The Reslient Earth
Scientists Discover The Sun Does Affect Earth's Climate
A quiet Sun comes 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. Currently the sun is in one of its least active periods since the Maunder Minimum, during the depths of the Little Ice Age. What does this have to do with global warming and climate change? It just may be why things keep getting colder as climate activists tell us Earth is melting down.
The year 2008 was unusually quite. There were no sunspots observed on 266 of the year's 366 days (73%). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days. Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008. But that has not proven to be the case. Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year's 90 days (87%). “This is the quietest sun we've seen in almost a century,” says sunspot forecaster David Hathaway of NASA’s Marshall Space Flight Center in Huntsville, Ala.
“We're experiencing a very deep solar minimum,” says solar physicist Dean Pesnell of NASA’s Goddard Space Flight Center in Greenbelt, Md. Careful measurements by several NASA spacecraft have also shown that the sun's brightness has dimmed by 0.02 percent at visible wavelengths and a whopping 6 percent at extreme UV wavelengths since the solar minimum of 1996. In a way, the calm is exciting, says Pesnell. “For the first time in history, we're getting to observe a deep solar minimum.”
Normally the Sun's surface is marred by dark areas known as sunspots. They mark regions of intense magnetic activity, which inhibits convection, forming dark areas of reduced surface temperature. They are often accompanied by solar flares and prominences—eruptions from the solar surface that affect the Sun's energy output. During periods of peak activity sunspots, solar flares and coronal mass ejections are common, resulting in the Sun emitting slightly more energy than during periods of low activity. The amount of energy that strikes Earth's atmosphere—called total solar irradiance (TSI)—fluctuates by about 0.1 percent over the course of the sun's 11-year cycle, even though the soft X-ray wavelengths, shown in the NASA/ESA image below, vary by much greater amounts.
To see just how spot free the Sun currently is look at this shot of our local star taken by SOHO, the Solar and Heliospheric Observatory, on 4/9/2009. As can be seen the Sun's surface is almost without blemish. Click on the image below to view the current image or visit this site for a complete overview of the current solar weather environment from NASA.
A dramatic correlation between sunspots and global temperatures can be seen in historical records going back several centuries. During the Maunder Minimum, a period of diminished solar activity between 1645 and 1715, sunspots were rare on the face of the sun, sometimes disappearing entirely for months to years. This period coincides with the Little Ice Age, an historically famous time of abnormal low temperatures. It is certainly too early to claim that we are entering another pronounced solar minimum; to match those historical minima in depth and longevity, the current minimum will have to last considerably longer than it has so far.
As can be seen from the graph below, the correlation between sunspots and temperature is quite pronounced, with climate following sunspot activity much better than resent charts of fluctuating temperatures vs. steadily increasing CO2. Are the events connected? Scientists cannot say for sure, but it seems quite likely. Slowdowns in solar activity, as evidenced by reductions in sunspot numbers, are known to coincide with decreases in the amount of energy discharged by the sun.
While climate scientists claim the 0.1% change in total solar irradiance (TSI) is not enough to reverse global warming on its own, new scientific evidence from NASA points to changes in the type of solar radiation arriving at the top of Earth's atmosphere as a possible trigger for other powerful climate regulating mechanisms. Scientists have discovered, that while total solar irradiance changes by only 0.1 percent, the change in the intensity of ultraviolet light varies by much larger amounts. Research shows such variations in the Sun's emissions can affect the ozone layer and the way energy moves both vertically and horizontally through the atmosphere.
Recent observations indicate that the westerly jet stream in the Southern Hemisphere is accelerating. This directly affects the surface temperatures, the extent of sea ice, the variability of storm tracks, the location of arid regions, the strength of the wind-driven oceanic circulation, and the exchange of CO2 and heat between atmosphere and ocean. In a 2008 paper in Science, S. W. Son, et al., indicated that the role of ozone on global climate change has been underestimated, particularly by the IPCC models. Quoting from the paper:
In the past several decades, the tropospheric westerly winds in the Southern Hemisphere have been observed to accelerate on the poleward side of the surface wind maximum. This has been attributed to the combined anthropogenic effects of increasing greenhouse gases and decreasing stratospheric ozone and is predicted to continue by the Intergovernmental Panel on Climate Change/Fourth Assessment Report (IPCC/AR4) models. In this paper, the predictions of the Chemistry-Climate Model Validation (CCMVal) models are examined: Unlike the AR4 models, the CCMVal models have a fully interactive stratospheric chemistry. Owing to the expected disappearance of the ozone hole in the first half of the 21st century, the CCMVal models predict that the tropospheric westerlies in Southern Hemisphere summer will be decelerated, on the poleward side, in contrast with the prediction of most IPCC/AR4 models
The paper goes on to say: “The detailed mechanisms through which stratospheric ozone affects the tropospheric westerly jet remain unclear at present.” Their analysis suggests that stratospheric processes, and ozone recovery in particular, may be able to affect climate in major ways. NASA says changes in the Sun can have major impact on stratospheric ozone. Combine these two discoveries and you have a mechanism for small changes in solar activity to have a disproportional impact on earthly climate. And this is not the only “cosmic connection” proposed for climate change.
Work by Heinrich Svensmark, of the Danish Space Research Institute, and Eigil Friis-Christensen indicates the lack of solar activity may be a controlling factor for increased low level cloud cover. Cloud cover is something that has vexed climate modelers for years, and is listed by the IPCC as one of the poorly understood factors influencing Earth's climate. It is accepted that increased low level cloud cover can lead to cooling of Earth's surface. Svensmark's theory of cosmoclimatology establishes a link between solar activity, cosmic rays, cloud cover and climate regulation.
If this theory is correct, times of low solar activity (meaning low sunspot levels) should be times of cooling temperatures here on planet Earth. The solar minima of 1901 and 1913, for instance, were even longer than what we're experiencing now. Temperature records show a distinct dip in temperature during this time period so perhaps Svensmark, et al., are on to something. We discussed this theory in great detail in The Resilient Earth, chapter 11. A well written book on the discovery and formulation of the theory is Henrik Svensmark and Nigel Calder's book, The Chilling Stars.
All of these scientific discoveries are leading open minded scientists to question climate science dogma, which says that variation in the Sun's output has no measurable impact on climate. Why is the constancy of the Sun assumed by most climate scientists? It may be, in part, because most climate scientists are practitioners of Earth bound science: glaciology, biology, oceanography, atmospheric physics, etc. Having to consider influences from beyond our planet further complicates Earth's climate system, which is already more complicated than science fully comprehends.
Every week, new journal articles appear unveiling previously unknown relationships among physical phenomena. According to Science Daily there's a big “what if” being murmured about throughout the scientific community. And that is, “what if—as many assume—much longer solar cycles are also at work?” This according to Judith Lean, a solar physicist at the U.S. Naval Research Laboratory in Washington, D.C. In that case, it's not impossible that long-term patterns—operating over hundreds or thousands of years—could cause even more pronounced swings in TSI.
Pesnell believes sunspot counts should 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. Unfortunately, modern technology cannot predict what comes next. Competing models by dozens of solar physicists disagree, often sharply, on when this solar minimum will end and how big the next solar maximum will be. This great uncertainty stems from one simple fact: much like Earth's climate system, no one fully understands the underlying physics of the sunspot cycle.
If these depressed levels of solar activity continue, what happens to all the predictions of rising temperatures and accompanying natural disasters? No one really knows, despite what many self-aggrandizing climate science types tell the news media. The harsh fact is that climate science is really still in its infancy and is unable to accurately predict future climate on our planet. There exist other, scientifically credible theories of climate regulation besides the IPCC's anthropogenic CO2 mantra. How all this will shake out in the end is anyone's guess so hang on, because we are in for a wild ride, both scientifically and climatologically.
Be safe, enjoy the interglacial and stay skeptical.