Daily Sun: 02 Jul 08; The sun is blank--no sunspots. What does this have to do with global warming?

Question

Daily Sun: 02 Jul 08

The sun is blank--no sunspots.

Credit: SOHO/MDI

What does this have to do with global warming?

http://www.spaceweather.com/

Answer 1

Not much - we are in a solar activity minimum at the moment so this is to be expected. The 11-tear cycle of solar activity and sunspots have a minor impact upon climate variations and a big impact on the ionosphere and radio communications but there is no correlation between this cycle and long term climate change (there are some indications that longer solar cycles may have a stronger affect).

EDIT to sfavourite:

This is a matter of semantics... "Global Warming" is a quick term normally used to refer to the rapid climate change and overall warming of the planet in the past century.

This climate change is so significantly different from 'natural' oscillations in climate, whether short- or long-term, that it is considered to be more analogous to the massive and rapid changes in climate that preceded the last five 'mass extinctions'.

When I said that sunspots are not a factor in GW I was using that definition of GW.

Sunspots, like seasons, precession of equinoxes, normal vulcanism, etc are part of the natural variations in climate that have, as you point out, some correlation with the Sporer, Maunder, and Dalton minima and the LIA (which, incidentally, was regional, not global in scope, like the MWP).

So, to rephrase:

Sunspots are not related to the rapid and extraordinary changes to global climate in the late 20th and early 21st centuries that is normally referred to as "Global Warming".

Sunspots are related to the normal variations in climate that are periodic, predictable and constrained.

Does that help?

Answer 2

Not sure why Adam C claims that sun spots have nothing to do with global warming when his first reference talks about sun spots and global warming.

"Don Easterbrook, a Professor Emeritus of geology at Western Washington University, has claimed that there is a cause-and-effect relationship between sunspot activity and global temperatures on Earth. It is also believed that sunspot activity has a direct effect on weather and climate change on the planet, the controversy over global warming has put scientists in opposition to each other, until more is known about the effects of sunspots and solar radiation levels and their exact relationship with Earth and its weather patterns (including temperature change) we must accept that there may be a correlation between global warming and sunspot activity."

Maybe Adam C was being sarcastic and my sense of humor just isn't good enough to get it.

From his second source...

"Incidentally, the Sporer, Maunder, and Dalton minima coincide with the colder periods of the Little Ice Age, which lasted from about 1450 to 1820. More recently it was discovered that the sunspot number during 1861-1989 shows a remarkable parallelism with the simultaneous variation in northern hemisphere mean temperatures (2). There is an even better correlation with the length of the solar cycle, between years of the highest numbers of sunspots. For example, the temperature anomaly was - 0.4 K in 1890 when the cycle was 11.7 years, but + 0.25 K in 1989 when the cycle was 9.8 years. Some critics of the theory of man-induced global warming have seized on this discovery to criticize the greenhouse gas theory."

Answer 3

Periods of low sunspot activity correlate very well with a cooling climate. The current amount of energy from the sun is about .6 W/M^2 lower than the peak of solar cycle 23 which occurred in 2003 or 5 years ago. It is almost a guarantee that that temperature will stay fairly flat or continue to fall, based on the reduced amount of radiation if this lull in in solar activity persists. If negative feedback's are at play, then temperatures could drop significantly over the next two decades.

Answer 4

Temperature variations correlate much better with solar activity and solar cycle length than they do with the use of hydrocarbon fuels.

http://www.oism.org/pproject/s33p36.htm

http://www.spacecenter.dk/research/sun-c...

http://www.geocraft.com/WVFossils/Refere...

http://arxiv.org/ftp/physics/papers/0702...

Answer 5

Very little.  Sunspots have only a minor impact on the amount of solar radiation the Earth receives.  More details:

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

Tomcat's first link, which is good data from qualified scientists, shows that well.  Note the units on the y-axis (left side of the graph), which cover a very limited range.  If the graph started at zero, you couldn't even see the change.

These guys have worked the numbers, showing that increased CO2 will more than compensate for that, and we'll continue to warm:

"Recent oppositely directed trends in solar

climate forcings and the global mean surface

air temperature", Lockwood and Frolich (2007), Proc. R. Soc. A

doi:10.1098/rspa.2007.1880

http://www.pubs.royalsoc.ac.uk/media/pro...

News article at:

http://news.bbc.co.uk/1/hi/uk/6290228.st...

Tomcat's second link is simply the ramblings of one geologist, and much less credible.

Answer 6

It means we will be getting ever cooler. We we're on an upward swing of solar sunspot activity when we had our last warming trend.