Mega-Tree Plantations in Deserts for Carbon Dioxide Sequestration

Planting Millions of Trees in the Deserts might augment Global Atmospheric Effects; Modeling and Economic Evaluation is needed

Som Karamchetty
somkdsr@verizon.net

Abstract:
Global water scarcity and extreme weather conditions are expected to cause severe problems for humans all over the world. International conflicts for the available water resources are emerging and will only exacerbate, unless remedial actions are implemented. Basically, the water scarcity and extreme weather conditions are caused by global heating, which is, in turn, a result of deforestation and excessive use of fossil fuels.
The consequences of continued carbon dioxide (CO2) emissions and greenhouse gas (GHG) build up are expected to lead to disastrous climate changes. In order to thwart such detrimental effects on the earth in the next couple of decades, large scale reductions in the emission of greenhouse gases are advocated. Use of renewable energy resources (solar, wind, and water) and nuclear power are being advanced from the input point of view. Additionally, industrial processes for carbon dioxide (CO2) capture and sequestration are also under development.
However, it is generally known that trees can act as carbon dioxide absorbers as well as augmenters of atmospheric abnormalities. Therefore, we should ask if mega-scale plantation of trees in the deserts of the world could be the natural solution to this man-made problem.
Since any mega-scale project is very expensive and the consequences can be equally huge, computer modeling to verify and validate the technical feasibility and economic viability is suggested. Such modeling consists of three parts: 1) Computation of CO2 sequestration by tree plantations, 2) Consequential effects on the atmosphere (rains and temperatures) based on the sizes and location of such plantations, and 3) Economic viability of such plantations.
The aim of this note is to suggest such a modeling program.

Overview of the Problem:
Global water scarcity and extreme weather conditions have become common place and they are expected to cause severe problems for humans all over the world in the next few decades. International conflicts for the available water resources are emerging and are expected to exacerbate. Basically, the water scarcity and extreme weather conditions are caused by global heating, which is, in turn, a result of deforestation and excessive use of fossil fuels by the rapid industrialization in the last two centuries.
Emissions of several important greenhouse gases that result from human activity have increased substantially since large-scale industrialization began in the mid-1800s. Most of these human-caused (anthropogenic) greenhouse gas (GHG) emissions were carbon dioxide (CO2) from burning fossil fuels. [1]
According to Carbon Brief, “Scientists have developed a set of pathways for how technology, energy and land use, and the concentration of greenhouse gases in the atmosphere could change over the centuries ahead. The four “Representative Concentration Pathways” (RCPs) each provide a plausible description of the future, based on socio-economic scenarios of how the global society grows, develops, and uses land and energy.” [2] We have only a short time before drastic action is required to prevent disastrous consequences to future human populations.
Quoting a study [3] published in Science Advances on February 13, 2018, James Temple writes, “Heat waves, downpours, and dry spells worse than any in recorded history would become between three and five times more likely.” [4]
The greenhouse effect occurs when greenhouse gases (GHG), particularly carbon dioxide, collect close to the Earth’s surface. The sun’s rays penetrate the atmosphere and are then trapped by the accumulation of carbon dioxide, causing the temperature within the atmosphere to rise dramatically. Some heat is absorbed by the Earth’s surface, only to be radiated back into the atmosphere later. Although a small percentage of the heat is able to exit the atmosphere, a larger portion remains trapped in the Earth’s atmosphere. [5]
In recent years, carbon dioxide emissions have become a serious environmental concern on a global scale. Because of their impact on the greenhouse effect, which ultimately causes climate change, scientists and individuals around the globe have become increasingly concerned with their environmental impact in relation to carbon dioxide. [6]
“New studies of severe storms and catastrophic floods help to confirm that rising greenhouse gas levels actually do increase the odds of such extreme weather events—and perhaps make them stronger.”[7] Seethraman of ET Bureau stated [8], “In the event of a temperature rise of 2° Celsius by 2050, India will have to import more than twice the foodgrain it will be required to without climate change. It’s a mission whose importance can’t be overstated.”

Major Approaches to Solve the Problem:
Carbon sequestration and alternate renewable energy sources are contemplated as solutions to reduce the grave effects of global warming. Several major technical efforts are being pursued and research is under way.
In a Technology Review article, James Temple discusses the magnitude of work required to reduce Greenhouse gases. [9]

Current Proposal:
It is worthwhile evaluating if mega-scale tree plantation can augment and eliminate the greenhouse gas problem. It is important to note that with ever increasing global population there has been a great demand on land and the existing forests are being converted into crop lands. Hence, it is not feasible to expect the conversion of existing farm lands into tree farms. Thus, the focus here is neither on the existing forests nor on the farm land. If deserts are chosen for such tree plantations, diversion of otherwise useful land is avoided. We may take two examples of deserts:1) The Sahara desert, which covers an area of 3,600,000 sq mi. [10] and 2) The Thar desert in India, which covers an area of 77,000 sq mi. [11]
It is known that trees absorb carbon dioxide and also cool the environment. By planting millions of trees in the deserts of the world, we will bring significantly positive impact on the global atmosphere. But, modeling is essential to determine the changes such large scale tree plantation would bring to the global atmosphere and the climate. Concurrently, economic modeling will help in evaluating the economic viability of such a proposal.

Influence of Trees:
American Forests, a Washington, D. C. based organization has some interesting facts about the contribution of trees to life on the earth. The author uses some of the facts (reproduced below) from their website and makes some preliminary calculations in this paper. [12]
• One mature tree absorbs carbon dioxide at a rate of 48 pounds per year.
• In one year, an acre of forest can absorb twice the CO2 produced by the average car’s annual mileage.
• Deforestation accounts for up to 15 percent of global emissions of heat-trapping gases.
• Two mature trees provide enough oxygen for one person to breathe over the course of a year.
• Forests are the largest forms of carbon storage, or sinks, in the U.S.
• In one day, one large tree can absorb up to 100 gallons of water and release it into the air, cooling the surrounding area.
• Forests improve public health by keeping pollutants out of our lungs by trapping and removing dust, ash, pollen and smoke.
From the literature, we gather that an acre of land may contain 500 mature trees. Thus, a square mile of land (i.e. 640 acres) would take 320,000 trees, and those trees can absorb 7,680 tons or 6,860 tonnes (i.e. 320,000 times 48 pounds per year) of Carbon Dioxide (CO2) per year.
Those trees can also absorb 95 billion pounds (320,000 times 100 gallons times 8.36 times 365) of water and release it into the air, cooling the surrounding area. Thus, massive tree plantation in the deserts would also depress the temperature of the atmosphere over the deserts, provided that much water is supplied.
This will have consequential effects on the pattern of global atmosphere.

Costs of Planting and Maintaining Trees:
Tree planting may cost about $100 per tree in US urban areas. [13] Considering that we are discussing tree planting in deserts but in hundreds to thousands of square miles, the costs could be (higher in some respects and lower in some other respects) estimated to be anywhere from $25 to $200 per tree including maintenance costs. Then, the planting and life time maintenance costs per square mile would be from $8 million to $64 million (320,000 times $25 to $200).
It is understood that the desert soil cannot support the growth of small saplings to grow into mature trees. It is hoped that trees that are about five-year old that were grown (potted in good soil) in nurseries elsewhere will be transplanted in the deserts along with the necessary soil.
Since deserts do not have water to sustain the trees, it is essential to set up desalination plants to produce and supply fresh water for the trees. The cost of desalinated water is estimated to be about 0.5 $/m3. [14], [15], [16], and [17] Therefore, it only costs $0.20 per day per tree. (100 gallons/264 cu m/day = 0.4 cu m /day and one cubic meter (or 264 gallons) of desalinated water costs $0.50.) Thus, the costs of water are small while the initial installation costs (for logistics and machinery to supply water) could be an important parameter.
Detailed costs for the maintenance of trees and the income from them are presented in some publications, which may be referred for detailed project estimates. [18], [19], and [20]

Magnitude of the Tree Requirement:
Global carbon dioxide emissions from fossil fuel use were 35.9 gigatonnes (billion tonnes) in 2014. [21] In order to absorb all this carbon dioxide, we will need to have 5 million square miles (35.9 billion tonnes/ 6,860 tonnes per square mile) of mature trees. It will require more than covering the whole Sahara desert with mature trees.
Or, by covering the entire Sahara Desert with mature trees, 25 billion tonnes (3,600,000 sq mi times 6,860 tons per square mile) of CO2 can be absorbed. In other words, the Sahara desert can absorb about 70 percent of the global CO2 if it is filled with mature trees.
For 300 megatons per year (i.e. 300 million tons) of CO2, [22] put out by the European Union (EU), 40,000 square miles (300,000,000 tons / 7,680 tons/square mile) of trees will be needed.

Virtual modeling of the atmosphere:
Such large scale tree plantation in the deserts may not be undertaken without virtual modeling to verify and validate the effects of millions of new trees in the deserts. We need to run atmospheric weather and climate models with such concentrated mega tree farms in the deserts added to the current global weather and climate models. The results could show the changed global weather and climate patterns. Exercising such models for longer time horizons would also reveal if we are causing any unintended but adverse consequences. If the results are encouraging, and the economic models support the economic viability, such generation of new forests in the deserts can be undertaken. IBM is said to have announced [23] its intention to “invest in technologies to predict natural disasters like floods and cyclones in India, …” It would be prudent for IBM to develop atmospheric and climate models to evaluate the effect of a mega-scale tree plantation in the Thar desert in India.



Economics:
By calculating the investment costs, maintenance expenses, it is possible to estimate the unit cost of sequestering carbon dioxide by mega-tree plantations. According to a blog on the Gold Standard website, the monetary value of a ton of reduced carbon dioxide emissions for afforestation or reforestation is $177. [24] Using this value, a square mile of trees will yield nearly $1.4 million per year (7,680 tons per year times $177 per ton). The Sahara desert filled with trees will yield $5 trillion per year (3.6 million times $1.4 million). This results in a Payback period of 5.6 or 45 years (8/1.4 or 64/1.4).
There are additional income streams or saving streams possible when we consider the economics of saving habitable land, which might otherwise the inundated by the rising sea due to global warming and the value of timber from the mega tree complexes. The changes caused by atmospheric effects such as more favorable rains and favorable temperatures in most parts of the earth could also be additional gains. Such costs and benefits for mega tree plantations in deserts can be compared to other technological methods for carbon sequestration that are currently under investigation.

Conclusions and Recommendations:
Based on the above cursory analysis (very approximate that it is), tree plantation on a mega scale could solve the greenhouse gas problem and may even yield highly beneficial weather patterns. It may allow us to enhance the green cover to control global heating and also create a pattern of rains and atmospheric temperatures that benefit the humans.
It is recommended that as a first step, virtual atmospheric modeling effort and economic viability calculations should be undertaken by global organizations and governments.

References:
[1] https://www.eia.gov/energyexplained/index.php?page=environment_how_ghg_affect_climate
[2] https://www.carbonbrief.org/analysis-four-years-left-one-point-five-carbon-budget
[3] http://advances.sciencemag.org/content/4/2/eaao3354
[4] https://www.technologyreview.com/s/610269/missing-the-paris-climate-target-by-just-a-little-means-raising-the-odds-of-extreme-weather/?utm_source=newsletters&utm_medium=email&utm_content=2018_05_24&utm_campaign=the_download
[5] https://sites.duke.edu/tlge_sss29/carbon-dioxide-emissions/greenhouse-effect/
[6] https://sites.duke.edu/tlge_sss29/carbon-dioxide-emissions/carbon-dioxide/
[7] https://news.nationalgeographic.com/news/2011/01/110116-climate-change-greenhouse-gas-floods-storms-water/
[8] https://economictimes.indiatimes.com/news/company/corporate-trends/tackling-climate-change-is-tough-also-a-huge-business-opportunity/articleshow/64900024.cms?utm_source=ETMyNews&utm_medium=HPMN&utm_campaign=AL1&utm_content=20
[9] https://www.technologyreview.com/s/610457/at-this-rate-its-going-to-take-nearly-400-years-to-transform-the-energy-system/?utm_source=newsletters&utm_medium=email&utm_content=2018_05_24&utm_campaign=the_download
[10] https://en.wikipedia.org/wiki/Sahara
[11] https://en.wikipedia.org/wiki/Thar_Desert
[12] http://www.americanforests.org/explore-forests/forest-facts/
[13] https://howmuch.net/costs/tree-install
[14] https://watereuse.org/wp-content/uploads/2015/10/WateReuse_Desal_Cost_White_Paper.pdf
[15] https://www.advisian.com/en-us/global-perspectives/the-cost-of-desalination
[16] http://www.ros.hw.ac.uk/bitstream/handle/10399/2996/BinMarshadSMH_0814_sbe.pdf?sequence=1&isAllowed=y
[17] https://www.pmu.edu.sa/kcfinder/upload/files/Review_of_Saudi_Arabia_Municipal_Water_Tariff.pdf
[18] http://www.aces.edu/pubs/docs/A/ANR-1132/ANR-1132.pdf
[19] http://forestandrange.org/southernpine/index.htm
[20] https://pubs.ext.vt.edu/446/446-604/446-604.html
[21] https://www.co2.earth/global-co2-emissions
[22]
https://www.euractiv.com/section/circular-economy/news/circular-economy-vital-to-eus-quest-to-kill-emissions-study/
[23] https://economictimes.indiatimes.com/tech/software/ibm-to-invest-in-tech-to-predict-floods-cyclones-in-india/articleshow/64319639.cms
[24] https://www.goldstandard.org/blog-item/carbon-pricing-what-carbon-credit-worth

-0-