It is heartening to know that various governments are waking up to combat the global warming. In this regard this is a note on how to combat it in a meaningful way.
1. Combating global warming has broadly two components:
a. Decreasing the release of green house gases and,
b. Sequestering the green house gases, of which CO2 is the component, from atmosphere.
2. Battle has to be fought on both the fronts but it is found that emphasis is only on the former. There is not sufficient emphasis on the later. It must be understood that even with best efforts we can only reduce the emission of greenhouse gas but we cannot eliminate it altogether. So the amount of green house gases in the atmosphere will only increase with time. Hence we need to concentrate on sequestering the green house gases also.
3. When it comes sequestering CO2 there is nothing on the planet, it is repeated nothing, except a growing tree that can do it. This is a very important fact that must be understood if we want to fight global warming in a realistic way.
4. It is a well known fact that a plant purifies environment but we need to understand how after all a plant does purifies environment. And is there any way to quantify the amount of purification done by various plants?
5. The process which purifies the environment is a well known process ie photosynthesis and there is an unambiguous way to measure the amount of purification done by a plant. Photosynthesis is natural processes that uses CO2, releases O2 and produces various forms of sugar ie C6H12O6.
6. The amount of carbon sequestered by a plant can actually be measured without any ambiguity as explained below.
a. The byproduct of the photosynthesis is cellulose or C6H12O6 or wood. Hence the physical manifestation of the photosynthesis is the increase in volume and weight of the plant.
b. It is possible ie the rate of sequestration of CO2 may differ from plant to plant ,which is also evident from that fact that different tree/plants grow at different rates , but the sum total of the CO2 sequestered has to be proportional to dry biomass ie the biomass from which the water has been removed.
c. In fact empirically it can be said that for every 180 tons of dry wood produced, 264 tons of CO2 is consumed and 192 tons of O2 is given out.
7. Not so evident but another important contribution of a growing tree is that apart from conversion of CO2 to O2 a growing plant also absorbs heat. This is nothing but the sunlight that would have otherwise converted into heat had it not been used for photosynthesis. This is why we feel cooler under a tree. So a tree also helps the global warming by storing heat.
8. Above stated facts can be understood by the reverse logic like as follows. Suppose we cut a tree and burn it. We get mainly two things: CO2 and heat. By simple logic of conservation of energy and chemical constituents it can be safely assumed that this was the amount of heat and CO2 absorbed by the plant while growing.
9. Now the issue comes that if photosynthesis is the key to carbon sequestration then why emphasis on tree only as every plant does photosynthesis. Here it is important to understand that though there are various form of C6H12O6 like sugar, cellulose, carbohydrate, oil (as happens in say pine trees) etc but timber is the only way CO2 remains blocked for a longer period of 5-100 years. In all other forms either it is burnt, consumed or decomposed within a year or so releasing the entire CO2. Hence though all the plants excluding CO2 can sequester CO2 but the form in which it does, the same cannot be stored for long period of more than maximum 5 years and on average 1 year.
10. Inferences that can be drawn from above analysis is as follows:
a. There is nothing on the planet other than a growing tree that can reduce CO2. Meaning thereby that tree has to central to any program of combating global warming.
b. We should substitute fuel wood not timber. In fact For long term it is much more beneficial to promote use of timer rather than substituting as it is the only meaningful way to store CO2. The so called substitute of timber produce more green house gases during their making.
c. If an item which is substituting wood consumes less energy during its production than what is produced by burning the equivalent amount of wood, then only it is beneficial to environment else it is more harmful, at least from environmental point.
d. There is a need to promote plywood industry in big way which helps in using even the inferior quality of wood to be used as timber which otherwise would have been used as fuel-wood.
e. A fully grown tree which is not growing in volume may be good for wild life but is doing no good to the environment as the sum total of CO2 taken in and given out almost balances each other. Hence felling of mature tree, using it as timber (not fuel-wood) and planting new trees is the best solution to global warming.