A giant Antarctic ice sheet could be saved from sliding into the sea and melting – threatening millions of people – by generating billions of tons of artificial snow.
Scientists say the collapse of the West Antarctic ice sheet collapse – which would threaten many cities including New York with catastrophic flooding – may be prevented by snowing trillions of tons of ocean water onto it.
They claim that pumping ocean water onto coastal regions surrounding parts of the ice sheet and converting it to snow may prevent its meltdown.
But the project would need “unprecedented” feats of engineering – including the installation of several thousand wind turbines in the inhospitable region.
Researchers are analysing the feasibility of stabilising the ice sheet by generating trillions of tons of additional snow by pumping ocean water onto the glaciers and distributing it with snow cannons.
They say the proposal would crerate a “substantial environmental hazard” in one of the world’s last pristine regions – to prevent sea level rise for some of the world’s most densely populated areas.
Study co-author Professor Anders Levermann, of the Potsdam Institute for Climate Impact Research (PIK) in Germany, said: “The fundamental trade-off is whether we as humanity want to sacrifice Antarctica to save the currently inhabited coastal regions and the cultural heritage that we have built and are building on our shores.
“It is about global metropolises, from New York to Shanghai, which in the long term will be below sea level if nothing is done.
“The West Antarctic Ice Sheet is one of the tipping elements in our climate system.
“Ice loss is accelerating and might not stop until the West Antarctic ice sheet is practically gone.”
He said warm ocean currents have reached the Amundsen Sea Sector of West Antarctica – a region comprising several glaciers that are prone to instability.
Underwater melting of the glaciers triggered their speed-up and retreat.
Prof Levermann said the process is already now responsible for the largest ice loss from the continent and provides an “accelerating contribution” to global sea level rise.
For the study, the researchers employed computer simulations to project the dynamic ice loss into the future.
They confirmed earlier studies suggesting that even strong reduction of greenhouse gas emissions may not prevent the collapse of the West Antarctic ice sheet.
Study co-author Dr Johannes Feldmann, also of PIK, said: “We investigated what could stop a potential collapse in our simulations and increased the snowfall in the destabilised region far beyond observations.
“In fact, we find that an awful lot of snow can indeed push the ice sheet back towards a stable regime and stop the instability.
“In practice, this could be realized by an enormous redisposition of water masses – pumped out of the ocean and snowed onto the ice sheet at a rate of several hundred billion tons per year over a few decades.”
He added: “We are fully aware of the disruptive character such an intervention would have.
“Uplifting, desalinating and heating the ocean water as well as powering the snow canons would require an amount of electric power in the order of several ten thousand high-end wind turbines.
“Putting up such a wind farm and the further infrastructure in the Amundsen Sea and the massive extraction of ocean water itself would essentially mean losing a unique natural reserve.
“Further, the harsh Antarctic climate makes the technical challenges difficult to anticipate and hard to handle while the potential hazardous impacts to the region are likely to be devastating.”
He said the risks and costs of such an unprecedented project must be weighted very carefully against its potential benefits.
Dr Feldmann added: “Also, our study does not consider future man-made global warming.
“Hence this gigantic endeavour only makes sense if the Paris Climate Agreement is kept and carbon emissions are reduced fast and unequivocally.”
The simulations show that a minimum of 7,400 gigatons of artificial snowfall applied over 10 years would be required to stabilise the ice sheet.
But the simulations do not include projected ocean and atmospheric warming due to climate change, possible snowfall increase in coming decades, or fracturing in the ice shelf caused by future atmospheric warming, all of which could influence ice sheet collapse.
Prof Levermann concluded: “The apparent absurdity of the endeavour to let it snow in Antarctica to stop an ice instability reflects the breath-taking dimension of the sea-level problem.
“Yet as scientists we feel it is our duty to inform society about each and every potential option to counter the problems ahead.
“As unbelievable as it might seem: in order to prevent an unprecedented risk, humankind might have to make an unprecedented effort, too.”