What If the Oceans Disappeared?

By: Gallagher Flinn  | 
The Arizona desert is vast.
Without oceans, rain would be rare. Without rain, Earth would become one huge desert. John Kershner/Hemera/Thinkstock

The good news: We wouldn't have time to miss the dolphins. The bad news: We'd be too busy dealing with everything in the world being on fire. Imagining Earth without water, it would be hard to focus on anything else.

The oceans are the most important support system for life on Earth — maybe even necessary for evolution on any planet in the first place [source: Cullum]. So it begs the question: without sea levels and deep ocean trenches here to play a vital role in our environment, how would our planet cope?


The Benefits of Earth's Ocean Water

Oceans basically have two life-supporting roles. First, they absorb and distribute solar radiation. Without water, harsh rays from the sun would bake the equator while distributing almost no energy to the poles, especially in the winter.

Fortunately for us, water does a great job of absorbing energy, and the oceans regulate temperatures around the Earth. Currents circulate warm tropical waters to the north and south and cold water back to the equator, distributing heat energy so that no place gets too hot for life to survive and warming colder areas.


Second, the oceans feed the water cycle — the movement of water from the seas to the air and clouds and back again to the sea or to fall on dry land. When water is heated at the equator, it evaporates and becomes clouds. As warm air rises, it also draws in cooler air from underneath.

This process stimulates more even heat distribution, turning places where it would otherwise be too cold to live into lush, balmy gardens. That's why the Mediterranean is so temperate and why there are places in Scotland, warmed by the Gulf Stream, where you can grow palm trees.


How Much Water Would Be Left?

But let's get back to what would happen if the oceans were gone. In this scenario, we're going to say the oceans have turned to dirt. We'd like to give ourselves a small window of survivability, so let's say the dirt is moist enough that it won't immediately turn the planet into an enormous dust storm.

The oceans are gone, but we still have some water. Let's take stock. Ice caps, lakes and rivers (which now flow to vast expanses of soil) and underground water are still available. Added together, those sources total about 3.5 percent of our present water supply, the other 96.5 percent having disappeared with the oceans. That's not enough to get a decent worldwide water cycle going, even if we melted the ice caps. (About 68.7 percent of Earth's fresh water is frozen in glaciers, ice caps and permanent snow, mostly in Antarctica [source: USGS].)


Without clouds forming over the ocean, rain would be incredibly rare, and the planet would become desert. We'd watch our lakes and water supplies dwindle a little more every year until nothing was left. Meanwhile, the ocean floor and its mid ocean ridges would be exposed to ambient temperatures, creating huge potential changes in how our planet behaves. This could impact everything from global temperatures to the activity of tectonic plates and volcanos.

Worse Than the Ice Age?

Humans might survive for a while near our homes. We would still have access to groundwater and might get some underground hydroponic farms working. But on the surface, plants and animals would begin to die out immediately. While trees can survive for a while without water, eventually everything would become so dry that fires would span the continents.

This would be a multifaceted problem for humans: Aside from the usual problems associated with fire (such as burning to death), the blazes would release tons of carbon dioxide into the progressively stifling atmosphere, accelerating global warming. For humankind, the situation would be more inhospitable than the ice age.


The sun would continue to pound the equator, turning it into a furnace with no relief from circulating ocean currents. Meanwhile greenhouse gases from the world's fires would trap the sun's energy close to the ground. Some difference in temperature between night and day would create high- and low-pressure systems and produce wind, but the average temperature on Earth would be 153 degrees Fahrenheit, making surface life impossible for even the hardiest desert animals [source: Philander].

Last Stop... Antarctica?

People would have to move. Humanity's only hope would be the window when the Antarctic ice sheet was still intact, prompting massive migrations to the Southern Hemisphere. As temperatures across the globe rose and Earth's surface became uninhabitable, all of our energy would go toward collecting Antarctic ice underground, where it would be safe from evaporation.

We might try to build some kind of self-sustaining biosphere underground, but Antarctica's remoteness would make it difficult. Just getting there would be hard enough, given the unpredictable sea level. And survivors would find a flooded wasteland and no infrastructure or resources — no mines, no roads, no food. It's unlikely enough people would survive to finish the project. The few remaining stragglers would dwell in underground bunkers.


Things would get worse. On the planet's surface, all plant life is gone. As the world burns, the atmosphere would become less and less oxygenated, perhaps becoming unbreathable for humans, even if they could somehow tolerate the extreme surface temperatures. The land would fry.

Assuming humans could survive much longer in our Antarctic bunkers, there would be no way to restart a healthy carbon cycle or bring temperatures back down to reasonable, livable levels. As humans ran out of the scant resources we'd packed along to Antarctica, we'd die off. Earth's only survivors would be small colonies of chemosynthetic bacteria hidden underground in hot springs. Without oceans, everyone else dies.


The Woods Hole Oceanographic Institution

Fortunately, we aren't walking into this extinction level event without a watchful eye on the situation. The Woods Hole Oceanographic Institution is a non-profit research organization based out of Woods Hole, Massachusetts. This private institution, which is committed to studying the oceans and marine life, is also monitoring the effects of global warming.

With research groups like the Woods Hole Oceanographic Institution studying the rising sea levels, ocean acidification, and changes in ocean circulation, we can at least breathe easier knowing that some of humankind's smartest minds are watching the situation closely.


Lots More Information

Related Articles

  • Cullum, Jodie et al. "The importance of planetary rotation period for ocean heat transport." Astrobiology. Vol. 14, No. 8. 2014.
  • Ocean Explorer. "How does the ocean affect weather on land?" Office of Ocean Exploration and Research. June 21, 2013. (May 2, 2015) http://oceanexplorer.noaa.gov/facts/climate.html
  • Philander, S. George. "Our Affair with El Niño: How We Transformed an Enchanting Peruvian Current into a Global Climate Hazard." Princeton University Press. 2008.
  • Roach, John. "Source of Half Earth's Oxygen Gets Little Credit." National Geographic News. June 7, 2004. (May 2, 2015) http://news.nationalgeographic.com/news/2004/06/0607_040607_phytoplankton.html
  • Stewart, Robert. "Oceanography in the 21st Century: The Ocean and Climate." 2005. (April 15, 2015) http://oceanworld.tamu.edu/resources/oceanography-book/oceansandclimate.htm
  • U.S. Geological Survey. "How much water is there on, in and above the Earth?" U.S. Department of the Interior. March 19, 2014. (April 15, 2015) https://water.usgs.gov/edu/earthhowmuch.html