Why did earth turn white?

Answer & Explanation:

Scientists believe that three to four severe ice ages, which froze nearly or all of the surface, occurred between 750 million and 580 million years ago, probably because Earth's land masses were all located at or near the equator, which resulted in increased weathering. Weathering is when wind and precipitation break down rocks and minerals on the planet's surface. The process leads to decreased carbon dioxide levels in the atmosphere, which allows more heat to dissipate from the surface and into space, cooling the planet.Once the world iced over, carbon dioxide brought up by volcanoes could no longer be removed from the atmosphere: there were no rivers, no rain or snow and no weathering. For millions of years, carbon dioxide levels climbed, eventually rising to about 300 times what they are today.

When scientist examine data such as historical documents, they are using the "scientific methods"

Ithink its because more have died recently than in the past.