World’s ice is melting faster than ever

World’s ice is melting faster than ever

ESA World’s ice is melting faster than ever

As global temperatures increase, the melting of the massive ice sheets that blanket Antarctica and Greenland has accelerated, making a significant contribution to sea-level rise. In total, Earth is losing around a trillion tonnes of ice each year which is not being replenished.

CPOM director, Andrew Shepherd of the University of Leeds is a leading climate scientist working with ESA and NASA. Join Andrew as he discusses how long-term satellite observations from ESA’s Climate Change Initiative are key in monitoring changes in ice sheets over decades.

Extreme ice melting in Greenland raises global flood risk

Article first published by the University of Leeds 02.11.21

Global warming has caused extreme ice melting events in Greenland to become more frequent and more intense over the past 40 years according to new research, raising sea levels and flood risk worldwide

Over the past decade alone, 3.5 trillion tonnes of ice has melted from the surface of the island and flowed downhill into the ocean.

That’s enough melted ice to cover the entire UK with around 15 metres of meltwater, or cover the entire city of New York with around 4,500 metres.

The new study, led by the University of Leeds, is the first to use satellite data to detect this phenomena known as ice sheet runoff from space.

The findings, published in Nature Communications, reveal that Greenland’s meltwater runoff has risen by 21% over the past four decades and has become 60% more erratic from one summer to the next.

Important step
Lead author Dr Thomas Slater, a Research Fellow in Leeds Centre for Polar Observation and Modelling, said: As we’ve seen with other parts of the world, Greenland is also vulnerable to an increase in extreme weather events.

As our climate warms, it’s reasonable to expect that the instances of extreme melting in Greenland will happen more often observations such as these are an important step in helping us to improve climate models and better predict what will happen this century.

The study, funded by the European Space Agency (ESA) as part of its Polar+Surface Mass Balance Feasibility project, used measurements from the ESA’s CryoSat-2 satellite mission.

The research shows that over the past decade (2011 to 2020), increased meltwater runoff from Greenland raised the global sea level by one centimetre. One-third of this total was produced in just two hot summers (2012 and 2019), when extreme weather led to record-breaking levels of ice melting not seen in the past 40 years.

Raised sea levels caused by ice melt heightens the risk of flooding for coastal communities worldwide and disrupts marine ecosystems in the Arctic Ocean that indigenous communities rely on for food.

It can also alter patterns of ocean and atmospheric circulation which affect weather conditions around the planet.

Extreme weather
During the past decade, runoff from Greenland has averaged 357 billion tonnes per year, reaching a maximum of 527 billion tonnes of ice melt in 2012, when changes in atmospheric patterns caused unusually warm air to sit over much of the ice sheet. This was more than twice the minimum runoff of 247 billion tonnes that occurred in 2017.

The changes are related to extreme weather events, such as heatwaves, which have become more frequent and are now a major cause of ice loss from Greenland because of the runoff they produce.

Dr Slater said: There are, however, reasons to be optimistic. We know that setting and meeting meaningful targets to cut emissions could reduce ice losses from Greenland by a factor of three, and there is still time to achieve this.

These first observations of Greenland runoff from space can also be used to verify how climate models simulate ice sheet melting which, in turn, will allow improved predictions of how much Greenland will raise the global sea level in future as extreme weather events become more common.

Greater understanding
Study co-author Dr Amber Leeson, Senior Lecturer in Environmental Data Science at Lancaster University, said: Model estimates suggest that the Greenland ice sheet will contribute between about 3 and 23 cm to global sea-level rise by 2100.

This prediction has a wide range, in part because of uncertainties associated with simulating complex ice melt processes, including those associated with extreme weather. These new spaceborne estimates of runoff will help us to understand these complex ice melt processes better, improve our ability to model them, and thus enable us to refine our estimates of future sea level rise.

Finally, the study shows that satellites are able to provide instant estimates of summer ice melting, which supports efforts to expand Greenland’s hydropower capacity and Europe’s ambition to launch the CRISTAL mission to succeed CryoSat-2.

ESA’s CryoSat mission manager, Tommaso Parrinello, said: Since it was launched over 11 years ago, CryoSat has yielded a wealth of information about our rapidly changing polar regions. This remarkable satellite remains key to scientific research and the indisputable facts, such as these findings on meltwater runoff, that are so critical to decision-making on the health of our planet.

Looking further to the future, the Copernicus Sentinel Expansion mission CRISTAL will ensure that Earth’s vulnerable ice will be monitored in the coming decades. In the meantime, it is imperative that CryoSat remains in orbit for as long as possible to reduce the gap before these new Copernicus missions are operational.

Further information
Increased variability in Greenland Ice Sheet runoff from satellite observations is published 1 November in Nature Communications.
DOI: 10.1038/s41467-021-26229-4

Contact press officer Lauren Ballinger with media enquiries.

Image credit: Ian Joughin surface meltwater flowing towards the ocean through a channel in Greenland.

Leeds research inspires glacier names to mark COP26

Article first published by the University of Leeds

A glacier in West Antarctica has been formally named after the city of Glasgow to mark its hosting of the COP26 climate change conference.

The Scottish city will welcome more than 100 world leaders to COP26, the 26th UN Climate Change Conference of Parties, from this weekend until Friday 12 November. The conference marks a key moment in human history for our response to climate change, especially given the impact of the COVID-19 pandemic.

The Glasgow Glacier is one of nine areas of fast flowing ice in the Getz basin to be named after locations of major climate treaties, conferences and reports, following a request by University of Leeds scientists.

CPOM PhD Researcher Heather Selley, from Leeds School of Earth and Environment, and an Enrichment Student at the Alan Turing Institute, identified 14 glaciers in the Getz basin of West Antarctica that are thinning and flowing more quickly into the ocean.

Her study, published in February 2021, revealed that 315 gigatonnes of ice has been lost from the Getz region over the last 25-years, adding 0.9 mm to global mean sea level – the equivalent of 126 million Olympic swimming pools of water.

To mark 42 years of collaboration on international science and climate policy decision-making, Heather requested that the nine unnamed glaciers in her study be named after the locations of major climate treaties, conferences and reports. Five of the glaciers were previously named for US explorers, researchers and officials working in the region.

The proposal was submitted by the Foreign, Commonwealth & Development Office on behalf of the UK Government and supported by the UK Antarctic Place-names Committee. The names will now be added to the international Composite Gazetteer for Antarctica, for use on maps, charts and future publications.

Heather said: “Our study was the first to show that glaciers in this remote region of Antarctica were speeding up. The glaciers are named in chronological order, with Geneva Glacier marking the first ever climate summit in 1979 on the west of the Getz study region and Glasgow Glacier marking the upcoming COP26 on the east.”

“Naming the glaciers after these locations is a great way to celebrate this international collaboration on climate change science and policy over the last 42 years. We wanted to permanently mark the outstanding effort the scientific community has put into measuring the present-day impact of climate change, and its predicted future evolution.”

Amanda Milling, Foreign Commonwealth and Development Officer for Polar Regions, said: “Naming these fast-flowing glaciers sends a clear message that time is running out for action on climate change. It also recognises the importance of global collaboration as we look towards Glasgow and COP26.”

“Scientists estimate that over the past 25 years the Getz region has added the equivalent of 126 million Olympic swimming pools of water to world oceans, due to climate change. The time is now for urgent action.”

Dramatic changes in ice cover and images of the Antarctica have become synonymous with the climate crisis. Over the last 40 years, satellites have observed huge iceberg calving events, change in the flow of glaciers and regions of rapidly thinning ice, all of which improves our understanding of how the ice sheet contribution to sea level rise has changed and provides essential evidence of the impact of climate change.

The 500km-long Getz ice shelf was discovered during the 1940s by the United States Antarctic Service (USAS) and the US Navy. It was first mapped by the United States Geological Survey from US Navy air pictures taken between 1962 – 65, and named by the USAS after George F Getz of Chicago, who helped furnish the seaplane for the expedition.

Modern exploration of the area is done using satellite imaging, with space playing an increasing role in helping scientists to monitor, understand and tackle climate change. The European Space Agency earth observation data provides high-resolution satellite images taken every six days by Sentinel-1, part of the Copernicus Programme satellite constellation. This allows researchers to measure localised speed changes with ever greater detail.

Dr Anna Hogg, Associate Professor in Leeds’ School of Earth and Environment, said: “The climate crisis affects all of us, whether through flooding of our homes, increased storm frequency, reduced crop harvests, or the loss of habitats and biodiversity in the natural environment, with some communities impacted much more than others. Whilst these new glacier names celebrate the knowledge gained through scientific collaboration and the action taken through policy, it is clear now that much more must be done.”

“I am inspired by the school climate strikes, which remind all of us that we are only temporary gatekeepers, and have a responsibility to protect planet Earth for the next generation. There is no doubt that there’s a need for urgent action, we have great hope in the power of international collaboration which can enable significant progress to be made at COP26 this year.

“The recent IPCC AR6 report finds that unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, it will not be possible to limit warming close to 1.5°C or even 2°C.”

Heather will be presenting this work in her side event “West Antarctica: Getz on the run” at the COP26 Climate Conference on Wednesday 10 November at 10am GMT. It is a Blue Zone event in the International Cryosphere Climate Initiative (ICCI) Cryosphere Pavilion which will be live streamed on Facebook, Twitch, Cryosphere Pavilion Youtube and ICCI Youtube.

Nine newly-named glaciers

The Geneva Glacier flows at the western end of the Getz Ice Shelf and was named after the world’s first climate conference in 1979.

The Rio Glacier lies further east and commemorates the first Earth Summit in 1992 where the United Nations Framework Convention on Climate Change (UNFCCC) was opened for signatures along with its sisters the Rio convention, the UN convention on biological diversity and the UN convention to combat desertification.

The Berlin Glacier flows further east and is named after the first Conference of Parties (COP) in 1995 which assessed the progress of dealing with climate change. It marked the uniting of the world to tackle climate change and the agreement on a mandate for future negotiations.

Still further east lies the Kyoto Glacier commemorating the formal adoption of the Kyoto Protocol at COP3 in 1997, which legally bound developed countries to emission reduction targets.

The Bali Glacier marks the release of the Intergovernmental Panel on Climate Change forth assessment report (AR4) in 2007. Around this time climate science entered into the popular consciousness. At the thirteenth Conference of Parties (COP13) parties agreed on the Bali road map, which charted the way towards post-2012 outcome with a working group on long-term cooperative action under the convention.

The Stockholm Glacier honours the Intergovernmental Panel on Climate Change fifth assessment report (AR5) approval session in 2014. This report represents the biggest ever coming together of scientists at the time.

The Paris Glacier memorialises the agreement of a legally binding treaty in 2015 which aimed to limit global warming to well below 2°C, preferably below 1.5°C, compared to pre-industrial levels. It was adopted by 196 parties that together represented at least 55 % of the global greenhouse gas emissions.

The Incheon Glacier marks the meeting of the IPCC to consider the special report of global warming of 1.5°C in 2015. This marked the first time the three different IPCC working groups worked together to produce a report in an interdisciplinary manner.

Finally, the Glasgow Glacier flows at the very east end of the Getz basin and is named after Glasgow which will host the 26th UN Climate Change Conference of Parties (COP26) later this year. It marks a key moment in human history for our response to climate change especially given the impact of the COVID-19 pandemic.

Further information

“Widespread increase in dynamic imbalance in the Getz region of Antarctica from 1994 to 2018” was published in Nature Communications on 23 February 2021. DOI: 10.1038/s41467-021-21321-1

For further information and interviews, contact the University of Leeds press office via pressoffice@leeds.ac.uk.

Getz ice shelf photo credit: Pierre Dutrieux