levels not seen for thousands of years, it is possible it could account for a significant amount of the early 20th century warming, but as there has been no significant trend in sunspots since 1985, the last 20 years of warming cannot be attributed to it.

Answer 6

There is considerable evidence climate change coincides with solar cycles.  Few sunspots=global cooling, Lots of sunspots=global warming.  The mechanism isn't fully understood, but the link is undeniable.  This past century has been one of the most active in 8,000 years.  One would HAVE to expect the climate to be at its warmest as a result.  

Man's emissions have no effect on solar cycles.

Answer 7

Sun spots happen in times of increased solar radiation.  The sun spots result from the sun's magnetic field.  The sun spots result in solar storms that sometimes affect our magnetosphere which helps keep cosmic rays at bay.  Times of increased solar activity may increase the occurrence of cosmic rays that theoretically may increase cloud cover.  These forces tend to counteract each other but it is extremely complex.  Today we live in a period of relatively high sun spot activity and solar output.  During the Little Ice Age, as someone alluded to, there was very little sunspot activity.  When the sun is dimmer, there is less sun spot activity.

There are more cycles of solar activity than just the commonly known one that is 11 years.  There are much longer intervals as discussed in the attached link

http://en.wikipedia.org/wiki/Solar_cycle

Answer 8

oh my god you're an idiot.

infra red radiation is part of sunlight. that's thermal energy.

l2science

Answer 9

basics;

http://environment.newscientist.com/chan...

several articles

http://www.realclimate.org/index.php/arc...

heavy duty maths

http://tamino.wordpress.com/2008/04/05/s...