Energy Innovation partners with the independent nonprofit Aspen Global Change Institute (AGCI) to provide climate and energy research updates. The research synopsis below comes from AGCI Community Science Manager Elise Osenga. A full list of AGCI’s updates is available online at https://www.agci.org/solutions/quarterly-research-reviews.

California is currently living out the old adage, “It never rains but it pours.” Following years of severe drought across the western United States, atmospheric rivers began sweeping into the state last December, bringing intense rain and snowfall. Throughout the new year and into the following months, storms continued to slam both Northern and Southern California with intense precipitation.

This March, rainstorms caused flooding, mudslides, and a levee breach at low elevations. In California’s Sierra Nevada range, snowpack reached as much as 269 percent of “normal” in some locations by the end of February (compared to 1991-2020), with extreme snowfall collapsing structures and closing highways. Concern is also rising that this year’s deep snow could produce even more intense flooding as warmer spring temperatures create snowmelt runoff and precipitation switches from snow to rain at higher elevations.

This is a far cry from 2022, when California recorded its driest January, February, and March in over a century, and drought records were set across the western U.S. Similar trends are observable around the world. The European Alps have seen declining average annual snow cover since 1971—a trend unprecedented in the last 600 years. Multi-year droughts have also created challenges in South America (although heavy snows in July 2022 brought some relief to the Andes in Chile and Peru).

Snowpack is of utmost concern in mountain communities, where it affects everything from flower blooms to wildlife survival and from recreational economies to municipal and agricultural water supplies. As the impacts of climate change intensify, experts predict fundamental shifts in mountain hydrologic cycles, with consequences for snow-reliant people and ecosystems. Understanding what those alterations will look like is a complex challenge. California can serve as a case study to help connect the dots between rising temperatures and regional atmospheric patterns and to reconcile forecasts of a future that brings both more extreme droughts and more extreme floods.

Atmospheric rivers and megafloods in a high-risk future

One of the largest determinants of winter precipitation is the season’s pattern of atmospheric rivers. Corridors of air that contain high amounts of water vapor, atmospheric rivers flow from near the equator to higher latitudes, typically bringing high wind speeds and heavy rainfall or snow—especially when they encounter mountainous terrain.

Recent research from Huang et al. (2022) warns that climate change impacts to atmospheric rivers in the Pacific could combine with a warming-driven shift in precipitation falling as rain rather than snow to increase the likelihood of massive flooding in California. Running ARkStorm 2.0, a disaster scenario program for California, and using various future climate conditions, Huang et al. found that for each 1 degree Celsius increase in global atmospheric temperatures, California saw a rapid increase in the likelihood of a historic megaflood on par with California’s Great Flood of 1861-1862 (Figure 1).

Warmer temperatures and increased flood risk are linked by both the intensity of precipitation events and whether the precipitation falls as rain versus snow. Warmer air can hold more water vapor than cool air, and this study found that as the atmosphere warms, more atmospheric rivers will carry moisture loads that can generate extreme precipitation in the western U.S.—a finding supported by other studies, including Kirchmeier-Young and Zhang (2020), Michaelis et al. (2022), and Corringham et al. (2022).

Furthermore, flood risk associated with intense precipitation events may be regionally compounded by the impacts of warmer temperatures. Huang et al. found warming temperatures were associated with a greater proportion of the increased precipitation falling as rain rather than as snow. Under a high-emissions climate change trajectory, the probability of a megaflood on par with the Great Flood of 1861-1862 more than triples by 2060, marking a 600 percent increase in risk.

Reconciling a future that is both wetter and drier

How does a more flood-prone future square with studies that predict a drier future for California and elsewhere and the oft-discussed “aridification of the American West”? Again, atmospheric rivers and regional warming play a role.

Research from NASA indicates that although warmer air temperatures may contribute to wetter and more intense atmospheric rivers, the total number of atmospheric rivers bringing precipitation (of any quantity) to the western U.S. may decrease—meaning fewer significant, water-providing storms. When meteorological droughts (droughts caused by below average precipitation) do occur, they’re likely to be exacerbated by the warming climate, with impacts to both summer and winter hydrologic cycles.

So what will these changes mean for future snowpack? A recent study by Weider et al. (2022) projects snowpack volume could decline over the coming century across the Northern Hemisphere. This study assessed potential changes to seasonal snow cycles in multiple mountainous regions by using a set of 40 simulations from a global climate model to better understand the range of possibilities. Comparing projections for 2070-2099 to a 1950-1969 baseline, the researchers classified areas where greater than 3 cm of snow were present for more than three months at a time.

They found that warmer future climate scenarios were associated with thinner and less widespread snowpack by the year 2100, although changes to snowpack were not evenly distributed across the hemisphere. This decline in snowpack was in turn associated with a decrease in the number of days with freezing temperatures, leading to a shorter snow season. Additionally, Weider et al. found a shift in timing, with more runoff and peak streamflow earlier in the calendar year and a greater percentage of snow melt occurring before the peak snow water equivalent (SWE) for previous decades (Figure 2). These timing changes create challenges for water management.

Looking ahead to 2100, a study by Rhoades et al. (2022) also projects declining snowpack within the American Cordillera, a series of mountain ranges across western North and South America that includes California’s Sierra Nevada. The study compared high-resolution models to identify events where SWE fell below the 30th percentile compared to average historical snowpack. Rhoades et al. found that parts of the Cordillera consistently fell into low- to no-snow values for the second half of this century, with the low-snowpack trend beginning to emerge as early as 2025. Similar to Weider et al.’s findings, changes to the Cordillera snowpack were tied in part to an increase in temperature, which translated into fewer days below freezing and a larger proportion of precipitation falling as rain rather than snow.

As noted by Weider et al., warming-driven shifts in quantity and timing of snowmelt create challenges for water managers, because when a larger proportion of runoff comes from rain instead of snow, timing of water supplies becomes less predictable. Additionally, there is much still to learn regarding broader cascading impacts across ecological and freshwater systems and how these relate to human systems (including food production, recreation, and water quality).

Preparing for the future

Collectively, these studies paint a picture of a future California marked by less snow on average than in historic periods, punctuated by episodic extreme precipitation events. The magnitude and pace of changes may be determined by emissions pathways, but multiple studies show that even under low-emissions scenarios, California and other locations dependent on snowpack for their water will face conditions for which historical records cannot provide a template.

As water supplies tied to snowpack are projected to become less predictable in quantity and timing, Rhoades et al. emphasize the increased importance of adaptive water storage infrastructure and innovative management approaches, particularly for regions that lack such infrastructure. Meanwhile, Huang et al.’s prediction of increased megastorms demonstrates a different kind of challenge for water infrastructure and building codes: preparedness for floods and extreme precipitation events. Proactive thinking and designing for both wetter and drier conditions may aid in planning for a future that differs from the past.

Wieder et al. emphasize the need to think beyond human infrastructure, noting that understanding feedbacks between ecological systems and snowpack will be essential to effective adaptation approaches for mountain communities. Rhoades et al. also emphasize the importance of developing “conceptual frameworks”—analytical approaches that identify connections between system variables.

Whether preparing for drought or excess water, findings from across all studies indicate that high-emissions scenarios will accelerate and exacerbate hydrologic changes. Rhoades et al. find that the rate of carbon emissions determines how soon low- to no-snow conditions emerge, while Huang et al. find that risk of extreme flooding increases with each degree of atmospheric warming, even when the climate has already warmed. Corringham et al. similarly find that impacts in the western U.S. differ by climate scenario: the ~$1 billion/year average spending on atmospheric river-related flood damage over the past 40 years doubles under an intermediate-emissions scenario (RCP4.5) but more than triples under a high-emissions scenario (RCP8.5). Consequently, the speed and scale of climate warming will play a significant role in determining recurrence of catastrophic events in the coming decades. Collectively, these studies indicate that successful climate mitigation activities carried out now can dramatically reduce the severity of future impacts from atmospheric rivers, floods, and droughts.

Featured research:

Carrer et al., “Recent Waning Snowpack in the Alps Is Unprecedented in the Last Six Centuries,” Nature Climate Change 13 (2023): 155-160, https://www.nature.com/articles/s41558-022-01575-3.

T.W. Corringham et al., “Climate Change Contributions to Future Atmospheric River Flood Damages in the Western United States,” Scientific Reports 12 (2022), https://www.nature.com/articles/s41598-022-15474-2.

Huang and D.L. Swain, “Climate Change Is Increasing the Risk of a California Megaflood,” Science Advances 8, no. 32 (2022), https://www.science.org/doi/full/10.1126/sciadv.abq0995.

 M.C. Kirchmeier-Young and X. Zhang, “Human Influence Has Intensified Extreme Precipitation in North America,” PNAS 117, no. 24 (2020), pnas.org/doi/10.1073/pnas.1921628117.

A.C. Michaelis et al., “Atmospheric River Precipitation Enhanced by Climate Change: A Case Study of the Storm that Contributed to California’s Oroville Dam Crisis,” Earths Future 10, no. 3 (2022),https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2021EF002537.

A.M. Rhoades et al., “Asymmetric Emergence of Low-to-No Snow in the Midlatitudes of the American Cordillera,” Nature Climate Change 12 (2022): 1151–1159, https://doi.org/10.1038/s41558-022-01518-y.

W.R. Weider et al., “Pervasive Alterations to Snow-Dominated Ecosystem Functions Under Climate Change,” PNAS 119, no. 30 (2022), https://www.pnas.org/doi/abs/10.1073/pnas.2202393119.

The post Atmospheric Rivers, Floods, And Drought: The Paradox Of California’s Wetter And Drier Climate Future appeared first on Energy Innovation: Policy and Technology.

As the impacts of climate change intensify, experts predict fundamental shifts in mountain hydrologic cycles, with consequences for snow-reliant people and ecosystems. California can serve as a case study to help connect the dots between rising temperatures and regional atmospheric patterns.
The post Atmospheric Rivers, Floods, And Drought: The Paradox Of California’s Wetter And Drier Climate Future appeared first on Energy Innovation: Policy and Technology.[#item_full_content]

Energy Innovation partners with the independent nonprofit Aspen Global Change Institute (AGCI) to provide climate and energy research updates. The research synopsis below comes from AGCI Program Director Emily Jack-Scott and AGCI Program Associate Devan Crane. A full list of AGCI’s updates covering recent climate change and clean energy pathways research is available online at https://www.agci.org/solutions/quarterly-research-reviews.

Recent research highlights how 65 percent of food system emissions come from the production, processing, transport, and consumption of just four emissions-intensive foods: beef, milk, rice, and corn (maize).

Faced with high food prices and continuous disruptions to supply chains, many households in the United States are appreciating afresh what it takes to grow, gather, and deliver the food they consume on a daily basis. But what the average consumer may not fully recognize is the extent to which their everyday food choices contribute to emissions of greenhouse gasses (GHGs). The food system as a whole accounts for a whopping 35 percent of global emissions, and consumer decisions like diet and shopping patterns greatly influence those emissions.

Emerging research is beginning to shed light on actions that consumers and producers can take to reduce food system impacts on the climate and move toward a “net-zero” system in which all emissions produced are offset by sequestration processes.

Emissions from farm to table to landfill

Emissions are generated at every stage of the food system, from the production of food on farms to transport and refrigeration to processing and packaging to consumer dietary choices and, ultimately, to food waste. Seventy percent of total food system emissions come from land-use change. For example, when a forest—which naturally absorbs and stores carbon dioxide as trees grow—is logged and converted to grazing or agricultural land, GHGs are released as trees decompose. Additional emissions result from tilling soils and applying fertilizers for agricultural production. The remaining food system emissions are attributable to other stages such as transport, packaging, and waste. With rising populations and growing appetites for emissions-intensive foods, emissions are projected to increase 50 percent by 2050 under business-as-usual conditions.

In a 2022 paper published in Nature Scientific Reports, Ciniro Costa, Jr., and colleagues highlight how 65 percent of food system emissions come from the production, processing, transport, and consumption of just four foodstuffs: beef, milk, rice, and corn (maize). By focusing on these emissions-intensive foods, the authors modeled 60 scenarios of interventions that could reduce emissions across the global food system. They found that a net-zero food system could be achieved through widespread adoption of system-wide efficiency improvements, shifts toward plant-forward diets, nature-based sequestration, and adoption of emerging technologies.

Most of the low-emissions interventions analyzed (70 percent) utilize existing know-how and technologies: reducing deforestation, better managing manure, improving feed and breeding (which can reduce methane emissions from livestock), reducing nitrogen fertilizer overuse and runoff, and adopting renewable energy and energy efficiency. Sequestration approaches such as agroforestry and low- or no-till agriculture also have significant co-benefits such as soil and water conservation. Greater adoption of low-emissions practices means less reliance on sequestration will be needed to achieve a net-zero emissions food system.

Emissions from food loss and waste

Reducing food loss and waste is an additional practice that Costa and colleagues emphasize. Food loss and waste alone account for 8-10 percent of all global GHG emissions (Ribbers et al., 2022), with approximately 1.3 billion tons of food perishing annually (Ouro-Salim and Guarieri, 2021). Food loss and food waste are often considered in tandem, but they are distinct issues. Food loss typically refers to loss of edible food before harvest or in the supply chain (e.g., due to inability to harvest all of a crop before it begins to rot, or poor refrigeration during transport). Food waste, by contrast, refers to loss of edible food due to consumer behavior, (e.g., over-ordering at a restaurant or poor planning that leads to groceries expiring and becoming inedible) (Kumar et al., 2022).

Notably, there are significant differences between high-income and low-income countries when it comes to food loss and waste. In high-income countries, food waste makes up 50 percent of overall losses, whereas food waste in low-income countries accounts for only 5 percent of overall losses (Kumar et al., 2022). In low-income countries, food loss is more of a problem and typically results from systemic challenges, such as lack of access to non-local markets, storage, transportation, refrigeration, and harvesting technology (Ouro-Salim and Guarieri, 2021). Reducing food waste in high-income countries is largely a voluntary act for the consumer, with very few waste-reduction enforcement policies in place (Stancu and Lähteenmäki, 2022).

Food waste can also vary by type of food, and high-nutrition foods like fresh produce are especially at risk of waste. Qin and Horvath found in their 2022 study published in Resources, Conservation & Recycling that in the U.S., household food waste can be the largest source of food loss emissions. In the case of cherries, for instance, extreme loss and waste nearly triple emissions: for every kilogram (2.2 lbs) of cherries consumed by a household, another kilogram is lost during production and transit, and a third kilogram is wasted post-purchase (see Figure 1).

Reducing food loss and waste is one way households and individuals have the power to significantly reduce their climate impact, especially in high-income countries. So what holds us back? Why do so many U.S. consumers waste food, especially when it is increasingly expensive and in some instances sporadically available? And what other choices can consumers make to reduce emissions from the food they eat?

Psychology of reducing food waste

In a 2022 paper in Food Policy, co-authors Violeta Stancu and Liisa Lähteenmäki examined food-related behaviors that contribute to consumer food waste, including consumer self-identities, purchasing tendencies, and disgust sensitivity (how easily disgusted a person is by a food’s perceived edibility). They argue that a better understanding of these drivers can help inform more targeted policy and public awareness campaigns.

In a related paper in Global Environmental Change led by Daphne Ribbers, researchers investigated behavioral motivations akin to the consumer self-identities outlined by Stancu and Lähteenmäki. While the two concepts are similar, motivation “can be defined as the process that determines the … direction of behavior, and is generally understood as the reason why humans continue, or terminate a specific behavior” (Ribbers et al., 2023), whereas self-identities refer to “behaviors that are in line with … the label that people use to describe themselves” (Stancu and Lähteenmäki, 2022). Both studies examined the environmental, moral, financial, and social dimensions of these drivers of behavior.

Stancu and Lähteenmäki found that individuals with frugal and environmental self-identities and in older demographics were less likely to waste food, whereas individuals prone to impulse buying, with high disgust sensitivity, and with higher incomes were more likely to waste food. They also found that in-store marketing and retail stimuli can influence individuals to purchase more than was planned (impulse buying), leading to food waste. These factors point to an opportunity for awareness campaigns that can help consumers limit impulse buying and adopt mindful shopping behaviors. Retailers could also be held accountable to reduce food waste by using marketing strategies that don’t prey on impulsive tendencies.

Individuals who are more easily disgusted by perceived food imperfections were also found to be more wasteful. The perception that food was inedible was largely influenced by misunderstanding the common food-labeling system of “best-by” and “use-by” dates. “Best-by” dates relate to food quality, whereas “use-by” dates relate to food safety. Checking edibility by smell or taste when a food is past its labeling date, rather than automatically tossing food, could reduce food waste. Education campaigns focused on increasing food labeling knowledge could help lessen confusion and reduce food being thrown out prematurely.

Ribbers and colleagues found that consumers who waste less food were significantly motivated by environmental and moral factors: awareness of environmental impacts or feeling guilt about wasting food. Interestingly, financial and social motivations (frugality or the concern of appearing wasteful to others, respectively) were not significant motivations to avoid food waste. The authors caution that there may be instances in which financial motivations are significant and may be intertwined with environmental and moral motivations. As in Stancu and Lähteenmäki’s study, Ribbers found that older people typically waste less food.

Both papers also noted that future research should focus on behaviors and culturally specific motivations for more targeted solutions and policy.

Individual actions to reduce food emissions

In addition to reducing food waste, individual consumers have opportunities to limit their food emissions footprint by reducing superfluous packaging and by embracing dietary shifts.

Often consumers only consider the food waste they can physically see and touch, (e.g., scraping a plate into the trash at the end of a meal or forgetting a leftover box the restaurant packed up). In reality, consumers contribute to an entire waste cycle that stems from the energy and water used during production, harvest, material extraction, packaging creation, packaging, transportation, storage, consumption, and wastage/misuse (see figure 2). Consumers should also consider the end-of-life consequences of waste: pollution, millennia-long breakdown times, and overflowing landfills (Qin and Horvath, 2022).

For instance, use of plastic packaging has increased sharply in recent decades, from 2 million tons in 1950 to 381 million tons in 2015. Some packaging helps reduce waste by extending the shelf life of foods and protecting them during transport, but not all packaging has the same emissions. In a 2022 analysis in Resources, Conservation and Recycling, co-authors Mengqing Kan and Shelie Miller focused on the environmental impacts of plastic packaging across a food’s entire lifecycle as well as its annual consumption. The authors then compared the energy used over various foods’ life cycles to equivalent vehicle emissions to put the results into more familiar terms for non-scientists.

Kan and Miller found that, based on average US per capita annual consumption rates, while emissions from food packaging are significant, for most products they pale in comparison to per capita emissions from other everyday activities like driving. Most of the food packaging in the study had annual per capita emissions equivalent to less than a day of driving (the average person in the U.S. drives 30 miles per day). Notable exceptions included carbonated beverages, crunchy chicken breast, certain types of milk, and bottled water. The authors also note significant co-benefits to limiting packaging, such as reducing the environmental impacts of extraction and disposal, especially for products disposed of improperly.

Dietary shifts are another significant way consumers can limit their personal food emissions. Virtually all scenarios that point to a net-zero food system rely on consumers shifting to a more plant-forward diet, especially in high-income countries. Demand for livestock products like beef and milk must be reduced by 10-25 percent to attain low-emissions or net-zero goals (Costa et al., 2022).

Livestock contribute to food system emissions through the food they consume and excrete, as well as the water and land needed for their production. In a 2022 paper published in the Proceedings of the National Academy of Sciences, Claudia Arndt and colleagues studied several ways to reduce methane gas emissions from livestock without reducing productivity by changing their diet formulations and grazing practices alongside breeding and genetic standards. Several combinations of mitigation strategies even increased animal production. The study found that adoption of any one of these strategies alone would not attain global emissions reduction goals by 2030, but adopting multiple effective strategies would achieve target reductions.

Reducing emissions at the livestock production stage is critical to overall reduction of food system-related GHG emissions. But ultimately, consumer demand for livestock products must be curbed to lower overall emissions. Development of new plant proteins is one way to shift consumer diets to meat alternatives and meal substitutions (Costa et al., 2022).

Beyond individual actions

 While individual consumers have a great deal of agency to curb emissions by reducing food waste and packaging and choosing more plant-forward diets, governments and investors must also design policies and financial mechanisms to lessen emissions throughout the food system.

Circular economy practices can help redirect food from landfills by donating still-good foods for human and animal consumption or channeling inedible foods to composting, bio products, and sewage/wastewater treatment facilities (Ouro-Salim and Guarieri, 2021).

In their scenarios to achieve a net-zero emissions food system, Costa and colleagues found that while most low-emissions interventions were based on existing technologies, only about 50 percent would be cost effective at a price less than $100/ton of carbon dioxide. They lay out the following timeline of actions most likely to achieve net-zero emissions while increasing production of food for growing populations, favoring the most cost-effective interventions in the near future:

Governance and finance mechanisms will be needed to reduce deforestation and emissions from high-emitting crops and livestock and promote sequestration at the scale required to reduce global food emissions. For strategies that are already cost effective, traditional bank loans should be explored. To promote practices that are less cost effective, public dollars can be strategically invested in private ventures to reduce initial risks of early adoption and scale up carbon markets. The authors also spotlight the need for long-term philanthropic and patient private capital investments in high-risk emerging technologies.

Featured Research

Costa Jr, C., Wollenberg, E., Benitez, M., Newman, R., Gardner, N. and Bellone, F., 2022. Roadmap for achieving net-zero emissions in global food systems by 2050. Scientific Reports, 12(1), p.15064.

Kan, M. and Miller, S.A., 2022. Environmental impacts of plastic packaging of food products. Resources, Conservation and Recycling, 180, p.106156.

Kumar, S., Srivastava, M.S.K., Mishra, A. and Gupta, A.K., Ethically–Minded Consumer Behavior: Understanding Ethical Behavior of Consumer towards Food Wastage.

Ouro‐Salim, O. and Guarnieri, P., 2022. Circular economy of food waste: A literature review. Environmental Quality Management, 32(2), pp.225-242.

Qin, Y. and Horvath, A., 2022. What contributes more to life-cycle greenhouse gas emissions of farm produce: Production, transportation, packaging, or food loss?. Resources, Conservation and Recycling, 176, p.105945.

Ribbers, D., Geuens, M., Pandelaere, M. and van Herpen, E., 2023. Development and validation of the motivation to avoid food waste scale. Global Environmental Change, 78, p.102626.

Stancu, V. and Lähteenmäki, L., 2022. Consumer-related antecedents of food provisioning behaviors that promote food waste. Food Policy, 108, p.102236.

The post Reducing Food System Emissions, One Bite At A Time appeared first on Energy Innovation: Policy and Technology.

The food system accounts for 35 percent of global emissions, but new research shows how consumers and producers can act to reduce food system impacts on the climate and move toward a net-zero system.
The post Reducing Food System Emissions, One Bite At A Time appeared first on Energy Innovation: Policy and Technology.[#item_full_content]