How regulations can backfire on climate change

Oxford Professor Dieter Helm has a great recent NYT op-ed that illustrates the law of unintended consequences for regulations designed to reduce global warming.  Helm points out that although Europe has invested heavily in green technologies, it has made less progress in reducing carbon emissions than the US. 

The reason?  In the US we have cut down on coal and substituted natural gas.  Both are carbon-based but natural gas is much cleaner.  Europe has cut back on coal usage in its manufacturing processes, but because it is now importing more goods from China there is no net global reduction in coal usage.  Coal that would have been burned in Europe is now being burned in China.  Also some areas in Europe are cutting back on nuclear-generated electricity and are burning more coal.  Helm, like most economists, advocates a carbon tax that would apply regardless of the source.