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Why the food system is the next frontier in climate action

Posted on 26 April 2023 by Guest Author

This is a re-post from Yale Climate Connections by Daniel J. O'Brien and Devan Crane. While predicated on accepted scientific findings, this article includes conclusions of the authors and is presented to our readers as an informed perspective.

While recent federal bills have advanced climate solutions through the lenses of infrastructure, electricity production, and transportation, policymakers are now turning their attention to another major source of planet-heating emissions: the food system. In its March 2023 report on U.S. biotechnology and biomanufacturing innovation, the White House emphasized a coming focus on climate-centric agriculture. In February, a group of House representatives launched a task force to ensure that the 2023 farm bill contains strong climate provisions.

Why this new focus on the food system?

In 2018, the Intergovernmental Panel on Climate Change, or IPCC, — a body of experts created to inform governments about scientists’ state of knowledge on climate change — laid out a report detailing the consequences of global warming of more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels. Above this threshold, Earth’s climate would change in dangerous ways, including frequent heat waves, rising sea levels that flood coastal cities, and biodiversity failures that could disrupt entire ecosystems. Per the IPCC’s 2023 report, we have already hit 1.0°C of warming.

Absent any revolutionary changes in dietary patterns or agricultural production practices, global food production and consumption is projected to contribute an additional 0.7 to 0.9°C of warming, sending us crashing through the looming 1.5°C ceiling.

Historically, changing food production and consumption practices has been slowly growing in importance in climate policy decision-making. With up to 0.5°C of mitigation potential, the food system presents governments, corporations, and individuals with the next great opportunity for impactful climate action.

Where do food-related emissions come from?

From farming and transportation to packaging and consumption, food-system-related emissions contribute to climate change in numerous ways. Identifying where those emissions come from will allow us to cut the footprint of the food system in the coming decades.

According to the United Nations, nearly two-thirds of food emissions stem from land use and land-use changes. Trees and grasslands naturally absorb and store carbon dioxide as they grow. But across the world, forests are torn down at an annual rate of 10 million hectares — an area the size of South Korea — in large part for agricultural expansion. As these trees are cleared, they release stored carbon into the air, nullifying the climate storage impact they would have had over their lifetimes. Similarly poor management practices of pastures, grasslands, and croplands reduce lifetime soil carbon sequestration potentials.

Another major contributor to food-system pollution is food loss and waste. Food loss occurs largely before food reaches the consumer due to poor supply-chain management or lack of technology or markets to avoid spoilage during transportation. Food waste, by contrast, is the result of end-consumer behavior—and, on its own, causes 8 to 10% of all human-caused heat-trapping pollution. High-income countries predominantly struggle with food waste issues, while low-income countries grapple more with food loss.

When food is wasted, so too is all the energy used in its production and transport. Further, food waste sent to landfills breaks down, releasing significant amounts of methane, a heat-trapping gas with 25 times the warming potency of carbon dioxide.

Food loss and waste are particularly problematic when it comes to produce. For example, for every carton of cherries consumed, farmers need to produce three cartons. That’s because for every unit eaten, one is wasted by consumers and another is lost between the farm and retail stages.

A pie chart showing that most produce is lost before it's eaten.(Image credit: Energy Innovation Policy & Technology)

According to a recent study, several factors contribute to consumers’ wasteful behaviors. For instance, some people are put off by imperfections in food appearance. Misunderstandings around “best-by” vs. “use-by” dates further exacerbate waste issues. Understanding these drivers of consumer waste can help inform targeted policies and educational campaigns.

At-home food waste is inherently more tangible to consumers — like when you forget that bag of now-slimy spinach in the refrigerator or scrape leftovers into the trash can — and therefore serves as a ripe opportunity to build awareness. But helping people understand earlier life-cycle loss can also help them develop more mindful habits. Educating consumers on how food is lost during harvesting, farm-to-retail transportation, or when surplus is left on store shelves can encourage them to buy locally sourced food, only buy what they need, and reduce wasteful practices.

Dietary shifts needed to change how we use land

Another recent study that mapped out potential pathways to a net-zero-emissions food system found that virtually all paths to net-zero relied on consumers pivoting to a more plant-forward diet. Specifically, to reach net-zero, we must reduce livestock products by 10 to 25%.

Raising livestock for consumption is an emissions-heavy process. Some heat-trapping gases come from tilling soils and applying fertilizers, but the biggest source is land-use change. Almost 40% percent of all habitable land across the globe is now used for meat and dairy production. If demand for animal products were reduced, this area could be reforested with trees or restored to diverse grasslands that absorb carbon dioxide as they grow.

The potential to reduce demand for animal protein has also grown in the last decade with the development of technologies to produce affordable meat alternatives that closely resemble animal-based meat in appearance and taste. Based on plants or microorganisms, these proteins’ production release significantly less emissions than traditional, commercial-scale livestock cultivation. According to the World Economic Forum, investment in plant-based protein offers the highest heat-trapping pollution savings per dollar of invested capital of any sector but remains significantly under-invested. This burgeoning industry offers a major opportunity for smart policymaking and investing.

Beyond individual decisions

Though consumer decisions can reduce food-system emissions, well-designed policies at all levels can facilitate both consumer- and pre-consumer-level change.

Stores can adopt circular economy practices, redirecting food from landfills by donating still-good food for human and animal consumption and routing inedible foods to composting, bioproducts, and sewage and wastewater treatment facilities. These actions will cut down on food loss and waste and have created many new services for consumers. Many people can now access composting/biofuel services, donate to food banks, or subscribe to a farm share for “ugly” fruits and vegetables that do not meet grocery stores’ visual standards.

At the supply-chain level, energy-efficiency improvements can be made both on the farm and along the downstream food chain. Smart irrigation techniques can reduce agricultural water and energy waste. Changes to industrial operations, like switching off not-in-use machinery and improving process heat equipment’s insulation, can add up to 20 to 30% energy-use savings.

For their part, governments have distinct agency over the future of our food systems. Leaders are in a position to incentivize afforestation and reforestation as consumer diets pivot to less land-intensive products, enact regulations that support lower-emissions foods, and shift farm subsidies toward plant-based proteins.

Due to a growing global population, food demand is expected to rise by as much as 50 to 110% over the coming decades. Nonetheless, emerging research suggests that we can abate more than 55% of anticipated warming from global food consumption by reducing food loss and waste, shifting diets, and adopting production practices that prevent heat-trapping pollution. By confronting food system challenges, we can keep our planet from warming and have our cherry pie too.

Daniel J. O’Brien is a policy analyst at Energy Innovation. Devan Crane is a program associate at Aspen Global Change InstituteBoth organizations are Yale Climate Connections content-sharing partners.

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Comments 1 to 7:

  1. The last paragraph indicates population is expected to grow by 50 to 110% over the coming decades, and yet we can abate 55% or more of anticipated warming. Does the 55% abatement mean 55% abatement of per-capita emissions or 55% of total emissions for a baseline year of something like 2022? IF this is 55% abatement of per-capita emissions, then it would seem that population will grow as fast or faster than we can reduce per-capita emissions, so that the net ag-related emissions will continue to grow. Or am I missing something?

    Do the authors have an estimate for baseline, per-capita GHG emissions (quantified in CO2e) in a world where we do all the right things to reduce ag-related emissions?

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  2. Evan,

    I agree that the last paragraph is stated poorly. The answers to your questions may be in the two studies linked to in that paragraph:

    • “50 to 110%” contains per capita and global total values evaluated to 2050. However, a quick scan finds the following within that report: “How do the +60% to +110% figures compare to our findings? We find that under SSP2 (which, like the FAO projections, is regarded as a business-as-usual scenario), total food consumption will increase by 51%, with a 95% confidence interval of +45% to +56%. This is substantially lower than the FAO2 and Tilman et al.1 projections of 60–110%.”
    • “research suggests” has the following in its Abstract: “We find that global food consumption alone could add nearly 1 °C to warming by 2100. Seventy five percent of this warming is driven by foods that are high sources of methane (ruminant meat, dairy and rice). However, over 55% of anticipated warming can be avoided from simultaneous improvements to production practices, the universal adoption of a healthy diet and consumer- and retail-level food waste reductions.”

    So it is not clear how the last paragraph comes to be stated the way it has been stated.

    However, my criticism of the report is that it fails to mention the following fairly obvious realities:

    • Immediate significant reduction of harm done can be achieved by reducing unnecessary consumption. Few people want to discuss that ‘herd of elephants in the room’ because that would reduce perceptions of economic prosperity that are based on all the unnecessary consumption, especially the conspicuous unnecessary consumption displays of higher status – like eating more meat.
    • The current developed socioeconomic results are loaded with harmful unsustainable activities. The system aspires to ‘meet the wishes of the winners of competition for status, power, popularity and profit’ and ignore, dismiss or make excuses for the harmful systemic inequities of the developed ‘starting point’.
    • The obvious best ‘ideal’ action to aspire to is all humans being governed, self-governing preferred, to limit their harmful actions to ‘essential (necessary) needs’ and limit the harmfulness of those essential needs. That means that anything beyond ‘essential needs’ has to ‘ideally’ be strictly limited, again preferably by self-governing, to harmless actions.

    An example of the report being written from the biased perspective of a '(potentially unwitting) promoter of the harmful unsustainable status quo' is the unquestioned inclusion of the following:

    "According to the World Economic Forum, investment in plant-based protein offers the highest heat-trapping pollution savings per dollar of invested capital of any sector but remains significantly under-invested. This burgeoning industry offers a major opportunity for smart policymaking and investing."

    That promotes 'unnecessary' industrial food production, potentially with many other harms 'but the focus is restricted to the climate impact'. Local family cooperatives producing 'natural meat in ways that sequester carbon' combined with diets corrected to consume less meat would be a better solution ... but that would reduce opportunities for investors and diminish their developed perceptions of wealth ... but 'investors pursuing their maximum benefit' are not necessarily beneficial, especially if they employ populist misleading messaging to hide or excuse harm done, especially if they promote positive perceptions that some people can be tempted to hope to obtain from more harm done.

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  3. OPOF, thanks, as always, for your comments. However you slice it, ag-related emissions are a tough nut to crack. I eat primarily a plant-based diet, but during periods where I physically work hard, I have a difficult time keeping going without adding in a bit more dairy or some meat.

    I know a person who used to be vegetarian, but after having cancer his doctor recommended he start eating meat again.

    No doubt people in developed countries eat excessively and eat more meat and dairy than needed, but from my own experience I also know that the body has minimum requirements that change based on lifestyle (how hard I'm working) and current physical condition (my friend with cancer, or other conditions). No doubt in a world where we are properly feeding everyone, the GHG emissions will go up, just because properly nourishing everyone will require many to eat more and perhaps to eat more foods that are associated with higher GHG emissions.

    So I restate my last question. Do the authors have an estimate for baseline, per-capita GHG emissions (quantified in CO2e) in a world where we do all the right things to reduce ag-related emissions and where all people are properly nourished, but not over-nourished?

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  4. Evan,

    Your question may be questionable.

    The climate change issue is primarily about human actions that are increasing ghgs in the carbon cycle (increasing the balanced state of ghgs in the atmosphere and causing other harms like increased CO2 absorption in oceans).

    That perspective helps identify and understand the differences between the variety of ghg impacts caused by human actions. Most important, it helps understand that some causes of CO2e from human food production and consumption are ‘not the concern’.

    Steady-state production of ghgs from food production and consumption is not the primary concern. That would be a sustainable carbon cycle. Food production and consumption that increases the level of ghgs, especially the use of fossil fuels, is the primary concern. An increasing population that eats less ‘higher impact food like meat or rice’ can actually result in a reduction of the steady-state level of ghgs. In addition to an increasing population having less consumption, the remaining consumption can be changed to be less harmful, like developing meat and rice production that does not cause as much ghg impact.

    Therefore, an answer to the question about the ‘per capita CO2e’ is that, due to the current developed problem of significant excess ghgs, especially CO2, already in the atmosphere, unnecessary CO2e impacts from human activity need to be ended and actions that will reduce the steady-state ghg levels in the atmosphere are required. (The peak level of ghg increase due to the historic, and continuing, lack of interest in seriously restricting harmful and unnecessary actions will undeniably be a harmfully excessive level).

    Also, the required changes of food production and consumption for the collective of human activity to be more sustainable will vary by region. Regions that currently have more people eating less than a ‘diet necessary for healthy living’ can be expected to have increasing impacts. But if such a region also has a significant amount of harmful unnecessary food consumption, due to a significant status gap in that region's society, then that region could, depending on how much harmful consumption is occurring in the region, reduce the total regional level of ghg impacts while the less fortunate in the region increase their impacts.

    PS. The titles of the two study reports linked in the last paragraph you are questioning are informative (the reports are even more informative): “A meta-analysis of projected global food demand and population at risk of hunger for the period 2010–2050” and “Future warming from global food consumption”. However, developed socioeconomic-political biases can bias what is investigated, how it is investigated, and how it is reported. That is likely a significant root cause of the populist political attacks on less biased science that establishes a requirement for significant changes of developed beliefs and actions, especially if it highlights the need for rapid changes of popular and profitable developments. It may also be why I did not see the obvious problem of harmful over-consumption being highlighted.

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  5. Evan @3

    "I know a person who used to be vegetarian, but after having cancer his doctor recommended he start eating meat again."

    This statment  got my attention, having recently read about the cancer risks of high meat diets. Had a look on the internet and this came up:

    "Results from a large-scale analysis show that following a vegetarian or pescatarian (fish-eating) diet could significantly reduce the risk of developing cancer – but even limiting red and processed meat to five meals a week or less may also have a benefit...."

    "Compared with regular meat-eaters, the risk of developing any type of cancer was lower in low meat-eaters (2% less), fish-eaters (10% less), and vegetarians (14% less). This means that the absolute reduction in cancer diagnoses for vegetarians was 13 fewer per 1,000 people over ten years, in comparison to regular meat-eaters.",vegetarians%20(14%25%20less).

    The study is large, recent and significant.

    Now I'm not vegetarian or promoting vegetarianism per se. A low meat diet, especially a diet low in red meat, sounds sensible and makes for a decent reduction in emisssions. 

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  6. OPOF#4, I am not any kind of expert on GHG emissions in the food cycle, but from what I've seen and read, there are baseline emissions that are difficult to eliminate, such as methane emissions due to rice cultivation. I've heard and read of 1 ton CO2e/person/year as a reasonable baseline estimate (read the Conclusions here where they refer to an emissions floor).

    nigelj#5, I don't disagree with your statements about the benefits of a vegetarian diet. My friend is a particular case in that he had cancer, and for his specific situation his doctor recommended he give up his vegetarian diet because his body needed animal protein to fight the effects of the cancer he had. So his was a special case, but it still highlights that there is not always a one-size fits all answer.

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  7. Evan @6,

    I briefly reviewed the 2014 Research Article you pointed/linked to (note it is almost 10 years old). I would update my previous comments to add that human actions causing increased N2O in the nitrogen cycle are to be considered the same way I refer to impacts on the carbon cycle. And I would add that there are other good reasons for more aggressive reduction of nitrogen cycle impacts than climate change (refer to Planetary Boundaries).

    I will also clarify that reducing methane emissions from rice is still an opportunity for reducing the peak level of ghg impacts even if that methane could be considered to be ‘part of the natural carbon cycle (an action that does not increase the amount of carbon in the carbon cycle the way that burning fossil fuels or leaks of methane from fossil fuel operations or permafrost melting do).

    More specifically, the report’s evaluated floor level of non-CO2 emissions from food production and consumption (Global total 7 GtCO2e/year by 2050 with more if population continues to grow beyond 2050 and also influenced by 'potential changes of attitudes towards being less harmful') appears to be based on the perceived willingness of the UK population, at the time the report was prepared, to learn and be less harmful consumers. And the evaluated UK willingness is extended globally with all people expected to want develop to live in ways comparable to the less harmful ways that the UK population was evaluated to be willing to live.

    The following is a quote from the “Options and barriers to mitigating food system non-CO2 emissions - Agriculture” section of the Research Article:

    “For both N2O and CH4, socioeconomic and environmental circumstances dictate the extent to which changed agricultural technologies and practices can deliver cuts in emissions at a systems level. Stakeholders suggested that important factors influencing uptake of mitigation options affecting the UK revolve around cost, dominant practices, the aging farming community and attitudes of ‘young farmers’, existing infrastructure, cultural norms, changing climate as well as a feedback linked to levels and patterns of consumption.”

    A quote from the “Options and barriers to mitigating food system non-CO2 emissions - Consumption” section of the Research Article:

    “Within the UK consumption-based scenarios, the most significant dietary change considered was a 70% per capita cut in meat consumption, with the deficit replaced with rises in other food types. However, even with changes to per capita meat consumption, absolute emissions levels are driven by population growth (consistent across the scenarios) as well as growth in per capita consumption levels. Population growth per se strongly constrains N2O mitigation, as crops for consumption and for feed for livestock continue to require manure or mineral fertilizer. Barriers to changing patterns of consumption are confirmed through consumer focus group analysis: moderate changes in meat consumption (20% per capita) were considered in line with financial pressures to reduce expenditure given the context of the 2009–2012 recession, whereas a 70% reduction was perceived too substantial a change for many [Citation33].”

    That indicates that the evaluation was (likely unwittingly) biased by accepting questionable opinions like ‘the higher cost of being less harmful is a valid reason to be more harmful’ and ‘the developed popularity of eating more meat is a valid reason to not reduce meat consumption’. Note that I tried to present both of those points in a way that highlights that populist political misleading messaging significantly caused those attitudes to develop to be so influential that they compromise the evaluation and the way it is reported.

    Quote from “Discussion - Implications for cumulative GHG emissions”

    “Finding ways of reliably reducing non-CO2 emissions will become increasingly pressing as global demand for food rises. A wide range of feasible CH4 mitigation options were put forward by stakeholders, taken from the literature and quantitatively assessed during the scenario process, providing evidence for greater scope for achieving substantial CH4 mitigation than for N2O. This, coupled with the much longer lifetime of N2O compared with CH4 as well as the influence of carbon cycle feedbacks in raising the GWP of CH4 from 21 to 34, highlights the critical importance of fully exploiting CH4 mitigation potential whilst increasing the research effort towards developing agricultural systems that can minimize N2O production.”

    That indicates that if the developed research bias is corrected there could be more reduction of N2O resulting in a lower ‘floor level’.

    Quote from “Discussion - Implications for managing and mitigating CO2”

    “The focus here on non-CO2 reinforces other studies that identify the existence of an emissions floor, further emphasizing an urgent need to mitigate CO2 emissions where it is most feasible and quickest to do so. The higher the non-CO2 floor, the more rapidly CO2 emission cuts are needed within the constraints of a chosen climate target. Conversely, relying on a low or non-existent emissions floor suggests a larger CO2 budget is available, again relaxing the rates of mitigation for a chosen climate change target, delivering a more palatable but less realistic assessment of the climate change challenge.”

    This emphasizes that the learning from the report is that more rapid efforts to reduce fossil fuel use are required.

    Quotes from the “Conclusion” of the research article:

    “A continuation of absolute growth in global N2O emissions, despite assuming optimistic mitigation has, because of cumulative emissions, direct implications for how urgently and deeply to cut both CO2 and CH4 for an assumed climate target.”

    This reinforces the need for more research to reduce N2O and the need to more aggressively cut CO2 and CH4 unless new research develops viable ways to rapidly reduce N2O.

    “As energy systems become decarbonized, global non-CO2 emissions largely associated with food consumption and production will increase in the share of annually produced GHGs. Emphasizing the importance of making cuts in food-related emissions highlights an urgent need for policymakers in Annex B nations to consider not only technological and supply-side interventions, but tackle the thorny issue of levels and types of consumption. Unlike large-scale infrastructure developments, measures tackling consumption and demand have the potential to cut emissions of CO2 and non-CO2 alike in the short term and could improve the diminishing chances of remaining within the carbon budget commensurate with the 2ーC threshold.”

    That highlights the need for policymakers to “tackle the thorny issue of levels and types of consumption” because the reports conclusion is that current over-developed populations are not as willing to be less harmful as they should be.

    A quote from the “Future perspectives” part of the research article:

    “If the challenges posed by climate change are to be overcome, at least in part, a meeting of minds to define problems can offer new, much needed insights. This is already emerging in some quarters, with an increase in interest from research funders around the food–water–energy nexus as well as a rise in the number of researchers keen to engage in genuinely interdisciplinary activity. Of course disciplinary research may, out of necessity, continue to dominate, but the emerging expertise in interdisciplinary research needs support and encouragement given the extent of the systemic and complex challenges facing society.

    "The climate change challenge becomes ever more urgent each year, with time limiting the options available for mitigating emissions to be largely those that can deliver change in the short term. Perhaps with agronomists, biologists, engineers, political and social scientists working increasingly in single units, systemic ‘solutions’ to the climate challenge can be found. Specialists in demand and consumption require the same prominence in the portfolio of research endeavour as technologists, physical scientists and engineers. Only then will resilient options be derived and ultimately implemented in a timescale befitting of the scale of change facing society.”

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