Geoengineering Technology BriefingOct 2020

GEOENGINEERINGMONITOR.ORG Analysis and critical perspectives on climate engineering info@geoengineeringmonitor.org

EnhancedPhotosynthesisDescription and purpose of the technologyPhotosynthesis enhancement is a theoreticalgeoengineering technology based on the ideathat plants and algae can be geneticallymodified to exhibit “more efficient”photosynthetic traits, leading those organismsto absorb and metabolize more CO2. Accordingto critics of the approach, enhancingphotosynthesis by converting plants is a high-tech, high-risk project, with high risks to foodsecurity in particular.1 There are seriousconcerns that accompany all geneticengineering of plant life, involving unexpectedside effects, risks of contamination in naturalsystems, poorly-understood long-term impactson humans and ecosystems, and corporatecontrol.

Proponents primarily justify research intoaltering the photosynthesis of plants throughfood security arguments: that world populationis growing, crop yields have reached a plateauand, given growing demands for food and fuel inthe face of climate change, we must find a wayto increase crop yields. For geoengineeringphotosynthesis engineers, “the key remainingroute to increase the genetic yield potential ofour major crops”2 is enhancingphotosynthesis. However, sincethis modification is designed toremove more CO2 byphotosynthesis from theatmosphere, carbon dioxideremoval (CDR) aims are alsoused to justify this research.The anticipated CDR effects ofenhanced photosynthesis arebased on the assumption thatthe additional CO2 that would beabsorbed by the geneticallymodified plants wouldpermanently remain in soils orat the bottom of the sea.

Actors involvedThe C4 Rice Project is a collaboration betweenscientists from Europe, North America andAsia. Kick-started in 2008, it has been

supported by the Bill andMelinda Gates Foundation tothe tune of US$ 25 million offunding so far. The project aimsto transform rice – a plant withC3-photosynthesis – into a plantwith C4-photosynthesis, aimingto theoretically increase yields,enhance nitrogen use and wateruse efficiency, improveadaptation to hotter and drierclimates and eventually removemore CO2 from the atmosphere.The present funding phase aimsto develop a prototype of ricewith C4-photosynthesis.3

Reality Check:

Its justa theory

Its beingimplemented

The use of monocultures of crops genetically modified toreflect more light could exacerbate land grabs and forced

displacement.

Point ofIntervention:

GEOENGINEERINGMONITOR.ORG Analysis and critical perspectives on climate engineering info@geoengineeringmonitor.org

Critics question the wisdom of using rice as thetarget crop for such extreme geneticengineering, in a time of water stress, and whenit is one of the worlds staple crops, and thepillar of the livelihood of billions of people.4

Notwithstanding, some researchers considerrice “an ideal crop” to practice C4 engineeringusing synthetic biology because it was the firstcrop species to have its genome sequenced andhas large amounts of physiological, genetic andgenomic data available.

Rice could pave the way to engineeredC4 wheat, C4 cotton and C4 trees.5 In time,proponents say, switching major crops toenhanced photosynthesis on a large scalewould theoretically draw down large amounts ofCO2.

The European Union funded its own“3To4” project from 2012 to 2016, with an overallbudget of €8.9 million. A consortium of privateand public-sector researchers tried to enhancephotosynthesis by engineering thecharacteristics of C4 photosynthesis intoC3 crops. Supporting the C4 Rice Project hasbeen another project focus. While theresearchers were focusing initially on rice as amodel crop, they “envisage rapid transfer oftechnological advances into mainstream EUcrops, such as wheat and rape.”6 Private sectorconsortium members included Bayer CropScience and Chemtex Italia (now Biochemtex).The pan-European project BEEP(bio-inspired and bionic materials forenhanced photosynthesis) looks atphotosynthetic processes in a marineenvironment, aiming to understandthe mechanisms affectingphotosynthetic efficiency, forexample for marine bacteria andalgae, and to apply the insights for“boosting photosynthesis in livingorganisms”.7

Other research is currently underwayto show how plants’ absorption of CO2

could be increased synthetically.Synthetic biologists have builtentirely novel biochemical processesinto engineered organisms to speedup the carbon fixation process andmake plants better at turning carbondioxide into energy.

In 2016, a team of synthetic biologists at theGerman Max Planck Institute for TerrestrialMicrobiology in Marburg stitched together17 different enzymes from nine differentorganisms (e.g. gut bacteria, further microbesand plants) to achieve a proof-of-principle CO2-fixation pathway in an engineered organism thatexceeds what can be found in nature.

The so-called CETCH cycle includes threeengineered enzymes, among them a newsynthetic CO2-fixing enzyme that is nearly20 times faster than the most prevalent enzymein nature responsible for capturing CO2. Afterdemonstrating the process in vitro, theresearch team is now aiming to transplant theprocess into living cells. Future applications areenvisaged for higher biofuel and foodproduction.8

The genetic engineering of plant life is accompanied

by serious concerns andenhancing photosynthesisby converting C3 plants into

C4 plants is a high-tech, high-risk project.

The vast variety and diversity of maize is being lost because of intensive agriculture. This only reduces climate resilience

Photo by The International Maize and Wheat Improvement Center via Flickr

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GEOENGINEERINGMONITOR.ORG Analysis and critical perspectives on climate engineering info@geoengineeringmonitor.org

In another study, researchersenhanced crop productivity byreducing the time it takes plants to“recover” from detecting too muchlight.9 By adding proteins to certaintobacco plants, the engineeredplants grew up to 20% bigger, andthe focus is now achieving the samewith crops like rice, sorghum, andcassava. The research is alsofunded by the Bill and Melinda GatesFoundation.

A research project conducted bythe Chinese Qingdao Institute ofBioenergy and BioprocessTechnology aims to combine CO2-uptake, enhanced microalgalphotosynthesis and biofuel-production by genetically modifyingthe microalgae Nannochloropsisoceanica. The objective is toimprove the microalgal tolerance tohigh levels of CO2 to establish amicroalgae production with flue gasfor oil production.10

The California-based Salk Institute announcedthe commercialization of the “Ideal Plant”around 2025. The Ideal Plant Project appliesgene editing methods to enhance plants’capacity to store carbon and to resistdecomposition, by increasing the amount ofsuberin, a plant substance comparable to cork,in plant roots.

The US company ZeaKal is presently furtherdeveloping and testing its “PhotoSeed” plants, incooperation with chemical companyDow DuPont. According to ZeaKal, enzymaticreactions in PhotoSeed plants have beengenetically modified for enhancedphotosynthesis, growth rates and CO2 uptake.11

Impacts of the technologyThe ability to manipulate photosynthesisimplies control over just about everything thatdetermines how and if a plant survives andthrives: how efficiently it uses water andnutrients to grow and produce the biomass thatwe use for food, fibre and fuel, as well as howefficiently it fixes CO2 and releases oxygen.

The genetic engineering of plant life isaccompanied by serious concerns andenhancing photosynthesis by convertingC3 plants into C4 plants is a high-tech, high-riskproject. Jill E. Gready, Research Professor atthe Australian National University, argues:“pursuit and public promotion of some veryhigh-tech solutions for photosynthesisimprovement with high risk of failure… presenta high-level risk to food security as they providefalse confidence that the problem is beingaddressed, and, by diverting funds, lead to lostopportunity for R&D with greater likelihood ofsuccess and impact.”12

Cornell University’s Norman Uphoff, anothercritic, has spearheaded an agroecologically-based method of cultivating rice known as theSystem of Rice Intensification. He recentlypublished data demonstrating that a change infarm management practices – such as widerspacing of plants and increased soil aeration –can dramatically increase rice yields beyondwhat has been thought possible, and withoutincreased dependence on chemical inputs orgenetic engineering.13

Billions of people depend on rice harvests – what if genetically engineered rice had unintended consequences on traditional varieties?

Photo by SarahTz via Flickr

GEOENGINEERINGMONITOR.ORG Analysis and critical perspectives on climate engineering info@geoengineeringmonitor.org

Endnotes1 Gready (2014) Best-fit options of crop staples for food security: productivity, nutrition and sustainability, in: Jha, et al.

(2014) Handbook on Food, chapter 15, page 4062 Long, et al. (2015) Meeting the Global Food Demand of the Future by Engineering Crop Photosynthesis and Yield

Potential, in: Cell, Vol. 161:56-66, https://doi.org/10.1016/j.cell.2015.03.0193 ETC Group and Heinrich Böll Foundation (2020) Geoengineering Map, https://map.geoengineeringmonitor.org4 ETC Group and Heinrich Böll Foundation (2015) Outsmarting Nature? Synthetic Biology and Climate Smart

Agriculture, Communiqué 114, https://www.boell.de/en/2015/11/30/outsmarting-nature-synthetic-biology-and-climate-smart-agriculture

5 Zhu, et al. (2010) C4 Rice – an ideal arena for systems biology research, in: J Integr Plant Biol., Vol. 52(8):762 - 770,https://doi.org/10.1111/j.1744-7909.2010.00983.x

6 CORDIS (2016) 3to4: Converting C3 to C4 photosynthesis for sustainable agriculture, CORDIS project database of theEuropean Union, accessed: February 2020, https://cordis.europa.eu/project/id/289582; ETC Group and Heinrich BöllFoundation (2020)

7 ETC Group and Heinrich Böll Foundation (2020)8 Schwander, et al. (2016), A synthetic pathway for the fixation of carbon dioxide in vitro, in: Science, Vol. 354(6314):900

- 904, http://doi.org/ 10.1126/science.aah5237 ; ETC Group and Heinrich Böll Foundation (2020)9 Kromdijk, et al. (2016) Improving photosynthesis and crop productivity by accelerating recovery from

photoprotection, in: Science, Vol. 354(6314): 857 - 861, http://doi.org/10.1126/science.aai887810 ETC Group and Heinrich Böll Foundation (2020)11 ETC Group and Heinrich Böll Foundation (2020)12 Gready (2014)13 Uphoff (2013) Rethinking the concept of ‘yield ceiling’ for rice: implications of the System of Rice Intensification (SRI)

for agricultural science and practice, in: Journal of Crop and Weed, Vol. 9(1):1 – 19,http://www.cropandweed.com/vol9issue1/1.1.html

Reality checkResearch into photosynthesis enhancement iswell underway and projects are moving fromengineering in vitro to engineering crop plants.However, the effectiveness of enhancedphotosynthesis as a method for carbon storageis mostly theoretical, particularly because thereare many uncertainties related to thepermanence of the absorbed carbon in soils orsea.

Further readingETC Group and Heinrich Böll Foundation,“Outsmarting Nature? Synthetic Biology andClimate Smart Agriculture”:http://www.etcgroup.org/content/outsmarting-nature/report

This video summarizes what the researchersare trying to achieve through photosynthesisenhancement but doesn’t discuss the potentialimpacts:www.youtube.com/watch?v=Av0dTk9KzlY