In the two decades since he first wrote about global warming, Bill McKibben has become the most visible environmental activist in the United States, pioneering new methods of social protest, and redefining the way environmental groups practice politics. Today he is at the center of the US climate movement.

The energy and climate challenge of the 21^st century is easy enough to describe. For a world of 9 or 10 billion people to live at the per capita wealth and (highly efficient) energy consumption equivalent of present-day Germany, we will need three to four times as much energy as we consume today. If carbon dioxide levels in the atmosphere are to stop increasing, then nearly all of that future energy consumption must come from technologies that produce zero emissions.

Germany’s solar program will generate electricity at quadruple the cost of one of the most expensive nuclear power plants in the world, according to a new Breakthrough Institute analysis, raising serious questions about a renewable energy strategy widely heralded as a global model.

After clear warnings from scientists more than 20 years ago, the issues of human-caused climate change and fossil-fuel-dominated energy should be on the way into the environmental history books. Sadly, they’re not, which is why we need a new global movement of nuclear support.

A bit like the CFC/ozone dilemma, we should by now be enjoying disputes about just how the success came about, and focusing attention on more challenging sources of emissions.

After the European Parliament voted down a proposal to prop up its flagship emissions trading scheme (ETS), most observers finally admitted what has been obvious for a while: the program is contributing little to accelerating the decarbonization of the European economy. However, a few eternal but confused optimists see the program as working just fine. Here are a few thoughts in response to that bit of pushback.

Over the last few decades, humans achieved one of the most remarkable victories for social justice in the history of the species. The percentage of people who live in extreme poverty — under $1.25 per day — was halved between 1990 and 2010. Average life expectancy globally rose from 56 to 68 years since 1970. And hundreds of millions of desperately poor people went from burning dung and wood for fuel (whose smoke takes two million souls a year) to using electricity, allowing them to enjoy refrigerators, washing machines, and smoke-free stoves.

Do the math: simply repeating 2011’s renewable installations for three additional years, through 2014, would thus displace Germany’s entire pre-Fukushima nuclear output.

Or so claims Amory Lovins in a new piece about renewable energy in Germany. Anyone with a passing knowledge of the level of nuclear power in Germany will recognize this claim is utter nonsense within about two seconds. However, since Lovins appears incapable, or unwilling, to do the basic arithmetic, let’s do it here. A couple minutes on Google can find a summary of German solar and wind installations in 2011: