This month's shock new bestseller in Germany is a climate skeptical book called Die Kalte Sonne ("The Cold Sun."). It's shocking not just because Germany has, up till now, been one of Europe's most ecologically correct economies, but also because its co-author Professor Fritz Vahrenholt is one of the country's best known environmentalists.

If Al Gore or David Suzuki or NASA's Jim Hansen were suddenly to renounce man-made global warming, it could hardly be more surprising. Up until two years ago, Vahrenholt was Germany's Godfather of Green: a green activist and former environment minister for the State of Hamburg. In his new book, however, published by one of Germany's most respected, mainstream publishers Hoffman und Campe, Vahrenholt pours cold water on the notion of catastrophic man-made global warming. He accepts that the planet has warmed by 0.8 degrees C in the last century – but not the idea that this is anything to worry about.

Vahrenholt first began to smell a rat two years ago when he was asked to review an IPCC report on renewable energy. According to blogger P Gosselin he was not impressed:

“He found hundreds of errors. When he pointed them out, IPCC officials simply brushed them aside. Stunned, he asked himself, “Is this the way they approached the climate assessment reports? Vahrenholt decided to do some digging. His colleague Dr. Sebastian Lüning also gave him a copy of Andrew Montford’s The Hockey Stick Illusion.

He was horrified by the sloppiness and deception he found. Persuaded by Hoffmann & Campe, he and Lüning decided to write the book. Die kalte Sonne cites 800 sources and has over 80 charts and figures. It examines and summarizes the latest science. Conclusion: climate catastrophe is called off.

Vahrenholt's dramatic change of heart has caused predictable rage in German green circles. The University of Osnabruck recently disinvited him from a speaking engagement on February 8 claiming his views were "provocative". Traditionally skeptical views like his are dismissed as "being in the pay of Big Oil." But with Vahrenholt the charge just does not stick. As German magazine Focus reports, Vahrenholt has for years been an advocate of renewables, not fossil fuels:

“Since 2001 he has worked for companies that earn their money with renewable energy, first for Repower Systems, a leading manufacturer of wind turbines. Since 2008 for Innogy, the largest German investor in renewable energy. The RWE subsidiary invested over one billion Euros annually in CO2-free electricity. Accordingly, it would be in his interest to celebrate the transformation of energy by the Federal Government.

However, he does the opposite."The promotion of photovoltaics is madness," he said in Munich. "It is the most uneconomic form of climate protection." He still considers wind power to be reasonable. But his earlier euphoria was dampened, as he experienced in 2008 and 2009 that the wind sometimes pauses for weeks in Central Europe. He began to learn about cyclical fluctuations in air pressure, which exert a strong influence on the wind patterns and the climate.

Die Kalte Sonne's popularity reflects a growing skepticism among the German public about the likelihood of climate catastrophe. Today only 31 per cent of Germans are afraid of global warming. In 2006, the figure was twice as many.

But this newfound climate realism may yet come too late to save Germany from a looming energy crisis. This has been caused partly by the Angela Merkel government's electorally popular but economically short-sighted decision to phase out nuclear power (in the wake of last year's Japanese earthquake disaster). As Germans are beginning to discover to their cost, the "great transition" to renewable energy is not running smoothly.

As Financial Times Deutschland reported in November, 2011:

“Fritz Vahrenholt, CEO of RWE's renewable division, warned against the "danger of blackouts" given the rapid shutdown of many German nuclear power plants and pointed to rising energy prices and the growing import of nuclear power. At the same time, the nuclear energy phase-out also removes a source of revenue for investments in green power for energy suppliers. Lack of electricity grids are further slowing down the development of renewables; delays are caused by bureaucratic procedures and citizen protests.

The situation is critical for wind energy, which plays a central role in the energy concept of the government. On Wednesday, the electricity network operator Tennet, which has to wire all offshore installations in the North Sea, warned that to wire dozens of wind farms at a same time, as planned, would fail due to "lack of financial, human and material resources of all involved"; as it is written in an urgent letter to the Chancellor's Office, the Economic and Environment Ministries: "The conditions have to be substantially revised and the burden has to spread over more shoulders."

Germany's solar revolution has proved just as ineffectual. According to Spiegel Online the drive for solar – in a country not generally renowned for its abundance of sunshine – has cost the German taxpayer more than 100 billion Euros in subsidies.

Solar energy has gone from being the great white hope, to an impediment to a reliable energy supply. Solar farm operators and homeowners with solar panels on their roofs collected more than €8 billion ($10.2 billion) in subsidies in 2011, but the electricity they generated made up only about 3 percent of the total power supply, and that at unpredictable times.

The distribution networks are not designed to allow tens of thousands of solar panel owners to switch at will between drawing electricity from the grid and feeding power into it. Because there are almost no storage options, the excess energy has to be destroyed at substantial cost. German consumers already complain about having to pay the second-highest electricity prices in Europe. Until now, Chancellor Angela Merkel had consistently touted the environmental sector's "opportunities for exports, development, technology and jobs." But now even members of her own staff are calling it a massive money pit.

Then again, in Europe as in the US, the drive for renewables was never really about practical economic considerations. It always had much more to do with the quasi-religious, anti-capitalist zeal of campaigners like Professor Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research and chairman of the Scientific Advisory Council on Global Environmental Change (WBGU), an influential advisory committee for the German Chancellor Angela Merkel.

In April 2011, the WBGU presented a report entitled "World in Transition - Social Contract for a Great Transformation". The main theses of the WBGU are as follows: The current economic model ("fossil industrial metabolism") is normatively untenable. "The transformation to a climate friendly economy... is morally as necessary as the abolition of slavery and the outlawing of child labor." The reorganization of the world economy has to happen quickly; nuclear energy and coal have to be given up at the same time and very soon.

As Vahrenholt noted in Die Welt, this is akin to the sweeping totalitarian measures undertaken in the Soviet Union in the 1920s and 1930s or in China under Mao's Great Leap Forward. Germany, warned Vahrenholt, is in danger of "Sliding head over heels into eco dictatorship."

His new bestseller Die Kalte Sonne could not come at a more welcome or necessary juncture.