Melting ice sheets and rising sea temperatures could trigger ‘climate domino effect’, scientists warn
As climate change continues to weaken the planet’s ice sheets and sea temperatures continue to rise, the ice sheets and oceans risk destabilizing each other, causing a “climate domino effect” that has far-reaching consequences for the planet’s population.
The new findings, published in the journal Earth System Dynamic, looked at the West Antarctica ice sheets, Greenland and the warm Atlantic Gulf Stream and Amazon rainforest.
Nearly a third of the more than 3 million computer simulations they conducted 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, not in our favor — the risk is clearly increasing the more we heat our planet,” said Jonathan Donges, head of PIK’s FutureLab on Earth Resilience in the Anthropocene, in a statement. statement.
Donges continues: ‘It rises sharply between 1 and 3°C. If greenhouse gas emissions and the resulting climate change cannot be stopped, the upper level of this warming range would likely be exceeded by the end of this century. With even higher temperatures, more tipping cascades can be expected, with devastating effects in the long term.’
Weakened West Antarctica and Greenland ice sheets, combined with Atlantic Gulf Stream and Amazon rainforest, could cause ‘climate domino effect’
Nearly a third of the more than 3 million computer simulations the researchers conducted saw domino effects even if 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 think
In May, a separate study suggested that the Greenland ice sheet, the planet’s second largest, is nearing “accelerated melting.”
However, they couldn’t determine whether the ice sheet is decades away from the tipping point or whether it had already reached it.
SEA STANDS UP TO 4 FEET PER YEAR 2300 . RISE
Global sea levels could rise by as much as 1.2 meters (4 feet) by 2300, even if we meet the Paris climate targets for 2015, scientists warn.
The long-term change will be driven by a thaw of ice from Greenland to Antarctica, which will redraw global coastlines.
Sea level rise threatens cities from Shanghai to London, to low-lying parts of Florida or Bangladesh, and to entire countries like the Maldives.
It is vital that we curb emissions as soon as possible to prevent an even bigger increase, a German-led team of researchers said in a new report.
By 2300, the report predicted that sea levels would rise by 0.7-1.2 meters, even if nearly 200 countries fully meet the targets under the 2015 Paris Agreement.
The goals of the agreements include reducing greenhouse gas emissions to zero by the second half of this century.
Ocean levels will rise inexorably as the industrial gases already emitted that trap heat will linger in the atmosphere and melt more ice, the report said.
In addition, water naturally expands when it gets warmer than four degrees Celsius (39.2 F).
Every five years of delay after 2020 in reaching a peak in global emissions would mean an additional 20 centimeters (8 inches) of sea level rise by 2300.
‘Sea level is often communicated as a very 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 , Reuters told Reuters.
None of the nearly 200 governments that have signed the Paris Agreements is on track to deliver on its promises.
In August 2020, experts from Germany found that the Greenland ice sheet lost 532 gigatons in mass, the largest ever recorded.
Separately that month, some researchers said the ice sheet had already passed the “point of no return.”
Because Earth system models are still too complex to simulate how a tilt event would occur, the researchers used an approach that focused on temperature thresholds.
“That way, we were able to take into account the significant uncertainties associated with these features of tipping interactions,” explains Jürgen Kurths, head of PIK’s Complexity Science Research Department.
The interaction between the ice sheets, the Gulf Stream and the Amazon — which may already be at a tipping point — suggests they are more intertwined than researchers currently think.
“We find that the interaction of these four tilting elements may make them more vulnerable overall due to long-term mutual destabilization,” said one of the study’s co-authors, Potsdam Institute researcher Ricarda Winkelmann, while this does not add a prediction, but rather a risk analysis.
“The mutual feedbacks tend to lower the critical temperature thresholds of the West Antarctic Ice Sheet, the Atlantic Ocean Circulation and the Amazon Rainforest,” Winkelmann added. In contrast, the temperature threshold for a tilting of the Greenland ice sheet can be increased with a significant slowdown in the North Atlantic flow heat transport.
All in all, this could mean that we have less time to reduce greenhouse gas emissions and still avoid tipping processes.’
The melting ice caps are the starting point for any tilting cascade. The Atlantic Ocean then emits the domino effect, which ultimately affects the Amazon.
It’s not clear how long the tilting process would take — it could take thousands of years for the polar ice sheets to melt, with much of the melt ending up in the oceans.
This would affect coastal cities and major disruption in areas such as New York, Los Angeles and Mumbai, among many others around the world.
According to the United Nations, about 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 make the chain of events even larger than thought.
“It would therefore be a risky gamble to hope that the uncertainties work out in a good way, given what is at stake,” explains Winkelmann.
‘As a precautionary measure, rapid reduction of greenhouse gas emissions is indispensable to limit the risks of crossing tipping points in the climate system and possible knock-on effects.’
GLACIER AND ICE SHEET MELTING WOULD HAVE A ‘DRAMATIC IMPACT’ ON GLOBAL SEASIDES
If the Thwaites Glacier in West Antarctica collapses, sea levels could rise by up to 3 meters worldwide.
Sea level rise threatens cities from Shanghai to London, to low-lying parts of Florida or Bangladesh, and to entire nations like the Maldives.
In the UK, a rise of 2 meters (6.7 ft) or more could cause areas such as Hull, Peterborough, Portsmouth and parts of East London and the Thames Estuary to be flooded.
The glacier’s collapse, which could start with decades, could also flood major cities like New York and Sydney.
Parts of New Orleans, Houston and Miami in the southern US would also be particularly hard hit.
A 2014 study conducted by the Union of Concerned Scientists looked at 52 sea level indicators in communities across the US.
Based on a conservative estimate of the predicted sea level rise based on current data, it has been determined that the tide will increase dramatically in many locations on the eastern and gulf coasts.
The results showed that most of these communities will experience a sharp increase in the number and severity of tidal flooding in the coming decades.
By 2030, more than half of the 52 communities surveyed are expected to experience an average of at least 24 tidal floods per year in exposed areas, assuming moderate sea level rise. Twenty of these communities could see a tripling or more in tidal flooding.
The mid-Atlantic coast is expected to see some of the largest increases in flood frequency. Places such as Annapolis, Maryland and Washington DC can expect more than 150 tidal floods per year, and 80 or more tidal floods can occur in several locations in New Jersey.
In the UK, a two-metre (6.5 ft) rise would almost completely submerge large parts of Kent by 2040, according to the results of a paper published in Proceedings of the National Academy of Science in November 2016.
Areas on the south coast such as Portsmouth, as well as Cambridge and Peterborough would also be hard hit.
Towns and villages around the Humber Estuary, such as Hull, Scunthorpe and Grimsby, would also experience severe flooding.