Waste generation is a natural process for us as humans in the environment. Every single human being on the planet is a generator of waste–though to widely varying volumes.
In traditional development models, waste production increases directly as a result of higher living standards and increased economic development. Thus present projections for 2050 estimate that the global population will generate 3.88 billion tonnes (3,880,000,000,000 kilograms!) of waste each year – an alarming increase of 73% from 2020.
But what does waste have to do with climate change?
Besides the problem of pollution when waste isn’t managed well, managed waste is a significant source of the greenhouse gas emissions that is at the core of the climate crisis.
You may recall that methane is much more potent in creating the greenhouse effect that leads to global warming.
Methane only persists in the atmosphere for around 12 years, but it is much more potent in terms of the greenhouse effect. In fact, pound for pound, its global warming impact is almost 30 times greater than that of carbon dioxide over a 100-year period. While methane can come from natural sources like wetlands, more than half of all global methane emissions come from human activities like natural gas production and livestock-based agriculture.
GHG Emissions from Waste
When it comes to total greenhouse gas (GHG) emissions, the waste management sector makes a relatively minor contribution, at approximately 3-5% of total human-derived emissions. But when we look at methane specifically, waste is one of the three key methane-emitting sectors (after agriculture and oil & gas), contributing about 20% of global methane emissions.
Thus, while waste is presently a major source of emissions, what is most important to note is that the waste sector has the potential to become a major saver of emissions, while being a minor source of them. This is because the prevention, reduction and recovery of waste could avoid emissions in all other sectors of the economy, while cutting that large methane figure.
But what exactly are the sources of emissions from waste and waste management?
- Emissions of methane from landfilling: Solid waste emissions from landfills and dumps represent the absolute majority of methane emissions from the waste sector. Here, organics decay slowly over decades, releasing what is commonly known as landfill gas (LFG), a combination of methane and carbon dioxide. The amount of methane produced by a landfill is primarily based on the amount of organics in the waste stream. Globally, organic waste makes up about 65% of waste generated, with food and green waste comprising the largest share.
- Emissions of fossil-derived carbon dioxide and nitrous oxide from incineration: All our efforts to avoid incineration as the final stage of generated waste stress the importance of recycling materials. In particular, there is a general global consensus that the climate benefits of waste avoidance and recycling far outweigh the benefits of any waste treatment technology, even where energy is recovered during the process.
- Emissions of fossil-derived carbon dioxide from waste, collection, transportation, and processing: A large proportion of the emissions generated by waste management come about by the collection, transportation and deposit of waste to landfills and other sites. Large waste vehicles, or garbage trucks, have significantly higher fuel consumption than standard cars. A large number of waste collection companies still operate in a very old-school way, collecting bins with a fixed schedule, for example, once a week. This may result in the collection of empty or half-empty bins and, therefore, in the creation of unnecessary GHG emissions from the garbage trucks.
Other emissions come from halogenated compounds with high global warming potentials used in waste electrical and electronic equipment (WEEE)–as refrigerants and insulating foam in fridges and freezers.
Waste Management-Emissions Solutions
Thankfully, there are many proven solutions to reduce methane from the waste management sector today, with up to 60% of these mitigation measures having low or negative costs.
Many of us are familiar with the “reduce, reuse, recycle” slogan that forms the waste hierarchy. This phrase is used to demonstrate waste management options in order of environmental preference, and stress that landfilling and disposal are a last resort option. Adding two other stages before the landfill, creates a modified version from the World Resources Institute (RMI, 2022):
Food waste prevention involves reducing the amount of food that we consider to be “waste,” and diverting it for use. In practice this can mean promoting “ugly” produce programs, revising food best-by and use-by dates so good food is not thrown away, linking large producers of food waste to food banks, and raising awareness of the importance of waste prevention, among a variety of other solutions. In addition to keeping usable food out of landfills, these actions help increase food security and lower upstream GHG emissions from food production.
Organic waste diversion is the next step in keeping this waste out of landfills. Organic waste can be separated at the source by household and other waste generators (i.e., keeping a separate bin for food waste in your kitchen) or at a facility designed for separating mixed municipal waste. Source separation by waste generators is the technically preferred option as it reduces contamination — bits of plastic or glass winding up in the waste — which is important for most treatment options. There are often other cultural and socioeconomic considerations that impact organic waste diversion program design. The two most common organic waste treatment options are composting and anaerobic digestion.
Finally, dump site rehabilitation and landfill design & operation is critical to capturing methane generated from organics that are not diverted, as well as waste already in landfills and unmanaged dumps. Open dumps, present in much of the developing world, pose human and environmental health and safety risks. Though up-front costs are high, dumps can be redesigned to include environmental control systems, including covers that oxidize methane as it is released and LFG capture. Existing sanitary landfills with LFG capture systems can focus on maximizing collection and use of the generated gas.
In the Caribbean
Thanks to population growth and urbanization, as well as globalization, Caribbean governments are now struggling with an urgent and large-scale solid waste problem that poses a risk to the health, safety and natural beauty of the islands—which, without action, will only become more complex, damaging and costly in years to come.
In many islands across the Caribbean, landfills are overfilled and dumps proliferate. According to Forbes, 10 of the world’s 30 largest per-capita plastic polluters are Caribbean islands, the worst culprit being Trinidad and Tobago. Much of this plastic is of course not derived from the Caribbean, but imported here as packaging and materials for products exported into the Caribbean from elsewhere (usually, the US, China and Europe).
Recently, seven Caribbean countries banned single-use plastic as the ocean plastic problem has become more serious. While these measures are a good start, there is still much to be done.
In several Caribbean countries, waste collection and disposal throughout the production and consumption cycle present significant financial, environmental, and public health challenges. The region also faces increasing waste production, and waste characterization studies suggest that organic waste is the predominant waste stream with a growing volume of plastics. Plastics have made their way into the marine environment, posing a threat to human health and the tourism sector on which many island economies depend.
Despite developing national and municipal level policies, many states are challenged with fragmented overarching policy frameworks where guidance on various aspects of the waste management process is scattered across a broad spectrum of legislative areas. Waste-related policy guidance is commonly found within legislation related to public health, marine and coastal management, hazardous substance management, tourism, and trade. In addition, the institutional arrangements in the region are as varied as the waste-related policy and legal frameworks, with responsibilities shared among different actors across government ministries and departments.
In this scenario, integrated solid waste management through a circular economy approach has been identified by CARIFORUM Member States as a priority for the region. Therefore, the Zero Waste in the Caribbean initiative, under the theme New Ways, New Waves, will support strengthening national legislative frameworks and establishing a regional policy structure to support sub-regional and Caribbean-wide action.
For more, read up on the UNEP Zero Waste in the Caribbean initiative. Other resources:
Author: Alicia Richins
Sustainable Impact Strategist | SDG Champion | Climate Justice Advocate | Climate Futures Writer
