Composition of Earth's Mantle Revised

It is thinking that has changed, not the mantle. <...significantly different than previously thought...> simply means "the scientists have changed their minds".

Yes, It means they just keep changing their guess.

You mean like global warming, ummm climate change, ummm extreme weather events, ummm, shrinking ice, expanding ice, ummm more earthquakes, less drought, more drought, we said there would be more hurricanes, but . . .. . . damn it. Why can't the weather just see the incontrovertible evidence?

Like the way our CO2 is melting the ice sheets?

http://www.decodedscience.com/antarctic-ice-sheet-melting-geothermal-heat-contributes-to-warming/46565

http://www.dailymail.co.uk/sciencetech/article-2389991/Global-warming-Scientists-discover-heat-INSIDE-Earth-melting-areas-Arctic-ice.html

Don't worry though, these pesky facts won't stop the global control freaks from using CO2 to suffocate freedom, along with transferring the majority of global manufacturing and wealth to China.