Asia – The World’s Tip?


Advertisements

How to feed a growing population healthy food without ruining the planet



File 20190112 43529 sfajtu.jpg?ixlib=rb 1.1
For many of us, a better diet means eating more fruit and vegetables.
iStock, CC BY-NC

Alessandro R Demaio, University of Copenhagen; Jessica Fanzo, Johns Hopkins University, and Mario Herrero, CSIRO

If we’re serious about feeding the world’s growing population healthy food, and not ruining the planet, we need to get used to a new style of eating. This includes cutting our Western meat and sugar intakes by around 50%, and doubling the amount of nuts, fruits, vegetables and legumes we consume.

These are the findings our the EAT-Lancet Commission, released today. The Commission brought together 37 leading experts in nutrition, agriculture, ecology, political sciences and environmental sustainability, from 16 countries.

Over two years, we mapped the links between food, health and the environment and formulated global targets for healthy diets and sustainable food production. This includes five specific strategies to achieve them through global cooperation.




Read more:
How to conserve half the planet without going hungry


Right now, we produce, ship, eat and waste food in a way that is a lose-lose for both people and planet – but we can flip this trend.

What’s going wrong with our food supply?

Almost one billion people lack sufficient food, yet more than two billion suffer from obesity and food-related diseases such as diabetes and heart disease.

The foods causing these health epidemics – combined with the way we produce our food – are pushing our planet to the brink.

One-third of the greenhouse gas emissions that drive climate change come from food production. Our global food system leads to extensive deforestation and species extinction, while depleting our oceans, and fresh water resources.

To make matters worse, we lose or throw away around one-third of all food produced. That’s enough to feed the world’s hungry four times over, every year.

At the same time, our food systems are at risk due to environmental degradation and climate change. These food systems are essential to providing the diverse, high-quality foods we all consume every day.

A radical new approach

To improve the health of people and the planet, we’ve developed a “planetary health diet” which is globally applicable – irrespective of your geographic, economic or cultural background – and locally adaptable.

The diet is a “flexitarian” approach to eating. It’s largely composed of vegetables and fruits, wholegrains, legumes, nuts and unsaturated oils. It includes high-quality meat, dairy and sugar, but in quantities far lower than are consumed in many wealthier societies.

Many of us need to eat more veggies and less red meat.
Joshua Resnick/Shutterstock

The planetary health diet consists of:

  • vegetables and fruit (550g per day per day)
  • wholegrains (230 grams per day)
  • dairy products such as milk and cheese (250g per day)
  • protein sourced from plants, such as lentils, peas, nuts and soy foods (100 grams per day)
  • small quantities of fish (28 grams per day), chicken (25 grams per day) and red meat (14 grams per day)
  • eggs (1.5 per week)
  • small quantities of fats (50g per day) and sugar (30g per day).

Of course, some populations don’t get nearly enough animal-source foods necessary for growth, cognitive development and optimal nutrition. Food systems in these regions need to improve access to healthy, high-quality diets for all.

The shift is radical but achievable – and is possible without any expansion in land use for agriculture. Such a shift will also see us reduce the amount of water used during production, while reducing nitrogen and phosphorous usage and runoff. This is critical to safeguarding land and ocean resources.

By 2040, our food systems should begin soaking up greenhouse emissions – rather than being a net emitter. Carbon dioxide emissions must be down to zero, while methane and nitrous oxide emissions be kept in close check.

How to get there

The commission outlines five implementable strategies for a food transformation:

1. Make healthy diets the new normal – leaving no-one behind

Shift the world to healthy, tasty and sustainable diets by investing in better public health information and implementing supportive policies. Start with kids – much can happen by changing school meals to form healthy and sustainable habits, early on.

Unhealthy food outlets and their marketing must be restricted. Informal markets and street vendors should also be encouraged to sell healthier and more sustainable food.




Read more:
Let’s untangle the murky politics around kids and food (and ditch the guilt)


2. Grow what’s best for both people and planet

Realign food system priorities for people and planet so agriculture becomes a leading contributor to sustainable development rather than the largest driver of environmental change. Examples include:

  • incorporating organic farm waste into soils
  • drastically reducing tillage where soil is turned and churned to prepare for growing crops
  • investing more in agroforestry, where trees or shrubs are grown around or among crops or pastureland to increase biodiversity and reduce erosion
  • producing a more diverse range of foods in circular farming systems that protect and enhance biodiversity, rather than farming single crops or livestock.

The measure of success in this area is that agriculture one day becomes a carbon sink, absorbing carbon dioxide from the atmosphere.

Technology can help us make better use of our farmlands.
Shutterstock

3. Produce more of the right food, from less

Move away from producing “more” food towards producing “better food”.

This means using sustainable “agroecological” practices and emerging technologies, such as applying micro doses of fertiliser via GPS-guided tractors, or improving drip irrigation and using drought-resistant food sources to get more “crop per drop” of water.

In animal production, reformulating feed to make it more nutritious would allow us to reduce the amount of grain and therefore land needed for food. Feed additives such as algae are also being developed. Tests show these can reduce methane emissions by up to 30%.

We also need to redirect subsidies and other incentives to currently under-produced crops that underpin healthy diets – notably, fruits, vegetables and nuts – rather than crops whose overconsumption drives poor health.

4. Safeguard our land and oceans

There is essentially no additional land to spare for further agricultural expansion. Degraded land must be restored or reforested. Specific strategies for curbing biodiversity loss include keeping half of the current global land area for nature, while sharing space on cultivated lands.

The same applies for our oceans. We need to protect the marine ecosystems fisheries depend on. Fish stocks must be kept at sustainable levels, while aquaculture – which currently provides more than 40% of all fish consumed – must incorporate “circular production”. This includes strategies such as sourcing protein-rich feeds from insects grown on food waste.

5. Radically reduce food losses and waste

We need to more than halve our food losses and waste.

Poor harvest scheduling, careless handling of produce and inadequate cooling and storage are some of the reasons why food is lost. Similarly, consumers must start throwing less food away. This means being more conscious about portions, better consumer understanding of “best before” and “use by” labels, and embracing the opportunities that lie in leftovers.

Circular food systems that innovate new ways to reduce or eliminate waste through reuse will also play a significant role and will additionally open new business opportunities.




Read more:
Australian communities are fighting food waste with circular economies


For significant transformation to happen, all levels of society must be engaged, from individual consumers to policymakers and everybody along the food supply chain. These changes will not happen overnight, and they are not the responsibility of a handful of stakeholders. When it comes to food and sustainability, we are all at the decision dining table.

The EAT-Lancet Commission’s Australian launch is in Melbourne on February 1. Limited free tickets are available.The Conversation

Alessandro R Demaio, Australian Medical Doctor; Fellow in Global Health & NCDs, University of Copenhagen; Jessica Fanzo, Bloomberg Distinguished Associate Professor of Global Food and Agriculture Policy and Ethics, Johns Hopkins University, and Mario Herrero, Chief Research Scientist, Food Systems and the Environment, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

India unveils the world’s tallest statue, celebrating development at the cost of the environment


Ruth Gamble, La Trobe University and Alexander E. Davis, La Trobe University

India’s Prime Minister Narendra Modi will today inaugurate the world’s largest statue, the Statue of Unity in Gujarat. At 182m tall (240m including the base), it is twice the height of the Statue of Liberty, and depicts India’s first deputy Prime Minister, Sardar Vallabhbhai Patel.

The statue overlooks the Sardar Sarovar Dam on the Narmada River. Patel is often thought of as the inspiration for the dam, which came to international attention when the World Bank withdraw its support from the project in 1993 after a decade of environmental and humanitarian protests. It wasn’t until 2013 that the World Bank funded another large dam project.

Like the dam, the statue has been condemned for its lack of environmental oversight, and its displacement of local Adivasi or indigenous people. The land on which the statue was built is an Adivasi sacred site that was taken forcibly from them.




Read more:
India’s development debate must move beyond Modi


The Statue of Unity is part of a broader push by Modi’s Bharatiya Janata Party (BJP) to promote Patel as a symbol of Indian nationalism and free-market development. The statue’s website praises him for bringing the princely states into the Union of India and for being an early advocate of Indian free enterprise.

The BJP’s promotion of Patel also serves to overshadow the legacy of his boss, India’s first prime minister, Jawaharlal Nehru. Nehru’s descendants head India’s most influential opposition party, the Indian National Congress.

The statue was supposed to be built with both private and public money, but it attracted little private investment. In the end, the government of Gujarat paid for much of the statue’s US$416.67 million price tag.

The statue under construction, January 2018.
Alexander Davis

The Gujarat government claims its investment in the statue will promote tourism, and that tourism is “sustainable development”. The United Nations says that sustainable tourism increases environmental outcomes and promotes local cultures. But given the statue’s lack of environmental checks and its displacement of local populations, it is hard to see how this project fulfils these goals.

The structure itself is not exactly a model of sustainable design. Some 5,000 tonnes of iron, 75,000 cubic metres of concrete, 5,700 tonnes of steel, and 22,500 tonnes of bronze sheets were used in its construction.

Critics of the statue note that this emblem of Indian nationalism was built partly with Chinese labour and design, with the bronze sheeting subcontracted to a Chinese firm.

The statue’s position next to the controversial Sardar Sarovar Dam is also telling. While chief minister of Gujarat from 2001 to 2014, Modi pushed for the dam’s construction despite the World Bank’s condemnation. He praised the dam’s completion in 2017 as a monument to India’s progress.

Both the completion of the dam and the statue that celebrates it suggest that the BJP government is backing economic development over human rights and environmental protections.

The statue’s inauguration comes only a month after the country closed the first nature reserve in India since 1972. Modi’s government has also come under sustained criticism for a series of pro-industry policies that have eroded conservation, forest, coastal and air pollution protections, and weakened minority land rights.

India was recently ranked 177 out of 180 countries in the world for its environmental protection efforts.

Despite this record, the United Nations’ Environmental Programme (UNEP) recently awarded Modi its highest environmental award. It made him a Champion of the Earth for his work on solar energy development and plastic reduction.

The decision prompted a backlash in India, where many commentators are concerned by the BJP’s environmental record.




Read more:
Bridges and roads in north-east India may drive small tribes away from development


Visitors to the statue will access it via a 5km boat ride. At the statue’s base, they can buy souvenirs and fast food, before taking a high-speed elevator to the observation deck.

The observation deck will be situated in Patel’s head. From it, tourists will look out over the Sardar Sarovar Dam, as the accompanying commentary praises “united” India’s national development successes.

But let’s not forget the environmental and minority protections that have been sacrificed to achieve these goals.


This article was amended on November 7, 2018, to clarify the role of Chinese companies in the statue’s design and construction.The Conversation

Ruth Gamble, David Myers Research Fellow, La Trobe University and Alexander E. Davis, New Generation Network Fellow, La Trobe University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

What the world needs now to fight climate change: More swamps



File 20180911 144473 k9w2ui.jpg?ixlib=rb 1.1
Freshwater cypress swamp, First Landing State Park, Va.
VA State Parks, CC BY

William Moomaw, Tufts University; Gillian Davies, Tufts University, and Max Finlayson, Charles Sturt University

“Drain the swamp” has long meant getting rid of something distasteful. Actually, the world needs more swamps – and bogs, fens, marshes and other types of wetlands.

These are some of the most diverse and productive ecosystems on Earth. They also are underrated but irreplaceable tools for slowing the pace of climate change and protecting our communities from storms and flooding.

Scientists widely recognize that wetlands are extremely efficient at pulling carbon dioxide out of the atmosphere and converting it into living plants and carbon-rich soil. As part of a transdisciplinary team of nine wetland and climate scientists, we published a paper earlier this year that documents the multiple climate benefits provided by all types of wetlands, and their need for protection.

Saltwater wetland, Waquoit Bay Estuarine Research Reserve, Mass.
Ariana Sutton-Grier, CC BY-ND

A vanishing resource

For centuries human societies have viewed wetlands as wastelands to be “reclaimed” for higher uses. China began large-scale alteration of rivers and wetlands in 486 B.C. when it started constructing the Grand Canal, still the longest canal in the world. The Dutch drained wetlands on a large scale beginning about 1,000 years ago, but more recently have restored many of them. As a surveyor and land developer, George Washington led failed efforts to drain the Great Dismal Swamp on the border between Virginia and North Carolina.

Today many modern cities around the world are built on filled wetlands. Large-scale drainage continues, particularly in parts of Asia. Based on available data, total cumulative loss of natural wetlands is estimated to be 54 to 57 percent – an astounding transformation of our natural endowment.

Vast stores of carbon have accumulated in wetlands, in some cases over thousands of years. This has reduced atmospheric levels of carbon dioxide and methane – two key greenhouse gases that are changing Earth’s climate. If ecosystems, particularly forests and wetlands, did not remove atmospheric carbon, concentrations of carbon dioxide from human activities would increase by 28 percent more each year.

Wetland soil core taken from Todd Gulch Fen at 10,000 feet in the Colorado Rockies. The dark, carbon-rich core is about 3 feet long. Living plants at its top provide thermal insulation, keeping the soil cold enough that decomposition by microbes is very slow.
William Moomaw, Tufts University, CC BY-ND

From carbon sinks to carbon sources

Wetlands continuously remove and store atmospheric carbon. Plants take it out of the atmosphere and convert it into plant tissue, and ultimately into soil when they die and decompose. At the same time, microbes in wetland soils release greenhouse gases into the atmosphere as they consume organic matter.

Natural wetlands typically absorb more carbon than they release. But as the climate warms wetland soils, microbial metabolism increases, releasing additional greenhouse gases. In addition, draining or disturbing wetlands can release soil carbon very rapidly.

For these reasons, it is essential to protect natural, undisturbed wetlands. Wetland soil carbon, accumulated over millennia and now being released to the atmosphere at an accelerating pace, cannot be regained within the next few decades, which are a critical window for addressing climate change. In some types of wetlands, it can take decades to millennia to develop soil conditions that support net carbon accumulation. Other types, such as new saltwater wetlands, can rapidly start accumulating carbon.

Arctic permafrost, which is wetland soil that remains frozen for two consecutive years, stores nearly twice as much carbon as the current amount in the atmosphere. Because it is frozen, microbes cannot consume it. But today, permafrost is thawing rapidly, and Arctic regions that removed large amounts of carbon from the atmosphere as recently as 40 years ago are now releasing significant quantities of greenhouse gases. If current trends continue, thawing permafrost will release as much carbon by 2100 as all U.S. sources, including power plants, industry and transportation.

Kuujjuarapik is a region underlain by permafrost in Northern Canada.
Nigel Roulet, McGill University., CC BY-ND

Climate services from wetlands

In addition to capturing greenhouse gases, wetlands make ecosystems and human communities more resilient in the face of climate change. For example, they store flood waters from increasingly intense rainstorms. Freshwater wetlands provide water during droughts and help cool surrounding areas when temperatures are elevated.

Salt marshes and mangrove forests protect coasts from hurricanes and storms. Coastal wetlands can even grow in height as sea level rises, protecting communities further inland.

Saltwater mangrove forest along the coast of the Biosphere Reserve in Sian Ka’an, Mexico.
Ariana Sutton-Grier, CC BY-ND

But wetlands have received little attention from climate scientists and policymakers. Moreover, climate considerations are often not integrated into wetland management. This is a critical omission, as we pointed out in a recent paper with 6 colleagues that places wetlands within the context of the Scientists’ Second Warning to Humanity, a statement endorsed by an unprecedented 20,000 scientists.

The most important international treaty for the protection of wetlands is the Ramsar Convention, which does not include provisions to conserve wetlands as a climate change strategy. While some national and subnational governments effectively protect wetlands, few do this within the context of climate change.

Forests rate their own section (Article 5) in the Paris climate agreement that calls for protecting and restoring tropical forests in developing countries. A United Nations process called Reducing Emissions from Deforestation and Degraded Forests, or REDD+ promises funding for developing countries to protect existing forests, avoid deforestation and restore degraded forests. While this covers forested wetlands and mangroves, it was not until 2016 that a voluntary provision for reporting emissions from wetlands was introduced into the U.N. climate accounting system, and only a small number of governments have taken advantage of it.

Models for wetland protection

Although global climate agreements have been slow to protect wetland carbon, promising steps are starting to occur at lower levels.

Ontario, Canada has passed legislation that is among the most protective of undeveloped lands by any government. Some of the province’s most northern peatlands, which contain minerals and potential hydroelectric resources, are underlain by permafrost that could release greenhouse gases if disturbed. The Ontario Far North Act specifically states that more than 50 percent of the land north of 51 degrees latitude is to be protected from development, and the remainder can only be developed if the cultural, ecological (diversity and carbon sequestration) and social values are not degraded.

Also in Canada, a recent study reports large increases in carbon storage from a project that restored tidal flooding to a saltmarsh near Aulac, New Brunswick, on Canada’s Bay of Fundy. The marsh had been drained by a dike for 300 years, causing loss of soil and carbon. But just six years after the dike was breached, rates of carbon accumulation in the restored marsh averaged more than five times the rate reported for a nearby mature marsh.

Ten feet (3 meters) of carbon-rich soil accumulation along Dipper Harbour, Bay of Fundy, New Brunswick, Canada, has been radiocarbon dated to have accumulated over 3,000 years.
Gail Chmura, McGill University, CC BY-ND

In our view, instead of draining swamps and weakening protections, governments at all levels should take action immediately to conserve and restore wetlands as a climate strategy. Protecting the climate and avoiding climate-associated damage from storms, flooding and drought is a much higher use for wetlands than altering them for short-term economic gains.

This article has been updated to add a link to the Scientists’ Second Warning to Humanity.The Conversation

William Moomaw, Professor Emeritus of International Environmental Policy, Tufts University; Gillian Davies, Visiting Scholar, Global Development and Environment Institute, Tufts University, and Max Finlayson, Director, Institute for Land, Water and Society, Charles Sturt University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Climate change will reshape the world’s agricultural trade



File 20180905 45172 1x5qj2a.jpg?ixlib=rb 1.1
Australia’s grain exports will suffer under climate change.
Alpha/Flickr, CC BY-NC

Luciana Porfirio, CSIRO; David Newth, CSIRO, and John Finnigan, CSIRO

Ending world hunger is a central aspiration of modern society. To address this challenge – along with expanding agricultural land and intensifying crop yields – we rely on global agricultural trade to meet the nutritional demands of a growing world population.




Read more:
How many people can Australia feed?


But standing in the way of this aspiration is human-induced climate change. It will continue to affect the issue of where in the world crops can be grown and, therefore, food supply and global markets.

In a paper published today in Nature Palgrave, we show that climate change will affect global markets by reshaping agricultural trading patterns.

Some regions may not be able to battle climate impacts on agriculture, in which case production of key commodities will decline or shift to new regions.

The challenge

The negative impacts of climate change on agricultural production are of great concern to farmers and decision-makers. The concern is increasingly shared by governments including those most hostile to the advancement of climate change mitigation.

Even the United States, which has opted out of the Paris Agreement, acknowledged at last year’s G7 summit that climate change was one of a number of threats to “our capacity to feed a growing population and need[ed] to be taken into serious consideration”.

The UN median population projection suggests that the world population will reach some 10 billion in 2050. Between 2000 and 2010, roughly 66% of the daily energy intake per person, about 7,322 kilojoules, was derived from four key commodities: wheat, rice, coarse grains and oilseeds. However, the most recent UN report on food security and nutrition shows that world hunger is on the rise again and scientists believe this is due to climate change.




Read more:
World hunger is increasing thanks to wars and climate change


We must ask: what is the cost of adapting to climate change versus the cost of mitigating carbon emissions? And assuming that changes in climate and crop yields are here to stay, are we prepared for permanent agricultural shifts?

Disruptions and opportunities

Agricultural production is significantly affected by climate change. Our results suggest that global trade patterns of agricultural commodities may be significantly different from today’s reality – with or without carbon mitigation. This is because climate change and the implementation of a carbon mitigation policy have different effects on a regions’ agricultural production and economy.

Take the US, which in 2015 had 30% of the global market share of coarse grains, paddy rice, soybeans and wheat. We modelled production between 2050-59 under two scenarios: in a world 2℃ average temperature rise, and with a 1.5℃ increase. In both cases, the US market share would shrink to about 10%.




Read more:
As global food demand rises, climate change is hitting our staple crops


China is currently a net importer of these commodities. If temperature increases by 1.5℃, we expect to see an increase in exports of some products, like rice to the rest of Asia.

(However, it’s worth bearing in mind that limiting warming would be very expensive for China, as it would need to absorb a costly technological transition to a low carbon economy.)

China’s story is different in the 2℃ scenario. Our projections suggest that climate change will make China, as well as other regions in Asia, more suitable to produce different commodities.

China’s economy will keep expanding, whilst the new climatic conditions create opportunities to produce other food commodities at a greater scale and export to new regions.

Our results also suggest that, regardless of the carbon policy scenarios, Sub-Saharan Africa will become the greatest importer of coarse grains, rice, soybeans and wheat by 2050. This significant change in Sub-Saharan Africa imports is driven by the fact that the largest increase in human population by 2050 will occur in this region, with a significant increase in food demand.

In our research Australia was aggregated in “Oceania” with New Zealand. The exports from Oceania to the rest of the world comprised about 1.6% of the total in 2015, which is dominated by wheat exports from Australia.

Our projections suggest that carbon mitigation policies would favour the wheat industry in this region. The opposite occurs without carbon mitigation: the production and exports of wheat are projected to decline due to climate change impacts on agriculture.

The benefits of mitigation

A recent report published by the European Commission about the challenges of global agriculture in a climate change context by 2050 highlights that

…emission mitigation measures (i.e. carbon pricing) have a negative impact on primary agricultural production […] across all models.

However, the report does not mention the technological costs to buffer (or adapt to) the effect of climate change on agriculture.

Our results suggest that the cost paid by the agricultural sector to reduce carbon dioxide emissions is offset by the higher food prices projected in the non-mitigation scenario, where agricultural production is significantly affected by climate change. We found that there is a net economic benefit in transitioning to a low carbon economy. This is because agricultural systems are more productive under the mitigation scenario, and able to meet the demand for food imposed by a growing population.




Read more:
Australian farmers are adapting to climate change


Mitigating CO₂ emissions has the side benefit of creating a more stable agricultural trade system that may be better able to reduce food insecurity and increase welfare.

Changes in the agricultural system due to climate are inevitable. It is time to create a sense of urgency about our agricultural vulnerabilities to climate change, and begin seriously minimising risk.The Conversation

Luciana Porfirio, Research Scientist, Agriculture & Food, CSIRO | Visiting fellow at the Fenner School of Enviroment & Society, CSIRO; David Newth, Team Leader, Australian And Global Carbon Assessments, CSIRO, and John Finnigan, Leader, Complex Systems Science, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The world of plastics, in numbers



File 20180731 136649 3pwnd5.jpg?ixlib=rb 1.1
Millions of tons of plastic are manufactured every year.
Bert Kaufmann/Wikimedia, CC BY

Eric Beckman, University of Pittsburgh

From its early beginnings during and after World War II, the commercial industry for polymers – long chain synthetic molecules of which “plastics” are a common misnomer – has grown rapidly. In 2015, over 320 million tons of polymers, excluding fibers, were manufactured across the globe.

https://datawrapper.dwcdn.net/AGbTV/2/

Until the last five years, polymer product designers have typically not considered what will happen after the end of their product’s initial lifetime. This is beginning to change, and this issue will require increasing focus in the years ahead.

The plastics industry

“Plastic” has become a somewhat misguided way to describe polymers. Typically derived from petroleum or natural gas, these are long chain molecules with hundreds to thousands of links in each chain. Long chains convey important physical properties, such as strength and toughness, that short molecules simply cannot match.

“Plastic” is actually a shortened form of “thermoplastic,” a term that describes polymeric materials that can be shaped and reshaped using heat.

The modern polymer industry was effectively created by Wallace Carothers at DuPont in the 1930s. His painstaking work on polyamides led to the commercialization of nylon, as a wartime shortage of silk forced women to look elsewhere for stockings.

When other materials became scarce during World War II, researchers looked to synthetic polymers to fill the gaps. For example, the supply of natural rubber for vehicle tires was cut off by the Japanese conquest of Southeast Asia, leading to a synthetic polymer equivalent.

Curiosity-driven breakthroughs in chemistry led to further development of synthetic polymers, including the now widely used polypropylene and high-density polyethylene. Some polymers, such as Teflon, were stumbled upon by accident.

Eventually, the combination of need, scientific advances and serendipity led to the full suite of polymers that you can now readily recognize as “plastics.” These polymers were rapidly commercialized, thanks to a desire to reduce products’ weight and to provide inexpensive alternatives to natural materials like cellulose or cotton.

Types of plastic

The production of synthetic polymers globally is dominated by the polyolefins – polyethylene and polypropylene.

Polyethylene comes in two types: “high density” and “low density.” On the molecular scale, high-density polyethylene looks like a comb with regularly spaced, short teeth. The low-density version, on the other hand, looks like a comb with irregularly spaced teeth of random length – somewhat like a river and its tributaries if seen from high above. Although they’re both polyethylene, the differences in shape make these materials behave differently when molded into films or other products.

https://datawrapper.dwcdn.net/rLRq0/4/

Polyolefins are dominant for a few reasons. First, they can be produced using relatively inexpensive natural gas. Second, they’re the lightest synthetic polymers produced at large scale; their density is so low that they float. Third, polyolefins resist damage by water, air, grease, cleaning solvents – all things that these polymers could encounter when in use. Finally, they’re easy to shape into products, while robust enough that packaging made from them won’t deform in a delivery truck sitting in the sun all day.

However, these materials have serious downsides. They degrade painfully slowly, meaning that polyolefins will survive in the environment for decades to centuries. Meanwhile, wave and wind action mechanically abrades them, creating microparticles that can be ingested by fish and animals, making their way up the food chain toward us.

Recycling polyolefins is not as straightforward as one would like owing to collection and cleaning issues. Oxygen and heat cause chain damage during reprocessing, while food and other materials contaminate the polyolefin. Continuing advances in chemistry have created new grades of polyolefins with enhanced strength and durability, but these cannot always mix with other grades during recycling. What’s more, polyolefins are often combined with other materials in multi-layer packaging; while these multi-layer constructs work well, they are impossible to recycle.

https://datawrapper.dwcdn.net/8k8H3/3/

Polymers are sometimes criticized for being produced from increasingly scarce petroleum and natural gas. However, the fraction of either natural gas or petroleum used to produce polymers is very low; less than 5 percent of either oil or natural gas produced each year is employed to generate plastics. Further, ethylene can be produced from sugarcane ethanol, as is done commercially by Braskem in Brazil.

How plastic is used

Depending upon the region, packaging consumes 35 to 45 percent of the synthetic polymer produced in total, where the polyolefins dominate. Polyethylene terephthalate, a polyester, dominates the market for beverage bottles and textile fibers.

Building and construction consumes another 20 percent of the total polymers produced, where PVC pipe and its chemical cousins dominate. PVC pipes are lightweight, can be glued rather than soldered or welded, and greatly resist the damaging effects of chlorine in water. Unfortunately, the chlorine atoms that confer PVC this advantage make it very difficult to recycle – most is discarded at the end of life.

Polyurethanes, an entire family of related polymers, are widely used in foam insulation for homes and appliances, as well as in architectural coatings.

https://datawrapper.dwcdn.net/eTHAO/3/

The automotive sector uses increasing amounts of thermoplastics, primarily to reduce weight and hence achieve greater fuel efficiency standards. The European Union estimates that 16 percent of the weight of an average automobile is plastic components, most notably for interior parts and components.

Over 70 million tons of thermoplastics per year are used in textiles, mostly clothing and carpeting. More than 90 percent of synthetic fibers, largely polyethylene terephthalate, are produced in Asia. The growth in synthetic fiber use in clothing has come at the expense of natural fibers like cotton and wool, which require significant amounts of farmland to be produced. The synthetic fiber industry has seen dramatic growth for clothing and carpeting, thanks to interest in special properties like stretch, moisture-wicking and breathability.

The ConversationAs in the case of packaging, textiles are not commonly recycled. The average U.S. citizen generates over 90 pounds of textile waste each year. According to Greenpeace, the average person in 2016 bought 60 percent more items of clothing every year than the average person did 15 years earlier, and keeps the clothes for a shorter period of time.

Eric Beckman, Professor of Chem/Petroleum Engineering, University of Pittsburgh

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