Climate change is emerging as a major challenge for modern society. The basic mechanics of climate change are, by now, well understood:

• the world is warming
• much of the warming is due to human emissions of greenhouse gases, and
• the changes are set to accelerate in the future, bringing diverse, severe impacts around the world.

The globally-focused IPCC (Intergovernmental Panel on Climate Change) Fourth Assessment Report, as well as the UK-led Stern Review, have informed the current debate on climate change – on the basis of the seriousness of the problem as well as the feasibility of solutions – and have contributed to strengthening the efforts aimed at agreeing a consolidated climate regime post 2012.

In this sense COP15, to be held 7–18 December 2009 in Copenhagen, will be crucially relevant. Its expected outcomes will act as a turning point in the pathway towards a global solution.

Although official statistics about the post-consumer waste seem to show it as a small contributor to global greenhouse gas (GHG) emissions (less than 5%), with total emissions of approximately 1300 million tonnes of CO₂ or equivalent in 2005, the contribution of the solid waste management sector to mitigation may be significant. This figure only includes direct emissions from waste (primarily methane from landfill facilities) and not total emissions associated with society’s waste management as a whole – emissions that may be significantly reduced. For example, emissions which are related to the collection and transportation of waste ‘disappear’ into the statements of traffic emissions, and emissions that may be avoided by material or energy recovery of waste appear in the figures for emissions from industry and energy generation.

Since waste is generated and managed at the global level, and since it represents an energy and material resource, an intelligent design of waste management and prevention may contribute, with substantial and even more or less cost-neutral reductions, in society’s emissions of greenhouse gases. Therefore, the waste management industry could be part of the solution by turning waste into a resource. The waste management sector is a key player in overall resource management at the global level.

How can waste management help?

Waste management tools should be directed towards the effective mitigation of GHG and the provision of sustainable co-benefits.

Moreover, waste prevention, minimization, material recovery, recycling and reuse represent a growing potential for indirect reduction of GHG emissions, through decreased waste generation, lower raw material consumption, reduced energy demand and fossil fuel substitution or avoidance.

The most important issue is post-consumer waste could be a renewable energy resource, where the value is exploited through biomass production, anaerobic digester biogas, thermal processes and even through landfill gas utilization.

The overall activities described are in line with those identified in the Fourth Assessment of the IPCC:

• existing waste-management practices can provide effective mitigation of GHG emissions from this sector: there is a wide range of mature, environmentally-effective technologies that are available to mitigate emissions and provide public health, environmental protection, and sustainable development co-benefits
• the mitigation of GHG emissions from waste must be addressed in the context of integrated waste management
• most technologies for waste management are mature and have been successfully implemented for decades in many countries. Nevertheless, there is significant potential for accelerating both the direct reduction of GHG emissions from waste as well as extended implications for indirect reductions within other sectors
• life cycle analysis (LCA) is an essential tool for consideration of both the direct and indirect impacts of waste management technologies and policies
• using LCA and other decision-support tools, there are many combined mitigation strategies that can be cost-effectively implemented by the public or private sector.

Optimum design of waste management may lead to a win-win situation, where consumption is limited hand-in-hand with a reduction in overall emissions of both greenhouse gases and other environmentally harmful gases – and without significant drawbacks in gross domestic products, and maybe even along with a contribution to economic growth on a sustainable basis.

Image showing reductions in greenhouse gas emissions Source: DEFRA Click here to enlarge image

This may be achieved regardless of the actual technological level of waste management in a given country. Optimization of a given management form can always lead to a reduction in greenhouse gas emissions. Therefore, the conference has a global outset as well as a global aim, and thus UNFCCC (United Nations Framework Convention on Climate Change) and ISWA (International Solid Waste Association) are key players.

Overall life cycle

The entire material flow and associated emissions of greenhouse gases must be seen in an overall life cycle context, no matter where in the world and regardless of present collection, treatment and disposal methods. And this is the aspect that the waste and climate conference wishes to bring into focus. For example, there is no point increasing emissions from the collection stage beyond the benefits gained from a given alternative form of treatment; nor is there any point in exploiting a carbon dioxide (CO₂)-neutral energy content in a waste product in thermal treatment, if total CO₂ avoidance may be maximized by material recovery of the waste product.

The UK’s DEFRA (Department for Environment, Food and Rural Affairs) has, in Table 1 on page 65, illustrated the global life cycle perspective in which we should consider greenhouse effects from waste management.

Click here to enlarge image

In the following text we present a number of examples of how the waste management sector may contribute to reductions in greenhouse gas emissions within the different spheres. In the intelligent design of overall waste management, these individual measures may be infinitely combined and contribute to optimization, regardless of time and place.

Reuse/prevention

The reuse of products – bottles being a good example – for their original purpose, significantly prevents waste generation and the energy consumption for manufacture of new bottles is avoided, thus avoiding significant CO₂ emissions. Generally, prevention of waste generation limits resource consumption, and therefore the emissions of greenhouse gases associated with the necessary energy consumption for extraction and processing of the resources. However the calculations must naturally still be made in a life cycle perspective. Will it, for example, cause larger emissions of greenhouse gases to collect, rinse and refill bottles, compared with discarding the used ones and producing new bottles? If so, it makes no sense to reuse, at least not from a climate change perspective.

Optimization of collection logistics

Logistics optimization (exploitation of return logistics in supply chain, compaction, lower collection frequency, etc.) of collection of those wastes that are generated in spite of prevention initiatives, and the change to CO₂-neutral fuels in the collection, can lead to reductions in total emissions of greenhouse gases per tonne of waste.

Material recycling

Recycling of materials in collected waste, in line with reuse, leads to significant avoidance of greenhouse gas emissions, though with less net benefit since it also costs energy to recover and reprocess materials (however, generally much less than in virgin production).

Furthermore, both in reuse and recycling very significant and often neglected environmental impacts are avoided; impacts in addition to climate effects are associated with extraction and processing of resources and are related to the so-called ‘hidden flows’ arising concurrently with the material flows actually involved in industrial production and manufacturing processes.

An average citizen in the industrialized world has an annual mobilization of around 50 tonnes of materials at the global level – of which two thirds remain ‘hidden flows’. By recycling copper instead of producing new copper, 13–19.7 tonnes of CO₂ equivalents are saved per tonne. Similarly energy, and thus CO₂ emissions, are saved by recycling other metals such as aluminium and steel or by recycling, for example, plastics and glass or paper and cardboard. When paper is manufactured from existing paper, the trees that would otherwise have been used for paper manufacture continue to grow and while growing they take up CO₂ from the atmosphere and thus work like a ‘sink’. Saved CO₂ emissions and saved ‘hidden flows’ in recycling, compared with virgin manufacture, appear in Table 1.

Reduction potentials in thermal recovery

By incinerating waste at modern, energy-efficient waste incineration plants, up to 98% of the energy contained in the waste can be recovered as heat and power. Furthermore, depending on the capacity and outlet of the district heating network, this energy can be utilized throughout the year – in the summer months in the form of district cooling – and thus substitute fossil energy sources. Incineration also reduces the weight and volume of waste – it is hygienized and xenobiotic organic compounds are destroyed – allowing for utilization of the residues, for example, for construction purposes where they may substitute virgin raw materials which would otherwise have caused energy consumption (and thus CO₂ emissions) in their manufacture.

Diversion of organic waste from landfill

Diversion of organic waste away from landfill, to biogas, composting or incineration facilities, can reduce emissions of the aggressive greenhouse gas of methane from landfills. If residues from biogasification are used as a fertilizer and soil improver in agriculture, further CO₂ emissions per tonne of waste are saved in the avoided manufacture of commercial fertilizer, substitution of peat and long-term storage of organic carbon in the soil. Just as a further, hardly-quantifiable, reduction will be achieved in the form of reduced energy consumption in agriculture through easier soil cultivation.

By capturing and burning methane from landfills already containing organic waste, or where organic waste for historical or financial reasons is still landfilled, greenhouse gas contributions from the facility can be reduced – even more so if the energy contained in the collected landfill gas is utilized for power and heat generation, thus substituting fossil fuels.

ISWA’s role

ISWA is the leading international association representing all aspects and partners within the waste industry. It collaborates with national and international organizations in research, studies and proposals, to fulfil its declared mission ‘To Promote Sustainable Waste Management Worldwide.’

Another example of reduction in greenhouse gas emissions DEFRA Click here to enlarge image

ISWA may have a key role contributing to emission reduction through its working groups and its almost 40 national members – among which there are not only developed countries, but also the main developing ones. To this end, ISWA has instituted a ‘task force’ whose main goals are:

• getting concepts and mechanisms right. Reviews and analyses of assessment methodologies are carried out for different stages of the cycle of products from raw materials to the end of life, or for services/treatments of waste within their life cycle. Improved definitions, resource conservation, and fossil carbon counting will be important aspects in these studies
• providing exemplary cases for specific issues, such as institutional frameworks, carbon markets, and awareness policies, as well as cross-cutting issues between the waste sector and other sectors (industry, energy, agriculture, transport, buildings and forestry)
• organizing workshops and facilitating conferences and dissemination of results, with the aim to facilitate the interaction between the sectors’ key stakeholders (researchers, managers and administrators).

All the conclusions of this task force will be presented in Copenhagen, 3–4 December 2009, at an event organized with DAKOFA (Danish Waste Management Association) the national member of ISWA in Denmark, and in a prelude side event to the main COP15 conference.

Atilio Savino is President of ISWA. He is also former Secretary of Environment and Sustainable Development in Argentina 2003–2006, and former Vice President of the Bureau of the Conference of the Parties of the United Nations Framework Convention on Climate Change (2006)
e-mail: sav@dakofa.dk

Suzanne Arup Veltzé is Master of Law and Managing Director of the Danish Waste Management Association, and former Managing Director of ISWA 1997–2007

The DAKOFA and ISWA conference on Waste and Climate, 3–4 December 2009

The conference will seek consensus about accounting (CO₂ contribution from management processes and preventive measures, including estimates of products’ carbon footprints avoided through recycling, etc.) and system boundaries in life-cycle assessments, in view of arriving at a common ground for further action.

To read more about the conference please visit: www.wasteandclimate.org