COP21 and the absence of oceanic pollution

Though representatives from 195 countries came together to share knowledge, exchange ideas and seek a commitment from world leaders to mitigate the environmental emergencies that the world is now facing, oceanic plastic pollution didn't rear its ugly head at the COP21 climate talks in late 2015 (COP21, 2015).

Plastic pollution and climate change are synonymously linked, if you drew a venn diagram with plastic pollution in one circle and climate change in the other, the link would be fossil fuel combustion. So why wasn't the issue of oceanic plastic pollution on the cards of the program?

As the Environmental Protection Agenecy dictate on their website: ''Most direct emissions come from the burning of fossil fuels for energy. A smaller amount, roughly a third, come from the use of fuels in production (e.g., petroleum products used to make plastics).'' (EPA, 2015)


And as Anna Cummins from the 5 Gyres institute stated: "What does plastic pollution have to do with climate change? They both have their root in fossil fuels." 

With economies developing across the world and the subsequent rise in industrial plastic production to facilitate consumer lifestyles, never before has it been more necessary to create a global program regarding the reduction in plastic pollution.

With current estimates of 8 million tonnes of plastic entering our oceans every year, this figure will surely increase as world economies develop.

Who will clean up the oceans now? And how?

The UK and the Plastics 2020 Challenge

This is just a short blog giving an overview of a national UK policy. The plastics 2020 challenge is an approach to reduce the quantity of plastic sent to landfill, initiated in 2009 this scheme is an industry lead initiative to increase resource efficiency. The initiative was set up to work across the plastic supply chain and with the government.

The aim of the initiative is to 'reduce, reuse, recycle and recover', through the use of greener waste management schemes and plastic use reduction.

Recycle the possibilities are endless

The current global emphasis on disposable goods means that currently around 30% of plastics are reused and recycled, with the majority of the rest ending up in landfill and marine ecosystems several innovative approaches have been designed to tackle the problem.

Adidas have just announced the first pair of sports shoes with an upper made entirely from recycled oceanic waste. British designer Alexander Taylor's running shoe was unveiled during an event for Parley for the Oceans, an initiative that encourages the repurpose of waste.

Let me tell you, as a lover of turquoise and the ocean. They're pretty (Christmas present please mum).

This beautiful shoe is symbolic of the potential for things as ugly as waste, signifying a potential turning point in the plastic production industry:

''There is no reason why materials with similar characteristics to those that we use every day with conventional production processes cannot be simply replaced by ocean plastic materials," Taylor told dezeen magazine. 

During the production process, the original ADIDAS manufacturing process was used, but the upper material was replaced with plastic fibre sourced from pellets and nets. The innovative material use has inspired other companies to follow suite. G-Star RAW in collaboration with Pharrell Williams have released a denim clothing collection with items made from recycled oceanic plastic waste. 

One such company making a product ENTIRELY from oceanic plastic right now is Method, a small soap company. The company teamed up with beach clean up groups in Hawaii to use litter as their primary material to make the world's first bottles from plastic waste. This smart, environmentally conscious method of production demonstrates how simple design and innovation can tackle environmental problems.

David de Rothschild sailed 8000 nautical miles of the Pacific Ocean on The Plastiki Boat which was  made out of 12,500 recycled water bottles. Through the showcasing of smarter design features his aim was to raise awareness and prompt consumers to view ''waste as a resource''.

Realistically, these companies are merely making symbolic gestures to sustainable production with the release of a few products which include small sections of garment made from recycled waste. But perhaps the real point here is the public traction that such well known companies are bringing and the huge spotlight with which they're highlighting the severity of plastic waste within the oceans. 

Oceanic Environmental Legislation

Reducing marine pollution has been a topic in environmental debates since the 1970s, with the first international legislation passed in 1972 at the Convention on the Prevention of Marine Pollution by Dumping of Wastes and other Matter (The London Convention or LC for short) and others passed in the years since have had a hugely positive impact on the marine pollution from ships and other vessels. Another international law designated in 1977 by the UN banned dumping at sea, since 1988 this has been in effect so ships arnt allowed to pollute, only 79 countries ratified.
When it comes to oceanic pollution from ocean vessels a major problem is enforcement of regulation, particularly on open waters. An estimated 6.5 million tonnes plastic are thrown overboard each year, representing 20% of the global rate of plastic pollution dumped in the worlds oceans. When it comes to international environment doctrines, major problem in their effectiveness is enforcement of law.

The success of this legislation is deemed minimal given that 80% of marine pollution originates from land based sources and so further legislation is required to mitigate pollution.

In terms of national laws regarding oceanic pollution there area several categories which can be introduced: enforced biodegradability standards, banned chemicals, banned single use products, enforced recycling, required pollution controls and production responsibility clear up schemes.

G C Ray and J F Grassle in their seminal 1991 paper Marine Biological Diversity state that ''no effort to conserve biological diversity is realistic outside the economics and policies that drive the modern world'' (Ray & Grassle, 1991, page 456). The union of science, economics and public policy may therefore be fundamentally important in the maintenance of marine biodiversity. The use of a financial incentive to prompt conservation efforts and decrease plastic oceanic pollution is apparent when considering the recent tax applied to one use plastic bags. From October 2015 Britain imposed a 5p tax on single use plastic bags, joining the 25% of the globe enforcing the bans.
















The WWFN has estimated that over 100,000 whales, seals and turtles die every year as a result of eating or being trapped in plastic bags. But with the ever increasing global ban on plastic bags these numbers shall decrease and marine ecosystems recover.

Beauty and the biodiversity: what are you washing down the drain?

Today I decided to do a little detective work into cleaning products found around my flat. As a student finding environmentally responsible products is pretty much impossible. From toothpastes to facial cleansers you might be surprised to find out that the sparkly glitters and 'microbeads' in many of the everyday products we use are in fact microplastic and, I'm afraid to say, end up in our beautiful oceans. 

You may think, nay its not too bad, there are sewage treatment facilities that clean our dirty water and the ocean is indeed a pretty huge place. 

Think again....

Recent scientific papers have shown that an increasing amount of marine organisms, such as crustaceans, plankton, filter-feeding molluscs to fish and even seabirds! 

This is because the micro plastics found within beauty products, less than 1mm in diameter, cannot be filtered out during water treatment processes. And with over 300,000 microbeads found in your average tube of facial wash you can imagine the environmental damage that cumulative consumer use could cause. 

These particles can affect a greater number of organisms than larger pieces of plastic, making them even more dangerous. They can block the digestion tract of fish species,

But they can also absorb harmful chemicals effectively turning them into toxic pills 

They can also stay within the marine environment for over 50 years before plastic degradation can occur. 

Initiatives such as the 5gyres and campaign are currently trying to raise public awareness of the issue by sending around a petition to put pressure on the beauty industry into becoming more environmentally responsible (get !INVOLVED! by clicking the link):

 “…I support the elimination of plastic polyethylene micro-beads in all personal care products and urge Procter & Gamble to take the environmentally responsible action of removing them from their products by no later than January 1st, 2015.”

If you don't want to ditch that face scrub just yet, heres a link to a range of totally natural products that will do an even better job than chemical and plastic based exfoliants. Environmental goddesses/ gods rejoice!

Gyres and garbage

As explained in the previous blog within oceanography a gyre is a system of converging ocean currents, caused by the coriolis effect of wind patterns.

Where ocean currents converge the accumulation of plastic has lead to several marine scientists describing the area as ‘garbage patches’, due to the huge amounts of debris trapped on decadal to millenial timescales. Within the worlds oceans 6 major garbage patches can be found globally, one per subtropical basin and one in the Barents Sea. Surface currents converge and subduct in locations, loosing energy, hence the ability to transport debris is reduced and so it accumulates in oscillatory patterns. The Hjulstrom Diagram is useful in this sense in understanding the relation between velocity and accumulation. Debris is generally less dense than sea water and so accumulates on the surface in ‘garbage patches’ in areas of convergence.

The Northern Atlantic Subtropical gyre (NASG) is the most popularly investigated within academia, with an estimated 2500 particles per square kilometre (Law et al, 2010). In their 2010 report Law et al used a time series of various data sources between 1986- 2008 along with the primary collection of 6136 surface plankton net tows to collect buoyant plastic pieces (99% plastic samples collected were less dense than sea water). 62% of the tows collected plastic particles, with the highest concentration of samples in the immediate vicinity of the NASG (83% particles collected) and the largest sample containing 1069 plastic pieces. The NASG subtropical convergence lead to the highest concentration of plastics as velocities were measured at a very low 2 cms-1. Law concluded that between 1990 and 2000 that the average concentration of plastic pollution with the NASG showed statistically significant temporal increases.

One issue to note with Laws methodology is that it is estimated that only 50% plastic pollution produced is buoyant, therefore any results produced maybe inaccurate or underestimated by a factor of 2 (Cozar et al, 2013). Another is the fact that plastic pollution is measured via abundance rather than mass, as the size distribution of particles should be taken into account when investigating pollution levels.

When comparing the NASG to other gyre systems around the world the NASG is often discussed as being the most polluted. The following bar chart shows the concentrations of plastic pollution within oceanic gyres as compilated from a variety of data sources by Cozar et al (2013). The dataset is compiled from 3070 samples, which had a frequency occurrence of plastic debris in 88% of the samples.  The chart confirms the accumulation zones of plastic pollution within each of the subtropical gyres.


The chart shows nonaccumulation zones as blue boxes, outer accumulation zones as green boxes and inner zones as red boxes (representing the inner of the gyres) whilst the black lines represent the mean. 

Van Sebille et al in their paper describe fluctuations in ocean garbage patches on an interrannual basis. The seasonal fluctuations in plastic pollution levels are apparent and labelled as ‘leaky’ garbage patches, due to the migration of pollution within the gyres. These fluctuations could be due to a variety of causes, such as seasonal fluctuations in gyre positions, wind patterns or due to the removal of pollution by oceanic sinks such as marine organisms. The vast inaccuracies associated marine data collection could also be the cause of the variation. 

Ocean circulation

Within the ocean the source of pollution does not always determine where the plastics end up. The target pathways of marine pollutants are determined by a combination of the circulatory patterns of the world’s oceans and the pollutant source, as shown in the above video. 

The oceans circulate due to the Earths rotation and winds (Easterlies and Westerlies) moving surface water. The convergence of currents leads to the formation of gyres, where velocity decreases and suspended debris such as pollutants accumulate.

Several attempts have been made within science to map the spatial distribution of plastic pollution in the worlds oceans.

One initial attempt to map the spatial distribution of plastics was computed using the trajectories of surface buoys of the Global Drifter Program by Van Sebille et al (2012). The source distribution and variation of plastic was simulated via this method, utillizing the produced matrix of ocean circulation patterns the evolution of plastic from any point within the oceans can be modelled.

As shown in the model there are high concentrations of plastic in areas where ocean currents converge such as the northern Atlantic and Pacific gyres. High concentrations are also evident in coastal areas due to their proximity to source and the deposition of material on beaches by the oceans. Within coastal industrial areas there is variation in plastic accumulation as a result of the areas relative proximity to industrial areas (Browne, 2011).

Cozar et al present a map of plastic debris on the open ocean (Cozar et al, 2013), the map shows the ships route whilst the coloured circles indicate volume of plastics at sample sites. They grey zones indicate the presence of gyres and correlate with high plastic concentrations as shown by the large red circles.

(Above map is sourced in Cozar et al, 2013)

Microplastic workshop review

In 2010 the GESAMP (The Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection) met at UNESCO-IOC in Paris to discuss new and emerging issues affecting the marine ecosystem: the effect of microplastics was chiefly discussed.

Participants represented the scientific community, the plastics industry, policy makers and NGOs, creating a forum from which to inform GESAMP, who would in turn inform other agencies such as the FAO, IAEA, UN and UNDP.

Two principle sources of microplastic were offered:
1) Plastic resin pellets from plastics manufacturing, abrasives and cosmetics
2) Plastic fragments from the deterioration of larger pieces, mainly litter

Knowledge of the distribution of microplastics is currently emerging in scientific literature. Some recent articles discuss the characteristics and behaviour of various sized plastic particles and the role of said variables in determining the pollutants fate.

These will be explored in later blogs

Affect of oceanic pollution on marine biodiversity: in response to Laura Marriot

When considering the current state of the worlds ecosystems, it is proposed that 15 of the Earths 24 ecosystems area in decline, due to their reduction in biodiversity (Hooper et al, 2012). It is also estimated by Barnosky et al (2011) that in the next 2-300 years species will decline at a rate 100 times that of natural extinction rates. It is agreed in the literature that the loss of biodiversity is a global crisis requiring international solutions.

Why is this important?

The oceans ecosystems are no different. Anthropogenic impacts are affecting marine ecosystems and biodiversity in a big way.

With particular reference to the affects of oceanic plastic pollution it is estimated that at least 267 marine species are affected by entanglement or ingestion including seabirds, fish, turtles, seals and whales (Allsopp et al, 2006).

Within scientific literature it is agreed that plastics accumulate persistent, toxic contaminants such as PCBs, DDT and PBDEs (GESAMP, 2010). The large surface to volume ratios of plastic facilitate this chemical exchange. As such upon ingestion by marine organisms the material acts as a vector, passing toxins through the food chain.

This can have a potentially harmful impact on human health.

Other affects of oceanic plastic pollution are less obvious. Plastics when accumulated in near surface waters can act as a sanctuary for microbial communities, potentially introducing 'alien species' into the ecosystem. The accumulation of plastics can also lead to areas of oxygen becoming deoxygenated as gaseous exchange between the near surface ocean and atmosphere is reduced. This can lead to the asphyxiation of marine organisms and the creation of 'marine dead zones'.

Future predictions

With expected increases in the human population and concurrently plastic pollution the strain on the marine ecosystem will become increasingly worse. 

Micro plastics

These results confer with the findings of Jambeck (discussed in the earlier blog post 'How much of our trash ends up in the oceans), who found that only 2% of the worlds annually produced plastic waste ended up in the oceans.

Given a quadrupling of plastic production in recent years we would expect to see that oceanic plastic pollution has as such increased. Given the laxities of pollution legislation it seems unlikely that pollution levels have dropped. This conundrum leads me to ask the question: where has all the pollution gone?

Given the properties of plastic scientists have begun to consider that the relative abundance and mass of plastics within the oceans isn't as high as models predicted due to:

• Biodegradation of 'macro' sized plastic to smaller particles 'microplastics' (Law et al, 2010)
• Sinks of pollution

One potential sink of plastic pollution is proposed by Thompson et al (2004). Thompson identifies th presence of micro plastic accumulation on shorelines and in the water column, whereas comparatively large plastic pieces accumulate in near surface waters. Thompson continues in later work to identify the presence of plastic on the deep sea floor and in other remote regions of the globe, after exploring sites in the Mediterranean Sea and the Indian and Atlantic Oceans.  Thompson concludes that every square kilometre of deep ocean contains 4 billion plastic fibres, compared with a billion fibres found in surface and coastal waters. Thomson results show a large prevalence of microfibres within the ocean system, stating that its presence is ubiquitous in the deep sea.

Since the work of Law and Thompson the NOAA in the USA has defined microplastics as plastic fragments less than 5mm in diameter (Arthur et al, 2009).

Work by Goldstein et al (2012) confers with the work of Thompson in agreeing that micro plastic abundance is increasing in the oceans.

Shifts in paradigm

Within academia the mal effects of oceanic plastic population began to be recognised during the 1970s.

Plastic pollution literature ranges from describing the effects of beach litter (Gabrieldes et al, 1991) to studies on the sea floor plastic accumulation (Galgani, 1995) and offshore floating debris.

Recently the topics discussed within literature have expanded, due to new discoveries and developments within technology. A Scopus review of the most cited marine pollution articles of the past 5 years shows a paradigm shift towards discussion regarding the size of plastics, with microplastics (those under 1mm) and their effects being explored.

The first 'International workshop on the Occurence, Effects and Fate of Microplastic' occurred in 2008. This was the first international setting in which microplastics were agreed to pose a significant problem to the marine environmental, due to the longevity of the material and potential to be ingested by marine organisms.

How much of our trash ends up in the worlds oceans?

As a follow up to last weeks blog this week I have been researching the volume of plastic that is estimated to be in the worlds oceans.

Public environmental literature often states that 8 million tonnes of plastic enter the oceans each year (Parker, 2015).

However within scientific literature the abundance and distribution of marine plastics is often deemed 'unknown'. There are several studies which attempt to clarify estimates, however agreement between papers is often quite dicey.

Jambeck and colleagues from the University of California created a successful model to estimate the abundance of oceanic debris, through the combination of population and economic data from 192 coastal countries. They estimate via the use of per capita production of plastic pollution in coastal countries that the annual input of oceanic pollution as fluctuating between 4.8-12.7 million metric tonnes (MT), with an estimated 9.1 million MT inputted during 2015. If pollution rates continue to increase with population and plastic production growth, then by 2025 they estimate that 155 million MT will be inputted into the worlds oceans. This estimate is over 10 times the quantity of current levels, extrapolated from the same exponential increase in pollution as seen in recent years. Arguably it seems unlikely that exponential increases in plastic pollution will occur given environmental legislation and future mitigation schemes.

Where does all the pollution come from?

There has been a recent shift in where the production of plastic pollution originates. Typically the majority of marine debris originated from more developed countries with high industrial output, whilst less developed more rural economies produced less non organic waste. Industrialisation in developing countries has lead to high levels of plastics and synthetics being produced elsewhere, shifting the spatial source of pollution.

(Parker, 2015)

This chart reflects the highest amounts of plastic waste flowing into the oceans annually. Bangladesh ranks 10th overall, with 867,879 tons inputted into the oceans annually.

Issues of scale

When attempting to assess the scale of the pollution existent within the oceans several major problems become apparent:

1. Lack of data

This problem arrises due to the scale of the investigation. The oceans cover 361 million km2 of the Earths surface, physically measuring and mapping plastic pollution within seems a difficult and costly venture. Globally there is an asymmetry in the location of data collection, with greater amounts of data collected in the northern hemisphere. Within the literature there is a call for increased data collection in the southern hemisphere and remote areas.

The scale of the oceans provide a fundamental issue concerning the methodology of estimating global pollution. The scaling up of direct measurements and modelling techniques are often used, though like any extrapolation issues ensue. Data collection consists of the measurement of plastic concentrations at various points along boat routes and extrapolated to provide global estimates.

One such attempt to estimate global plastic pollution is evident in Eriksen et al (2014), whereby they collected plastic pollution data via surface net tows and visual survey transects.

Field locations at 1571 sites

As can be seen in the image above field locations cover only a small fraction of the ocean surface and so modelling extrapolations from field data may be erroneous. Eriksen et al estimated used primary and secondary data to estimate that the ocean contains at a minimum 5.25 trillion particles of plastic, weighing 268,940 tons. This minimum predicted is just 0.1% of global plastic production (288 million tons of plastic produced globally in 2012) and so this figure seems an underestimate and possibly erroneous.


    2.   Diversity of methodologies in assessing plastic pollution

Currently within literature several methods are utilised when attempting to assess marine plastic pollution, which can lead to varying results and estimates. From collecting plastic in plankton nets to assessing plastic pollution via a by sight 'transect' to taking water samples.

The solution to pollution is not dilution!

The oceans cover over 71% of the Earths surface, their vast size and depth meant that until recently the major paradigm of thought was that 'the solution to pollution is dilution'. 

Fergusson, of the Council of the British Plastics Federation, stated in 1974 that ‘‘plastics litter is a very small proportion of all litter and causes no harm to the environment except as an eyesore’’. It wasn't until Laist (1987) recognised plastic debris as harmful to marine life, that environmental science moved its eye from the terrestrial sphere to the hydrosphere.

In hind sight the old 'dilution' policy seems rather short sighted, given the rapid increases in population and consumerism of the late 20th century (Pollution, 2015).

Regardless of the sheer scale of the world's oceans plastic pollution is now a ubiquitous component of marine areas, due to the materials buoyancy and durability. The long decomposition rates of plastics present very serious risks as large quantities can accumulate and remain within the oceans on decadal to centennial timescales.

The longevity, abundance and robustness of the material has led to marine plastic pollution being described as ''one of the most serious emerging threats to marine biodiversity'' by the Convention on Biological Diversity (CBD, 2015)

Consuming plastic

'The plastic age heralded the world free from moths and rust and full of colour... nations more independent from natural resources' (Yarsley & Couzens, 1945).

I never thought that I'd research the history of plastics during a degree in Geography, but here I find myself with 12 google chrome tabs open with varying titles from 'Plastic Statistics' to 'A European History of Plastic'. Knowledge of the evolution in the production, content and in particular the disposal of plastic seems extremely prevalent to understanding the impacts that plastic has on the worlds oceans.

Given that plastics are a purely modern phenomena the material has a relatively short history, but regardless of time the scope of its impact on the modern world is huge.

The first recordings of plastics in use refer to the use of natural materials such as rubber gum and cellulose in the 1820s. From its origins in natural materials plastic evolved to the earliest synthetics between 1900-1929, where pre modern plastics were recognised as long chain molecules (an element of extreme significance when considering plastics decomposition times). From the 1930s plastic emerged as a leading world industry, given its versatility and inexpensive production costs it revolutionised most industries. Use of plastic material is evident in all industries, spreading in consumption across the world.

As can be seen in figure 1 during the 20th century the production and demand of plastic increased exponentially, coinciding with humanity's increase in population and consumption. Contemporary production of plastics provide for a wide variety of markets and an even wider variety of products. Global production of plastics rose to 288 million tonnes in 2012, a 2.8% increase compared to the statistics of 2011.

(Figure 1. graph courtesy of Plastics Europe)

So if plastic is used to produce mostly everything, what happens to it when its no longer of use to us? When you upgrade your ipod? When jelly shoes goes out of fashion? When your trusty Asda shopping bag gets a tear in rendering it a completely useless sheet of orange plastic?

This will be followed up in the following blog...

Let's talk trash: discourse in the media concerning marine pollution

Environmental issues have long been considered hot topics in global media, however the marine environment is rarely discussed. Media tends to focus on the more tangible terrestrial environment that which we can relate to. My primary example for comparison here is the sheer volume of articles relating to the fate of Cecil the lion. The global attention and environmentalism inspired by the loss of a single organism from a single species is astounding.

When it comes to the marine environment, an entire sphere of the Earth, global media seems reluctant to discuss it.

Recently the issue of plastic in the worlds oceans has been exposed by global media, highlighting what many marine scientists discovered as early as the 1970s (CNN, 2014). This shift in media focus only came as a response to the recent downings of airplanes in the oceans, when satellite driven searches mistook vast areas of marine pollution as 'sighted debris' of the wreckages hindering search attempts. Plastic pollution has remained for some time since at the forefront of media, with Time Magazine and other newspapers releasing articles concerning the issue (Time Magazine, 2015) .

This isn't the first time that the scale of plastic pollution has been written about in the fish eye focus of popular media. Captain Charles Moore has been writing and campaigning about the problem since discovering the Great Pacific Garbage Patch in 1997 (Algalita, 2015). He has since explored more than 40,000 miles of the North Pacific Ocean, highlighting its plight to the media. The following video from TED.com illustrates Moore's research.

From messages in bottles to fields of plastic: welcome

Hello and welcome to my blog discussing humanities pollution of the worlds oceans.

We rely on the worlds oceans for a variety of reasons. They regulate our climate, they give us oxygen, they give us food. But we've turned our oceans into a plastic trash can.

This blog will investigate mans affect on the hydrosphere, with particular emphasis on the role of plastics based pollution. During the course of this blog I hope to discuss a range of subtopics: pollution variation, environmental concerns, ecological concerns, current management schemes and future predictions.

Humanities domination over the Earth system began on a global scale with the onset of the Industrial Revolution. During this time capitalism emerged, production yields intensified, populations expanded and consumerism developed. Mans exploitation of the Earth's resources was unprecedented, as was his ingenuity and his environmental pollution.

Presently the range of pollutants that humanity produces increases with each new invention. During the 1960s and 70s pollution in the worlds oceans was dominated by pesticides and herbicides, in the 1980s and 90s it was polluted by horrendous oil spills (Popularmechanics, 2015). 

Now there is one main pollutant which is having astronomically detrimental affects on the worlds oceans...

Plastic. 

Plastic based products have only been in production for around 60 years and so their effects as oceanic pollutants have a brief history. But that is not to say that the physical dimension of the problem is small, as plastics account for 60% of all marine debris and affect every ocean on the planet. On a temporal scale plastics are predicted to remain within the ocean for between 10-100 years due to the plastics durability and non biodegradable properties. 

Plastic pollution within the oceans has detrimental results for marine environments, with a range of affects, from creating marine 'dead zones' spanning tens of kilometres, to individually affecting marine fauna. Within science there is a general consensus that the increased levels of plastic pollution have lead to a number of species becoming endangered. Thus, humanities corruption of the Earth system has lead to some rather drastic suggestions that we are creating the 'great sixth extinction phase' (The Guardian, 2015).

See video below for an introduction of the proposed topic (Video courtesy of the US Department of State).