Fritz Vahrenholt, the the grandfather of global warming who after he changed his position was shunned, or rather:- The believer who never was.
Varenholt had studied Chemistry in Münster and started his professional career at the federal Umweltbundesamt (environmental protection agency) in Berlin and the Ministry for Environment of Hesse. From 1984 till 1990 he was in a leading role in Hamburg, first as Staatsrat for environment, 1990 to 1991 for the administral Senatskanzlei, and the Umweltsenator (senator for the environment) in Hamburg from 1991 to 1997.In 1998 he entered the energy industry and until 2001 was on the Board of Deutsche Shell AG, a Shell subsidiary. In 2001 he moved to post of CEO of the wind turbine company REpower Systems AG and remained there until 2007. From February 2008 he was CEO of electric power company RWE subsidiary RWE Innogy, a post he will step down from in mid-2012. Prof. Dr. Varenholt has a doctorate in Chemistry. In 1999 he was made an Honorary Professor of chemistry at the University of Hamburg.Global Warming Skepticism
Vahrenholt is skeptical of human-induced global warming. In 2012 Vahrenholt together with geologist Sebastian Lüning published Die kalte Sonne: warum die Klimakatastrophe nicht stattfindet (The Cold Sun: Why the Climate Crisis Isn’t Happening), a book asserting that climate change is driven by variations in solar activity. They predict the Earth is entering a cooling phase due to periodic solar cycles, and will cool by 0.2 to 0.3 degrees C by 2035. Other contributors are Nir Shaviv, Werner Weber, Henrik Svensmark and Nicola Scafetta.Vahrenholt’s claims have been met with criticism from Global Warming experts who have argued his arguments contain errors. He has also been criticized for misrepresenting the IPCC, and the evidence for Global Warming.   
The claim Vahrenholt was a believer and now sceptic is from notrickszone denial blog quoting the German media : SPIEGEL features a story on environment expert Prof. Dr. Fritz Vahrenholt, author of the new book Die kalte Sonne” (The Cold Sun). Vahrenholt’s underlying message is “It’s also the sun, stupid!”
THE CLIMATE REBEL
With heretical claims, RWE manager Fritz Vahrenholt is causing a commotion: ‘The climate catastrophe is not taking place’, the environment expert claims. The sun is being underestimated as a natural climate factor. ‘The sun has been weak since 2005′, Vahrenholt said in a DER SPIEGEL interview. ‘We can only expect cooling from it for the time being.’”
Fritz Vahrenholt, 62, who holds a doctorate in chemistry, has been a rebel throughout his life. “Perhaps it’s just part of my generation,” he says.
He is typical of someone who came of age during the student protest movement of the late 1960s, and who fought against the chemical industry’s toxic manufacturing plants in the 1970s. His party, Germany’s center-left Social Democratic Party (SPD), chose him as environment senator in the city-state of Hamburg, where he incurred the wrath of the environmental lobby by building a waste incineration plant, earning him the nickname “Feuerfritze” (Fire Fritz). He worked in industry after that, first for oil multinational Shell and then for wind turbine maker RePower, which he helped develop. Now, as the outgoing CEO of the renewable energy group RWE Innogy, he is about to embark on his next major battle. “I’m going to make enemies in all camps,” he says.
………I don’t claim that I know precisely whether the sun is responsible for a 40, 50 or 60 percent share of global warming. But it’s nonsense for the IPCC to claim that the sun has nothing to do with it.
In the same interview Vahrenholt reveals himself to be more lukewarm rather than sceptical
SPIEGEL: If we take your book to its logical conclusion, it will be unnecessary to reduce CO2 emissions at all.
Vahrenholt: No. Even a temperature increase of only one degree would be a noticeable change. But I am indeed saying that climate change is manageable because the cooling effects of the sun and the ocean currents give us enough time to prepare. In any case, it will be easy for us in Germany to adjust.
Vahranholt admits he is doing no original research. His environmental qualifications are also suspect as the quote demonstrates as well as his association with Shell. As for the believer who became a sceptic:- this seems to have derived from his book launch where he is described as being the founder of the German Green movement, a statement that is not true, he was an SPD politician who had the office of environment minster whilst the SPD and Greens were in coalition government. Spoke at the GWPF 2012 conference and reiterated his ‘green’ credentials.