Climate change:
Climate change has become the subject of concern with considerable debate as well as the foremost pressing environmental challenge and threat to global public health, and every living creature. The globally carbon dioxide(CO2) emission from the energy use is accelerating and it has been declared that world will generate 33.8 billion metric tons from 29.7 billion metric tons CO2 in 2007. As per the data provided by International Energy Agency, China and United State are the highest global emitter of carbondioxide and Global green house gases where together they emit 40% of global CO2 and 35% of total green house gases. Similarly data of World Data Bank 2010 report states that there is tremendous share of global carbon emission by developed nation. The per capita (metric tons) emission of CO2 by developed nations are mentioned as: USA=17.6, Canada=14.7, Russia=12.2, India=1.7. Various approaches has been developed for the carbon shrinkage and one among them is the use of Biochar.
 
Biochar, a carbon rich material produced from pyrolysis of  biomass in the absence of oxygen at high temperature has been reported to alleviate climate crisis, improve soil health and enhance crop production. Biochar is considered as the best alternatives for the atmospheric carbon sequestration and the shrinkage contributing synchronous benefits and opportunity for the generation of the distributed energy.  The production and utilization of the Biochar technology completely differs from another because this technique is carbon negative as it removes the maximum amount of the carbon dioxide from the atmosphere. Greenhouse gas emission is minimized by the conversion of biomass to biochar as this process locks up the carbon from the biomass into the biochar and thereby delaying the release of this carbon back to the atmosphere
When the use of the process of biochar sequesters more carbon than it emitted, it is carbon negative. Biochar holds 50% of the carbon biomass and it sequesters that carbon for centuries when applied into the soil, removing the CO2 from the active cycle and thus reduce overall amount of atmospheric CO2. Plant growth is also enhanced by this process as it absorbs more CO2 from atmosphere. Overall, these benefits make the biochar process carbon negative as long as biomass production is managed sustainably. Biochar system also needs to be taken into account, viz. emissions resulting from biomass growth, collection, pyrolysis, spreading and transport, to consider it a truly carbon negative. Due to its capability to actively minimize the atmospheric concentrations of greenhouse gases, biochar technology may be considered as geo engineering solution. It may also be considered as a long wave geo engineering option for climate change mitigation as it plays a role into the removal of excess CO2 from the atmosphere and maximize the level of long wave radiation leaving from the planet. A biochar system is a carbon sink, where agricultural crops are grown and is subsequently pyrolysed to produce biochar, which is then applied to soil .
This means that CO2 from atmosphere is sequestered as carbohydrates in the growing plants and that conversion of the plant biomass to biochar stabilizes the carbon. The stabilization of carbon in biochar delays its decomposition and ensures that carbon remains locked away from the atmosphere for hundreds to thousands of years. In addition, biofuels can also be made by utilizing the gases released during biochar production. In carbon cycle, plants remove CO2 from atmosphere via photosynthesis and convert it into biomass. But all of that carbon (99%) is returned to atmosphere as CO2 when plants die and decay, or immediately if biomass is burned as a renewable substitute for fossil fuels.
 
To sum up, in biochar cycle, half (50%) of that carbon is removed and sequestered as biochar and the rest half (50%) is converted to renewable energy co-products before being returned to the atmosphere. So addition of biochar has also promising role for the sequestration of the carbon in the environment.