New Sunspot Index Breaks Link Between Solar Activity and Climate Change

Posted August 11th, 2015 at 2:42 pm (UTC-5)
3 comments

Large field-of-view image of sunspots. The image has been colored yellow for aesthetic reasons. (Royal Swedish Academy of Sciences)

Large field-of-view image of sunspots. The image has been colored yellow for aesthetic reasons. (Royal Swedish Academy of Sciences)

A newly updated analysis of sunspot numbers over the last 400 years suggests solar activity has nothing to do with climate change, a discovery that eliminates a key argument used by those who question human caused climate change.

Some of those who suggest that climate change is not anthropogenic in nature contend that changes in the sun’s activity are responsible for any increase or decrease in global temperatures.

Scientists have been tracking that solar activity within the sun’s solar cycle by counting sunspots for years.

For the last 160 years scientists have relied on the Wolf Sunspot Number (WSN) – also called the International sunspot number, relative sunspot number, or Zürich number – to count the number of sunspots present on the surface of the sun.

Use of the WSN, since its introduction by Rudolph Wolf in 1856, has allowed scientists to develop a historical record of solar activity over time.

But in 1994 scientists began to question whether the WSN was an accurate method to build a reliable index of historical sunspot records.

Since telescope technology before modern times wasn’t as advanced as today the scientists thought that perhaps some smaller sunspots were being missed in the count.

So, a new counting method called the Group Sunspot Number (GSN) was created by Douglas Hoyt and Ken Schatten in 1994 and introduced in 1998.

Creators of this new way of counting sunspots said that they were able to add to amount of available sunspot data since it included measurements made further back into the sunspot historical record by Galileo, Thomas Harriot and Christoph Scheiner.

However there are huge discrepancies between the WSN and GSN for sunspot measurements made before 1885 and around 1945.  This has become a contentious issue among scientists for some time.

One of the links between solar activity and climate change that’s often cited by the non-believers of human caused climate change is a time period called the Maunder Minimum.

A drawing of the Sun made by Galileo Galilei on 23 June 1613 showing the positions and sizes of a number of sunspots. Galileo was one of the first to observe and document sunspots. (The Galileo Project/M. Kornmesser)

A drawing of the Sun made by Galileo Galilei on 23 June 1613 showing the positions and sizes of a number of sunspots. Galileo was one of the first to observe and document sunspots. (The Galileo Project/M. Kornmesser)

During the Maunder Minimum, which took place between 1645 and 1715, scientists noticed fewer sunspots on the sun’s surface.  Winters throughout this time were also unusually harsh.

Some scientists have said that following the end of the Maunder Minimum, which was also the beginning of the industrial revolution, a new period of increased solar activity began.

This period of increased solar activity, which is said to have peaked in the late 20th century with the Modern Grand Maximum, also happened to coincide with a rise in global temperatures.

While the GSN index reflected this pattern of increased solar activity the WSN didn’t show such a pattern.

A group of scientists led by Frédéric Clette, Director of the Sunspot Index and Long-term Solar Observations program at the World Data Center, Ed Cliver from the National Solar Observatory and Leif Svalgaard of Stanford University have found that the discrepancies between the WSN and GSN were due to a major calibration error in the Group Sunspot Number.

So scientists reconciled and recalibrated the sunspot index which has eliminated the discrepancies between the WSN and GSN.

The resulting new sunspot index called the Sunspot Number Version 2.0, which also includes the older historical data of the GSN, shows that solar activity has been constant over the past few centuries without any noteworthy long-term upward trends in solar activity since 1700.

This means that any rise in global temperatures since the beginning of the industrial revolution or end of the Maunder Minimum cannot be attributed to an increase in solar activity.

The scientists presented their new sunspot index at the International Astronomical Union’s 29th General Assembly being held in Honolulu, Hawaii through August 14th.

Rick Pantaleo
Rick Pantaleo maintains the Science World blog and writes stories for VOA’s web and radio on a variety of science, technology and health topics. He also occasionally appears on various VOA programs to talk about the latest scientific news. Rick joined VOA in 1992 after a 20 year career in commercial broadcasting.

3 responses to “New Sunspot Index Breaks Link Between Solar Activity and Climate Change”

  1. Nikola Milovic says:

    Based on all these papers, documents on millions of pages with diagrams and “evidence” shows that almost nothing has been proven, and that it is related to the causes of climate change, particularly to the causes of the cycle of sunspots.
    How can it be anything to argue and argue about anything, unless he has no proof.
    For example: Does anyone know How is the sunspot cycle by about 11.2 YEAR? Who is it that causes creates these sunspots and so that it takes place in cycles of about 11.2 years? Or to form a butterfly diagram of these spots for about 123 years?
    If it does not, whether it makes any sense to discuss it and deceive both themselves and all those who read millions of pages, written explaining this phenomenon, but no true evidence.
    When forming the sunspot cycle of about 11.2 years and for the butterfly diagram of the 123 years. Calculate: 11.2×11 = 123.2,
    It is certain that amount, an average of 11.2 years is dependent on the person who causes these changes, but it is changing for millions of years with different intensities.
    In all these present evidence and data, there is a lot of useful and current, but the main “culprit” is not detected. If detected, will not be known for all past and future time, and for a short present, as these intensities change of even one second to about 10 ^ 11 years.
    I offer cooperation to solve the riddle of this millennium.
    Note: Sunspots are not the cause of climate change, but these are only indicators that something in the solar system by changing certain laws, and that goes for the whole solar system.
    How can you know how to measure the number of sunspots, the sun we see in terms of volume by around 27-30 days or successively around 12-13 times a year.?

  2. Bill says:

    A comprehensive climate change model must be developed that takes into account not only sunspot activity, but volcanic activity, CO2, etc. We cannot pass draconian laws that will destroy the global economy without knowing what we are doing.

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