Photosynthesis Plays a Significant Role in
Climate Change Mitigation But...

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Photosynthesis is relevant in climate change mitigation. With the growing concerns about global warming and its causal effect on climate change, it is important to enrich one's understanding about photosynthesis and its application in mitigating climatic change.

Increased concentration of atmospheric CO2 due to human activities, such as the use of coal in industries and the use of petrochemical fuels in locomotives, is largely recognized as responsible for global warming through greenhouse effect. This takes exception to the criticism coming from the so-called "skeptics" notably Singer and Avery (2007).

The authors argue that global warming is a natural event that occurs every 1,500 years. They also claim that any panic against perceived disastrous effect of global warming on plant and animal survival and on biodiversity is misplaced, arguing that living organisms have the natural ability to adapt.

In support of the greenhouse effect, Miller (2001) explained that many greenhouse gases are involved. However,  mainly responsible is the carbon dioxide which contributes 50-60% to the rise in global temperature. It is mainly generated from the burning of fossil fuels like coal, with an increasing contribution by motor vehicles.

In turn, global warming has led to climate change, referring to extreme events such as typhoons, excessive rainfall, and drought. According to PCARRD (n.d.), climate change events pose a grave threat to agriculture, forestry, natural resources, and other systems which supply life-giving provisions.

Climate change can also lead to loss of biodiversity on a global scale. Consequently, a loss of biodiversity can have serious impacts on people’s livelihoods (MacIver and Dallmeir 2008).

There is an overwhelming consensus, therefore, that appropriate climate change mitigation strategies must be implemented without further delay.These strategies necessarily involve measures designed to reduce CO2 generation and the reduction of the levels of atmospheric CO2. One strategy exploits the process of photosynthesis in plants.

Photosynthesis involves the absorption of carbon dioxide from the atmosphere and its incorporation into organic compounds within the plant body.This process has been exploited in formulating climate change mitigation strategy called carbon dioxide sequestration, the absorption of carbon dioxide from the atmosphere and its long-time storage within the plant body.

Increased concentration of atmospheric CO2 up to 1500 ppm can in fact favor photosynthesis (Lantican 2001), however, a balancing act is necessary. According to Lovejoy (2010), the maximum safe limit for biodiversity is an atmospheric carbon dioxide concentration within the range of 350-450 ppm. This is equivalent to about 2°C warming. Above this CO2 concentration, the ensuing temperature becomes dangerous to biological diversity.

In 2003, the air contained about 0.034% (340 ppm) of CO2. This translates to about 7 x 1011 (700 billion) tons of carbon. In comparison, the aggregate amounts of carbon in plants as carbohydrate was about 4.5 x 1011 (450 billion) tons (Moore et al. 2003). This indicates that perennial plants play a major role in climate change mitigation.

Through carbon dioxide sequestration, a large volume of atmospheric CO2 can be absorbed and stored for a long period of time as it is fixed or incorporated in the carbohydrates, proteins, and lipids within the plant. According to Miller (2001), each tree during its entire life has the capacity of absorbing carbon dioxide equivalent to the average amount released in the process of combustion by a car that is driven for 42,000 kilometers.

CO2 is ultimately returned to the atmosphere in the process of organic matter decomposition or combustion, but with perennial trees this process is delayed.The release of CO2 is further delayed indefinitely where plant parts are used in the production of pieces of furniture, or processed into products like engineered bamboo.This is why climate change mitigation strategies include the adoption of tree planting and greening programs, including agroforestry.


(More info on biodiversity: Consider Invasive Plant Species in Crop Farming)


But here are lingering questions:

With massive planting of trees, it is expected that a large number of these trees will die at about the same time. It may take years, even centuries, but die they will even without man's involvement. These trees or their parts will then rot. Taken together, massive amount of CO2 will be released to the atmosphere upon decomposition in the same manner that this greenhouse gas is released in the burning or combustion of fossil fuels. To be clear, fossil fuels are likewise mostly of plant origin and products of photosynthesis (click on to read related page What is Photosynthesis?).

The possibility exists, therefore, that the mitigation of today will result to future aggravation. We may be long gone, but will the future generation agree that the massive tree planting programs now advocated are a perfect strategy for climate change mitigation? Are we not saving the planet Earth now only to kill it later? Are we leaving a lasting legacy for the enjoyment of tomorrow?

The author of this page admits that the answers to these questions are beyond his competence, but speculates anyway that there must be some other techniques attached to the tree planting programs. It would be a huge help if authorities on the field will shed light.

For it is with correct information that we can make an exacting decision. Towards an informed application of science and agriculture indeed!

Click on this link to read news report on pine trees being one of the biggest contributors to air pollution

REFERENCES

LANTICAN RM. 2001. The Science and Practice of Crop Production. Los Baños, Laguna: SEAMEO SEARCA and UPLB. 330 p.

LOVEJOY TE. 2010. Climate change. In: Sodhi NS, Ehrlich PR, editors. Conservation Biology for All. Great Clarendon Street, Oxford: Oxford University Press. p. 153-162.

MACIVER D, DALLMEIR F. 2008. Climate change and biodiversity in the Americas. Symposium held at the Smithsonian Tropical Research Institute, Panama, February 25-29, 2008. Retrieved January 6, 2012 from www.climatechangeandbiodiversity.ca.

MILLER GTJr. 2001. Environmental Science: Working with the Earth. 8th ed. Pacific Grove, CA: Brooks/Cole. 549 p.

MOORE R, CLARK WD, VODOPICH DS. 2003. Botany. 2nd ed. Boston, Massachusetts: McGraw-Hill. 919 p.

[PCARRD] PHILIPPINE COUNCIL FOR AGRICULTURE, FORESTRY AND NATURAL RESOURCES RESEARCH AND DEVELOPMENT. n.d. Philippine S&T Agenda on Climate Change: Agriculture, Forestry and Natural Resources Sectors, 2010-2016. Retrieved December 29, 2011 from www.wesvarrdec.org/downloadable_files/PCARRDSTA.doc.

SINGER SF, AVERY DT. 2007. Unstoppable Global Warming: Every 1500 Years. Lanham, Maryland: Rowman & Littlefield Publishers, Inc. 260 p.

(Ben G. Bareja July 2012)


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