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human activity and the destruction of the planet

Disappearing arctic polar ice cap – can this affect the Gulf Stream and the Jet Stream?

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In Chapter 1 of my book, I provide evidence that the arctic ice is shrinking.  This is shown graphically in Figure 14 (page 34), which I reproduced, with acknowledgements to Andy Lee Haveland.  Because the size of the arctic ice varies throughout the year, and summer to winter, it is important to take measurements throughout the seasons of the year.

The figure below, published in my book with permission, gives an idea of what has been happening between 1979 and 2016.  arctic-death-spiral

Each colour represents a different month of the year and the difference in the size of the ice throughout the year shows how much it has shrunk during the period 1979-2016.  The stark difference between 1979 and 2016 can be seen best at the top of the graph.

Now, NASA has produced a time-lapse video showing the movement of the ice as it pulses through the seasons.  The video is posted on YouTube with this description, “Arctic sea ice has not only been shrinking in surface area in recent years, it’s becoming younger and thinner as well.”  The video can also be seen on the following website:

NASA releases time-lapse of the disappearing Arctic polar ice cap

This last winter (2017-18) has been very much colder in the UK and other parts of Europe and this has led to some people denying that global warming is happening.  The crazy thing is that, whilst Britain was in the grip of a lengthy period of freezing weather and large falls of snow, at the north pole it was warmer than usual, reaching melting point in some places, with temperatures up to 20 degrees higher than normal.  Similar temperature anomalies were also reported for some of the US and Canada.

The reality is that this phenomenon is all part of the unstable weather patterns that are being caused by climate change.

Now, in the latest issue of New Scientist (No. 3169, 17th March 2018), Colin Barras describes new research, which might suggest that changes in the North Atlantic current (the northern part of the Gulf Stream), could result in a shut-down, leading to even greater sea-level rise on Atlantic coasts and more intense droughts in Africa.

https://www.newscientist.com/article/mg23731693-200-polar-melt-may-shut-down-the-atlantic-current-that-warms-europe/

Marilena Oltmanns and her colleagues have studied the salinity of sea water and its temperature in the area just south of Greenland (Irminger Sea) between 2002 and 2014.  They found that, in summer, the sea had much warmer temperatures and lower salinity.  This would suggest that fresh water (melt from Greenland and the Arctic) is flooding into this area and affecting the currents and convection process.  This was more likely to happen after particularly mild winters.  In 2010-11, conditions were mild, resulting in an accumulation of fresh water in the sea, 40% of it still there even after the end of winter.  These findings are reported in Nature Climate Change, doi.org/cmbw.

Oltmanns believes that, if several warm years occur in succession, there would be a build up of fresh water, impeding the process of convection.  This might result in a shut-down of the North Atlantic current.  This might bring about the end of the North Atlantic’s relatively mild climate and the ameliorating effects of the Gulf Stream.

Other writers and researchers are proposing other impacts too, as far reaching as Africa and South America, though at this time much of it is still speculation.

Further information about the North Atlantic current can be found in Wikipedia, from which the following diagram has been taken.

2000px-North_Atlantic_currents.svg

 

Could this mean that the prolonged freezing period experienced in the UK and Europe last winter could become the norm?

Since writing the above, I have come across a review of scientific articles about the state of the Arctic ice cap, written by Vanessa Spedding.  It can be found on the Scientists for Global Responsibility website, as follows:

http://www.sgr.org.uk/resources/state-arctic-heightens-focus-climate-policy

The main conclusion of this review is that the presence of a summer ice-free Arctic can be an indicator of how well the world is sticking to the 1.5 degree Paris Agreement target for global warming.  There is a very low chance of an ice-free Arctic at 1.5 degrees but at 2 degrees, the chance rises to 39%.  At 3 degrees, 73%.  Full details of this work can be seen in an article by Screen and Williamson at:

11. Screen JA, Williamson D (2017). Ice-free Arctic at 1.5 °C? Nature Climate Change, vol.7, pp.230–231. DOI: 10.1038/nclimate3248.  https://www.nature.com/nclimate/journal/v7/n4/full/nclimate3248.html

Another 15 articles are cited in Spedding’s review. One of them, from Prof. Jennifer Francis of the Institute of Marine and Coastal Sciences at Rutgers University in the USA, suggests that there is a link between a warming Arctic and a disrupted jet stream, with effects on Northern hemisphere weather patterns.

Now, in August 2018, a report in The Guardian suggests that the oldest and thickest sea ice in the Arctic has started to break up for the first time ever, opening waters north of Greenland that are normally frozen the year round – an area that is often called “the last ice area”.  It is believed that this has occurred because of the abnormal heatwave in northern Europe in the summer of 2018. In the past, the ice in this region has packed together and is over 4 metres thick, with ridges up to 20 metres.

Full details about this and other concerns of climate scientists can be seen at:

https://www.theguardian.com/world/2018/aug/21/arctics-strongest-sea-ice-breaks-up-for-first-time-on-record?CMP=twt_a-science_b-gdnscience

ANTARCTICA

As regards Antarctica, the situation is just as grim, though different from the Arctic. A British-led study, using satellite tracking, showed that a region of ice the size of Greater London vanished from the edge of Antarctica between 2010 and 2016.

The 1,463 square kilometres of underwater ice at the base of the Antarctic ice sheet melted under the influence of warm ocean water currents. Scientists demonstrated how the massive ice sheet is retreating as its edges, fed by a multitude of glaciers, are eroded.

See: https://www.aol.co.uk/news/2018/04/02/antarctic-ice-area-the-size-of-london-lost-in-six-years/?ncid=webmail

The lead researcher, Dr Hannes Konrad, from the University of Leeds, said: “Our study provides clear evidence that retreat is happening across the ice sheet due to ocean melting at its base, and not just at the few spots that have been mapped before now. This retreat has had a huge impact on inland glaciers, because releasing them from the sea bed removes friction, causing them to speed up and contribute to global sea level rise.”

The biggest changes were seen in West Antarctica, where more than a fifth of the ice sheet had retreated across the sea floor faster than the general pace of deglaciation.

The findings have been published on 2nd April 2018 in the journal Nature Geoscience. See: https://www.nature.com/articles/s41561-018-0082-z

Previous studies had indicated an expansion of sea ice in the antarctic region but this latest study used grounding lines as indicators of ice-sheet instability.

 

Further posts will be added here as they emerge.

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