This one is for Silke (from the Jet Propulsion Lab, via Hot Air)
Long-term climate records are a key to understanding how Earth's climate changed in the past and how it may change in the future. Direct measurements of light energy emitted by the sun, taken by satellites and other modern scientific techniques, suggest variations in the sun's activity influence Earth's long-term climate. However, there were no measured climate records of this type until the relatively recent scientific past.
Amazing. To actually think that the big ball that hangs in the daytime sky, and is, incidently, bright enough to blind us, could have an influence on the climate.
Alexander Ruzmaikin and Joan Feynman of NASA's Jet Propulsion Laboratory, Pasadena, Calif., together with Dr. Yuk Yung of the California Institute of Technology, Pasadena, Calif., have analyzed Egyptian records of annual Nile water levels collected between 622 and 1470 A.D. at Rawdah Island in Cairo. These records were then compared to another well-documented human record from the same time period: observations of the number of auroras reported per decade in the Northern Hemisphere. Auroras are bright glows in the night sky that happen when mass is rapidly ejected from the sun's corona, or following solar flares. They are an excellent means of tracking variations in the sun's activity.
The study covered a period from before the Global Climate Optimum, also known as the Medieval Warm Period, into the Little Ice Age.
The researchers found some clear links between the sun's activity and climate variations. The Nile water levels and aurora records had two somewhat regularly occurring variations in common – one with a period of about 88 years and the second with a period of about 200 years.
So the Sun can actually cause warming. Hard to imagine that a giant nuclear furnace responsible for keeping the Earth from becoming a ball of ice could actually, you know, go through phases that warm and cool the Earth.
So what causes these cyclical links between solar variability and the Nile? The authors suggest that variations in the sun's ultraviolet energy cause adjustments in a climate pattern called the Northern Annular Mode, which affects climate in the atmosphere of the Northern Hemisphere during the winter. At sea level, this mode becomes the North Atlantic Oscillation, a large-scale seesaw in atmospheric mass that affects how air circulates over the Atlantic Ocean. During periods of high solar activity, the North Atlantic Oscillation's influence extends to the Indian Ocean. These adjustments may affect the distribution of air temperatures, which subsequently influence air circulation and rainfall at the Nile River's sources in eastern equatorial Africa. When solar activity is high, conditions are drier, and when it is low, conditions are wetter.
But the majority of what is causing that wopping 1 degree Celcius change upward over the past 150 years couldn't possibly be the Sun now, could it? Has to be Mankind. Because otherwise, the global warming as caused by Mankind zealots could push to destroy the developed countries industrial bases, and make lots of money themeselves while pushing it, but not living the life. Just ask Al "I own several non global warming friendly houses, take limo's, fly all over the world, and owned a zinc mine" Gore.
More: Info on the Sun:
- The Sun's output is not entirely constant. Nor is the amount of sunspot activity. There was a period of very low sunspot activity in the latter half of the 17th century called the Maunder Minimum. It coincides with an abnormally cold period in northern Europe sometimes known as the Little Ice Age. Since the formation of the solar system the Sun's output has increased by about 40%.
- In what could be the simplest explanation for one component of global warming, a new study shows the Sun's radiation has increased by .05 percent per decade since the late 1970s
- The sun's energy output is 386 billion megawatts each second, this is caused by the process of nuclear fusion.
- the Sun's energy output is equivalent to about 4 trillion trillion 100 watt light bulbs!
Interesting.
