While there are many compelling arguments in favor of Wind and Wave energy, there are few that go against these sources of power. According to Axel Kleidon, Mark Buchanan and others, Wind and Wave energy are essential components of our Climate system and once we start tapping their energy, Earth's climate will begin to change. They express caution against wide spread use of Wind and Wave power plants. While these arguments have compelling science behind them, we are still long way away from making any noticeable impact.

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http://www.newscientist.com/article/mg21028063.300-wind-and-wave-farms-could-affect-earths-energy-balance.html