United States Department of Agriculture Climate Hubs

Abstract In the United States Midwest region, the dormant or cold season has experienced significant change over the past several decades due to human-caused global warming, and changes are projected to continue or intensify through the end of the century. Realized and potential changes in crop chill hour accumulation and spring freeze injury risk are particularly concerning for specialty growers in the Midwest region, but relatively little work has been done to assess these changes and help guide producer management strategies accordingly. In this study, we use a combination of historical observations and CMIP6 multi-model ensemble projections to assess recent and projected changes in chill hour accumulation and spring freeze injury risk in the Midwest, using specific examples of apple and peach crops. We find chill hour accumulation has increased in much of the Midwest since 1950 and CMIP6 projections show continued increases through the next 70+ years. While the southern Midwest is projected to lose chill hours through late century, the rate of decrease likely does not necessitate a substantial shift to lower chill requirement fruit cultivars. All varieties of apples and peaches tested would still be chill hour suitable for all but the far southern Midwest by late century under even the highest emissions scenario. Model projections also show decreased spring freeze injury risk across the southern Midwest due to earlier last spring freeze dates and slightly later bloom dates. Most of the central and northern Midwest are projected to experience small or negligible changes in spring freeze injury risk due to roughly equivalent trends in spring freeze and bloom dates. We present an important assessment of climate change impacts on Midwest perennial cropping systems; however, more collaborative work is needed between scientists, practitioners, and providers to both assess the current and future specialty crop agriculture risks due to climate change and explore viable solutions to ensure a resilient and growing Midwest specialty crop industry in the face of changing climate, economic, and social systems.

The ongoing climate crisis merits an urgent need to devise management approaches and new technologies to reduce atmospheric greenhouse gas concentrations (GHG) in the near term. However, each year that GHG concentrations continue to rise, pressure mounts to develop and deploy atmospheric CO2 removal pathways as a complement to, and not replacement for, emissions reductions. Soil carbon sequestration (SCS) practices in working lands provide a low-tech and cost-effective means for removing CO2 from the atmosphere while also delivering co-benefits to people and ecosystems. Our model estimates suggest that, assuming additive effects, the technical potential of combined SCS practices can provide 30%-70% of the carbon removal required by the Paris Climate Agreement if applied to 25%-50% of the available global land area, respectively. Atmospheric CO2 drawdown via SCS has the potential to last decades to centuries, although more research is needed to determine the long-term viability at scale and the durability of the carbon stored. Regardless of these research needs, we argue that SCS can at least serve as a bridging technology, reducing atmospheric CO2 in the short term while energy and transportation systems adapt to a low-C economy. Soil C sequestration in working lands holds promise as a climate change mitigation tool, but the current rate of implementation remains too slow to make significant progress toward global emissions goals by 2050. Outreach and education, methodology development for C offset registries, improved access to materials and supplies, and improved research networks are needed to accelerate the rate of SCS practice implementation. Herein, we present an argument for the immediate adoption of SCS practices in working lands and recommendations for improved implementation.

Communication theory suggests that interactive dialog rather than information transmission is necessary for climate change action, especially for complex systems like agriculture. Climate analogs—locations whose current climate is similar to a target location’s future climate—have garnered recent interest as transmitting more relatable information; however, they have unexplored potential in facilitating meaningful dialogs, and whether the way the analogs are developed could make a difference. We developed climate context-specific analogs based on agriculturally-relevant climate metrics for US specialty crop production, and explored their potential for facilitating dialogs on climate adaptation options. Over 80% of US specialty crop counties had acceptable US analogs for the mid-twenty-first century, especially in the West and Northeast which had greater similarities in the crops produced across target-analog pairs. Western counties generally had analogs to the south, and those in other regions had them to the west. A pilot dialog of target-analog pairs showed promise in eliciting actionable adaptation insights, indicating potential value in incorporating analog-driven dialogs more broadly in climate change communication.

This fact sheet is the third installment of a four-part climate-smart agriculture series exploring the relationship between carbon farming, soil health, and soil amendments on CA croplands and rangelands. This fact sheet focuses on pulverized rock amendments and other fact sheets address the benefits of compost and biochar. The series is intended for members of the technical assistance community who advise CA growers on climate-smart agriculture.

This fact sheet is part of a series examining what we know about the impacts of drought on ecosystems and agriculture in the U.S. Caribbean.

Climate change is already impacting farm and forest lands throughout the northeastern United States. Temperatures are increasing and more rain is falling all at once with dry periods in between. With these changes comes greater variation and uncertainty in crop and livestock production. Without modifying management, agricultural profits may decline

In Chapter 3, we explored current knowledge about how direct and indirect impacts of climate change-along with other biophysical factors-may affect the productivity and sustainability of rangelands in California. However, many of the biggest challenges to rangeland sustainability do not primarily arise from climate or biology, but rather from social, economic, and policy-related factors. Climate risks need to be examined in this broader context. In this chapter, we provide a brief overview of these socioeconomic drivers of change in California rangelands, acknowledging that a full examination is beyond the scope of this report.

While the Midwestern USA ranks among the world’s most important corn-soybean production regions, the area also produces a variety of high-value specialty crops. These crops are an important component of the region’s rural economy with an estimated value of $1.8 billion in 2012. More profitable per-acre than many row crops, specialty crops also have higher production-related risks. They are generally more sensitive to climatic stressors and require more comprehensive management compared to traditional row crops. Temperature and precipitation fluctuations across the Midwest directly impact specialty crop production quantity and quality and indirectly influence the timing of crucial farm operations and the economic impacts of pests, weeds, and diseases. Increasingly variable weather and climate change pose a serious threat to specialty crop production in the Midwest. In this article, we assess how climate variability and observed climatic trends are impacting Midwestern specialty crop production using USDA Risk Management Agency data. In addition, we review current trends in grower perceptions of risks associated with a changing climate and assess sustainable adaptation strategies. Our results indicate that weather-induced losses vary by state with excessive moisture resulting in the highest total number of claims across all Midwestern states followed by freeze and drought events. Overall, specialty crop growers are aware of the increased production risk under a changing climate and have identified the need for crop-specific weather, production, and financial risk management tools and increased crop insurance coverage.

River governance is notoriously complex. Climate change will alter how people interact with rivers. Will current river governance structures serve us in the future? Or is it time to reconsider our current rules and regulations?

The effect of manganese [Mn(II)] on the pigments of cucumber (Cucumis sativus L., cv Poinsett 76) leaf and cotyledon tissues was investigated. Tissue disks (7 mm) were exposed to increasing Mn(II) concentrations from 100 μM to 2.5 mM. Acetone (carotenoid‐rich fraction) and acidified methanol (flavonoid‐rich fraction) extracts were analyzed by high performance liquid chromatography. Although none of the Mn(II)‐treated tissues showed visible damage, Mn(II) at concentrations of 250 μM and above significantly reduced (60%) the ß‐carotene levels of light‐incubated leaf tissues. A major Mn(II)‐induced, UV‐absorbing compound was observed in methanol extracts of cotyledonary tissues exposed to Mn(II) in the dark. In leaf tissues, Mn(II) reduced the levels of certain UV‐absorbing compounds under both light conditions. These results demonstrate that excess leaf Mn(II) can rapidly impair isoprenoid metabolism, altering tissue carotenoid composition. Furthermore, Mn(II) may also modify phenylpropanoid metabolism, changing the tissue flavonoid composition. Both situations could sensitize plant tissues to oxidative stresses, particularly enhanced solar UV‐B radiation, and may reduce the nutritional quality of leafy vegetables.