Renewable energy woes

A recent article in New Scientist features an interesting take on renewable energy from Axel Kleidon of the Max Planck Institute for Biogeochemistry. Apparently he doubts the thermodynamic wisdom of harnessing wind and wave energy. Extracting all this energy will create excess heat and affect the Earth’s energy balance – whatever that is. Unfortunately, no matter what the Earth’s energy balance may be, we can be quite sure nobody knows how to measure it.

Perhaps the sea will go flat and the winds will stop once we’ve sucked all the energy from them. Surreal thought. Sounds like an old-fashioned science-fiction story, which I'm sure is no coincidence.