Earth has an abundance of water, right? When you look at pictures of Earth from space a majority of its surface is covered in water. But that surface water is thin compared with the thickness of the crust, the mantle, and the core of the Earth – similar to the peel of an apple compared with its “meat” and core inside.
And the potable drinking water is a small portion of the water on the surface. Most of what you see on the surface is salty ocean water, which although it can be desalinated, is difficult and expensive to do.
So how abundant is that water actually? A new article on space.com by David A. Weintraub (professor of astronomy at Vanderbilt University) suggests that while it may be abundant now, if global warming continues at its current rate and beyond a few degrees above average (we’re currently at 0.8 degrees Celsius above average), we could go the way of Venus and Mars. Research suggests they originally had vast oceans of water but lost them. We know that Venus lost them to heat.
One effect of warming is that warmer air can hold more moisture. It doesn’t cool and let the water rain out as easily. Moreover, as the air warms, it dries the soil and evaporates the bodies of water more quickly. The oceans warm up; although more slowly overall, the surface heats up and the ocean circulation brings that warmer surface water to lower depths and as the cooler water comes to the surface, it is heated. Warmer water in the tropics is circulated to the northern latitudes as well, and cooler northern waters are brought to the tropics where it is heated. Thus, the oceans just keep getting warmer, and even if we were to stabilize carbon and methane levels to reduce global warming, the effect would be slow to affect the oceans, so the warm up of the oceans and the atmosphere would just continue.
I recommend reading the book Six Degrees: Our Future on a Hotter Planet by Mark Lynas, which details the effects by degrees of increase in global warming on our planet. It really spells out the future of the Earth if we continue to ignore this critical issue. Written by a journalist but based on the review of a slew of science research, it is no sci-fi apocalyptic fantasy. I’ll warn you that it becomes bleak at the 4-degree chapter and beyond.
The article by David Weintraub says that part of the problem of losing water is because of the make-up of water (hydrogen or deuterium and oxygen) and the ability of a planet to hold those constituent elements due to gravity. As water is broken down from natural processes, the lighter hydrogen gets lifted higher into the atmosphere and escapes, which is what happened on Venus and, potentially, what happened on Mars. Mars eventually had a much thinner atmosphere and a weaker magnetic field and the water boiled away, but when its atmosphere was thick enough to hold water its temperature was higher and could have led to this same effect.
Thus Weintraub asks us to consider, are we doomed to the same future as Venus and Mars when we ignore global warming or put off doing something about it? We would be wise to consider the question.
As a sidebar to this story, and as an update to my last article, I wonder if global warming or loss of water might not be added to the list of reasons we haven’t been contacted by extraterrestrials or they aren’t visible. It may be one of those natural disasters that complex cultures don’t address in time, or it may be that the water on some planets is so precarious that even if it sustains life at some point, it boils off or evaporates too quickly for them to mature to a stage where they can either attempt to communicate beyond their solar system or even leave the bounds of their atmospheres.
Perhaps water isn’t just the most necessary ingredient for life but also its greatest limit.
© 2015. Alan Eggleston. All Rights Reserved.