Saturday, 6 March 2010
NASA Admits Solar Variability ties to Climate Change
Well, it’s finally happened; NASA has admitted that the sun is a variable star, and that changes in solar irradiance may well effect the Earth’s climate.
This excerpt from NASA.gov:
For some years now, an unorthodox idea has been gaining favor among astronomers. It contradicts old teachings and unsettles thoughtful observers, especially climatologists.
“The sun,” explains Lika Guhathakurta of NASA headquarters in Washington DC, “is a variable star.”
But it looks so constant…
That’s only a limitation of the human eye. Modern telescopes and spacecraft have penetrated the sun’s blinding glare and found a maelstrom of unpredictable turmoil. Solar flares explode with the power of a billion atomic bombs. Clouds of magnetized gas (CMEs) big enough to swallow planets break away from the stellar surface. Holes in the sun’s atmosphere spew million mile-per-hour gusts of solar wind.
And those are the things that can happen in just one day.
Over longer periods of decades to centuries, solar activity waxes and wanes with a complex rhythm that researchers are still sorting out. The most famous “beat” is the 11-year sunspot cycle, described in many texts as a regular, clockwork process. In fact, it seems to have a mind of its own.
“It’s not even 11 years,” says Guhathakurtha. “The cycle ranges in length from 9 to 12 years. Some cycles are intense, with many sunspots and solar flares; others are mild, with relatively little solar activity. In the 17th century, during a period called the ‘Maunder Minimum,’ the cycle appeared to stop altogether for about 70 years and no one knows why.”
There is no need to go so far back in time, however, to find an example of the cycle’s unpredictability. Right now the sun is climbing out of a century-class solar minimum that almost no one anticipated.
“The depth of the solar minimum in 2008-2009 really took us by surprise,” says sunspot expert David Hathaway of the Marshall Space Flight Center in Huntsville, Alabama. “It highlights how far we still have to go to successfully forecast solar activity.”
That’s a problem, because human society is increasingly vulnerable to solar flare ups. Modern people depend on a network of interconnected high-tech systems for the basics of daily life. Smart power grids, GPS navigation, air travel, financial services, emergency radio communications—they can all be knocked out by intense solar activity. According to a 2008 study by the National Academy of Sciences, a century-class solar storm could cause twenty times more economic damage than Hurricane Katrina.
Right: Areas of the USA vulnerable to power system collapse in response to an extreme geomagnetic storm. Source: National Academy of Sciences. [more]
“Understanding solar variability is crucial,” says space scientist Judith Lean of the Naval Research Lab in Washington DC. “Our modern way of life depends upon it.”
Astronomers were once so convinced of the sun’s constancy, they called the irradiance of the sun “the solar constant,” and they set out to measure it as they would any constant of Nature. By definition, the solar constant is the amount of solar energy deposited at the top of Earth’s atmosphere in units of watts per meter-squared. All wavelengths of radiation are included—radio, infrared, visible light, ultraviolet, x-rays and so on. The approximate value of the solar constant is 1361 W/m2.
Clouds, atmospheric absorption and other factors complicate measurements from Earth’s surface, so NASA has taken the measuring devices to space. Today, VIRGO, ACRIM and SORCE are making measurements with precisions approaching 10 parts per million per year. Future instruments scheduled for flight on NASA’s Glory and NOAA’s NPOESS spacecraft aim for even higher precisions.
To the amazement of many researchers, the solar constant has turned out to be not constant.
“‘Solar constant’ is an oxymoron,” says Judith Lean of the Naval Research Lab. “Satellite data show that the sun’s total irradiance rises and falls with the sunspot cycle by a significant amount.”
At solar maximum, the sun is about 0.1% brighter than it is at solar minimum. That may not sound like much, but consider the following: A 0.1% change in 1361 W/m2 equals 1.4 Watts/m2. Averaging this number over the spherical Earth and correcting for Earth’s reflectivity yields 0.24 Watts for every square meter of our planet.
“Add it all up and you get a lot of energy,” says Lean. “How this might affect weather and climate is a matter of—at times passionate—debate.”
The claim that this is a new idea that is just gaining ground is untrue, however; astronomers have known about this variability for decades, first being postulated in the the late 19th century and gaining major traction in the 1960’s. According to an article by the AGU
“This long search reached a turning point in the 1960s, when convincing evidence of solar variability and of correlation between solar variation and climate change first became available. In 1961 Minze Stuiver found evidence of solar variability in 14C variations in the tree-ring record over the past millenium [Stuiver, 1961]: at times of greater solar activity the solar wind and its magnetic field shield the earth from 14C-generating cosmic rays, resulting in lower 14C absorption by living organisms. Later studies of the preceding 7.5 millennia revealed fluctuations in 14C concentration implying that variations in solar activity comparable to Maunder Minimum are commonplace over scales of 100 to 1000 years. Studies of 10Be have established proxy records of longer-term solar variability. [Hoyt and Schatten, 1997.]
Secondly, in the late ’60s the first measurements of solar irradiation were made from above the atmosphere. These and subsequent space-based measurements, far more sensitive than had been possible from ground-based platforms and relying on the most advanced instrumentation, showed that the solar “constant” did indeed vary. However, the time scale involved was too short to support conclusions about long-term climatic change. [Hufbauer, 1991]
John Eddy tied all these threads together in a now-famous paper of 1976. Examining the historical record, he argued that the current patterns of solar regularity and reliability — an 11-year solar cycle and a constant level of radiation — may likely be ephemeral phenomena amid a longer-term record of solar variability. Records of 14C and of naked-eye sightings of auroras, sunspots, and the solar corona all point to earlier minimums and at least one maximum of solar activity in the past 2000 years. These maxima and minima, Eddy claimed, coincide with periods of climatic extreme — the Little Ice Age of the sixteenth and seventeenth centuries and the Medieval Climatic Optimum of the eleventh through thirteenth centuries.
Eddy’s claims met with considerable scepticism, but evidence for solar variability and its influence on climate has become firmer over the last two decades. While Vladimir K–ppen had attempted a determination of global temperature in the early decades of this century, the first reliable estimates appeared in the early 1960s. In the mid-1980s P.D. Jones, T.M.L. Wigley and others made available the first global syntheses of surface-temperature measurements over both land and oceans. [Jones, et al., 1986; T.M.L. Wigley, 1986] These last estimates all agreed in showing global warming from the late nineteenth century to around 1940, a cooling to the mid-1960s, and substantial warming since then.
Anxiety over the contribution of greenhouse gases to global warming had motivated these calculations of global temperature. But Eddy’s line of argument suggested that part of the temperature change might result from solar variation. By the beginning of our own decade satellite measurements offered continuous, longer-term datasets than had been earlier available. The variations in solar luminosity they reported are sufficient to account for significant climate change, especially if linked to solar cycles on 100-year time scales [Reid, 1988 and 1992; Friis-Christiansen and K. Lassen, 1992; Ardanuy, 1992]. Studies of sun-like stars also point to eras of cyclic magnetic activity punctuated by periods, like our Maunder Minimum, of magnetic quiet. [Baliunas, 1992.]”
So now we see backtracking by the mainstream science community over the whole notion of Anthropogenic global Warming; Willie Soon was excoriated for making the claim that the sun was the dominant forcing in global warming, yet now he has been vindicated (assuming that there actually WAS any planetary warming, something in doubt given the fudging of data by CRU and GISS.)
NASA intends to study solar variability, and we should all welcome it; a large solar flare could crash the world’s communication network or worse. In 1859 an enormous solar flare - called the Carrington Event - blew out telegraph lines and damaged what meager electronic devices that existed. Aurora were visible in the Caribbean! Were such a flare to occur today, it would crash our satellite system, and the resulting EMP would likely blow out all of our finer computer and other electronic devices. Given that everthing we use today has some sort of sophisticated electronic devices - microchips, microcomputers, GPS systems, etc. we would find ourselves in serious trouble. Water stations would not pump water, no vehicles would be on the roads and those that were hardened would find getting gas difficult since pumps would be out, there would be no lights, food would not get to the public. It would be as if the world were suddenly thrown back to 1859, without the old infrastructure to support the much larger population. Chaos would ensue.
We need to know if such an event is coming.
We have wasted a large amount of time with the Global Warming issue, time that could have been better used to address real dangers. How much money has been wasted on computer models of CO2 armageddon that could have been used, say, to help Haiti improve their infrastructure? AGW has been catastrophic to the poor, who have been neglected in favor of Western Guilt and fashionable doomstay scenarios.