Greenland’s Hidden Secret

May 29, 2019 by

May 27, 2019 |

Greenland is the Key to Global Sea Level Rise – Part 3 of series

 

In this third and final part of a short series on Greenland, the focus is on why Greenland is now the most important factor for sea level rise worldwide. Part 1 explained why its strategic location is getting sharp new interest from the U.S. and China. Part 2  covered how global warming is changing Greenland dramatically, yet rising sea level is the least of their concerns.

This century Greenland will almost certainly be the biggest factor for global sea level rise. Its contribution will be far greater than the effect of thermal expansion of seawater, the major contributor of the last century. Antarctica, on the other hand, is much larger with greater ultimate potential, but is colder and not yet contributing as much as Greenland – though that could change as the West Antarctic Ice Sheet becomes more unstable. To recap the reasons why Greenland is presently “ground zero” for global sea level rise:

  • Ice sheet covers 80% of the island (approximate size of the eastern U.S.
  • Ice sheet thickness exceeds 10,000 feet (~3 km)
  • Full melting would cause 24 feet (7+ meters) of sea level rise globally
  • Warming of the planet is accelerating and the most severe warming happens in the Arctic, due to atmospheric and ocean currents as depicted on the graphic below.

Global average temperature in 2018 compared to the average for the last century. Note most of the heat is in the high north, causing Greenland to be the biggest source of global sea level rise at present. Graphic from NASA – GISS

 

Yet in the last decade scientists could not fully explain why Greenland was losing ice so quickly. This chart plots the massive ice loss in just the last fifteen years and the accelerating trend.

It was believed that Greenland was a solid island covered by the thick ice sheet and glaciers. But more sophisticated ice penetrating radar and measurement of the ice mass by satellites revealed the stunning image below. Under miles of ice was a hidden body of water.

In low areas, hidden beneath the enormous Greenland Ice Sheet, water is accelerating the melting and providing paths for water flow with the surrounding ocean. (Source NASA – JPL)

 

Because of the weight of the enormous ice sheet, over millions of years, the center area of Greenland has been depressed, pushed below sea level. As a result, there is seawater sloshing around under parts of the ice sheet. That accelerates the melting and largely solves the mystery why Greenland is melting so much faster than the models predicted. To wrap up this short update series, the inescapable truth is that remote Greenland will have a dominant role in the rate of sea level rise globally. This largely overlooked land mass will change coastlines all over the world as it melts. Miami, Shanghai, Mumbai, and Tokyo – and thousands of other coastal cities and rural communities fate will be determined by the melting of Greenland’s huge ice sheet. Yet most of the world ignores or underestimates the risk. The issues that compete for our attention seem endless: personal, political, economic, and environmental. All are important. Since sea level has not been higher in human history, it is easy to ignore the truth that it will rise, changing everything about our world. Nothing could be more real. In fact it will greatly affect all four of the categories underlined just above. That white giant seen on every map of the northern hemisphere should remind us of two top priorities, that are equally important:

  • Find ways to slow the warming, which comes mostly from carbon dioxide – the primary greenhouse gas (GHG) from burning fossil fuels.
  • Support bold adaptation for future flood events, and permanently higher sea level, which is now unstoppable.

 

Consider joining our exclusive fact-finding expedition to experience Greenland first-hand, September 8-15, 2019, via Iceland. For anyone working in leadership and public policy relating to climate change, the Greenland experience is an invaluable touchstone for the “stories” and personal experience that are so useful to connect with diverse audiences. Full information and a short video are available at http://www.greenland2019.johnenglander.net

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