When Will The End Come For The Oceans?

Climate change is unlikely to ever boil away Earth's oceans.  Credit: Shutterstock

 After accurate measurements began in the mid-20th century, Ocean temperatures are at their highest. And, things are only going to get worse in the coming years, due to human-induced climate change.

But could the oceans ever get so hot that they begin to boil if humans keep spewing greenhouse gases into the atmosphere,? Thankfully, human's current activities could likely never heat up the world enough to make that happen.

According to Zeke Hausfather, a climate scientist at Berkeley Earth, a temperature data analysis nonprofit organization, "Even if we burned all known fossil-fuel reserves, we wouldn't get nearly that warm. Though, it is worth saying that there are lots of bad climate impacts that happen a long way before the surface is literally hot enough to boil water."

Greenhouse gases like CO2 and methane raise Earth's temperatures by trapping the solar energy inside the atmosphere and surface, the energy that would otherwise radiate away into space. According to Hausfather, "About 93% of this extra heat gets absorbed by the ocean surface."  He further said, "The heat quickly mixes through the top 330 feet of water, a region called mixed layer, taking much longer to reach farther down". But in the last some years, scientists have observed the rise in temperature even in the ocean's deepest part.

Because specific heat capacity of water is greater than air, it can absorb a large amount of heat. According to Hausfather, "The top 8.2 feet of the ocean can hold the same amount of heat as the entire atmosphere above."

So, it's theoretically possible that oceans could get hot enough to boil. All the time, warm water molecules vaporize from the ocean surface. Greater amounts of water in the atmosphere will create a vicious feedback cycle because water vapor, itself is a greenhouse gas. so the world will be hotter overall. Hausfather said" Similar is supposed to have happened on Venus long ago, caused Venus's oceans to have boiled away. But because Earth is farther from the sun than Venus, it would require much more greenhouse gas in Earth's environment to reach that dismal point."

According to paper in the journal Nature Geoscience in  2013, to induce this "runaway greenhouse effect", Earth would need an amount of carbon dioxide that's about 10x more than what could be released from burning all energy resources. This type of analysis may have many caveats and uncertainties. Hausfather further said, "historically, our planet's oceans have fairly recoiled when it comes to climate extremes. For instance, hundreds of millions of years ago, our world had snowball Earth scenario during which the entire surface was covered by ice, while about 55 million years ago, global temperature was an average of 9 to 14 °F hotter (during the Paleocene–Eocene Thermal Maximum, PETM), but each time relatively stable temperatures returned."

Dying sun, dying Earth

Not only Human activities that possibly empty all the ocean. In the future, the sun will die and begin to expand (like the 'giant red star'). According to the Astronomer Robert Smith," Over the course of the next 7 billion years, Earth's temperature will slowly rise."

In 2008, Smith and his colleague Klaus-Peter Schroeder of the University of Guanajuato in Mexico has done calculations to figure out how Earth will die out. Smith said, "It is hard to say exactly when the oceans would begin to boil but this could happen around 1 billion years from now (high uncertainty in that figure).

At that point, the humans might have stopped adding greenhouse gases to the atmosphere and may have long gone the way of the dodos. But even once the oceans are done for, that doesn't mean life will vanish immediately.

 Smith further said, "It is possible that some simple life-forms might survive for a while without water, but in due course, the surface becomes molten, which would almost certainly remove the remaining traces of life."