When I was a kid growing up in a village in northern Idaho, I shoveled a lot of snow. We had little money, so we paid attention to what little we had.
On many winter days, my brother and I would circle the house with snow shovels, throwing the snow at the base of the house. The snow acted as insulation, thus reducing the amount of money my folks paid for heating oil.
When I attended college, I learned that some plants required a combination of hot and cold days. Apples, pears, and other plants require a certain number of days below freezing to allow flowers to form in the following spring. A reduction in chilling hours can lead to the absence of flowers, and therefore the absence of fruits. It must get cold during the annual dormant period.
An article published at Phys.Org on 6 January 2025 acknowledges the economic importance of consistently cold weather for apple production. The article is titled Prime apple growing areas in US face increasing climate risks. Here’s the lede: “Some of the most productive apple regions in America are facing big challenges from a changing climate, according to a Washington State University study.”
The following two paragraphs tell the story: “Researchers analyzed over 40 years of climate conditions that impact the growth cycle of apple trees from bud break and flowering through fruit development, maturation and color development.
While many growing areas are facing increased climate risks, the top three largest apple-producing counties in the U.S. were among the most impacted: Yakima in Washington, Kent in Michigan and Wayne in New York. In particular, Yakima County, the largest of the three with more than 48,800 acres of apple orchards, has seen harmful trends in five of the six metrics the researchers analyzed.”
The corresponding author of the peer-reviewed paper is quoted in the Phys.Org article: “We shouldn’t take the delicious apples we love to consume for granted. Changing climate conditions over multiple parts of the growth cycle pose potentially compounding threats to the production and quality of apples. Moving forward, it would be helpful to think about adaptations at different stages of apple growth that can minimize overall harmful impacts.”
The peer-reviewed study was published in Environmental Research Letters on 29 November 2024. Titled Changing climate risks for high-value tree fruit production across the United States, the open-access paper was created by five scholars. The Abstract tells the story: “Climate change poses growing risks to global agriculture including perennial tree fruit such as apples that hold important nutritional, cultural, and economic value. This study quantifies historical trends in climate metrics affecting apple growth, production, and quality, which remain understudied. Utilizing the high-resolution gridMET dataset, we analyzed trends (1979–2022) in several key metrics across the U.S.—cold degree days, chill portions, last day of spring frost, growing degree days …, extreme heat days (daily maximum temperature >34 °C), and warm nights (daily minimum temperatures >15 °C). We found significant trends across large parts of the U.S. in all metrics, with the spatial patterns consistent with pronounced warming across the western states in summer and winter. Yakima County, WA, Kent County, MI, Wayne County, NY—leading apple-producers—showed significant decreasing trends in cold degree days and increasing trends in [Growing Degree Days] and warm fall nights. Yakima county, with over 48,870 acres of apple orchards, showed significant changes in five of the six metrics—earlier last day of spring frost, fewer cold degree days, increasing [Growing Degree Days] over the overall growth period, and more extreme heat days and warm nights. These trends could negatively affect apple production by reducing the dormancy period, altering bloom timing, increasing sunburn risk, and diminishing apple appearance and quality. Large parts of the U.S. experience detrimental trends in multiple metrics simultaneously that indicate the potential for compounding negative impacts on the production and quality of apples and other tree fruit, emphasizing the need for developing and adopting adaptation strategies.”
It's not only apples at risk from climate change. It’s clean air and our entire food supply. A peer-reviewed paper published as part of the renowned Nature series of publications fills in a few of the details. Written by six scholars and published on 4 March 2025 in Nature Food, the open-access paper is titled Climate change threatens crop diversity at low latitudes. The Abstract provides abundant, relevant information: “Climate change alters the climatic suitability of croplands, likely shifting the spatial distribution and diversity of global food crop production. Analyses of future potential food crop diversity have been limited to a small number of crops. Here we project geographical shifts in the climatic niches of 30 major food crops under 1.5–4 °C global warming and assess their impact on current crop production and potential food crop diversity across global croplands. We found that in low-latitude regions, 10–31% of current production would shift outside the climatic niche even under 2 °C global warming, increasing to 20–48% under 3 °C warming. Concurrently, potential food crop diversity would decline on 52% (+2 °C) and 56% (+3 °C) of global cropland. However, potential diversity would increase in mid to high latitudes, offering opportunities for climate change adaptation. These results highlight substantial latitudinal differences in the adaptation potential and vulnerability of the global food system under global warming.”
The peer-reviewed paper continues the ongoing pattern of failing to mention that, according to governments of the world, Earth has already warmed more than 2 C above the 1750 baseline. This information comes from October 2023, more than 17 months ago.
The Main section of the peer-reviewed paper cites considerable peer-reviewed evidence: “Climate change threatens global food security and has already impacted the productivity of major food crops and geographically shifted cropping areas. Future projections indicate that increasing temperatures and changing precipitation patterns will decrease the yields of staple crops, especially at low latitudes, whereas agriculture in temperate regions could benefit from warmer average conditions. It has been estimated that by 2100, up to 30% of global food crop production could experience climate conditions that currently do not host major crop production anywhere across the globe. Although the existing research on climate change impacts has focused mainly on four global staple crops (rice, maize, wheat and soybean) or several crops aggregated, the projected rapid changes in climate conditions could challenge the adaptive capacity of current crop production across crop types, especially in the equatorial region.”
Never mind the 2100 date. We’re already on a fast track to losing habitat for food plants. It’s not only apples.
The Main section continues, again with abundant peer-reviewed evidence: “Changing climate conditions, together with various socio-economic factors such as market incentives, will probably influence the diversity of crop types that can feasibly be cultivated on current croplands. Higher diversity in local crop production supports the stability and the diversity of food supply at the national scale and the resilience of production to stressors such as pests and the increasingly frequent adverse weather conditions due to climate change. Furthermore, crop diversity allows climate change adaptation by selecting crops that are resilient to local climate conditions or by diversifying production (for example, through crop rotation). Several studies on the climatic suitability of croplands show that the optimal climate conditions for many food crops are shifting away from low-latitude regions towards mid to high latitudes. However, these studies mostly focus on district- to regional-scale analyses or cover a limited number of food crops, hence hindering quantitative comparisons of impacts between individual crops or analyses of potential food crop diversity across regions. Furthermore, existing studies analysing future changes in potential crop diversity at the global scale have focused on the environmental impacts of such changes, rather than the consequences for climate change adaptation potential in food crop production. Thus, a comprehensive and quantitative global view of the impacts of shifting climate suitability on current crop production, and changes in potential food crop diversity, is lacking.
To bridge this knowledge gap, we assess the future climatic suitability of global croplands for 30 major food crop types and quantify the changes in potential food crop diversity given climate conditions across four global warming levels ranging from 1.5 °C to 4 °C …. We delineate the climatic niche for each crop by applying the Safe Climatic Space concept, which maps the current climatic space of the major production areas of each crop (contributing to the largest 95% of production) using three climate parameters: annual precipitation, biotemperature and aridity …. Then, under future climate conditions, we examine which locations would fall outside these climatically fixed, crop-specific Safe Climatic Spaces, both on the current production areas of each crop and on the total cropland of all crops …. Applying the Safe Climatic Space concept for individual crops, instead of combined production, and extending projections on the total global cropland area allows us to holistically project global changes in the climatic potential of croplands and to globally identify hotspots of increasing or decreasing climatic suitability, for example, for all cereal crops. Additionally, it allows us to analyse changes in the potential diversity of food crops, which is important for the resilience of crop production, given future temperature and moisture conditions.”
It’s not only apples. It’s not only low latitudes. As indicated in the Main section, supported by abundant peer-reviewed evidence: “Changing climate conditions … will probably influence the diversity of crop types that can feasibly be cultivated on current croplands.”
Perhaps I’m merely pessimistic with respect to the human response to climate change. However, I am confident that the probably in the latter sentence is a certain definitely: “Changing climate conditions … will definitely influence the diversity of crop types that can feasibly be cultivated on current croplands.” It’s already happening. There is nowhere to go but down.
Author
"Dr. Guy McPherson is an internationally recognized speaker, award-winning scientist, and the world’s leading authority on abrupt climate change leading to near-term human extinction. He is professor emeritus at the University of Arizona, where he taught and conducted research for twenty years. His published works include 14 books and hundreds of scholarly articles. Dr. McPherson has been featured on TV and radio and in several documentary films. He is a blogger, cultural critic, and co-host of his own radio show “Nature Bats Last.” Dr. McPherson speaks to general audiences across the globe, and to scientists, students, educators, and not-for-profit and business leaders who seek their best available options when confronting Earth’s cataclysmic changes." source
Latest Peer-Reviewed Journal Article:
McPherson, Guy R., Beril Sirmack, and Ricardo Vinuesa. March 2022. Environmental thresholds for mass-extinction events. Results in Engineering (2022), doi: https://doi.org/10.1016/j.rineng.2022.100342.
