CO2 Emissions : CO2 is naturally present in the atmosphere. It takes important part in creating greenhouse effect. Greenhouse effect is responsible for maintaining the inhabitable temperature on earth.
CO2 plays another important role for the life in the earth. It is the member of the earth’s carbon cycle. Carbon cycle refers to the circulation of carbon among the atmosphere, oceans, soil, plants, and animals.
Human activities have been adding greenhouse gases in the atmosphere. Among all the greenhouse gases being added in the atmosphere by humans, CO2 accounts about 80%. Its high concentration has been built up in the atmosphere because of its very high emission by human activities. The degradation of CO2 sinks such as forests is also contributing towards increase in its concentration in the atmosphere. The result is the changes in the carbon cycle and increase in global average temperature.
Main sectors responsible for CO2 emissions and their contribution are given below.
Combustion of fossil fuels such as coal, petroleum and natural gases releases CO2 into the atmosphere. Fossil fuel combustion for energy and transportation is the primary source of the CO2 emissions. CO2 is also being emitted by certain industrial process such as cement manufacturing. The land use change such as clearing of the forests for agriculture and other use also contribute towards its release into the atmosphere which otherwise would have been absorbed by the forests.
Electricity makes the economic sector which is the most responsible for CO2 emissions. It is responsible for emitting more than (41%) of the CO2.
The majority of the electricity in the world comes from the combustion of fossil fuels such as by burning of coal. Coal is the most used fuel for electricity production. It is also the most carbon intensive fuel which increases the carbon foot print of electricity generation tremendously.
About 92% of the total electricity produced is consumed to power the industrial, residential and commercial sectors. Among these three, the industrial sector is the most power consuming. Examples of electricity intensive industries are chemicals, iron/steel, cement, aluminum as well as pulp and paper production industries.
The second largest source of anthropogenic CO2 emissions after the electricity production is the transportation sector. It is heavily dependent on the combustion of fossil fuels such as gasoline and diesel. Transportation includes humans and goods on land, marine and air accounts for more than 22% of the total CO2 emissions. Within this sector marine shipping is responsible of about 14% CO2 emissions while the aviation is responsible for 11 % of the global emissions.
There are many industrial processes that produce CO2 such as cement manufacturing and consumption, production of iron and steel. Fossil fuel combustion alone is not the reason of CO2 emissions in these industries. In fact it is one of the most prevalent reasons.
The total CO2 emitted for the year 2014 was estimated to be 35.7 billion tonnes. In this total global CO2 emissions the percentage share of six largest CO2 emitting countries were: China (30%), United States (15%), European Union (EU-28) (9.6%), India (6.6%), Russian Federation (5.0%) and Japan (3.6%).