Tuesday, March 6, 2012
The Blue Planet's New Water Budget: Do We Have Enough?
Researchers have examined 3.8 billion year old minerals from Greenland which are derived from the Earth’s primordial oceans in order to approximate the ancient water budget. (Credit: Image courtesy of University of Copenhagen)
Investigating the history of water on Earth is critical to understanding the planet's climate. One central question is whether Earth has always had the same amount of water on and surrounding it, the same so-called "water budget." Has Earth gained or lost water from comets and meteorites? Has water been lost into space? New research into Earth's primordial oceans conducted by researchers at the Natural History Museum of Denmark at the University of Copenhagen and Stanford University revisits Earth's historical water budget.
The results have just been published in the Proceedings of the National Academy of Sciences.
Water accounts for about ½ of a thousandth of Earth's total mass, despite the fact that roughly 70% of the planet's surface is covered by this substance so vital to survival. Indeed, water is a relatively "rare substance" on our "Blue Planet."
Where does water come from?
"One of the absolutely most intriguing things about Earth is that there are oceans of water and that the presence of liquid water has enabled the existence of life on Earth. Therefore, questions concerning how Earth got its oceans, where the water came from and -- whether we are losing or gaining water from space -- are fundamental questions in the understanding of the Earth's history," says Emily Pope of the Nordic Center for Earth Evolution at the Natural History Museum of Denmark, University of Copenhagen.
Earth's "little bit" of water is divided among a variety of reservoirs. Therefore, a fairly accurate assessment of how much water currently exists on Earth can be made. But now, Emily Pope and her colleagues at the Natural History Museum of Denmark and Stanford University have also been able to determine that liquid water was also in existence upon the young Earth, billions of years ago. And, more consequentially, they have been able to approximate the ancient water budget.
The researchers have done this by examining 3.8 billion year old minerals from Greenland which are derived from Earth's primordial oceans.