2011: The year in extreme weather

Unsurprisingly, I have to disagree with you Rockdoc. Solar radiation and solar irradiance (those two are very distinct and not necessarily corresponding) are not the driving forces for the climate changes being seen now (let me make sure I am clear before anyone makes assumptions about that sentence: they affect the global temps, are not the driving forces at this time, but they have been in the past). We are currently in an unusually low solar minimum, yet global temperatures are hotter than they would've been had we not been adding so much CO2 and other GHGs to the atmosphere plus clear-cutting forests, etc, and are still breaking records despite that lull (see 2010 here , 2009 here , and 2008 here .

The upcoming cycle change is to increase to more activity, although it is expected to be below average activity meaning something like the minimums of cycles past. Despite that, unless there is significant volcanic activity that increases particulates in the atmosphere, temperature trends are unlikely to be affected significantly by the lower solar energy - the planet will still warm due to increasing greenhouse gases trapping more energy.
First, 2 citations on the current solar activity and a 3rd on what it means for global temps:
http://science.nasa.gov/science-news/sc ... arminimum/
Deep Solar Minimum
April 1, 2009:

Quiet suns come along every 11 years or so. It's a natural part of the sunspot cycle, discovered by German astronomer Heinrich Schwabe in the mid-1800s. Sunspots are planet-sized islands of magnetism on the surface of the sun; they are sources of solar flares, coronal mass ejections and intense UV radiation.

The current solar minimum is part of that pattern. In fact, it's right on time. "But is it supposed to be this quiet? In 2008, the sun set the following records:

A 50-year low in solar wind pressure:
A 12-year low in solar "irradiance":
A 55-year low in solar radio emissions:
Pesnell believes sunspot counts will pick up again soon, "possibly by the end of the year," to be followed by a solar maximum of below-average intensity in 2012 or 2013.

http://science.nasa.gov/science-news/sc ... atchedpot/
Solar Activity Heats Up
April 14, 2011

Back in 2008, the solar cycle plunged into the deepest minimum in nearly a century. Sunspots all but vanished, solar flares subsided, and the sun was eerily quiet. This particular solar minimum, however, was lasting longer than usual, prompting some researchers to wonder if it would ever end.

As 2011 unfolds, sunspots have returned and they are crackling with activity.

There have been 24 numbered solar cycles since researchers started keeping track of them in the mid-18th century. In an article just accepted for publication by the Space Weather Journal, Turner shows that, in all that time, only four cycles have started more slowly than this one.

http://www.wired.com/wiredscience/2011/ ... m-climate/
Sunspot Drop Won’t Cause Global Cooling
By Brandon Keim Email Author
June 15, 2011

News that solar activity might fizzle for a few decades has prompted talk of a new “Little Ice Age,” even a quick fix for global warming. In fact, the meaning of the latest sunspot reports is still being debated, as Andrew Revkin at Dot Earth has chronicled. But even if they really do portend a decades-long solar lull, studies already point to a minimal effect on climate.

More recently, in a 2010 Geophysical Research Letters study , Georg Fuelner and Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research asked the question directly: What would happen if Earth experienced another 70-year-long solar minimum?

In a nutshell: It’s going to be much, much hotter in the future, solar minimum or not.

*Note: One of the authors of that paper, Fuelner, has a commentary on their paper at realclimate.org, it is cited below.

Next, an article on recent quantification of human-caused vs natural contributions to the current climate changes seen:
http://www.nature.com/news/three-quarte ... ade-1.9538
Three-Quarters of Climate Change Is Man-Made
An independent study quantifies the human and natural contributions, with solar radiation contributing only minimally
By Quirin Schiermeier | 04 December 2011

Natural climate variability is extremely unlikely to have contributed more than about one-quarter of the temperature rise observed in the past 60 years, reports a pair of Swiss climate modelers in a paper published online December 4. Most of the observed warming—at least 74 percent—is almost certainly due to human activity, they write in Nature Geoscience.

Since 1950, the average global surface air temperature has increased by more than 0.5 degree Celsius. To separate human and natural causes of warming, the researchers analyzed changes in the balance of heat energy entering and leaving Earth—a new "attribution" method for understanding the physical causes of climate change.

Changes in solar radiation—a hypothesis for global warming proffered by many climate skeptics—contributed no more than around 0.07 degree C to the recent warming, the study finds.

Huber, M. & Knutti, R. Nature Geoscience (2011) http://www.nature.com/ngeo/journal/v5/n ... o1327.html

Finally, 6 references to recent analyses by climatologists on solar irradiance and solar radiation on global warming. There are many older such articles not cited here at [url=http://www.realclimate.org" onclick="window.open(this.href);return false;]http://www.realclimate.org[/url], feel free to search for more than is here for additional information:
http://www.realclimate.org/index.php/ar ... d-minimum/
What if the Sun went into a new Grand Minimum?
Guest Commentary by Georg Feulner
19 June 2011

During a meeting of the Solar Physics Division of the American Astronomical Society, solar physicists have just announced a prediction that the Sun might enter an extended period of low activity (a ‘grand minimum’) similar to the Maunder Minimum in the 17th century. In this post I will explore the background of this announcement and discuss implications for Earth’s climate.

it is certainly interesting to explore what effects such a minimum might have on 21st century climate if it did occur. This is precisely the question Stefan Rahmstorf and I investigated in a study published last year (see also our press release. (Earlier estimates for the size of this effect can be found here and here .)

Critics of this result might argue that the solar forcing in these experiments is only based on the estimated change in total irradiance, which might be an underestimate, or that does not include potential indirect amplifying effects (via an ozone response to UV changes, or galactic cosmic rays affecting clouds). However, our model reproduces the historic Maunder minimum with these estimates of solar irradiance. Furthermore, even if one multiplied the solar effects by a huge factor of 5 (which is unrealistic), no absolute cooling would take place (the temperatures would be temporarily cooler than the base scenario, but the trends would still be warming).

http://www.realclimate.org/index.php/ar ... n-the-sun/
How large were the past changes in the sun?
— rasmus @ 23 August 2011

We only have direct observations of total solar irradiance (TSI) since the beginning of the satellite era and substantial evidence for variations in the level of solar activity (from cosmogenic isotopes or sunspot records) in the past. Tying those factors together in order to estimate solar irradiance variations in the past is crucial for attributing past climate changes, particularly in the pre-industrial.

How good are the new estimates? A major weakness of all such estimates – and Shapiro et al. is no different – is that the results cannot be tested on the basis of the last 30 years of solar observations. The paper is candid about this issue, and explains that this is partly because the time scale, on which their analysis rests, is 22 years.

So how do these new TSI-estimates relate to past climate variations and other forcings?

http://www.realclimate.org/index.php/ar ... et-fooled/
How easy it is to get fooled
— rasmus @ 19 February 2011

When you analyse your data, you usually assume that you know what the data really represent. Or do you? This has been a question that over time has marred studies on solar activity and climate, and more recently cosmic rays and clouds. And yet again, this issue pops up in two recent papers; One by Feulner (‘The Smithsonian solar constant data revisited‘) and another by Legras et al. (‘A critical look at solar-climate relationships from long temperature series.’). Both these papers show how easily it is to be fooled by your data if you don’t know what they really represent.

First of all, I really think these papers are worth reading, because sometimes there are papers published that do not appreciate the importance of meta-data (information about the data) and do not question what they really represent.

http://www.realclimate.org/index.php/ar ... relations/
More on sun-climate relations
— rasmus @ 9 March 2010

Four new papers discuss the relationship between solar activity and climate: one by Judith Lean (2010) in WIREs Climate Change , a GRL paper by Calogovic et al. (2010) , Kulmala et al. (2010) , and by Feulner and Rahmstorf (2010) . They all look at different aspects of how changes in solar activity may influence our climate.

So what can we learn from these articles? What we see is how science often works – increases in knowledge by increments and independent studies re-affirming previous findings, namely that changes in the sun play a minor role in climate change on decadal to centennial scales. After all, 2009 was the second-warmest year on record, and by far the warmest in the southern hemisphere, despite the record solar minimum. The solar signal for the past 25 years is not just small but negative (i.e. cooling), but this has not noticeably slowed down global warming . But there are also many unknowns remaining, and the largest uncertainties concern clouds, cloud physics, and their impact on climate. In this sense, I find it ironic that some people still rely on the cosmic rays argument as their strongest argument against AGW – it does involve poorly known clouds physics!

http://www.realclimate.org/index.php/ar ... l-stumper/
Solar spectral stumper
— gavin @ 7 October 2010

It’s again time for one of those puzzling results that if they turn out to be true, would have some very important implications and upset a lot of relatively established science. The big issue of course is the “if”. These data are measurements of how the solar output varies as a function of wavelength from an instrument called “SIM” (the Spectral Irradiance Monitor).

It has been known for some time that over a solar cycle, different wavelengths vary with different amplitudes. For instance, Lean (2000) showed that the UV component varied by about 10 times as much as the total solar irradiance (TSI) did over a cycle. What is a surprise is that for the visible wavelengths, SIM seems to suggest that the irradiance changes are opposite in sign to the changes in the TSI.

What are the implications of such a phenomena? Well, since the UV portion of the solar input is mostly absorbed in stratosphere, it is the visible and near-IR portions of the irradiance change that directly influence the lower atmosphere. Bigger changes in the UV also imply bigger changes in stratospheric ozone and temperature, and this influences the tropospheric radiative forcing too. Indeed, according to Haigh’s calculations, the combination of the two effects means that the net radiative forcing at the tropopause is opposite in sign to the TSI change. So during a solar minimum you would expect a warmer surface!

So is this result likely to be true? In my opinion, no. In the meantime, this is one of those pesky uncertainties we scientists love so much…

http://www.realclimate.org/index.php/ar ... 011-day-2/
AGU 2011: Day 2
group @ 7 December 2011

There were two interesting themes in the solar sessions this morning. The first was a really positive story about how instrumental differences between rival (and highly competitive) teams can get resolved. This refers to the calibration of measurements of the Total Solar Irradiance (TSI).

The other theme was the discussion of the spectral irradiance changes – specifically by how much the UV changes over a solar cycle are larger in magnitude than the changes in the total irradiance.