Climate change is affecting prime apple growing regions in US

Agriculture across the United States is facing significant challenges from climate variability and change, with specialty crops like apples particularly vulnerable. Apples, the most consumed fruit in the U.S., are vital to food security, nutrition, and the economy, generating nearly $3.1 billion annually. However, a changing climate poses growing risks to the crop’s production, quality, and marketability.

Recent research led by Washington State University and published in the journal Environmental Research Letters
analyzed over four decades of climate data, uncovering concerning trends. The study focused on six climate metrics that affect apple growth, from dormancy through harvest.

These metrics include cold degree days, chill portions, the last day of spring frost, growing degree days (GDD), extreme heat days, and warm nights. Trends in these metrics were assessed across the U.S., with special attention to Yakima County, WA; Kent County, MI; and Wayne County, NY—the top three apple-producing regions.

Apples require specific climate conditions throughout their growth cycle. Dormancy, occurring from November to March, demands sufficient cold hours to ensure proper flowering. A lack of chilling hours can lead to uneven blooming and significant crop damage.

Conversely, accelerated chill accumulation can disrupt the growth cycle, advancing bloom dates and increasing risks from late frosts. Rising GDD, which measures heat accumulation, can speed growth rates but also lead to heat stress, heightened irrigation needs, and increased pest activity.

Warmer summers introduce additional challenges. Prolonged heat can disrupt coloration, reduce fruit size, and increase the risk of sunburn. Extreme heat days, defined as days exceeding 34 °C (93 °F), and warm nights, with temperatures above 15 °C (59 °F), were found to have particularly detrimental effects on apple appearance and quality. These changes compound over the growth cycle, impacting overall yield and marketability.

“Changing climate conditions over multiple parts of the growth cycle pose potentially compounding threats to the production and quality of apples,” said Deepti Singh, a climate scientist and the study’s corresponding author. “Moving forward, it would be helpful to think about adaptations at different stages of apple growth that can minimize overall harmful impacts.”

Temperature is not the only concern. Changes in precipitation patterns, including prolonged droughts and unseasonal rainfall, further complicate the scenario. Erratic rainfall during critical growth stages can affect pollination, nutrient uptake, and disease resistance. Combined with the effects of rising temperatures, these factors pose a multifaceted challenge to apple growers, requiring careful management and adaptation.

The study revealed that the western U.S. experienced the strongest and most detrimental climate trends. Yakima County, WA, which produces over 60% of the nation’s apples, showed alarming changes in five of the six analyzed metrics.

Significant decreases in cold degree days, earlier last spring frosts, and increases in both GDD and extreme heat days were noted. Warm nights during the fall season also became more frequent, impacting fruit coloration and quality.

The challenges in Yakima mirror broader risks across the U.S. For instance, in 2017, Georgia’s peach crop suffered a 70% loss due to insufficient chilling hours and a late spring freeze. In 2021, a record-breaking heatwave in the Northwest led to devastating losses: Washington’s apple production dropped by 2.4%, while Oregon saw up to 100% crop losses for blueberries and raspberries in certain areas. These weather extremes have not only financial implications but also long-term consequences for orchard health and soil quality.

“What goes on in different seasons can affect long-term health as well as the performance and productivity of the apple tree during that specific season,” explained Lee Kalcsits, a WSU tree physiologist. “So what goes on in the winter affects what happens in the spring, which affects the summer, and it just keeps going around in a cycle.”

Adding to the complexity, the timing of these seasonal shifts is becoming less predictable. For growers, this unpredictability makes it harder to plan for essential tasks such as pruning, pest control, and harvest scheduling.

For instance, an earlier-than-usual bloom can increase vulnerability to late frosts, which can wipe out an entire season’s yield. Similarly, extended dry periods can stress trees, reducing their ability to produce high-quality fruit.

Farmers in regions like Washington are already adapting to changing conditions. Measures such as netting and evaporative cooling are being used to protect crops from sunburn during extreme heat. However, more comprehensive strategies are necessary as climate risks intensify.

Kalcsits is leading a multi-institutional project funded by a $6.75 million USDA grant aimed at mitigating climate impacts on apple and pear crops. The initiative focuses on adaptive strategies that can be implemented nationwide, with Yakima serving as a key case study.

This project is exploring innovative approaches such as developing heat-resistant apple varieties, improving irrigation systems, and optimizing orchard layouts to reduce sun exposure.

“Washington is a great place to start to talk about adaptation,” noted Kirti Rajagopalan, a WSU biological systems engineer involved in the project. “If we can manage it here, then it’s likely manageable elsewhere too.”

Beyond farm-level adaptations, regional policies and collaborations are crucial. State and local governments can provide incentives for sustainable practices, while researchers can work closely with growers to implement findings in real-time.

For instance, predictive modeling tools can help forecast climate conditions and guide farmers in adjusting their practices accordingly. Such tools can inform decisions on when to irrigate, apply fertilizers, or deploy protective measures against frost.

The study emphasizes that understanding and mitigating risks requires a holistic approach. By examining climate impacts across the entire phenological cycle, researchers can better anticipate challenges and develop targeted solutions.

For example, projections of future trends in GDD, chill portions, and extreme heat can guide planning for new orchard locations, crop varieties, and irrigation systems. These efforts not only support apple growers but also contribute to broader agricultural resilience.

The risks posed by climate change to apple production extend beyond economic concerns. Apples contribute to dietary health and cultural heritage, underscoring the importance of preserving their production.

While growers adapt and researchers work to provide solutions, long-term strategies must also address broader issues such as carbon emissions and global warming. Without action, the impacts on apples and other perennial crops could exacerbate food insecurity and threaten rural economies.

“We shouldn’t take the delicious apples we love to consume for granted,” Singh said. “Adaptation is key, but so is addressing the root causes of climate change.”

As the climate continues to warm, collaborative efforts between researchers, farmers, and policymakers will be crucial. With strategic planning and innovation, the agricultural sector can work to safeguard apple production for generations to come.

Education and outreach will also play a vital role. Informing the public about the challenges faced by farmers can generate support for sustainable agriculture policies. Consumers can contribute by supporting local farms, reducing food waste, and advocating for climate action. Together, these efforts can help ensure a stable and sustainable future for apple production.

Note: Materials provided above by The Brighter Side of News. Content may be edited for style and length.

Like these kind of feel good stories? Get The Brighter Side of News' newsletter.