Carbon dioxide is a chemical element that exists as a gas in the Earth's atmosphere. CO2 is a colourless, odourless, incombustible gas found in the atmosphere and produced through respiration, combustion, and organic decomposition. Carbon dioxide is known as a greenhouse gas because it warms the Earth via the greenhouse effect. Carbon dioxide molecules in the atmosphere absorb and re-radiate long-wavelength infrared radiation (heat) from the Earth. This effectively traps heat around the earth. In this article, we will discuss Carbon Dioxide as Greenhouse Gas which will be helpful for UPSC exam preparation.

Composition of Carbon Dioxide as GHG

What are Greenhouse Gases?

• Greenhouse gases are gases that trap heat in the atmosphere.
• Water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone are the primary greenhouse gases in the Earth's atmosphere.
• Such gases in the atmosphere act as a blanket, trapping/absorbing some of the infrared radiation emitted by the earth and releasing some of it to it.
• However, any rise in such gases would result in more heat-trapping, increasing the earth's temperature, as represented in global warming.
• Without greenhouse gases, the average temperature of the Earth's surface would be around -18°C rather than the current average of 15°C.

What is Carbon Dioxide?

• Carbon dioxide (CO2) is the primary greenhouse gas emitted by human activity.
• Carbon dioxide is naturally present in the atmosphere as part of the Earth's carbon cycle (the natural circulation of carbon among the atmosphere, oceans, soil, plants, and animals).
• Human activities are altering the carbon cycle by adding more CO2 to the atmosphere and decreasing natural sinks.
• While CO2 emissions come from a variety of natural sources, human-related emissions are to blame for the increase in the atmosphere since the industrial revolution.

Carbon Dioxide as a Greenhouse Gas

• Carbon dioxide (CO2) is a significant heat-trapping gas, often known as a greenhouse gas, that is produced by the extraction and combustion of fossil fuels, wildfires, and natural processes such as volcanic eruptions.
• Carbon dioxide is a very significant meteorological gas because it is transparent to incoming solar radiation but opaque to outgoing terrestrial radiation.
• Carbon dioxide and other pollutants, together referred to as greenhouse gases, are emitted into the atmosphere as a result of both human and natural sources.
• Carbon dioxide absorbs some terrestrial radiation and reflects some of it back to the earth's surface. It is primarily responsible for the greenhouse effect.
• Because it is denser than air, its concentration is higher near the earth's surface.
• As a result of this process, the global temperature rises, resulting in a complex chain of events known as global climate change.
• Global climate change not only raises temperatures, but also changes the earth's natural weather patterns and climate.

Carbon Dioxide - Emissions and Trends

• Many factors influence changes in CO2 emissions from fossil fuel combustion, including population growth, economic growth, changing energy prices, new technologies, changing behaviour, and seasonal temperatures.
• Between 1990 and 2010, CO2 emissions increased in tandem with increased energy consumption by a growing economy and population.
• According to the World Meteorological Organisation (WMO) 2021 report, the increase in CO2 from 2019 to 2020 was slightly lower than the increase from 2018 to 2019, but it was more than the average yearly growth rate during the previous decade despite a 5.6% reduction in fossil fuel CO2 emissions in 2020 due to pandemic-related restrictions.
• Between 1990 and 2020, the potential for greenhouse gases to impact climate increased by 47%, with CO2 accounting for nearly 80% of this rise.
• Carbon dioxide (CO2) concentrations reached 413.2 parts per million in 2020, representing 149 percent of pre-industrial levels.
• Approximately half of the CO2 emitted by humans today remains in the atmosphere. The remaining half is occupied by oceans and land ecosystems.

CO2 - Emissions and Trends

Sources of Carbon Dioxide

• Carbon dioxide emissions come from both natural and anthropogenic sources.
• Decomposition, ocean release, and respiration are examples of natural sources.
• Anthropogenic sources include:
  • The use of fossil fuels to produce electricity.
  • The use of fossil fuels for transportation, such as gasoline and diesel.
  • Many industrial processes emit CO2 as a result of the combustion of fossil fuels.
• Several processes emit CO2 through chemical reactions that do not involve combustion, such as the production and consumption of mineral products like cement, the production of metals like iron and steel, and the production of chemicals, among others.

Impact of Carbon Dioxide Emissions

• While increased carbon dioxide levels can "increase water-use efficiency in crops" and "mitigate yield losses due to climate change," they can also cause nitrogen and carbon imbalances, reducing crops' essential nutrients like iron, zinc, and protein.
• Extreme weather events such as tropical storms, wildfires, severe droughts, and heat waves are caused by global warming.
• Carbon emissions have a direct impact on humans as well, increasing respiratory disease due to increased smog and air pollution.
• Carbon emissions can wipe out certain animal species and destroy crop yields and lands.
• Carbon emissions contribute to rising temperatures and decreased precipitation, altering growing conditions for many food crops.
• According to the Intergovernmental Panel on Climate Change, carbon emissions will cause global temperatures to rise by 1.5 degrees Celsius (2.5 degrees Fahrenheit) over the next 100 years.
• This minor change can have dramatic consequences for shorelines, particularly in densely populated areas where rising sea levels flood buildings and roads and disrupt shipping traffic.

Impact of Carbon dioxide emissions

Global Steps Taken to Address GHG Emissions

• Carbon Pricing: It is a tax imposed on carbon emissions to persuade polluters to limit the amount of greenhouse gas released into the atmosphere.
• Carbon sequestration: It is the technique of capturing waste carbon dioxide (CO2) from large point sources, such as fossil fuel power plants, and storing it somewhere where it will not be released into the atmosphere.
• COP 21: The Paris Climate Agreement mandates signatories to work toward net-zero emissions, which is crucial for reducing global warming. In this process, CO2 emissions from coal and gas power plants, as well as heavy industry, are captured, stored, and reused.

Steps Taken by India to Address CO2 Emissions

• National Wind-Solar Hybrid Policy 2018: It is an initiative to promote a large grid-connected wind-solar PV hybrid system for efficient transmission infrastructure and land usage
• National Solar Mission (2010): The goal is to establish India as a global leader in solar energy by establishing the key policy conditions.
• National Action Plan on Climate Change (NAPCC): It was established in June 2008 with the purpose of formulating a comprehensive policy to tackle climate change.
• National Mission for Enhanced Energy Efficiency (NMEEE): It was established in 2011 with the purpose of developing the energy efficiency industry through the implementation of appropriate laws and regulations.
• Bharat Stage (BS) VI norms: These are government-mandated emission control requirements aimed at minimising air pollution.
• Recently, Scientists in India have developed a photochemical technique (photocatalyst) named the Conjugated Microporous Polymer (CMP) to convert carbon dioxide (CO2) to methane (CH4) as a value-added product.

Conclusion

Carbon dioxide is constantly exchanged between the atmosphere, the ocean, and the land surface as it is produced and absorbed by a wide range of microorganisms, plants, and animals. However, absent anthropogenic impacts, CO2 emissions and removal by these natural processes tend to balance. Since the beginning of the Industrial Revolution around 1750, human activities have significantly contributed to climate change by adding CO2 and other heat-trapping gases to the atmosphere. Other strategies include energy efficiency, conservation, carbon capture and sequestration, and carbon sequestration.

FAQs

MCQs

1. Which of the following is a primary source of carbon dioxide emissions?

A) Solar power
B) Deforestation
C) Wind energy
D) Geothermal energy

2. How does carbon dioxide contribute to global warming?

A) By blocking ultraviolet radiation
B) By reflecting sunlight back into space
C) By trapping infrared radiation in the atmosphere
D) By absorbing heat directly from the sun

3. Which human activity is responsible for most of the increase in carbon dioxide levels?

A) Use of renewable energy
B) Fossil fuel burning
C) Organic farming
D) Increased recycling

4. Which of the following actions can help mitigate the effects of carbon dioxide emissions?

A) Planting trees
B) Increasing fossil fuel usage
C) Expanding coal mining
D) Promoting deforestation

5. What international agreement aims to limit global carbon emissions?

A) Kyoto Protocol
B) Paris Agreement
C) Montreal Protocol
D) Geneva Convention

GS Mains Questions and Model Answers

Q1: Analyze the role of carbon dioxide in climate change and discuss global efforts to mitigate its impact.

Answer: Carbon dioxide is a major greenhouse gas responsible for trapping heat in the atmosphere, leading to global warming and climate change. The increased concentration of CO2 has resulted from human activities such as fossil fuel burning and deforestation. Its effects include rising global temperatures, melting ice caps, and disruptions to ecosystems. Efforts to mitigate CO2 emissions include transitioning to renewable energy sources, adopting energy-efficient technologies, and promoting carbon capture and storage (CCS). Additionally, international agreements such as the Paris Agreement aim to reduce global emissions and limit global temperature rise to below 2°C, enhancing climate resilience.

Q2: Discuss the environmental impacts of rising carbon dioxide levels and the strategies to address them.

Answer: Rising carbon dioxide levels contribute significantly to climate change by intensifying the greenhouse effect, leading to rising sea levels, extreme weather events, and biodiversity loss. CO2 also affects agricultural productivity by altering weather patterns and reducing crop yields. Strategies to address these impacts include reducing carbon emissions through sustainable practices such as adopting renewable energy, enhancing energy efficiency, and reforestation. Technological innovations like carbon capture and storage (CCS) are also being explored to reduce CO2 concentrations in the atmosphere. Strong policy frameworks like the Paris Agreement have brought nations together to collectively address climate change.

Q3: How can carbon capture technologies play a role in reducing global CO2 emissions, and what challenges do they face?

Answer: Carbon capture technologies capture CO2 emissions from industrial processes or the atmosphere and store them underground or in other forms, preventing CO2 from entering the atmosphere. These technologies have the potential to significantly reduce global CO2 emissions and contribute to meeting climate targets. However, challenges include the high cost of implementation, technological limitations, and the need for infrastructure to store captured CO2 safely. Additionally, public perception and regulatory issues related to carbon storage need to be addressed. Despite these challenges, advancements in carbon capture and storage (CCS) are critical to mitigating the impacts of climate change.

Previous Year Questions on Carbon Dioxide and Climate Change

1. UPSC CSE Mains 2018 (GS Paper 3):

Question: "Discuss the impact of increased carbon dioxide concentrations on global climate patterns and biodiversity."

Answer: Increased CO2 concentrations lead to global warming, altering weather patterns and ecosystems. Rising temperatures result in melting polar ice, affecting sea levels and weather extremes like droughts and floods. These changes disrupt biodiversity, causing shifts in habitats and threatening species survival. The primary contributors to rising CO2 levels are industrial activities, fossil fuel combustion, and deforestation. Mitigation strategies include promoting renewable energy sources and adopting carbon capture technologies.

2. UPSC CSE Mains 2020 (GS Paper 3):

Question: "Evaluate the role of international agreements in curbing carbon dioxide emissions and their effectiveness in achieving global climate goals."

Answer: International agreements such as the Kyoto Protocol and the Paris Agreement play a vital role in curbing CO2 emissions by setting global emissions reduction targets. The Paris Agreement aims to limit global temperature rise to well below 2°C. While these agreements have fostered cooperation and commitment among nations, their effectiveness is still debated, as some countries have not met their targets, and enforcement mechanisms remain weak. Nonetheless, they provide a framework for collective action and highlight the urgency of addressing climate change.