Sustainable shopping: tap water is best, but what bottle should you drink it from?



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The greenest option might be to get a disposable bottle but never dispose of it.
Shutterstock.com

Trevor Thornton, Deakin University and Simon Lockrey, RMIT University

Shopping can be confusing at the best of times, and trying to find environmentally friendly options makes it even more difficult. Our Sustainable Shopping series asks experts to provide easy eco-friendly guides to purchases big and small. Send us your suggestions for future articles here.


We have many options when it comes to how we drink water, given the large range of consumer products available, and Australia’s high standards of tap water.

But which option is the smartest choice from an environmental perspective?

According to the waste management hierarchy, the best option is one that avoids waste altogether. Recyclable options are less preferable, and landfill disposal the worst of all.

For water bottles, this suggests that keeping and reusing the same bottle is always best. It’s certainly preferable to single-use bottles, even if these are recyclable.




Read more:
Recycling can be confusing, but it’s getting simpler


Of course, it’s hardly revolutionary to point out that single-use plastic bottles are a bad way to drink water on environmental grounds. Ditching bottled water in favour of tap water is a very straightforward decision.

However, choosing what reusable bottle to drink it out of is a far more complex question. This requires us to consider the whole “life cycle” of the bottle.

Cycle of life

Life-cycle assessment is a method that aims to identify all of the potential environmental impacts of a product, from manufacture, to use, to disposal.

A 2012 Italian life-cycle study confirmed that reusable glass or plastic bottles are usually more eco-friendly than single-use PET plastic bottles.

However, it also found that heavy glass bottles have higher environmental impacts than single-use PET bottles if the distance to refill them was more than 150km.

Granted, you’re unlikely ever to find yourself more than 150km from the nearest drinking tap. But this highlights the importance of considering how a product will be used, as well as what it is made of.

What are the reusable options?

Metal bottles are among the most durable, but also require lots of resources to make.
Flickr CC

In 2011, we investigated and compared the life cycles of typical aluminium, steel and polypropylene plastic reusable bottles.

Steel and aluminium options shared the highest environmental impacts from materials and production, due to material and production intensity, combined with the higher mass of the metal bottles, for the same number of uses among the options. The polypropylene bottle performed the best.

Polypropylene bottles are also arguably better suited to our lifestyles. They are lighter and more flexible than glass or metal, making them easier to take to the gym, the office, or out and about.

The flip side of this, however, is that metal and glass bottles may be more robust and last longer, so their impacts may be diluted with prolonged use – as long as you don’t lose them or replace them too soon.

Health considerations are an important factor for many people too, especially in light of new research about the presence of plastic particles in drinking water.

Other considerations aside, is may even be best to simply buy a single-use PET plastic water bottle and then reuse it a bunch of times. They are lighter than most purpose-designed reusable bottles, but still long-lasting. And when they do come to the end of their useful life, they are more easily recycled than many other types of plastic.

Sure, you won’t look very aspirational, but depending on how many uses you get (as you approach the same number of uses as other options), you could be doing your bit for the environment.

Maintaining reusable options

There are a few things to bear in mind to ensure that reusable bottles produce as little waste as possible.

  1. Refill from the tap, as opposed to using water coolers or other bottled water that can come from many kilometres away, requiring packaging and distribution. Unsurprisingly, tap water has the lowest environmental impacts of all the options.

  2. Clean your bottle thoroughly, to keep it hygienic for longer and avoid having to replace grotty bottles. While cleaning does add to the environmental impact, this effect is minor in comparison to the material impacts of buying new bottles – as we have confirmed in the case of reusable coffee cups.




Read more:
Sustainable shopping: how to stop your bathers flooding the oceans with plastic


The verdict

To reduce your environmental impacts of a drink of water, reusing a bottle, whether a designer bottle or a single-use bottle you use time and again, makes the most sense from a life-cycle, waste and litter perspective.

The maintenance of your reusable container is also key, to make sure you get as many uses as you can out of it, even if you create minor additional environmental impacts to do so.

The ConversationUltimately, drinking directly from a tap or water fountain is an even better shout, if you have that option. Apart from the benefit of staying hydrated, you will reduce your impacts on our planet.

Trevor Thornton, Lecturer, School of Life and Environmental Sciences, Deakin University and Simon Lockrey, Research Fellow, RMIT University

This article was originally published on The Conversation. Read the original article.

Helping farmers and reducing car crashes: the surprising benefits of predators



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Whoosa vicious helpful predator? You are! Yes you are!
Sean Riley/Flickr, CC BY-SA

Christopher O’Bryan, The University of Queensland; Eve McDonald-Madden, The University of Queensland; James Watson, The University of Queensland, and Neil Carter, Boise State University

Humans may be Earth’s apex predator, but the fleeting shadow of a vulture or the glimpse of a big cat can cause instinctive fear and disdain. But new evidence suggests that predators and scavengers are much more beneficial to humans than commonly believed, and that their loss may have greater consequences than we have imagined.

Conflict between these species and people, coupled with dramatic habitat loss, is causing unprecedented predator and scavenger declines. Nearly three-fourths of all vulture species are on a downward spiral. African lions are projected to lose half of their range in the coming decades and leopards have lost upwards of 75% of their historic range. Many bat species are facing extinction.




Read more:
Extinction means more than a loss of species to Australia’s delicate ecosystems


In a recent paper in Nature Ecology & Evolution, we summarised recent studies across the globe looking at the services predators and scavengers can provide, from waste disposal to reducing car crashes.

The many roles our fanged friends play

Animals that eat meat play vital roles in our ecosystems. One of the most outstanding examples we found was that of agricultural services by flying predators, such as insectivorous birds and bats.

We found studies that showed bats saving US corn farmers over US$1 billion in pest control because they consume pest moths and beetles. Similarly, we found that without birds and bats in coffee plantations of Sulawesi, coffee profits are reduced by US$730 per hectare.




Read more:
Why do some graziers want to retain, not kill, dingoes?


It’s not just birds and bats that help farmers. In Australia, dingoes increase cattle productivity by reducing kangaroo populations that compete for rangeland grasses (even when accounting for dingoes eating cattle calves).

This challenges the notion that dingoes are solely vermin. Rather, they provide a mixture of both costs and benefits, and in some cases their benefits outweigh the costs. This is particularly important as dingoes have been a source of conflict for decades.




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Living blanket, water diviner, wild pet: a cultural history of the dingo


Predators and scavengers also significantly reduce waste in and around human habitation. This keeps down waste control costs and even reduces disease risk.

For example, golden jackals reduce nearly 4,000 tons of domestic animal waste per year in Serbia and over 13,000 tons across urban areas in Europe. Vultures can reduce over 20% of organic waste in areas of the Middle East. In India, vultures have been implicated in reducing rabies risk by reducing the carcasses that sustain the stray dog population.

One piece of research showed that if mountain lions were recolonised in the eastern United States, they would prey on enough deer to reduce deer-vehicle collisions by 22% a year. This would save 150 lives and more than US$2 billion in damages.

Weighing up the costs and benefits

Although these species provide clear benefits, there are well known costs associated with predators and scavengers as well. Many predators and scavengers are a source of conflict, whether it is perceived or real; particularly pertinent in Australia is the ongoing debate over the risk of shark attacks.




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These drastic costs of predators and scavengers are rare, yet they attract rapt media attention. Nevertheless, many predators and scavengers are rapidly declining due to their poor reputation, habitat loss and a changing climate.

It’s time for a change in the conservation conversation to move from simply discussing the societal costs of predators and scavengers to a serious discussion of the important services that these animals provide in areas we share. Even though we may rightly or wrongly fear these species, there’s no doubt that we need them.


The ConversationThe authors would like to acknowledge the contributions of Dr Hawthorne Beyer and Alexander Braczkowski.

Christopher O’Bryan, PhD Candidate, School of Earth and Environmental Sciences, The University of Queensland; Eve McDonald-Madden, Senior lecturer, The University of Queensland; James Watson, Professor, The University of Queensland, and Neil Carter, Assistant Professor, College of Innovation and Design, Boise State University

This article was originally published on The Conversation. Read the original article.

Climate change is slowing Atlantic currents that help keep Europe warm



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Natalie Renier/Woods Hole Oceanographic Institution, Author provided

Peter T. Spooner, UCL

The ocean currents that help warm the Atlantic coasts of Europe and North America have significantly slowed since the 1800s and are at their weakest in 1600 years, according to new research my colleagues and I have conducted. As we’ve set out in a new study in Nature, the weakening of this ocean circulation system may have begun naturally but is probably being continued by climate change related to greenhouse gas emissions.

This circulation is a key player in the Earth’s climate system and a large or abrupt slowdown could have global repercussions. It could cause sea levels on the US east coast to rise, alter European weather patterns or rain patterns more globally, and hurt marine wildlife.

We know that at the end of the last major ice age, rapid fluctuations in the circulation led to extreme climate shifts on a global scale. An exaggerated (but terrifying) example of such a sudden event was portrayed in the 2004 blockbuster film The Day After Tomorrow.

The recent weakening we have found was likely driven by warming in the north Atlantic and the addition of freshwater from increased rainfall and melting ice. It has been predicted many times but, until now, just how much weakening has already occurred has largely remained a mystery. The extent of the changes we have discovered comes as a surprise to many, including myself, and points to significant changes in the future.

The circulation system in question is known as the “Atlantic Meridional Overturning Circulation” (AMOC). The AMOC is like a giant conveyor belt of water. It transports warm, salty water to the north Atlantic where it gets very cold and sinks. Once in the deep ocean the water flows back southwards and then all around the world’s oceans. This conveyor belt is one of the most important transporters of heat in the climate system and includes the Gulf Stream, known for keeping western Europe warm.

Climate models have consistently predicted that the AMOC will slow down due to greenhouse gas warming and associated changes in the water cycle. Because of these predictions – and the possibility of abrupt climate changes – scientists have monitored the AMOC since 2004 with instruments strung out across the Atlantic at key locations. But to really test the model predictions and work out how climate change is affecting the conveyor we have needed much longer records.

Looking for patterns

To create these records, our research group – led by University College London’s Dr David Thornalley – used the idea that a change in the AMOC has a unique pattern of impact on the ocean. When the AMOC gets weaker, the north-eastern Atlantic Ocean cools and parts of the western Atlantic get warmer by a specific amount. We can look for this pattern in past records of ocean temperature to trace what the circulation was like in the past.

Another study in the same issue of Nature, led by researchers at the University of Potsdam in Germany, used historical observations of temperature to check the fingerprint. They found that the AMOC had reduced in strength by around 15% since 1950, pointing to the role of human-made greenhouse gas emissions as the primary cause.

In our paper, which also forms part of the EU ATLAS project, we found the same fingerprint. But instead of using historical observations we used our expertise in past climate research to go back much further in time. We did this by combining known records of the remains of tiny marine creatures found in deep-sea mud. Temperature can be worked out by looking at the amounts of different species and the chemical compositions of their skeletons.

We were also able to directly measure the past deep ocean current speeds by looking at the mud itself. Larger grains of mud imply faster currents, while smaller grains mean the currents were weaker. Both techniques point to a weakening of the AMOC since about 1850, again by about 15% to 20%. Importantly, the modern weakening is very different to anything seen over the last 1,600 years, pointing to a combination of natural and human drivers.

The difference in timing of the start of the AMOC weakening in the two studies will require more scientific attention. Despite this difference, both of the new studies raise important questions regarding whether climate models simulate the historical changes in ocean circulation, and whether we need to revisit some of our future projections.

The ConversationHowever, each additional long record makes it easier to evaluate how well the models simulate this key element of the climate system. In fact, evaluating models against these long records may be a crucial step if we hope to accurately predict possible extreme AMOC events and their climate impacts.

Peter T. Spooner, Research Associate in Paleoceanography, UCL

This article was originally published on The Conversation. Read the original article.

The shipping sector is finally on board in the fight against climate change



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Australia will have to regulate its considerable shipping industry.
PomInAus/shutterstock.com

Beatriz Garcia, Western Sydney University and Jolene Lin, National University of Singapore

For the first time, the massive global shipping sector has agreed to a 50% reduction in greenhouse gas emissions by 2050, in what’s been called a “historic” moment.

Maritime shipping, which carries about 80% of global trade by volume, contributes around A$9 billion directly to Australia’s gross domestic product, and A$11.8 billion indirectly.




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Sea transport has a relatively green image because ships emit less carbon dioxide per tonne and per kilometre than rail, truck or air transport. Yet, given its scale and rapid growth, it’s a major source of carbon emissions. Maritime transport emits around 1,000 million tonnes of CO₂ a year and is responsible for about 2.5% of global greenhouse gas emissions.

The international law

Despite being a major contributor to climate change, the powerful shipping industry has successfully lobbied to be excluded from obligations to reduce emissions under the 1997 Kyoto Protocol and, more recently, the 2015 Paris Agreement.

There are also no sector-wide emission reduction targets in maritime shipping under the United Nations Framework Convention on Climate Change (UNFCCC). In other key policy spaces, such as the International Maritime Organization (IMO) and the United Nations Convention on the Law of the Sea (UNCLOS), there are no obligations imposed on either states or shipping corporations to reduce maritime emissions.

Countries could potentially set emissions targets domestically, but they rarely set sectoral targets, especially for sectors that are heavily exposed to international trade. In this context, the shipping industry has been particularly footloose in its response to climate change.

It is therefore a cause for celebration that decades of negotiation have now yielded this agreement. The deal requires all IMO countries to reduce shipping emissions by 50% compared with 2008 levels.

Ships will be required to be more energy-efficient and to use cleaner energy such as solar and wind electricity generation. Currently, the shipping industry is overwhelmingly reliant on dirty, carbon-rich fuels such as heavy diesel.

Some stormy seas ahead

The climate deal has been described as “historic”, but not all countries are on board. Some, particularly island nations that are vulnerable to sea level rise, wanted a “far, far more ambitious” target. Others, including the United States, Brazil, Panama and Saudi Arabia, are strongly against it. Reconciling these differences will be a difficult task for the IMO.

It has always been technically difficult to accurately calculate the precise amount of fuel used during shipping operations. It’s even harder to allocate maritime emissions to specific countries.

Contributing to the potential confusion is the use of “flags of convenience”. This is where a ship’s owners register the vessel in a country other than their own, and fly the flag of the country where registered.

This is usually done to disguise the relationship between the vessel and its actual owner, due to the attractive, lower regulatory burdens that some open registries offer. Shipping corporations could also use flags of convenience to avoid mandatory emission reduction targets.

The way forward

As a result of the climate deal, states will eventually need to introduce domestic laws setting emission reduction targets for their shipping industry.

These targets could also be applied to ships that call at their ports. The good news is that there is potential synergy between such regulation and existing laws, such as the European Union regulation that requires ship owners and operators to monitor, report and verify CO₂ emissions from certain vessels that dock at European ports.




Read more:
Five ways the shipping industry can reduce its carbon emissions


The new climate deal has the potential to change the way shipping companies operate. It presents an opportunity for the shipping industry to become part of the solution rather than the problem when it comes to climate change.

The ConversationIt’s also a strong signal to other international industries, such as the aviation sector, that have largely escaped emissions reduction targets. If we can reduce emissions in such a large and complex sector as marine transport, it bodes well for the capacity of international frameworks to tackle other difficult problems.

Beatriz Garcia, Lecturer, Western Sydney University and Jolene Lin, Director, Asia Pacific Centre for Environmental Law, National University of Singapore

This article was originally published on The Conversation. Read the original article.

The recycling crisis in Australia: easy solutions to a hard problem



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The amount of landfill in Australia is expected to rise since China is no longer buying our recycling waste. But there are easy solutions to this big problem.
Nicolás Boullosa/flickr, CC BY

Ian A. MacKenzie, The University of Queensland

Ipswich residents have been told their recycling waste will now be dumped into landfill because it is too expensive for the local council to recycle.

This is a result of Australia’s recycling industry crisis. China’s recent ban on imported solid waste means that most of our waste has been stockpiled domestically and is not being recycled.

Last year alone we exported more than 600,000 tonnes of waste to China. Australia does not currently have the capacity to handle this volume.




Read more:
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In Queensland, this could not be happening at a worse time, given that the state will soon launch its own container refund scheme in a bid to boost recycling rates.

Unfortunately, the case of Ipswich Council is likely to be repeated around Australia. Many local councils will be feeling the strain and considering their options as they face their own recycling mess.

Use a stick

A crude, but ultimately effective, strategy would be to increase landfill levies to make this option more expensive.

This would create a clear and immediate incentive for businesses to consider exactly how much material they need to send to landfill. Until recently, Queensland had no levy on landfill. This prompted many New South Wales businesses to send their waste across the border for cheaper dumping.

Queensland recently re-introduced a levy to deter this practice, which will presumably normalise the amount of waste going into its landfills.

Increasing levies will mean a movement towards the correct cost of landfill while at the same time generating revenue than can be used to improve recycling infrastructure or, fingers crossed, even cut council tax rates.

Use a carrot

It’s hard to say exactly how much recycling is processed in Australia, as there’s no coherent national database of facilities. But, according to a 2011 government report, Australia generates roughly 50 million tonnes of waste a year, around 50-60% of which is recycled.




Read more:
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It is clear the domestic market is currently too small to increase the percentage of recycling it handles. To solve this, another simple solution would be to subsidise the cost of recycling this waste.

Subsidies would provide immediate incentives for local recycling plants to increase their processing of this material. In the long run, this may result in more investment in local recycling infrastructure that will be essential to cope with the volume of waste.

Subsidies are not new for Australian environmental policy. Indeed, we subsidise the reduction of greenhouse gases using the A$2.5 billion Emissions Reduction Fund. The same logic could be used for recycling.

A savvy policymaker could implement a recycling subsidy that is fully funded by the revenue generated by a waste levy, thus requiring no additional taxpayer funding.

Use a second, different, stick

So far the proposed polices have focused on the existing problems within the landfill and recycling industries, but we need to look more closely at the root of the problem: the generation of waste.

Effective policies could reduce excessive packaging by encouraging companies to rethink their product delivery.

One could tax product packaging, just as policymakers have done with the use of successful plastic bag taxes. In 2015 England adopted a 5p charge for plastic bags and their use fell by 85% in just six months.

Use a mirror

Understandably, implementing tax and subsidy policies may not please everyone. Luckily, changing patterns of behaviour to reduce waste without levies and subsidies is often quite easy and relatively cheap.

Some councils are taking the step of monitoring the contents of bins. This is done either by sending employees to physically inspect wheelie bins, or fitting garbage trucks with cameras to check what’s dumped into their trays. Some parts of Perth are trialling clear wheelie bins to encourage homeowners to reflect on what they’re putting in them.




Read more:
Why you’re almost certainly wasting time rinsing your recycling


We may instinctively object to being named and shamed for poor waste disposal habits, but it’s certainly a relatively cheap and effective way of changing community habits.

In a similar approach on the ABC’s War on Waste, a street of neighbours communally exposed the amount of rubbish they each generated, then pledged to reduce it.

Taking ownership of – and responsibility for – your own waste may prove an unlikely yet effective policy.

Don’t panic! We have options

All in all, we have plenty of options for dealing with our recycling. Now that China is no longer offering a cheap and convenient option to push our waste problems offshore, we have an opportunity to make positive and long-lasting change.




Read more:
We can’t recycle our way to ‘zero waste’


Using sensible policies, most effectively in combination, could make this a defining opportunity for our local recycling industry with great benefits for the Australian environment.

The ConversationWhat we need most is strong and consistent leadership from policymakers who can imagine a low-waste Australian society.

Ian A. MacKenzie, Senior Lecturer in Economics, The University of Queensland

This article was originally published on The Conversation. Read the original article.

Honeybees hog the limelight, yet wild insects are the most important and vulnerable pollinators



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Szefei / http://www.shutterstock.com

Philip Donkersley, Lancaster University

Pollinating insects like bees, butterflies and flies have had a rough time of late. A broad library of evidence suggests there has been a widespread decline in their abundance and diversity since the 1950s. This matters because such insects are critical both for the reproduction of wild plants and for agricultural food production.

The decline of these pollinators is linked with destruction of natural habitats like forests and meadows, the spread of pests such as Varroa mite and diseases like foulbrood, and the increasing use of agrochemicals by farmers. Although there have been well documented declines in managed honeybees, non-Apis (non-honeybee) pollinators such as bumblebees and solitary bees have also become endangered.

There are more than 800 wild (non-honey) bee species in Europe alone. Seven are classified by the IUCN Redlist as critically endangered, 46 are endangered, 24 are vulnerable and 101 are near threatened. Collectively, losing such species would have a significant impact on global pollination.

Though much of the media focus is on honeybees, they are responsible for only a third of the crop pollination in Britain and a very small proportion of wild plant pollination. A range of other insects including butterflies, bumblebees and small flies make up for this pollination deficit.

Butterfly pollinating during monsoon season.
Hitesh Chhetri / http://www.shutterstock.com

Not all pollinators are created equal

Pollinators also vary in their effectiveness due to their behaviour around flowers and their capacity to hold pollen. Bigger and hairier insects can carry more pollen, while those that groom themselves less tend to be able to transfer pollen more effectively. Bumblebees, for example, make excellent pollinators (far superior to honeybees) as they are big, hairy and do not groom themselves as often.

Where they are in decline, honeybees suffer primarily from pests and diseases, a consequence of poor nutrition and artificially high population density. This differs from other pollinators, where the decline is mainly down to habitat destruction. It seems pesticides affect all pollinators.

An ashy mining-bee (Andrena cineraria) settles in for a snack.
Philip Donkersley, Author provided

Save (all) the bees

Curiously, the issues facing non-Apis pollinators may be exacerbated by commercial beekeeping, and attempts to help honeybees may even harm efforts to conserve wild pollinators.

The problem is that there are only so many flowers and places to nest. And once the numbers of honeybees have been artificially inflated (commercial-scale beekeeping wouldn’t exist without humans) the increased competition for these resources can push native non-Apis pollinators out of their natural habitats. Honeybees also spread exotic plants and transmit pathogens, both of which have been shown to harm other pollinators.

The European honey bee (Apis mellifera) is the most common species of honey bee.
Philip Donkersley, Author provided

Over the coming decades, farmers and those who regulate them are faced with a tough challenge. Agricultural output must be increased to feed a growing human population, but simultaneously the environmental impact must be reduced.

The agriculture sector has tried to address the need to feed a growing population through conventional farming practices such as mechanisation, larger fields or the use of pesticides and fertiliser. Yet these have contributed to widespread destruction of natural landscapes and loss of natural capital.

Limited resources and land use pressure require conservation strategies to become more efficient, producing greater outcomes from increasingly limited input.

A mosaic of different flowers: these sorts of landscapes are paradise for bees.
Philip Donkersley, Author provided

Cooperative conservation

So-called agri-environment schemes represent the best way to help insect pollinators. That means diversifying crops, avoiding an ecologically-fragile monoculture and ensuring that the insects can jump between different food sources. It also means protecting natural habitats and establishing ecological focus areas such as wildflower strips, while limiting the use of pesticides and fertilisers.

As pollinating insects need a surprisingly large area of land to forage, linking up restored habitats on a larger scale provides far more evident and immediate benefits. However, so far, connections between protected areas have not been a priority, leading to inefficient conservation.

The ConversationWe need a substantial shift in how we think about pollinators. Encouraging land managers to work cooperatively will help create bigger, more impactful areas to support pollinators. In future, conservation efforts will need to address declines in all pollinators by developing landscapes to support pollinator communities and not just honeybees.

Philip Donkersley, Senior Research Associate in Entomology, Lancaster University

This article was originally published on The Conversation. Read the original article.

Africa is splitting in two – here is why



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Google Earth. Data SIO, NOAA, US Navy, NGA, GEBCO

Lucia Perez Diaz, Royal Holloway

A large crack, stretching several kilometres, made a sudden appearance recently in south-western Kenya. The tear, which continues to grow, caused part of the Nairobi-Narok highway to collapse. Initially, the appearance of the crack was linked to tectonic activity along the East African Rift. But although geologists now think that this feature is most likely an erosional gully, questions remain as to why it has formed in the location that it did and whether its appearance is at all connected to the ongoing East African Rift. For example, the crack could be the result of the erosion of soft soils infilling an old rift-related fault.

The Earth is an ever-changing planet, even though in some respects change might be almost unnoticeable to us. Plate tectonics is a good example of this. But every now and again something dramatic happens and leads to renewed questions about the African continent splitting in two.

The Earth’s lithosphere (formed by the crust and the upper part of the mantle) is broken up into a number of tectonic plates. These plates are not static, but move relative to each other at varying speeds, “gliding” over a viscous asthenosphere. Exactly what mechanism or mechanisms are behind their movement is still debated, but are likely to include convection currents within the asthenosphere and the forces generated at the boundaries between plates.

These forces do not simply move the plates around, they can also cause plates to rupture, forming a rift and potentially leading to the creation of new plate boundaries. The East African Rift system is an example of where this is currently happening.

The East African Rift Valley stretches over 3,000km from the Gulf of Aden in the north towards Zimbabwe in the south, splitting the African plate into two unequal parts: the Somali and Nubian plates. Activity along the eastern branch of the rift valley, running along Ethiopia, Kenya and Tanzania, became evident when the large crack suddenly appeared in south-western Kenya.

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Why does rifting happen?

When the lithosphere is subject to a horizontal extensional force it will stretch, becoming thinner. Eventually, it will rupture, leading to the formation of a rift valley.

Great Rift Valley, Tanzania.
Shutterstock

This process is accompanied by surface manifestations along the rift valley in the form of volcanism and seismic activity. Rifts are the initial stage of a continental break-up and, if successful, can lead to the formation of a new ocean basin. An example of a place on Earth where this has happened is the South Atlantic ocean, which resulted from the break up of South America and Africa around 138m years ago – ever noticed how their coastlines match like pieces of the same puzzle?.

Maps made by Snider-Pellegrini in 1858 showing his idea of how the American and African continents may once have fitted together.
https://en.wikipedia.org/wiki/Antonio_Snider-Pellegrini#/media/File:Antonio_Snider-Pellegrini_Opening_of_the_Atlantic.jpg

Continental rifting requires the existence of extensional forces great enough to break the lithosphere. The East African Rift is described as an active type of rift, in which the source of these stresses lies in the circulation of the underlying mantle. Beneath this rift, the rise of a large mantle plume is doming the lithosphere upwards, causing it to weaken as a result of the increase in temperature, undergo stretching and breaking by faulting.

Mantle plume (left).
Reprinted from Tetrophysics, Vol 513, Oliver Mearle, ‘A simple continental rift classification’ Copyright (2011), with permission from Elsevier.

Evidence for the existence of this hotter-than-normal mantle plume has been found in geophysical data and is often referred to as the “African Superswell”. This superplume is not only a widely-accepted source of the pull-apart forces that are resulting in the formation of the rift valley but has also been used to explain the anomalously high topography of the Southern and Eastern African Plateaus.

Breaking up isn’t easy

Rifts exhibit a very distinctive topography, characterised by a series of fault-bounded depressions surrounded by higher terrain. In the East African system, a series of aligned rift valleys separated from each other by large bounding faults can be clearly seen from space.

Topography of the Rift Valley.
James Wood and Alex Guth, Michigan Technological University. Basemap: Space Shuttle radar topography image by NASA

Not all of these fractures formed at the same time, but followed a sequence starting in the Afar region in northern Ethiopia at around 30m years ago and propagating southwards towards Zimbabwe at a mean rate of between 2.5-5cm a year.

Although most of the time rifting is unnoticeable to us, the formation of new faults, fissures and cracks or renewed movement along old faults as the Nubian and Somali plates continue moving apart can result in earthquakes.

However, in East Africa most of this seismicity is spread over a wide zone across the rift valley and is of relatively small magnitude. Volcanism running alongside is a further surface manifestation of the ongoing process of continental break up and the proximity of the hot molten asthenosphere to the surface.

A timeline in action

The East African Rift is unique in that it allows us to observe different stages of rifting along its length. To the south, where the rift is young, extension rates are low and faulting occurs over a wide area. Volcanism and seismicity are limited.

Towards the Afar region, however, the entire rift valley floor is covered with volcanic rocks. This suggests that, in this area, the lithosphere has thinned almost to the point of complete break up. When this happens, a new ocean will begin forming by the solidification of magma in the space created by the broken-up plates. Eventually, over a period of tens of millions of years, seafloor spreading will progress along the entire length of the rift. The ocean will flood in and, as a result, the African continent will become smaller and there will be a large island in the Indian Ocean composed of parts of Ethiopia and Somalia, including the Horn of Africa.

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Dramatic events, such as sudden motorway-splitting faults can give continental rifting a sense of urgency. However, rifting is a very slow process that, most of the time, goes about splitting Africa without anybody even noticing.

The ConversationThis article was updated and the headline changed on April 7 to reflect ongoing discussion by geologists about the cause of the large crack that appeared on the East Africa Rift and whether its location is related to the African continent split.

Lucia Perez Diaz, Postdoctoral Researcher, Fault Dynamics Research Group, Royal Holloway

This article was originally published on The Conversation. Read the original article.

Not so fast: why the electric vehicle revolution will bring problems of its own



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Electric cars are taking over – but they really as green as they look?
Jack Amick / flickr, CC BY-NC

Martin Brueckner, Murdoch University

After years of being derided as a joke by car manufacturers and the public, interest in electric vehicles has increased sharply as governments around the world move to ban petrol and diesel cars.

We have seen a tremendous rise in availability, especially at the premium end of the market, where Tesla is giving established brands a run for their money. Electric cars are likely to penetrate the rest of the market quickly too. Prices should be on par with conventional cars by 2025.

Electric cars are praised as the answer to questions of green and clean mobility. But the overall sustainability of electric vehicles is far from clear. On closer examination, our entire transport paradigm may need to be rethought.




Read more:
Australia’s ‘electric car revolution’ won’t happen automatically


Compared with combustion engines, electric transport has obvious advantages for emissions and human health. Transport is responsible for around 23% of energy-related carbon dioxide emissions globally. This is expected to double by 2050.

Motor vehicles also put a burden on society, especially in urban environments where they are chiefly responsible for noise and air pollution. Avoiding these issues is why electric vehicles are considered a key technology in cleaning up the transport sector. However, electric cars come with problems of their own.

Dirt in the supply chain

For one, electric vehicles have a concerning supply chain. Cobalt, a key component of the lithium-ion batteries in electric cars, is linked to reports of child labour. The nickel used in those same batteries is toxic to extract from the ground. And there are environmental concerns and land use conflicts connected with lithium mining in countries like Tibet and Bolivia.

The elements used in battery production are finite and in limited supply. This makes it impossible to electrify all of the world’s transport with current battery technology. Meanwhile, there is still no environmentally safe way of recycling lithium-ion batteries.

While electric cars produce no exhaust, there is concern about fine particle emissions. Electric cars are often heavier than conventional cars, and heavier vehicles are often accompanied by higher levels of non-exhaust emissions. The large torque of electric vehicles further adds to the fine dust problem, as it causes greater tyre wear and dispersion of dust particles.

Different motor, same problem

Electric vehicles share many other issues with conventional cars too. Both require roads, parking areas and other infrastructure, which is especially a problem in cities. Roads divide communities and make access to essential services difficult for those without cars.

A shift in people’s reliance on combustion cars to electric cars also does little to address sedentary urban lifestyles, as it perpetuates our lack of physical activity.

Other problems relate to congestion. In Australia, the avoidable social cost of traffic congestion in 2015 was estimated at A$16.5 billion. This is expected to increase by 2% every year until 2030. Given trends in population growth and urbanisation globally and in Australia, electric cars – despite obvious advantages over fossil fuels – are unlikely to solve urban mobility and infrastructure-related problems.

Technology or regulation may solve these technical and environmental headaches. Improvements in recycling, innovation, and the greening of battery factories can go a long way towards reducing the impacts of battery production. Certification schemes, such as the one proposed in Sweden, could help deliver low-impact battery value chains and avoid conflict minerals and human rights violations in the industry.

A new transport paradigm

Yet, while climate change concerns alone seem to warrant a speedy transition towards electric mobility, it may prove to be merely a transition technology. Electric cars will do little for urban mobility and liveability in the years to come. Established car makers such as Porsche are working on new modes of transportation, especially for congested and growing markets such as China.

Nevertheless, their vision is still one of personal vehicles – relying on electric cars coupled with smart traffic guidance systems to avoid urban road congestion. Instead of having fewer cars, as called for by transport experts, car makers continue to promote individualised transport, albeit a greener version.

With a growing population, a paradigm shift in transport may be needed – one that looks to urban design to solve transportation problems.

In Copenhagen, for example, bikes now outnumber cars in the city’s centre, which is primed to be car-free within the next ten years. Many other cities, including Oslo in Norway and Chengdu in China, are also on their way to being free of cars.

Experts are already devising new ways to design cities. They combine efficient public transport, as found in Curitiba, Brazil, with principles of walkability, as seen in Vauben, Germany. They feature mixed-use, mixed-income and transit-oriented developments, as seen in places like Fruitvale Village in Oakland, California.




Read more:
Designing suburbs to cut car use closes gaps in health and wealth


These developments don’t just address transport-related environmental problems. They enhance liveability by reclaiming urban space for green developments. They reduce the cost of living by cutting commuting cost and time. They deliver health benefits, thanks to reduced pollution and more active lifestyles. They improve social cohesion, by fostering human interaction in urban streetscapes, and help to reduce crime. And of course, they improve economic performance by reducing the loss of productivity caused by congestion.

The ConversationElectric cars are a quick-to-deploy technology fix that helps tackle climate change and improve urban air quality – at least to a point. But the sustainability endgame is to eliminate many of our daily travel needs altogether through smart design, while improving the parts of our lives we lost sight of during our decades-long dependence on cars.

Martin Brueckner, Senior Lecturer in Sustainability, Murdoch University

This article was originally published on The Conversation. Read the original article.