What happens if all the ice in the world melted?

What would happen if all the ice in the world just suddenly melted? Are we able to survive? Which countries would be affected the most? Ice covers 10 percent of the earth’s surface, and stores 75 percent of the planet’s freshwater, but just how important is it? We always hear about the melting ice caps and rising sea levels, and it’s certainly becoming a major issue that humankind will face. Rising temperatures are causing ice sheets around the world to shrink, and the consequences are potentially catastrophic. Other than being a store for freshwater, ice is integral to the way that our planet works.

Ice can be found in many places across the world, in glaciers, on mountain tops, and floating in the oceans- but more than 99 percent of the ice on earth, is located in the Greenland and Antarctic Ice Sheets. Between them, they cover a little more than 6 million square miles, which is larger than the United States and Mexico combined. This Arctic sea ice performs a number of functions. It helps to keep the polar regions cool, and influences the entire world’s climate by regulating temperatures in the ocean through a process known as thermohaline circulation. It is reflective, which means that around 80 percent of sunlight that shines on it bounces back into space. It’s also responsible for altering the direction and reducing the power of storms. In addition to this, thick ice sheets lie on top of arctic tundra and marine sediments act as a protective layer, preventing the release of high levels of powerful greenhouse gases like methane. During the peak of the last ice age, glaciers reached across large parts of Europe, North America, South America, and small regions in Asia. They were constantly thawing and refreezing and receded back as the ice age ended.

The level of ice coverage has never been consistent throughout the planet’s lifetime, so it’s possible that at least some of the signs of melting ice could be a part of a natural cycle. With all this being said, there’s still evidence that a different process is now occurring, and regions that have been covered in ice for millions of years are now seeing a change. A big factor in this is global warming. The increasing quantities of greenhouse gases in the atmosphere are resulting in more heat being retained in the environment. This is raising the average temperature across the globe, and weakening the integrity of the ice sheets.

This is just the beginning of a vicious cycle because when the ice melts, less sunlight is reflected back, so even more heat is retained within our atmosphere and thus, even more, ice melts. The real concern is what happens in the polar regions. They contain such huge volumes of water that it would have a devastating effect if released. If the smaller of the ice sheets in Greenland were to completely melt, it’s estimated that sea levels would rise by about 20 feet (6 meters). If the Antarctic ice sheet were to melt, the sea levels would rise by about 200 feet (60 meters). All low-lying islands and coastal regions would be flooded. In New York, the roads and streets of Lower Manhattan, for example, would be completely submerged after just an 8-foot rise (or about 2.5 meters).

In the past 3 decades, 8 low lying Pacific islands have been reclaimed by the ocean, where in some places the water levels have risen by almost half an inch per year since 1990. The Maldives are thought to be at imminent risk, and other low lying coastal regions, such as Bangladesh, are also being forced to prepare for the worst. Not only does put lives at risk, but it will force millions to flee those areas. An ocean rise of less than 10 feet could trigger a mass migration of millions of people which would completely change the population spread of the world, and force society to change along with it.

The story would be much worse if all of the ice melted, and the sea rose by more than 200 feet. The entire Atlantic seaboard of the US would be submerged. New Orleans, New York, and Charlestown, to name a few, would find themselves deep underwater and far from the new coastline. In Europe- Denmark, the Netherlands, the Western coast of the UK and large parts of France would be lost- and even Australia would develop a large lake near its center. With more than half of the world’s population living in coastal areas, this outcome would be disastrous.

This outlook is rather bleak, but the good news is there’s still of time to take preventative steps. Reducing our contribution to global warming is the obvious first step, but work also needs to be done to understand the complex geological processes that are at work. Extreme weather events will be more likely without ice sheets to subdue them, and the potential damage to ecosystems is unimaginable. Unfortunately, there are some places, such as the Maldives, that will likely suffer the consequences within our lifetimes, and resources will need to be kept aside to take care of those that are directly affected. At the current rate of melting ice, it’s thought there could be a further increase in sea level of 3 feet by the end of the century. But with the rate of melting constantly increasing, this could prove to be a massive underestimation. We may not experience any of the worst effects ourselves, but if we want to pass on a habitable planet to our descendants, it’s time we started making a change.