The Benefits of Increased CO₂
Global Greening and Increased Agricultural Productivity
The Benefits of Increased CO₂
Carbon dioxide (CO₂), often portrayed as a harmful byproduct of human activity, is an essential component of life on Earth. It serves as the foundation of photosynthesis, the process that sustains plant growth and, by extension, supports all terrestrial ecosystems. While elevated CO₂ levels are frequently cited as a primary driver of climate change—overshadowing the complex interplay of natural and anthropogenic factors that shape Earth’s climate—they also bring significant ecological and agricultural benefits. Understanding these benefits is critical to crafting balanced and effective environmental policies.
CO₂ is not merely a greenhouse gas but a vital element that drives plant growth, enhances global greening, boosts agricultural productivity, and strengthens ecosystem resilience. Recognizing the dual role of CO₂ in climate systems and biological processes is crucial for informed decision-making.
Global Greening: CO₂ Enhances Photosynthesis
One of the most well-documented effects of increased CO₂ levels is the phenomenon of global greening—the expansion of vegetation cover across the planet.
Mechanism of Greening
Photosynthesis: CO₂ is a fundamental input for photosynthesis, the process by which plants convert sunlight, water, and CO₂ into glucose and oxygen. Higher CO₂ levels accelerate this process, enabling plants to grow faster and larger (Taiz et al., 2015).
Water-Use Efficiency: Increased CO₂ reduces the amount of water plants lose during transpiration, allowing vegetation to thrive in arid and semi-arid regions (Franks et al., 2013).
Idso CD (2013) The positive externalities of carbon dioxide. Center for the study of Carbon Dioxide and Global Change
Empirical Evidence
Satellite Data: Observations from satellites confirm significant increases in global vegetation cover. Zhu et al. (2016) reported that 25–50% of Earth's vegetated areas have experienced greening, particularly in sub-Saharan Africa, India, and the Amazon.
Desert Reclamation: Elevated CO₂ levels have contributed to the re-greening of semi-arid regions, such as the Sahel in Africa, reducing desertification and improving land productivity (de Jong et al., 2013).
1. de Jong R, Schaepman ME, Furrer R et al (2013) Spatial relationship between climatologies and changes in global vegetation activity. Glob Change Biol 19:1953-1964, doi:10.1111/gcb.12193 2. NASA (2016) Carbon Dioxide Fertilization Greening Earth, Study finds Zhu Z, et al. (2016) Greening the Earth and its drivers, Nature Climate Change 6, 791-795 3. Munier et al. 2018 Satellite Leaf Area Index: Global Scale Analysis of the Tendencies Per Vegetation Type Over the Last 17 Years; Remote Sens. 2018, 10, 424;doi:10.3390/rs10030424
Agricultural Productivity: Feeding a Growing Population
The agricultural benefits of elevated CO₂ are substantial and critical for addressing global food security as the human population continues to grow.
Improved Crop Yields
Enhanced Growth: Higher CO₂ levels improve the growth rates of major crops like wheat, rice, and maize, boosting biomass production and yields (Idso, 2013).
Better Nutrient Use Efficiency: Plants exposed to elevated CO₂ often require fewer nutrients to grow effectively, reducing dependency on synthetic fertilizers.
Global Food Security
The United Nations Food and Agriculture Organization (UNFAO, 2012) reported significant increases in global grain production, a trend supported by the positive effects of rising CO₂.
Improved yields and resource efficiency are critical for meeting the food demands of a growing global population while minimizing agricultural expansion into natural habitats.
Water-Use Efficiency
Critical for Drought-Prone Areas: By improving plants' water-use efficiency, elevated CO₂ levels allow crops to survive and thrive under reduced water availability. This benefit is particularly important in regions facing water scarcity due to natural variability or human demand.
Economic Benefits
A meta-analysis by Lobell et al. (2008) concluded that rising CO₂ levels have already offset some of the yield losses attributed to climate variability, contributing to global agricultural stability.
1. Food: UNFAO (2012) United Nations Food and Agriculture Organization: World grain production 1961-2012. Food Outlook, May 2012, pg.1 2. CO2: Boden TA, Marland G, Andres RJ (2016) Global CO2 emissions and Fossil-Fuel Burning Cement Manufacture and Gas Flaring 1751-2013. CDIAC 3. Temp: HadCRUT4 (2017) The Hadley Climate Research Unit (HadCRUT4) annual global mean surface temperature dataset, I
Biodiversity and Ecosystem Resilience
In addition to its direct effects on vegetation and agriculture, CO₂ contributes to broader ecosystem resilience:
Forests: Elevated CO₂ accelerates tree growth, which enhances carbon sequestration and provides habitat for wildlife.
Wetlands and Grasslands: Increased CO₂ stimulates plant diversity in grasslands and wetland ecosystems, contributing to healthier and more resilient habitats (Leakey et al., 2009).
Wildlife: Greater vegetation cover provides food and shelter for herbivores and improves overall biodiversity.
Policy Implications
Efforts to drastically reduce CO₂ levels through restrictive policies must carefully consider the unintended consequences on food security, ecosystems, and economic growth.
Food Security Risks: Policies aimed at aggressive CO₂ reduction could harm agricultural productivity, especially in regions already struggling to meet food demand. Lower CO₂ levels could slow plant growth and increase vulnerability to droughts and other environmental stresses.
Ecological Trade-Offs: Reduced CO₂ concentrations might limit global greening, undermining the progress made in combating desertification and promoting ecosystem resilience.
Balanced Approach: Policymakers should focus on addressing real environmental challenges, such as pollution, while recognizing the benefits of CO₂ in supporting life on Earth.
Conclusion
CO₂ is not merely a greenhouse gas; it is the lifeblood of the biosphere, enabling photosynthesis and sustaining ecosystems. Its role in promoting global greening, boosting agricultural productivity, and enhancing biodiversity underscores its ecological importance. While efforts to mitigate climate change are necessary, they must be balanced with the recognition that CO₂ contributes to many essential natural processes. Policymakers should craft strategies that protect environmental health without undermining the benefits that CO₂ provides to life on Earth.
References
Ainsworth, E. A., & Long, S. P. (2005). What have we learned from 15 years of free-air CO₂ enrichment (FACE)? A meta-analytic review of the responses of photosynthesis, canopy properties, and plant production to rising CO₂. New Phytologist, 165(2), 351–372.
Franks, P. J., et al. (2013). Sensitivity of plants to changing atmospheric CO₂ concentration: From the geological past to the next century. New Phytologist, 197(4), 1077–1094.
Idso, C. D. (2013). The positive externalities of carbon dioxide. Center for the Study of Carbon Dioxide and Global Change.
Leakey, A. D., et al. (2009). Elevated CO₂ effects on plant carbon, nitrogen, and water relations: Six important lessons from FACE. Journal of Experimental Botany, 60(10), 2859–2876.
Lobell, D. B., et al. (2008). Prioritizing climate change adaptation needs for food security in 2030. Science, 319(5863), 607–610.
Taiz, L., et al. (2015). Plant Physiology and Development. Sinauer Associates.
Zhu, Z., et al. (2016). Greening of the Earth and its drivers. Nature Climate Change, 6(8), 791–795.