A new study by British researchers into ice loss from the world’s poles and glaciers seems to fulfull ‘worst case’ scenarios predicted some 30 years ago by the International Panel on Climate Change (IPCC)
The scientists from the University of Leeds,and Danish Meterological Institute, studied satellite images of the Earth’s ice covered surfaces in what is billed as the first study of ice loss from every region of the planet.
The study was published in the science journal Nature Climate Change under the title,”Ice sheet losses track high end sea level rise” (abstract only avail)
Dr Tom Slater, lead author of study and climate researcher at the Centre for Polar Observation and Modelling at the University of Leeds said, “Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and atmosphere, the rate at which they are melting has accelerated faster than we could have imagined”.
This study combined satellite observations and numerical models to show that Earth lost 28 trillion tonnes of ice between 1994 and 2017.
Although not directly involved in this study Andrew Shepherd, director of the Leeds University Centre for Polar Observation and Modeling says the global ice loss amounts to about a trillion tonnes a year.
The report also notes that ice loss rate has increased greatly since the 1990’s by 57%.
Shepherd says the annual ice loss would be the equivalent of covering the entire U.K in a sheet of ice 100 metres high.
A study last year of Antarctic ice mirrored this latest study in that the Antarctic ice is melting faster than before and the giant Thwaites glacier ice sheet is now unstable..
Another study last year showed that the Greenland ice sheet had it’s largest single day melt since recording began in the 1950’s. at 11.3 billion tonnes in one day.
The scientists say the massive melting of ice is contributing to sea level rise of 1.8cm since the 1990s which matches the IPCC predictions of the ‘worst case’ scenario.
Previously global warming causing thermal expansion of the oceans was the main driver of sea level rise, but now water from the world’s melting glaciers, ice sheets and polar regions has overtaken that as the main driver of sea level rise.
Dr Anna Hogg, study co-author of this latest study and climate researcher in the School of Earth and Environment at Leeds, quoted in Science Daily said, ” “If ice sheet losses continue to track our worst-case climate warming scenarios we should expect an additional 17cm of sea level rise from the ice sheets alone. That’s enough to double the frequency of storm-surge flooding in many of the world’s largest coastal cities.”
That seemingly small level of sea level rise nonetheless threatens some 16 million people to annual coastal flooding.
A previous study of Antarctic ice sheets published in 2019 stated, “Sea-level rise may accelerate significantly if marine ice sheets become unstable.(,,,) we show mathematically that the marine ice sheet instability greatly amplifies and skews uncertainty in sea-level projections with worst-case scenarios of rapid sea-level rise being more likely than best-case scenarios of slower sea-level rise”.
Bob Sandford is the chair in water and climate security at the United Nations University Institute for Water, Environment and Health. Quoted byt the CBC he said the Arctic is warming three to five times faster than elsewhere, and Greenland has warmed by six degrees in the past 60 years. He noted that changes in the poles and high mountains are occuring much sooner that predicted. He cites the scale of the massive ice loss in August 2019 in Greenland was not expected to occur until about 2070
“We can surmise from this that the changes humanity has made to the composition of the global atmosphere are not just going to be severe, they’re going to be sudden”, he said.
He also suggests that given these studies, that the number of people who could be affected by sea level rise is likely a conservative estimate.
additional information – sources
- CBC: A Tucker: Sep 9/20: Rise in sea level from ice melt in Greenland and Antarctica match worst-case scenario: Study
- CNN: E Reynolds: Antarcticas colossal Thwaites Glacier is melting fast and scientists may have discovered why
- Time: J Aguilera: Jul 11/19: A glacier the size of Florida is becoming unstable. It has dire implications for global sea levels
- Science Daily: Aug 31/20: Sea level rise from ice sheets track worst-case climate change scenario
- PNAS- Study: AA Robel et al: Jul 22/19: Marine ice sheet instability amplifies and skews uncertainty in projections of future sea level rise
- WBUR: Young/Raphelson: Sep 1/20: 28 trillion ton ice melt spells danger for sea level rise, climate change
- The Crysophere: T Slater et al: Aug 14/20: Earth’s ice imbalance
- Phys.Org: M Hood: Aug 21/20: Sea level rise quickens as Greenland ice sheet sheds record amount