A recent study indicates that the rate of energy captured by photosynthesis, known as “gross primary production,” could potentially increase towards the end of the century under high-emission scenarios. Lead author Dr. Jürgen Knauer from Western Sydney University’s Hawkesbury Institute for the Environment emphasizes the uncertainty surrounding plants’ future carbon dioxide (CO2) uptake and highlights the role of a well-established climate model in predicting sustained carbon uptake until the 21st century’s close.

Dr. Knauer explains that while plants annually absorb a substantial amount of CO2, mitigating the impact of climate change, uncertainties existed regarding their future capacity. The study, using detailed ecological models, addresses concerns raised by previous research suggesting reduced CO2 absorption in extreme climate conditions. The models consider critical physiological processes governing photosynthesis that are often overlooked in global assessments.

The research delves into aspects like the efficiency of CO2 movement within leaves, plant adaptations to temperature changes, and nutrient distribution in plant canopies. These factors significantly influence a plant’s ability to fix carbon, challenging conventional global models.

The study employs the worst-case emissions scenario, Representative Concentration Pathway (RCP) 8.5, projecting a continuous rise in emissions over the century. Although not the most likely scenario, it provides insights into potential future trends. The researchers also explore the most ambitious emissions scenario (RCP 2.6), revealing a slower increase in gross primary production in the first half of the century followed by a decline.

Co-author Professor Ben Smith, director of the Hawkesbury Institute, underscores the study’s contribution to future carbon cycle models. However, he warns against viewing increased plant photosynthesis as a standalone solution to the climate crisis. Professor Smith cautions that planting trees alone is not a comprehensive remedy and, at best, contributes during a transitional period as society moves away from fossil fuels. He emphasizes the ultimate necessity of eliminating emissions across all sectors to address the climate crisis effectively.

By Impact Lab