greenland ice mass

Greenland Ice Sheet melting 7x faster than in 1990s

Greenland Ice Mass

A new study published by IMBIE in Nature on 10th December reveals the rather startling news. The loss of ice in Greenland is rapidly accelerating and tracking the IPCC worst-case scenario.

Why does this matter?

If all the ice in Greenland melts then that releases enough water to raise the global sea level by over six meters. This is not a suggestion that this is going to happen overnight, nor is it a claim that it will happen by 2100. It is a fact-based observation regarding what is going on. Greenland ice loss matches the worst case scenario laid out within the IPCC’s predicted rates. Their high-end climate warming scenario as illustrated below …

Who or what is IMBIE?

IMBIE (Ice Sheet Mass Balance Inter-comparison Exercise) is an international scientific collaboration attempting to improve estimates of the amounts of ice contained in ice sheets around the world and of their contribution to sea level rise and to publish data and analyses concerning these subjects.

IMBIE was founded in 2011 and is a collaboration between the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) of the United States.

You can read more about IMBIE here.

Overview of the new Study?

Key Take-Home Message

Greenland is losing ice seven times faster than in the 1990s and is tracking the Intergovernmental Panel on Climate Change’s high-end climate warming scenario, which would see 40 million more people exposed to coastal flooding by 2100.

The study Team

The study was done by a team of 89 polar scientists from 50 international organisations. They have produced the most complete picture of Greenland ice loss to date. This Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) Team combined 26 separate surveys to compute changes in the mass of Greenland’s ice sheet between 1992 and 2018. Altogether, data from 11 different satellite missions were used, including measurements of the ice sheet’s changing volume, flow and gravity.

Greenland Study Findings

The study findings show that Greenland has lost 3.8 trillion tonnes of ice since 1992. That is enough to push global sea levels up by 10.6 millimetres. The rate of ice loss has risen from 33 billion tonnes per year in the 1990s to 254 billion tonnes per year in the last decade. That is a seven-fold increase within three decades.

In 2013, the Intergovernmental Panel on Climate Change (IPCC) predicted that global sea levels will rise by 60 centimetres by 2100. That puts 360 million people at risk of annual coastal flooding. This new study shows that Greenland’s ice losses are rising faster than expected. It is tracking the IPCC’s high-end climate warming scenario, which predicts 7 centimetres more.

Who led this Greenland Ice Mass study?

The assessment, led by Professor Andrew Shepherd at the University of Leeds and Dr Erik Ivins at NASA’s Jet Propulsion Laboratory in California. The study was supported by the European Space Agency (ESA) and the US National Aeronautics and Space Administration (NASA).

Study leadership insights

Professor Shepherd is quoted as follows:

“As a rule of thumb, for every centimetre rise in global sea level another six million people are exposed to coastal flooding around the planet.” 

“On current trends, Greenland ice melting will cause 100 million people to be flooded each year by the end of the century, so 400 million in total due to all sea level rise.”

“These are not unlikely events or small impacts; they are happening and will be devastating for coastal communities.”

The team also used regional climate models to show that half of the ice losses were due to surface melting as air temperatures have risen. The other half has been due to increased glacier flow, triggered by rising ocean temperatures.

Ice losses peaked at 335 billion tonnes per year in 2011. That is ten times the rate of the 1990s.  The rate of ice loss then dropped to an average 238 billion tonnes per year since then, this remains seven times higher and does not include all of 2019, which could set a new high due to widespread summer melting.

Dr Ivins said:

“Satellite observations of polar ice are essential for monitoring and predicting how climate change could affect ice losses and sea level rise”.

“While computer simulation allows us to make projections from climate change scenarios, the satellite measurements provide prima facie, rather irrefutable, evidence.” 

“Our project is a great example of the importance of international collaboration to tackle problems that are global in scale.”

Other Comments on the Greenland study

Guðfinna Aðalgeirsdóttir, Professor of Glaciology at the University of Iceland and lead author of the Intergovernmental Panel on Climate Change’s sixth assessment report, who was not involved in the study, said:

“The IMBIE Team’s reconciled estimate of Greenland ice loss is timely for the IPCC. Their satellite observations show that both melting and ice discharge from Greenland have increased since observations started.”

“The ice caps in Iceland had similar reduction in ice loss in the last two years of their record, but this last summer was very warm here and resulted in higher loss. I would expect a similar increase in Greenland mass loss for 2019.” 

“It is very important to keep monitoring the big ice sheets to know how much they raise sea level every year.”

University of Leeds have a Released a Clip

The following was published by the University of Leeds on 5th Dec 2019…

Greenland Ice Mass Loss – Further Reading

Greenland Ice Mass Loss – Tweets

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