Many believe that last year's extreme market volatility was heightened by high-frequency traders.

ECONOMIST: High-frequency trading

Quartz watches use very high-frequency oscillations of a crystal, which can be tuned with extreme precision to produce regular signals.

ECONOMIST: A luxury watchmaker is putting silicon in its timepieces

Record high temperatures are occurring with far greater frequency than in decades past, and crop yields decline sharply in extreme heat.

CNN: Extreme heat and droughts -- a recipe for world food woes