As the global climate continues its rapid transformation, the future of agriculture hangs precariously in the balance. Temperature extremes, unpredictable precipitation patterns, and escalating carbon dioxide levels are reshaping the environmental parameters within which essential food crops must survive and thrive. In an illuminating review published in The Philosophical Transactions of the Royal Society B, University of Illinois Urbana-Champaign’s Professor Stephen Long offers a comprehensive scientific perspective on the urgent need to "future-proof" the crops that feed billions. His synthesis of decades of photosynthesis research reveals not only the daunting challenges posed by climate change but also groundbreaking avenues that could safeguard and enhance crop productivity in the decades to come.
The atmospheric CO2 concentration, which hovered near 200 parts per million before the Industrial Revolution, surged past 427 parts per million in 2024 and is projected to hit approximately 600 parts per million by 2050. This unprecedented spike exerts profound physiological effects on plants, altering their growth patterns, photosynthetic dynamics, and water usage. While elevated CO2 can be beneficial by increasing photosynthetic rates, the complex interplay with heat stress, drought, and flooding frequently negates these advantages, amplifying vulnerability rather than alleviating it. Professor Long underscores how these converging stressors imperil plant development and reproductive viability, threatening global food security with potential crop failure on catastrophic scales.
Aside from carbon dioxide, the intensified heat waves expected by mid-century will challenge the intrinsic thermal tolerances of many staple crops. Photosynthesis, inherently sensitive to temperature fluctuations, often suffers from reduced enzyme activity and stability under excessive heat. This destabilization ripples through plant metabolism, curtailing net carbon assimilation and ultimately leading to yield declines. Moreover, prolonged droughts aggravate water scarcity, forcing plants to modulate leaf stomatal behavior, the microscopic pores critical for gas exchange. While partial stomatal closure conserves water, it inevitably restricts CO2 influx, creating a physiologically costly trade-off between sustaining hydration and maintaining photosynthetic carbon fixation.
In a striking advance that Professor Long highlights, researchers have identified and manipulated genetic pathways to minimize this trade-off. By increasing expression of specific sensor proteins that regulate stomatal aperture, plants can optimize water retention without compromising carbon uptake. Experiments with genetically engineered tobacco plants demonstrated a startling 15% increase in leaf-level water-use efficiency and a 30% reduction in overall water consumption. Tobacco’s rapid growth cycle and genetic malleability make it an ideal model for such pioneering work, with promising implications for transfer to crop species such as rice and wheat that feed vast populations.
Flooding presents an additional—and paradoxically elemental—threat. While excess water can drown crops like rice, certain cultivars possess innate tolerance to prolonged submergence. Through meticulous screening and evaluation, these flood-resilient varieties have been identified, raising hopes for breeding programs that can extend this resilience across diverse agroecosystems. The ability to survive two or more weeks underwater is a critical trait for regions increasingly prone to monsoon intensification and unpredictable rainfall extremes. By harnessing the genetic blueprints of flood-tolerant phenotypes, breeders can engineer cultivars capable of enduring and recovering from episodic inundations.
Professor Long also explores molecular strategies targeting rubisco, the enzyme that catalyzes the primary step in carbon fixation during photosynthesis. Rubisco notoriously exhibits suboptimal efficiency, with a tendency to catalyze wasteful oxygenation reactions under high temperature and CO2 conditions. Through genetic and biochemical modifications aimed at optimizing rubisco regulation and expression, photosynthetic performance can be enhanced even amidst elevated atmospheric CO2. This enzymatic fine-tuning holds enormous promise to bolster crop yields while optimizing resource use, further buttressing resilience in a less stable climate.
The saga of maize offers a poignant success story within this otherwise daunting landscape. Between 1980 and 2024, U.S. maize yields doubled—a testament to concentrated research efforts and substantial investments by industry leaders. Conversely, closer relatives like sorghum have witnessed a mere 12% improvement, underscoring disparities in resource allocation. Professor Long stresses the urgent need to bridge this investment gap, especially within the public domain where crops vital for direct human consumption languish without comparable support. Achieving scalable, globally impactful “future-proofing” hinges on mobilizing both public and private sectors in tandem.
Water-use efficiency is thus a core battleground in the quest for resilient crops. Enhanced drought tolerance confers not only survival advantages but also stabilizes yields across erratic seasons. Novel techniques that modulate stomatal density—effectively reducing the number of leaf pores—have achieved efficiency improvements of 15-20% without detrimental yield effects in rice and wheat. This delicate balancing act exemplifies the sophisticated, multifaceted approach necessary to overcome the myriad physiological constraints imposed by climate change.
Beyond genetics and breeding, Professor Long argues for holistic crop systems engineering that integrates mitigation strategies to abate atmospheric change itself. Agricultural practices that sequester carbon or reduce greenhouse gas emissions complement crop improvements, creating a virtuous cycle between climate regulation and food production. These integrated solutions present an ambitious blueprint for sustaining agricultural productivity while confronting environmental imperatives.
Nevertheless, the path forward is fraught with obstacles. The timeline for developing and deploying climate-resilient cultivars is lengthy, often spanning multiple growing seasons and regulatory hurdles. The financial and infrastructural demands for sustained research and implementation are substantial. Professor Long calls for a coordinated global response, emphasizing strategic investment in crop science innovation to safeguard humanity’s food supply against intensifying climatic stress.
While the challenges loom large, the review ultimately conveys a message of cautious optimism. Emerging scientific insights and technologies, when harnessed effectively, possess the transformative potential to reshape agricultural futures. By fortifying plant resilience at genetic, physiological, and system levels, researchers can help secure sustenance for a world confronting the harsh realities of environmental change.
Professor Long’s work, supported by Gates Agricultural Innovations and the Department of Energy’s Center for Advanced Bioenergy and Bioproducts Innovation, crystallizes the scientific consensus that adaptive crop development is indispensable for food security in the 21st century. As atmospheric CO2 ascends and climate variability accelerates, the imperative to innovate grows ever more urgent. The ability to “future-proof” crops may well determine the resilience of global food systems and the wellbeing of billions in the decades that lie ahead.
Subject of Research: Crop resilience to climate change; photosynthesis enhancement; water-use efficiency in plants
Article Title: Needs and opportunities to future-proof crops and the use of crop systems to mitigate atmospheric change
News Publication Date: 29-May-2025
Web References:
DOI: 10.1098/rstb.2024.0229
Stephen Long Lab at University of Illinois
Image Credits: Photo by Fred Zwicky
Keywords: Crop resilience, climate change adaptation, photosynthesis, water-use efficiency, genetic engineering, flood tolerance, stomatal regulation, rubisco optimization, maize yields, climate-smart agriculture
