Map Monday: what will our world look like when all the ice sheets melt?

We all know the polar ice is melting, and melting faster than one could have imagined. Just ask the polar bears. The Earth’s poles are sometimes called the canary in the coal mine for climate change. Why? Because the warming of the Earth hits the Arctic and Antarctic earlier and harder than everywhere else, which then in return impacts the weather and sea levels around the world. It starts because the atmospheric currents caused by the rotation of the Earth, affecting our weather every day and which flow naturally towards the poles, transport our carbon emissions and other pollutants up to the polar regions, where they accumulate. So even though nobody up there has produced the emissions and pollution, those regions reap the “rewards”. And as the air warms, and the sea ice and snow cover melt, the darker water and land that are now exposed absorb the sun’s rays, whereas the white snow cover and ice reflected the sun’s rays. It’s a double whammy.

Here’s an example of how much the polar ice in the Arctic has shrunk in the past 20 years.

Loss of polar ice since 2000. Image credit: NOAA – National Oceanic and Atmospheric Agency, climate.gov

Over 99% of all ice found on land is contained in the ice sheets covering Antarctic and Greenland. Even partial melting of this ice due to climate change will significantly contribute to sea level rise. If the Greenland Ice Sheet completely melts, scientists estimate that sea level would rise about 7 meters (23 feet). If the Antarctic Ice Sheet completely melts, sea level would rise by about 60 meters (200 feet). To give you an idea of how much impact even the 23 foot rise a melted Greenland ice sheet would have on our planet, believe it or not the Earth would actually rotate more slowly, with the length of the day becoming longer than it is today by about two milliseconds.

The Guardian newspaper has published a number of articles on this topic in the past year or so, including such headlines as ‘Greenland’s ice sheet melting seven times faster than in the 1990s’ and ‘The Arctic is in a death spiral. How much longer will it exist?’ It will exist in some modified form for a long, long time, but as a sad, broken version of its current self. And its time looks to be finite. Today, the Greenland ice sheet is losing mass about six-seven times faster than it was just a few decades ago. Between 2005 and 2016, melt from the ice sheet was the single largest contributor to sea level rise worldwide, though Antarctica may overtake it soon.

Image credit: Greenland’s ice faces melting death sentence

The other source of land ice is found in glaciers around the world, which have also been retreating at a rapid rate. Just as an example, there have been flooding and landslides in the Himalayas recently as ancient ice dams have melted away, sending glacial lakes careening down the mountains and through villages.

This map shows where glaciers have lost ice around the world in half a century – more than 9 trillion tons worth.

European Space Agency: Glaciers lost well over 9 trillion tons of ice in 55 years. 1961-2016. Contributed to 27 mm rise in ocean levels (~1 inch). (Click on this and any other map to zoom in on details.)

There is still some uncertainty about the full volume of glaciers and ice caps on Earth, but if they were all to melt, the sea level would rise approximately 70 m (230 feet) and flood every coastal city on the planet. Nearly 70 percent of Earth’s population lives within 160 kms (100 miles) of a coast, and huge amounts of infrastructure – including airports, ports, and roads, not to mention entire cities – lie in areas that could flood within decades. Small, low-lying island nations, city planners, homeowners – everyone needs to be aware of how much extra water they’ll need to prepare for.

Right now scientists believe that the Antarctic Ice Sheet may account for up to 30 cm (~1 ft.) of sea level rise between 2015 and 2100. Over the same 2015-2100 period, the Greenland Ice Sheet is expected to contribute an additional 1.5 to 14 cm (~.5 ft.), depending on the level of our greenhouse gas emissions. But as scientists learn more about the ice caps melting from below as well as above, undermining the upper surface and increasing the rate of melting, the new projections indicate that the ocean would rise several meters over 500 years.

All this melting activity is slowly but surely causing measurable increases in ocean levels. Measurable increases that are not going to start to decrease in a following year like the arrival of a drought on land. The intriguing maps that follow model what our world will be like when all the ice sheets completely melt, sometime in the next few thousand years, depending on how well we get climate change under control. This is modelling the full 230 foot sea rise.

As you investigate these maps, keep in mind that our shorelines will not stay as they are now and then suddenly retreat to these new shorelines long after we’re gone, as shown. No, they will recede slowly, year by year, until they reach these frightening new realities. A sobering thought. Sobering indeed.

North America.

Europe.

South America.

Asia. Land currently inhabited by 600 million Chinese would be underwater, as would all of Bangladesh and coastal India.

Australia. Australia would gain a new sea in the center of the continent but lose the coastal strip where more than 80 percent of the population currently lives.

Antarctica. Most of Antarctica would disappear!

So … what shall we do about climate change??? Seriously. And where should we build? Where should we live?!

 

Image credits: National Geographic Society, UCSB Geography, Pinterest.