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Earth’s Core Provides Climate Insights

March 14, 2011 Comments off

 

Summary: By studying the molten core of the planet Earth, scientists have uncovered new evidence that humans play a dominant role in changing Earth's climate. The study could have important implicaitons in understanding the future of life on our planet.

 

The latest evidence of the dominant role humans play in changing Earth’s climate comes not from observations of Earth’s ocean, atmosphere or land surface, but from deep within its molten core.

Scientists have long known that the length of an Earth day – the time it takes for Earth to make one full rotation – fluctuates around a 24-hour average. Over the course of a year, the length of a day varies by about 1 millisecond, getting longer in the winter and shorter in the summer. These seasonal changes in Earth’s length of day are driven by exchanges of energy between the solid Earth and fluid motions of Earth’s atmosphere (blowing winds and changes in atmospheric pressure) and its ocean. Scientists can measure these small changes in Earth’s rotation using astronomical observations and very precise geodetic techniques.

But the length of an Earth day also fluctuates over much longer timescales, such as interannual (two to 10 years), decadal (approximately 10 years), or those lasting multiple decades or even longer. A dominant longer timescale mode that ranges from 65 to 80 years was observed to change the length of day by approximately 4 milliseconds at the beginning of the Read more…