CO2 fertilization effect
The CO2 fertilization effect or carbon fertilization effect is the increased rate of photosynthesis in plants that results from increased levels of carbon dioxide in the atmosphere. The effect varies depending on the plant species, the temperature, and the availability of water and nutrients.[1] However, enhanced rates of photosynthesis in plants due to CO2 fertilization are only partially transferred to enhanced plant growth and any hypothesized CO2 fertilization response is unlikely to significantly reduce the human-made increases in atmospheric CO2 concentration over the next century.[2]
From a quarter to half of Earth's vegetated lands has shown significant greening over the last 35 years largely due to rising levels of atmospheric carbon dioxide.[3]
One related trend may be what has been termed "Arctic greening". Scientists have found that as northern portions of the planet warm up and total atmospheric carbon dioxide increases, there has been an increase in plant growth in these regions.[4]
Studies led by Trevor Keenan from the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) show that, from 2002 to 2014, plants appear to have gone into overdrive, starting to pull more carbon dioxide out of the air than they have done before. The result was that the rate at which carbon dioxide accumulates in the atmosphere did not increase during this time period, although previously, it had grown considerably in concert with growing greenhouse gas emissions. Keenan concluded “Unfortunately, this increase is nowhere near enough to stop climate change.”[5]
Decreases in minerals and impacts on human nutrition
Empirical evidence shows that increasing levels of CO2 result in lower concentrations of many minerals in plants tissues. Doubling CO2 levels results in an 8% decline, on average, in the concentration of minerals.[6] Declines in magnesium, calcium, potassium, iron, zinc and other minerals in crops can worsen the quality of human nutrition. Researchers report that the CO2 levels expected in the second half of this century will likely reduce the levels of zinc, iron, and protein in wheat, rice, peas, and soybeans. Some two billion people live in countries where citizens receive more than 60 percent of their zinc or iron from these types of crops. Deficiencies of these nutrients already cause an estimated loss of 63 million life-years annually.[7][8]
References
- ^ Cartwright, Jon (Aug 16, 2013). "How does carbon fertilization affect crop yield?". environmentalresearchweb. Environmental Research Letters. Retrieved 3 October 2016.
- ^ Kirschbaum, Miko U. F. (2011-01-01). "Does Enhanced Photosynthesis Enhance Growth? Lessons Learned from CO2 Enrichment Studies". Plant Physiology. 155 (1): 117–124. doi:10.1104/pp.110.166819. ISSN 0032-0889. PMC 3075783. PMID 21088226.
- ^ Zhu, Zaichun; Piao, Shilong; Myneni, Ranga B.; Huang, Mengtian; Zeng, Zhenzhong; Canadell, Josep G.; Ciais, Philippe; Sitch, Stephen; Friedlingstein, Pierre (2016-08-01). "Greening of the Earth and its drivers". Nature Climate Change. 6 (8): 791–795. Bibcode:2016NatCC...6..791Z. doi:10.1038/nclimate3004. ISSN 1758-678X.
- ^ "If you're looking for good news about climate change, this is about the best there is right now". Washington Post. Retrieved 2016-11-11.
- ^ Krotz, Dan (2016-11-08). "Study: Carbon-Hungry Plants Impede Growth Rate of Atmospheric CO2 | Berkeley Lab". News Center. Retrieved 2016-11-11.
- ^ Loladze, I. (2014). Hidden shift of the ionome of plants exposed to elevated CO2 depletes minerals at the base of human nutrition. eLife, 3, e02245.
- ^ Taub, D. R., Miller, B., & Allen, H. (2008). Effects of elevated CO2 on the protein concentration of food crops: a meta‐analysis. Global Change Biology, 14(3), 565-575.
- ^ Myers, Samuel S.; Zanobetti, Antonella; Kloog, Itai; Huybers, Peter; Leakey, Andrew D. B.; Bloom, Arnold J.; Carlisle, Eli; Dietterich, Lee H.; Fitzgerald, Glenn (2014-06-05). "Increasing CO2 threatens human nutrition". Nature. 510 (7503): 139–142. Bibcode:2014Natur.510..139M. doi:10.1038/nature13179. ISSN 0028-0836. PMC 4810679. PMID 24805231.