The delayed monsoon in India this year has been causing grave concerns all around with its unimaginable consequences on the agricultural front and the food security of the country. The weather experts are predicting a shortfall of 10-15% of rains compared to last year and this has been attributed to the 'El nino' effect in the Indian ocean resulting from global warming which, in turn is caused by uncontrolled emission of greenhouse gases like CO2. While scientists have been warning for many years about the consequences of such emissions on the weather, the consciousness has not percolated down to the politicians, bureaucrats and common man who are more concerned with to day's problems than the ones that can imperil life on this planet in future.
Mindless deforestation, under the pretext of infrastructure development and increased acreage for agricultural cultivation reduces the green cover so necessary to 'sink in' CO2 generated by the modern living styles. The fast rate of forest denudation in south Asia for increasing Palm cultivation and in Brazil for sugarcane production for biofuels are expected to have far reaching repercussion on weather changes in the coming years. Increased absorption of CO2 by the vast ocean tends to increase acidity of sea water putting in peril the diverse aquatic life and disturb the ecological equilibrium there. While expansion of agriculture is an unavoidable option for feeding the growing population, replanting on a massive scale is urgently called for. There are millions of acres of land lying fallow and millions of kilometers of roads with both the sides amenable for planting trees and all it requires is a pragmatic program to energise people to go for it.
Marine Algae, once considered as a potential CO2 sink, can help to some extent but cannot be a solution due to many practical constraints. Recent experiments to fertilize oceans using ferrous sulfate for facilitating algal blooms which could absorb CO2 do not justify investments in this strategy as algal bloom after CO2 assimilation do not sink to the ocean bottom but releases the gas back into the atmosphere nullifying the objectives of such exercises.
Scientists are excited about a clue they got recently from the Amazon basin in Brazil where natives have been using a black colored compost like material for fertilizing their exhausted agricultural lands for many years without anybody bothering to see what it is. Vast areas there contain this material up to 6 feet deep and the mystery of its real nature has since been established. Given the name 'Biochar', it turns out that the dense and loamy material is nothing but charcoal formed centuries ago by burning of biomass under oxygen starved conditions. It is a form of carbon, the burnt remains of plant and animal materials and could stay in tact in the earth for long without deterioration or destruction. Biochar refers to small pellets of charcoal when plant wastes such as wood chips are heated in a process without oxygen, called pyrolysis. When added to soil these pellets help to boost fertility of soil by retaining moisture better, besides efficiently storing CO2 and other green house gases indefinitely. Charcoal can adsorb over 60000 chemical substances including many gases, which are bound in the matrix of its honey comb structure with a surface area of about 3000 square feet per gm, by Van der waals force. This has made it one of the most effective tools during the last 15 years in fighting poisoning, pollution and for many other applications.
The 'Geosequestration', involving burying of polluting gases under ground or beneath the ocean floor is becoming a possible choice for overcoming green house gas problems. But considerations of cost and logistics make this approach unrealistic in the near future. Whether Biochar could be an answer to the global warming phenomenon remains to be seen as very little is known about the formation of this material in the Amazon basin. How plant and animal biomass can get converted into Biochar, especially on earth's surface needs to be studied. Two pre-requisites are absence of O2 and high temperature, both absent in the environment where Biochar was discovered. Manufacture of Biochar artificially may be inconceivable and impractical in to day's context. Probably Biochar discovery may translate into more efficient fertilizers for agriculture and green house control may be incidental.
V.H.POTTY
http://vhpotty.blogspot.com/
