What is greenhouse gas emissions?

Climate change caused by the greenhouse effect is a global phenomenon that has garnered significant attention due to its substantial impact on the surrounding environment. So, what is this phenomenon, and what are its harmful effects on humanity?

Definition

Greenhouse gases are gases that can absorb long-wave radiation (infrared) reflected from the Earth’s surface when illuminated by sunlight, subsequently dispersing heat back to the Earth, causing the greenhouse effect.

The main greenhouse gases include: water vapor, CO₂, CH₄, N₂O, O₃, and CFCs. In the solar system, the atmospheres of Venus, Mars, and Titan also contain greenhouse gases. Greenhouse gases significantly influence the Earth’s temperature; without them, the average surface temperature of the Earth would be about 33°C (59°F) cooler than it is now.

The main greenhouse gases include: water vapor, CO₂, CH₄, N₂O, O₃, and CFCs.

Based on the origin of emissions, trends, absolute levels, and the impact on the total greenhouse gas emission potential of countries, emission sources are divided into four main groups:

Energy: This is one of the largest sources of greenhouse gas emissions today. This sector typically contributes over 90% of CO₂ emissions and 75% of other greenhouse gases in developing countries. 95% of emissions from the energy sector are CO₂, with the remainder being CH₄ and NO in roughly equal amounts. Emissions in the energy sector are divided into three groups: emissions from burning fossil fuels (in energy industries, transportation activities, etc.); instantaneous emissions (i.e., the gases and vapors released from compression equipment due to leaks, unintended or infrequent from fuel extraction, processing, transportation, etc.); and carbon capture and storage activities. Among these, emissions from burning fossil fuels account for up to 70% of total emissions, particularly from power plants and oil refineries.

Industrial Processes and Product Use (IPPU): Emissions from the IPPU sector arise from industrial processing activities. The use of greenhouse gases in products and the use of carbon in fossil fuels not intended for energy production. The main emission sources are industrial processes that chemically or physically process raw materials. In these processes, many types of greenhouse gases are produced, including: CO₂, CH₄, N₂O, HFCs, and PFCs.

Agriculture, Forestry, and Land Use (AFOLU): Major sources of emissions include: CH₄ and N₂O emissions from livestock, rice cultivation, agricultural land, and burning activities in agriculture; CO₂ emissions/absorption in agriculture, forestry, and land use change. Overall, the AFOLU sector contributes about 30% of global greenhouse gas emissions, mainly due to CO₂ emissions from land use changes (largely due to deforestation) and CH₄, N₂O from crop cultivation and livestock farming.

Waste: Greenhouse gases that can arise in the waste sector include: CO₂, CH₄, and N₂O. Major emission sources include: landfilling solid waste; biological treatment of solid waste; incineration and open burning of waste; and wastewater treatment and discharge. Typically, CH₄ emissions from solid waste landfills (SWDS) account for the largest share of total greenhouse gases in this sector. CH₄ from wastewater discharge and treatment also plays a relatively significant role. Additionally, waste discharge, solid waste treatment, and wastewater also produce volatile organic compounds (NMVOCs), NOx, CO, and NH₃. NOx is primarily generated during waste combustion, while NH₃ is produced during composting. These two compounds can indirectly produce N₂O. However, the amount of N₂O is relatively small and insignificant.

Impact of Greenhouse Gases on Earth

Climate change is causing the average temperature on the Earth’s surface to rise due to the greenhouse effect, leading to extremely serious consequences.

The biggest challenge humanity faces today is the melting ice at the two poles. According to scientists, the effects of the greenhouse effect will melt ice sheets, potentially causing sea levels to rise by up to 1.5 meters, inundating coastal areas and low-lying land; Vietnam is also among those affected by melting ice.

The number of people affected by high temperatures is rapidly increasing, with many deaths occurring due to heatwaves.

Marine ecosystems are changing, land is gradually desertifying, soil is increasingly eroded, prolonged droughts are occurring, and forest areas are shrinking.

The equator is no longer a warm place year-round but is gradually turning into the largest desert on the planet. Natural disasters are becoming more frequent.

Reducing global greenhouse gas emissions is a crucial task for the entire world.

Current Status of Greenhouse Gas Emissions in Vietnam

Recognizing the importance of reducing global greenhouse gas emissions and understanding the impact on the country’s socio-economic development, Vietnam has supported the United Nations Framework Convention on Climate Change and actively participated in related legal agreements for climate change mitigation. Specifically, Vietnam signed the Climate Convention in 1992 and ratified it in 1994; signed the Kyoto Protocol in 1998 and ratified it in 2002; established a national steering committee to implement the Climate Convention and the Kyoto Protocol; and submitted the first National Communication (2003), the second National Communication (2010), and the first biennial update report (2014) to the Climate Convention Secretariat, reflecting the latest efforts in responding to climate change and greenhouse gas inventory.

Regarding the greenhouse gas inventory content, Vietnam conducted a national greenhouse gas inventory in 2010, carried out from 2013 to 2014 under the project “Strengthening National Greenhouse Gas Inventory Capacity in Vietnam” (2010-2014) funded by the Japan International Cooperation Agency (JICA). In 2010, the total greenhouse gas emissions in Vietnam were 246.8 million tons of CO₂ equivalent, including emissions from land use, land-use change, and forestry (LULUCF), and 266 million tons of CO₂ equivalent excluding LULUCF. From 1994 to 2010, total greenhouse gas emissions in Vietnam (including LULUCF) increased rapidly from 103.8 million tons to 246.8 million tons of CO₂ equivalent, with the energy sector being the fastest-growing, rising from 25.6 million tons to 141 million tons of CO₂ equivalent.

The emission situation in each sector of Vietnam is as follows:

Energy

In the energy sector in Vietnam, greenhouse gases are primarily emitted from fuel combustion and released during extraction and transportation processes. The total greenhouse gas emissions in the energy sector in 2013 were 151.4 million tons of CO₂ equivalent. Fuel combustion activities are prevalent in sectors such as electricity generation, industry and construction, transportation, agriculture/forestry/aquaculture, and some other sectors. This is the main activity generating greenhouse gases, accounting for about 86.1% of total national greenhouse gas emissions (MONRE 2017). Additionally, with the large consumption of fuel (approximately 60% of total fuel consumption), transportation activities also emit a significant amount of greenhouse gases into the atmosphere. Currently, on average, the transportation sector emits about 30 million tons of CO₂ equivalent per year. Emissions have rapidly increased over the years, more than doubling from 12.58 million tons (in 2000) to 29.7 million tons of CO₂ equivalent (in 2013). Among these, road transport emissions account for 90.9%; emissions from rail, waterway, and air transport account for nearly 10%. The civil aviation sector also has significant and increasing greenhouse gas emissions.

Industrial Processes and Products

For industrial processes, the main production types generating greenhouse gases are: cement production, lime production, ammonia production, and steel production. The total greenhouse gas emissions in industrial production in 2013 were 31.8 million tons of CO₂ equivalent. Among these, the cement production sector had the highest emissions, accounting for about 88.8% of total emissions from industrial production. This sector uses a significant amount of energy and generates a lot of emissions due to the requirement for extremely high temperatures.

Agriculture

According to the greenhouse gas inventory results in 1994 from the Ministry of Natural Resources and Environment, the greenhouse gas emissions in the agriculture sector were 52.45 million tons of CO₂ equivalent – accounting for 50.5% of the total greenhouse gas emissions in the country. By 2013, greenhouse gas emissions in this sector were 89.4 million tons of CO₂ equivalent – accounting for 34.5% of the total greenhouse gas emissions in the country. Among these, rice cultivation and agricultural land contributed the most, accounting for approximately 50% and nearly 27% of total emissions in the agriculture sector in 2013 (MONRE 2017).

Land Use, Land-Use Change, and Forestry

According to the Good Practice Guidelines for Land Use, Land-Use Change, and Forestry from 2003, land in Vietnam is classified into six types: forest land, agricultural land, grassland, wetland, residential land, and other types of land. The emission/absorption of greenhouse gases (GHGs) in this sector involves the process of changing carbon stock in: i) above-ground and below-ground biomass; ii) organic waste (dead trees, fallen branches and leaves); and iii) soil. Since 2010, the Land Use, Land-Use Change, and Forestry (LULUCF) sector has gradually shifted from being a net emitter of GHGs to a net absorber. GHG emissions in this sector decreased from 19.4 million tons (in 1994) to 15.1 million tons of CO2 equivalent (in 2000). Meanwhile, carbon absorption increased to 34.2 million tons of CO2 equivalent by 2013, with forest land and agricultural land being the largest sources of CO2 absorption (MONRE 2017).

Waste Management

In recent years, Vietnam has generated over 15 million tons of solid waste annually from various sources, with more than 80% originating from urban areas. However, only over 70% of solid waste in urban areas and about 20% in rural areas is collected and treated. The GHG emissions from this sector primarily include: CH4 emissions from landfills of collected solid waste; from industrial wastewater and domestic sewage; N2O emissions from domestic sewage sludge; and CO2 and N2O emissions from waste incineration.

Overall, emissions from the waste sector account for a small proportion. The total GHG emissions from this sector in 2013 were 20.7 million tons of CO2 equivalent, representing 7% of the national total emissions. Among these, urban wastewater had the largest share of GHG emissions, accounting for 45.6%. CH4 emissions from landfills accounted for 35.9% (MONRE 2017).

Vietnam is currently promoting the use of renewable energy, such as solar energy in industrial applications, to reduce GHG emissions, particularly in Ho Chi Minh City and Hanoi—regions with high greenhouse gas levels. Projects aimed at limiting GHG emissions are being developed and implemented in various sectors including urban planning, energy, transportation, industry, water management, waste management, construction, healthcare, agriculture, and tourism.

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