Sequestering Carbon in Soils

There is increasing emphasis on identifying strategies that will reduce the rate of enrichment of atmospheric CO2 by offsetting emissions caused by humans.

Major human caused sources of increasing CO2 equivalent emissions include the combustion of fossil fuel, cement manufacturing, deforestation and the burning of biomass, and land-use conversion including drainage of peatlands, soil tillage, animal husbandry.

We need to reduce CO2 , Methane  and Nitrous Oxide emissions and offset emissions through sequestration of carbon in soils and other terrestrial and inland aquatic ecosystems.

Land-use change, deforestation and soil cultivation have added CO2 equal to nearly 50 % of that caused by fossil fuel burning. Current rates of these activities are equal to 20 % of the emissions caused by fossil fuel burning. 

The Earth's natural systems, other than oceans and atmosphere, absorb over a third of the greenhouse gas emissions caused by humans every year. However the nearly two-thirds of the emitted carbon is added to the atmosphere and oceans every year and is fast pushing earth into a hot house state. 

A focus on fossil fuel emissions reduction as the primary solution to reversing climate change will continue to be ineffective

Replacing snow covered land with trees that absorb more sunlight in northern countries can actually accelerate warming regionally, creating a positive feedback loop that leads to further loss of highly-reflective snow and ice.

Climate researchers often suggest that the greatest potential for carbon sequestration in forests lies in the tropics; avoided deforestation, forest restoration and afforestation in these regions can play a significant role in mitigating global climate change.

Grassland biomes constitute approximately 40% of the global land surface area and possess massive potential for sequestering carbon in arid and semi-arid areas of the world. Healthy grasslands provide habitat for a biologically diverse range of plant and animal species, and also serve as a large reserve for soil carbon. Grasslands that sustain abundant stores of SOC have higher rates of water infiltration and retention and are less susceptible to environmental degradation such as soil erosion and drought. Although grasslands are currently facing desertification around the globe, proper land management can restore vegetation cover to protect soils from erosion and enhance the carbon sequestration capacity of these vital ecosystems.

While forests and dryland ecosystems contain the most soil carbon globally, the carbon density of wetland ecosystems is three and six times that of forests and grasslands/shrublands, respectively. The deep organic-rich soils of coastal wetlands contain carbon reserves that have been sequestered over millennia. These tidal ecosystems are able to store large quantities of carbon for two primary reasons: high-nutrient conditions that promote the rapid growth of carbon-sequestering plant biomass, and anaerobic soils that suppress microbial decomposition in the water-logged environment, allowing for long-term carbon storage. Tidal saline wetland ecosystems, including salt marshes and mangrove swamps, exhibit remarkable rates of below ground biomass production and enormous capacity as carbon sinks.

Conclusion : A focus on fossil fuel emissions reduction as the primary solution to reversing climate change will continue to be ineffective. Arbitrary goals to reduce emissions by 10, 30, 50 or even 80 percent are not going to prevent future warming. Basic scientific principles dictate that atmospheric CO2 concentrations will not decline without a significant rise in the carbon sequestration mechanisms of the biosphere. The good news is that there is enormous carbon sequestering potential in multiple ecological systems around the globe. The only question now is whether we will work to enhance the carbon storage capacities of nature or effectively continue to weaken them.

Acknowledgement : Text sourced entirely from this link.