Summer's Last Gasp (and..can humans impact the rotation of the Earth?)

Happy Friday Everyone! 

After some morning fog and low cloud, the skies cleared and it was another beautiful sunny day across the Lower Mainland. I'm tracking big changes in the forecast coming Sunday afternoon/evening.

I'll have more info tomorrow about the potential for thunderstorms and which areas are at highest risk to see some storms develop. Summer's planning on going out with a bang.  

Tomorrow I'll also recap some the flash flooding event that's happened in Colorado over the past couple of days (where some towns received over 200 mm of rain in 24 hours!). Truly shocking. My thoughts are with the communities affected. 





Can humans impact the rotation of the Earth?


The dam.jpg


Large capital projects can add very minuscule changes to the Earth's  moment of inertia. To better explain this concept picture a figure skater twirling around, and as soon as the arms are brought in, an increase in rotational speed is observed, with the mass brought closer to the axis of rotation. The following example is when mass has intentionally been moved further away from the center of our planet. 

The Three Gorges Dam project in China created a reservoir of approximately 39 trillion kilograms of water, which was raised 175 meters above its natural level. 

This is the equivalent of a figure skater extending their hands outward ever so slightly. The result for the rotational speed of the earth is thought to be .06 microseconds slower, which will add up to a full loss of a day in about 4 billion years.  



1)Astronomy: Is there any human activity that can lead to a substantial decrease in the speed of Earth's spin?
2) Three Gorges Dam and the Earth's rotation