The Human Effect On Antarctica

The previous post highlighted the effect that the melting Antarctic ice sheet was having on the human civilization and possible issues in the future. This post will underline the effects that humans are having on the continent and its wildlife. It will also assess the effect and significance of 3 core issues that could put the Antarctic ecosystem at risk. The 3 main topics are: Contamination, arrival of non-indigenous species, and exploitation of living marine species.


Humans have only started to affect Antarctica in the last 100 years due to its isolation and hostile climate. Tourism and fishing are the main threats to the ecosystem and habitat.


The organisation ASOC (Antarctic and Southern Ocean Coalition) has highlighted many issues generated by humans. One of the most important issues is that of contamination. Contamination in the form of oil and metalloid spills (such as zinc and arsenic) are major threats to the habitat of the Antarctic and can be ingested indirectly by animals such as penguins. The spills can also move into the ocean when ice that is contaminated melts.

Figure 1: These are abandoned fuel drums at the now closed Wilkes Station by the Australian government (source). The remnants of fuel could contaminate nearby water sources. 

Other chemicals have been transferred into the water around Antarctica including dichlorophenyldichloroethylene (DDE), a derivative of dichlorodiphenyltrichloroethane (DDT), a pesticide that was used globally. It has been found to be widespread in Antarctic organisms (Bargagli 2005) despite restrictions on its use under the Stockholm Convention on Persistent Organic Pollutants (SCPOP). The SCPOP is an environmental treaty in force from 2004 to prevent the production and use of persistent organic pollutants. I feel that contamination is the most serious problem due to its effects being felt in the oceans as well as on land. Furthermore, ASOC believe that contamination is the most widespread environmental impact of human activities.

The second issue is the introduction of alien (non-indigenous) species by humans (via ships and marine debris) and is another major concern for the wildlife of Antarctica. An example is that a hoverfly, Eristalis croceimaculata (a pollinating insect), was recorded on South Georgia in the sub-Antarctic, on a dandelion flower.
Seeds have been found on the boots of tourists which could adapt to the harsh climate and reproduce, creating a foothold in the environment and ecosystem. Seeds have also been found to have blown from South America, suggesting a natural element also brings non-indigenous species. However, Professor Chown in a BBC article about invasive species argues that "There is still an element of human agency about these wind blown cases in that the plants can only establish themselves under climatic conditions created largely through humanity's production of greenhouse gases." At present there is no obligation to eradicate invasive species in the Antarctic Treaty which was signed in 1958 and came into force in 1961.
The new species arriving could spread strains of disease that the native wildlife is not resistant to. If the non-indigenous species cause problems such as out competing indigenous species they could become invasive species.
If global warming continues, the Antarctic environment will become more suitable for invasive species which will put the native species and the entire ecosystem at risk.  

The third and final main issue is the exploitation of living marine species such as fish and other marine organisms. In the past, the Southern Ocean around Antarctica has been overfished and overexploited to the point where some species such as the marbled rock cod (Notothenia rossii) and mackerel icefish (Champsocephalus gunnari) have been placed by the IUCN (International Union for Conservation of Nature) as endangered species in the Antarctic region.

Figure 2: This graph from Tin et al (source) shows the decrease in the catch of marbled rock cod and mackerel icefish. After 1990, the drop in numbers is clearly visible and falls to almost zero. Sustainable fishing is definitely needed to help these fish populations to recover.


Birds like the black browed albatross have been caught in the long line fishing where birds have become entangled in the nets used to catch fish. Penguins and seals have also been caught up in nets and have not been able to escape and many have consequently died. In Croxall and Nicol's 2004 article, their opinion is that because the black browed albatross doesn't reach breeding maturity until 10 years old, do not necessarily breed every year, and only produce one fledgling, they are highly susceptible to adult mortality and may not get to the breeding age. In view of the mortality rates from longline fisheries, their decline could be potentially irreversible within two or three decades. I agree with this view and that the style of fishing must be changed to avoid the capture of birds like the albatross. I also feel that the populations of other animals like seals could have irreversible changes (decreasing in numbers) which will put a strain on the Antarctic ecosystem.


This post has focused on the issues that humans have brought to Antarctica and the following post will explain the solutions to tackle these three main problems.

Melting Antarctica's Effect On Humans

The last post featured information about if the Antarctic ice is melting or growing. The result was unclear but the consensus is that large parts of Antarctica, particularly in the west of the continent, are melting. This post will look at the effects the melting Antarctic cryosphere is having and will continue to have on humankind.
Figure 1: A melting iceberg (source) in Antarctica.


Effects of melting ice in Antarctica on humans:
The main cost to humans will be from eustatic sea level rise. Andrea Thompson and Climate Central published an article on Scientific American which states that if all of Antarctica's ice melted, sea levels would rise by over 200 feet. This may take thousands of years but melting of the ice has accelerated in the last 50 years due to global warming. For low lying nations such as Tuvalu where the highest point is just 16 feet or 5m above sea level, any rise in sea level is a cause for concern. It is estimated that in 30 to 50 years the people of Tuvalu will have to emigrate to countries such as New Zealand as climate change refugees. 2000 people have already moved to New Zealand to escape the inevitable sea level rise.
One particular glacier in the Amundsen embayment lost 18 percent of its thickness over the 18 years of the study. This contributes to sea level rise.
Figure 2: This map from Paolo, et al. in Science (source) shows the red as a loss of 5% to western Antarctica while the blue is an increase of 5% ice in eastern Antarctica. The black line on the graph at the bottom shows an overall decrease of volume, clearly illustrating that the ice of Antarctica is, on the whole, melting. This all raises sea levels further, impacting human livelihoods. The article from Science agrees with the NASA article that the East Antarctic is stable and even growing in some places while most of West Antarctica is melting.


People living in poorer, less developed countries are at risk due to a low capacity to cope. The Ganges delta in Bangladesh floods regularly in the monsoon season and as the country has a high population density and low HDI (Human Development Index), little is done to prevent flooding, whether it be building defences or educating people to deal with flooding. Sea level rise from the melting of Antarctica could enhance flooding in the monsoon season, causing loss of human life in many cases. I feel and many scientists will agree that for developing nations flooding is a constant hazard and is a problem that must be resolved if the nations are to develop sustainably.


Another concern is that the scientific stations in Antarctica could become closer to the shore due to melting ice. New scientific stations must be built further inland to counter this.


The next posts will discuss the impacts humans are having on the Antarctic continent and solutions to the growing problem.

NASA Article - Is It Accurate?

The previous post focused on the state of Antarctica's ice and if it was melting or not. One article by NASA argued that the ice cover was growing.
Jay Zwally, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland has calculated that the thickening of East Antarctica was 200 billion tons every year between 1992 and 2008. However, West Antarctica and the Antarctic Peninsula's loss of ice increased by 65 billion tons per year. Zwally believes that Antarctica is not contributing to sea level rise, rather, it is causing a fall in sea levels by around 0.23mm per year. The IPCC on the other hand has determined that Antarctica's melting is causing a rise in sea levels by 0.27mm per year. This debate will continue until more evidence is found.
Figure 1: An image (source) showing the fragmentation of ice surrounding Antarctica.
It is tempting to believe such a prestigious government agency but caution must be taken as other international organisations such as the IPCC say the complete opposite - that the Antarctic ice is melting at a record speed.
Figure 2: Map showing the rates of mass changes in Antarctica 2003-2008. By NASA (source).
This image above shows how the mass of the continent is changing. It is clear to see in west Antarctica that there is a loss in mass by over 4.0 Gt/yr. In contrast, parts of east and central Antarctica have increased in mass, in some places by 1.60 Gt/yr. This image of the mass changes gives a clear view into what parts of the continent are melting or growing and is a success for NASA. However, the IPCC and other organisation's results are more convincing than the NASA article as more independent research has been carried out. This has then been compiled into publishable and applicable data. It is difficult to measure how snow and ice change year on year so an ICESat mission was launched to show any changes. To help accurately measure ice changes in Antarctica, NASA is developing the successor to the ICESat mission, ICESat-2, which is scheduled to launch in 2018. At present, there is no clear result whether the NASA article is accurate and the status of the Antarctic ice will stay as a mystery until more evidence is found using ICESat-2.


The next post will concentrate on the impact the changing Antarctic cryosphere has had on humans and what effect humans will have on the cryosphere at present and in the future.

Antarctic Ice - Melting Or Growing?

So far, this blog has mainly focused on the melting of the Arctic ice sheet and how it has affected the Earth's physical geography and human geography. This post will give an insight into the melting (or growth as argued), of the Antarctic ice sheet.
There have been a number of recent news articles and scientific papers regarding the status of the Antarctic ice sheet. Some are reporting that the ice is growing and others that it is melting - who are we to believe?


A recent study published in the Journal of Glaciology by NASA outlined that widespread snowfall that has accumulated over the last 10,000 years has exceeded the melting of the ice. A news article from Global News has outlined the study. Jay Zwally, a glaciologist with NASA Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study, which was published on Oct. 30 in the Journal of Glaciology has calculated ice accumulation and melting. Ice in East Antarctica in particular has been shown to have increased in size by around 0.7 inches per year over the last 10,000 years. This is argued by NASA to have been enough to outweigh the melting of Antarctica's glaciers. In contrast, NASA has also agreed that some areas of West Antarctica are melting but overall believe that the ice is growing instead of melting. Olga Sergienko, a research glaciologist with the National Oceanic and Atmospheric Administration (NOAA) has said however that there are problems with these results due to a lack of data and the hostile environment the data needs to be collected in.


On the other hand, many other studies including the Intergovernmental Panel on Climate Change’s (IPCC) 2013 report say that Antarctica is overall losing land ice, mainly around the Antarctic Peninsula. In 2008, satellite data found that, on average, the continent is losing about 134 billion metric tons of ice per year. In my opinion, I agree with most other scientists that the west Antarctic ice sheet is decreasing and is adding to rising sea levels and that the East Antarctic ice is also melting, albeit at a slower pace. This opinion concurs with other scientists who have calculated that in the last decade, observations show that the melting in Antarctica, the Arctic and Greenland have risen the oceans by 12mm. The melting of the entire western ice sheet could cause a 4m sea level rise. This video shows the scale of the melting of the Antarctic ice sheet. In the future, this could only increase with the further melting of the crumbling cryosphere in both Antarctica and the Arctic.
Figure 1: This graph from NASA's Grace satellites illustrates that ice is being lost since 2008 (source).


In conclusion, there is no clear picture or view on whether the Antarctic ice is melting or growing. East Antarctica's melting status is an enigma and will continue to be until further research is carried out. The consensus and personal opinion has been that it is melting but NASA's research of mass changes in ice must also be considered in the coming years.
The next post will concentrate on the NASA report and its flaws and successes.

The Change Of The Thermohaline Circulation

This news article in the Washington Post highlights the issues of an arguably changing thermohaline circulation around the planet. It has effects on the melting (or crumbling as my blog title describes) cryosphere and the melting ice at the poles in particular can have an impact on the thermohaline circulation. The thermohaline circulation is a global cycle of water whereby warm water rises at the equator and then sinks as colder saline water at the poles.
Figure 1: NADW stands for North Atlantic Deep Water. This is by Stefan Rahmstorf's at the Potsdam Institute for Climate Impact Research (source).


A new study by Stefan Rahmstorf has observed a slowing of the thermohaline circulation. He argues that the North Atlantic ocean is cooling from a reduction of the Atlantic meridional overturning circulation (AMOC) despite the rest of the planet warming due to global warming. I agree that the North Atlantic has cooled as temperature studies have shown but its cooling is not enough to cause a reduction of the Gulf Stream which gives western Europe milder weather than the latitude would otherwise offer. A paper by Vellinga and Wood on the Global Climatic Imapcts Of a Collapse Of The North Atlantic Thermohaline Circulation explains that the North Atlantic temperature has decreased by 1-2 degrees C.







If the Greenland ice sheet melts to a high degree, the freshwater produced will freshen the cold saline water and make the water less salty which will in turn lessen the density of the water which will cause less to sink. This will cause a slowing of the circulation as explained in Rahmstorf''s article.

Figure 2: This is the global model of ocean temperature change in 2014/2015 showing the record coldest temperature in the North Atlantic (source).
Figure 3: This is the temperature change between 1901 and 2000 (source). This again shows cooling of the North Atlantic despite everywhere else warming.
A warming of the oceans could cause a reduction of the Gulf Stream which would cause cooler climates in western Europe. Further melting of the Greenland ice sheet in the future could contribute to further weakening of the AMOC.
The thermohaline circulation warming will accelerate thermal expansion of the oceans which will cause as positive feedback, melting the polar ice sheets due to warmer oceans. The albedo effect as explained in an earlier post would then enhance global warming.
This video illustrates the global ocean conveyor (thermohaline circulation) from Youtube.
The next post will focus on the melting of the Antarctic ice sheet and its possible impacts on both physical and human geography.

Effects Of The Albedo Effect

The paper published by Pistone et al in 2014 gives a numerical insight into the albedo effect and its influence on the melting polar ice sheets. The albedo effect is how much sunlight is reflected by a particular material such as ice or sea. All objects have an albedo score between 0 and 1. The darker an object, the more sunlight energy is absorbed and conversely the lighter an object, the more light energy is reflected. The paper by Pistone is informative and shows that the albedo in the Arctic has decreased from 0.52 to 0.48 W/m2 from 1979 and 2011.
Ice is white and therefore reflects most of the sun's energy and has a high albedo. At the poles, light is reflected by the ice sheets and gives a cooling effect. However with global warming, the cryosphere is melting which reduces the amount of ice present at the poles. More dark sea is exposed which has a much lower albedo. Having a lower albedo, more of the sun's energy is absorbed which produces a positive feedback effect where by the dark sea becomes warmer which in turn enhances global warming through thermal expansion of the oceans.
Figure 1: This image taken from Pistone's 2014 paper illustrates the melting of the Arctic sea ice in picture C between 2007 and 2011 (source).
Consequently, the image in D shows a lower albedo where the dark sea absorbs the sun's energy, lowering the albedo. These images show that the cryosphere is indeed melting. As 97% of all climate scientists believe that anthropogenic global warming is taking place, the albedo effect will be a major factor in the control of feedback mechanisms that can control global warming.


For humans, the positive feedback mechanism is not a short term change but long term. The effects will not be sudden but will happen over time. The main impact on humans are the rising sea levels which are produced by thermal expansion due to a lower albedo producing enhanced global warming.


The next post will focus on the thermohaline circulation and its effects on the melting cryosphere.

Melting Permafrost

(First see the post titled 'Introduction To The Crumbling Cryosphere before reading this post)
An interesting article on the melting permafrost from the BBC. I feel that Professor Vladimir Romanovsky is right saying that the permafrost in Alaska will start to thaw by 2070. The permafrost is permanently frozen soil that does not melt during the summer and that has been frozen for more than 2 years. The melting of the permafrost could have serious consequences.
Worryingly, there is undersea permafrost that contains large amounts of methane is starting to melt, particularly in Siberia. As methane is approximately 20 times more potent than carbon dioxide as a greenhouse gas, the more released from melting permafrost, the more global warming is enhanced. The Arctic sea ice and the Greenland ice sheet melting will be increased along with areas of Antarctica suffering record ice loss.
Figure 1: This image is from the National Snow and Ice Data Centre and shows the average amount of sea ice surrounding the polar regions (source). The sea ice cover in the spring and autumn months (September in the Arctic and March in the Antarctic) is minimal and future summers could lead to ice free poles. It is debated among climate scientists when exactly the Arctic could become ice free.
For humans, the Northwest Passage becoming ice free in the future could mean a quicker and more convenient shipping route to the Asian markets. However, a changing climate could mean that melting glaciers that provide drinking water to millions of people could disappear with the melting cryosphere.