As climate change continues to weaken the planet’s ice sheets and raise sea temperatures, the ice sheets and oceans could be at risk of destabilizing one another, causing a ‘climate domino effect’ that has wide-ranging implications for the planet’s population.
The new findings, published in the journal Earth System Dynamic, looked at the ice sheets West Antarctica, Greenland and the warm Atlantic Gulf Stream and the Amazon rainforest.
Nearly one-third of the more than 3 million computer simulations they ran found that domino effects between the ice sheets, the Atlantic Gulf Stream and the Amazon rainforest occur, even when the temperature rise is less than 2 degrees Celsius, the upper level as defined by the 2015 Paris Climate Agreement.
‘We’re shifting the odds, and not to our favor – the risk clearly is increasing the more we heat our planet,’ Jonathan Donges, Lead of PIK’s FutureLab on Earth Resilience in the Anthropocene, said in a statement.
Donges continued: ‘It rises substantially between 1 and 3°C. If greenhouse gas emissions and the resulting climate change cannot be halted, the upper level of this warming range would most likely be crossed by the end of this century. With even higher temperatures, more tipping cascades are to be expected, with long-term devastating effects.’
Weakened ice sheets West Antarctica and Greenland, combined with the Atlantic Gulf stream and Amazon rainforest, could cause a ‘climate domino effect’
Nearly one-third of the more than 3 million computer simulations the researchers ran saw domino effects, even when the temperature rise is less than 2 degrees Celsius
The interaction between the ice sheets, the gulf stream and the Amazon suggests they are more intertwined than researchers currently believe
In May, a separate study suggested that the Greenland ice sheet, the planet’s second largest, is close to tipping into ‘accelerated melting.’
However, they were unable to determine if the ice sheet is decades away from the tipping point or if it had already been reached.
SEA LEVELS COULD RISE BY UP TO 4 FEET BY THE YEAR 2300
Global sea levels could rise as much as 1.2 meters (4 feet) by 2300 even if we meet the 2015 Paris climate goals, scientists have warned.
The long-term change will be driven by a thaw of ice from Greenland to Antarctica that is set to re-draw global coastlines.
Sea level rise threatens cities from Shanghai to London, to low-lying swathes of Florida or Bangladesh, and to entire nations such as the Maldives.
It is vital that we curb emissions as soon as possible to avoid an even greater rise, a German-led team of researchers said in a new report.
By 2300, the report projected that sea levels would gain by 0.7-1.2 meters, even if almost 200 nations fully meet goals under the 2015 Paris Agreement.
Targets set by the accords include cutting greenhouse gas emissions to net zero in the second half of this century.
Ocean levels will rise inexorably because heat-trapping industrial gases already emitted will linger in the atmosphere, melting more ice, it said.
In addition, water naturally expands as it warms above four degrees Celsius (39.2°F).
Every five years of delay beyond 2020 in peaking global emissions would mean an extra 20 centimeters (8 inches) of sea level rise by 2300.
‘Sea level is often communicated as a really slow process that you can’t do much about … but the next 30 years really matter,’ lead author Dr Matthias Mengel, of the Potsdam Institute for Climate Impact Research, in Potsdam, Germany, told Reuters.
None of the nearly 200 governments to sign the Paris Accords are on track to meet its pledges.
In August 2020, experts from Germany found that the Greenland ice sheet lost 532 gigatons of mass, the largest ever recorded.
Separately that month, some researchers said the ice sheet had already past the ‘point of no return.’
Since Earth system models are too still complex to simulate how a tipping event would occur, the researchers used an approach focusing on temperature thresholds.
‘By doing so, we could take into account the considerable uncertainties related to these characteristics of tipping interactions,’ Jürgen Kurths, head of PIK’s Complexity Science Research Department, explained.
The interaction between the ice sheets, the gulf stream and the Amazon — which may be at a tipping point already — suggests they are more intertwined than researchers currently believe.
‘We find that the interaction of these four tipping elements can make them overall more vulnerable due to mutual destabilization on the long-run,’ one of the study’s co-authors, Potsdam Institute researcher Ricarda Winkelmann said, while adding this not a prediction, but rather a risk analysis.
‘The feedbacks between them tend to lower the critical temperature thresholds of the West Antarctic Ice Sheet, the Atlantic overturning circulation, and the Amazon rainforest,’ Winkelmann added. In contrast, the temperature threshold for a tipping of the Greenland Ice Sheet can in fact be raised in case of a significant slow-down of the North Atlantic current heat transport.
All in all, this might mean that we have less time to reduce greenhouse gas emissions and still prevent tipping processes.’
The melting ice sheets are the starting point for any tipping cascade. The Atlantic then transmits the domino effect, ultimately impacting the Amazon.
It’s not clear how long the tipping process would take to happen — it could take thousands of years for the polar ice sheets to melt, with much of the melt going into the oceans.
This would impact coastal cities, greatly disrupting areas such as New York, Los Angeles and Mumbai, among many others around the world.
According to the United Nations, approximately 2.4 billion, or 40 percent of the world’s population as of 2017 lived near the coasts.
In the US alone, 127 million people live in coastal counties, according to the National Ocean Service.
Winkelmann added that the analysis is ‘conservative,’ meaning there are several elements that have not been considered, which could cause the chain of events to be even greater than thought.
‘It would hence be a daring bet to hope that the uncertainties play out in a good way, given what is at stake,’ Winkelmann explained.
‘From a precautionary perspective rapidly reducing greenhouse gas emissions is indispensable to limit the risks of crossing tipping points in the climate system, and potentially causing domino effects.’
GLACIERS AND ICE SHEETS MELTING WOULD HAVE A ‘DRAMATIC IMPACT’ ON GLOBAL SEA LEVELS
Global sea levels could rise as much as 10ft (3 metres) if the Thwaites Glacier in West Antarctica collapses.
Sea level rises threaten cities from Shanghai to London, to low-lying swathes of Florida or Bangladesh, and to entire nations such as the Maldives.
In the UK, for instance, a rise of 6.7ft (2 metres) or more may cause areas such as Hull, Peterborough, Portsmouth and parts of east London and the Thames Estuary at risk of becoming submerged.
The collapse of the glacier, which could begin with decades, could also submerge major cities such as New York and Sydney.
Parts of New Orleans, Houston and Miami in the south on the US would also be particularly hard hit.
A 2014 study looked by the union of concerned scientists looked at 52 sea level indicators in communities across the US.
It found tidal flooding will dramatically increase in many East and Gulf Coast locations, based on a conservative estimate of predicted sea level increases based on current data.
The results showed that most of these communities will experience a steep increase in the number and severity of tidal flooding events over the coming decades.
By 2030, more than half of the 52 communities studied are projected to experience, on average, at least 24 tidal floods per year in exposed areas, assuming moderate sea level rise projections. Twenty of these communities could see a tripling or more in tidal flooding events.
The mid-Atlantic coast is expected to see some of the greatest increases in flood frequency. Places such as Annapolis, Maryland and Washington, DC can expect more than 150 tidal floods a year, and several locations in New Jersey could see 80 tidal floods or more.
In the UK, a two metre (6.5 ft) rise by 2040 would see large parts of Kent almost completely submerged, according to the results of a paper published in Proceedings of the National Academy of Science in November 2016.
Areas on the south coast like Portsmouth, as well as Cambridge and Peterborough would also be heavily affected.
Cities and towns around the Humber estuary, such as Hull, Scunthorpe and Grimsby would also experience intense flooding.