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Which is more sustainable: Paper or Plastic?
This next article in the ‘Sustainable Consumption Series” analyses the plastic vs. paper war and positions plastic as more sustainable than paper and other packaging materials such as aluminum and glass (wherever, replaceable)*.
Almost 7 million tonnes of plastic waste is dumped into the ocean every year and due to the non-biodegradable nature of plastics, their decomposition takes hundreds of years. Recently at the Clinton Global Initiative, the Plastic Disclosure project was launched by the Community of Socially Responsible Investors around the World with the goal of reducing plastic waste generation. The rate of plastic recycling is poor (only about 15%) according to the UNEP and disclosing the usage and consumption of plastics could act as a driver for the corporates to pull up this recycling rate.
Last few years Government of India and different state governments are acting against usage of plastic bags and suggesting use of paper or recycled paper believing latter to be environment friendly. But in a country like India, would it be correct to assume that paper is more sustainable than plastic? Or Is it a fallacy? This article compares the sustainability of paper and plastic by considering parameters of energy and water consumption and pollution, especially water pollution.
Before looking at sustainability of usage of different materials, let’s look at the definition of sustainability as given by World Sustainability Council. Sustainability is defined as “Meeting the needs of the present without compromising the ability of future generations to meet their own needs forever”.
The sustainability of paper and plastic have been compared over their life cycle, energy footprint and water footprint.
The Life Cycle of the Alternates
Life cycle Analysis of any product or material is the study of “cradle to grave” process and resources involved in it.
93% of paper is made out of trees(1). Steps involved are
- Logging and Transporting: Trees are cut using energy consuming machines or manpower, moved to a mill, where there is a wait period of 2-3 years for logs to dry (2).
- Debarking and Cooking: Logs are debarked, chipped into one inch squares and “cooked” under tremendous heat and pressure, thus using huge amount of energy.
- Digesting: These chips are digested with sulphurous acid and limestone, until the wood becomes pulp.
- Washing and bleaching: This pulp is washed; requiring thousands of liters of water then bleached using chorine or epoxy resins. Note that polluted water or Grey water (especially in India) goes mostly untreated and adds chorine/epoxy resins (3), besides sulphurous acid, heavy metals and other pollutants to the surrounding environment and ground water.
- Cutting to packaging: Cutting, packaging, printing and shipping requires labor and energy.
- Use, reuse, recycle and final disposal: We will deal with this aspect separately later in this article.
Polyethylene bags are derived from oil residues and come as pellets. Steps involved are
- Melting, tubing and cutting: Pellets are melted at around 300-340 degrees centigrade; a hot bar is dropped at intervals melting a line. Each melted line is cut and punched or stamped for making handles. - Transportation: Plastics, especially bags, are made locally in a region and don’t add much to energy and carbon footprint of transportation.
- Use, reuse, recycle and final disposal: Discussed later in this article.
The world produced 390.9 Million Tons of paper in 2008 4, losing 18.3 Million hectares of forest cover. [CEPI, key Statistics, 2009]. For each ton of paper produced, 17 Trees were cut!!
Now let us consider the energy consumption(5).
Water as one of the most important resources of the world creates the biggest impact on sustainability in the world, especially owing to its poor quality and scarcity in the developing world. For each m3 of pulp/paper producing tree, 214 to 1081 m3 of water (Green Water footprint*) is used, according to a 2010 UNESCO-IHE report.
For Example Water Footprint per Ton of paper products in Netherlands is given below:
For a country like India, where water is increasingly becoming a scarce resource with large misuse /pilferage owing to conflicts and riots, every ton of “writing and printing paper” produced requires about 1246m3 of water.
Packaging industry consumes around half of plastic and considerable volume of materials like Aluminum. Mostly plastic and aluminum are used in packaging due to qualities like strength, flexibility, weight, volume and, inertness. Paper and recycled paper are mostly used as a fad these days to replace carrier bags for shopping or for branding the institution green. Small bags are used in bio-fertilizer and pesticide industries.
Below are water foot print charts for these three different materials:
(Courtesy: Lund University Tetra Pak report)
So the water consumed by paper is around 935 times that of plastic. Something to ponder about the environment friendliness of paper!
These estimates contain only Blue and Green water footprints. Grey or polluted water is not included. Grey water includes surface and ground water. (Full report here)
Use, reuse, recycle and final disposal
Paper is mostly used for bags, stationery and special packaging purposes. These can’t be reused more than 2-3 times due to its inflexibility and strength. Recycled paper faces the same challenges.
Fundamentally Recycling increases the consumption of paper and plastic under an illusion that they can be recycled and hence consumption is not perceived in any negative light. Especially paper and recycled paper have reinforced the myth and a whole industry has been setup based on these myths.
Paper is mostly made of cellulose which is a complex natural polymer and degrades or composts only in presence of oxygen. Modern Landfills and sludge laden drains, where it lands up finally, unfortunately are anaerobic (without oxygen), so paper doesn’t degrade in landfills or drains as commonly believed. Actually there is evidence6 of a landfill, where a newspaper was discovered three decades later almost intact and readable.
Plastic on other hand is flexible and can be reused for at least 5-10 times. Recycling of certain plastics can be done and India is the biggest recycler in PET and polyolefin group vis a vis its consumption.
Plastic contains at least 20 most known polymers but hardly 3 or 4 major polymers are recyclable, though these recyclable polymers constitute the maximum volume (at least 80%) of the total polymers.
Reuse is always the best method to reduce consumption. Also according to a report, Wasted Opportunity by Institute of Mechanical Engineers, UK, producing energy from paper and plastic waste is more justifiable than recycling them. Except for PET (plastic bottles) and LDPE plastic shopping bags) recycling is more of a wasteful activity than a resource conservation method.
In India Delhi government has banned plastic in favor of paper/recycled paper products without even going into details that paper can only replace plastic only in miniscule applications like shopping bags. Milk, water, oil, pen, consumer goods and many industrial applications are dependent on plastics/polymers (4).
Pollution due to Pulp and Paper production is 3rd highest in India and the the contribution to pollution is summarized below:
Yet Paper and paper recycling is perceived as Environment friendly!
Besides the paper recycling industry uses a lot of chlorine and epoxy resins for cleaning of paper print/ink, which ultimately flow out as polluted water. This water seeps to the ground contaminating the ground water, thus entering the food chain as well.
In Indian context there is another dimension to paper recycling. The author while on a visit to recycled paper products factory in outskirts of Jaipur, India found that the polluted water collects near the homes of paper factory workers forming a small pond, which breeds malaria causing mosquitoes.
As one can conclude from evidence presented above paper and recycled paper is not only unsustainable in terms of energy but a major contributor to consumption and pollution of water. Plastic, the material which has contributed to development of science and used in widest repertoire of products, from pen to rocket nozzles is a great innovation of science.
Responsible waste management not only by the government and its agencies but little effort in separating and disposing by each of us would go a long way in shaping sustainable habits within our society.
The author Pranay Kumar is a sustainability activist and founder of Greenworks.
(1) Worldwatch Institute
(2) Financial Times, London April 25,2008
(4) www.greenworksbiz.com, MoEF,GoI,2009
(5) The Energy Research Institute