Image Source: UNDP

Introduction

As global development continues today, climate change has been one of the most discussed topics almost in every part of the world. Discussions about climate change started in 1824 after a French Mathematician and Natural Philosopher, Joseph Fourier, discovered that without an atmosphere, the earth would be colder than its average temperature. The debate further in 1859 as John Tyndall assessed certain gases and concluded that if changes occur in their concentrations, it will lead to climate change (American Institute of Physics, 2022). Since Fourier and Tyndall made these observations, the world has considered climate change critical. Climate change in the 1700s was considered natural until the 1800s, when humans started burning fossil fuels such as coal, gas, and oil (United Nations (UN), 2022) for different purposes. During the 1800s, coal was used as fuel for trains and ships, for heating homes, and for making iron and steel, while oil and gas were used for oil and kerosene lamps and gas lighting (U.S. Department of Energy, n.d; Building Green, 2010; National Grid, 2016). However, burning fossil fuels releases greenhouse gases (GHGs) that trap heat from the sun and allow temperatures to rise (UN, 2022), causing global warming. Those GHGs also come from livestock, municipal solid waste landfills, and fridges (European Union (EU), 2014; United States Environment Protection Agency, 2015). According to the Natural Resources Defense Council (2022), there are about five GHGs, including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), water vapour (H2O), and fluorinated gases (F-gases), contributing to global GHG emissions. CO2, CH4, and N2O account for about 66%, 16%, and 7% of total GHG emissions (World Meteorological Organization, 2021). Other GHGs, such as F-gases and H2O, contribute 11%.

How Does CO2 Contribute to Global Warming?

The National Aeronautics and Space Administration (NASA) described CO2 as any heat-trapping or GHG generated from wildfires, fossil fuels, and volcanic activities (NASA, 2020). However, when CO2 is released from wildfire, fossil fuel, or volcanic activity, air temperature and water vapour in the atmosphere increase, causing greenhouse heating (NASA Earth Observatory, 2011) and global warming. 

How Does CH4 Contribute to Global Warming?

CH4 is a GHG from natural gas systems, livestock, and wetlands (Climate and Clean Conditions Coalition, 2013). However, when natural gas products are used, they release CO2 and create a free passage for unburned CH4 into the atmosphere (Jordan, 2022). CH4 is also released into the atmosphere during enteric fermentation, manure management, forest-pasture conversion, and warming of wetland soil (Food and Agriculture Organization, 2013; Palay, 2021). Releasing CO2 and CH4 into the atmosphere creates a temperature change and thus causes global warming. 

How Does N2O Contribute to Global Warming?

According to the Alcohol and Drug Foundation (2021), N2O is a colourless gas used by people for sedation, pain relief, and intoxication. During these processes, N2O escapes into the atmosphere. The longer it takes in the atmosphere, the more its concentration increase, which depletes the stratospheric ozone and influences climate change (Stocker, 2013; Prather et al., 2015). 

How Does H2O Contribute to Global Warming?

Water vapour is gaseous water formed through evaporation and sublimation (Energy Education, 2017). During evaporation, water changes from liquid to gas (Water Science School, 2019 a); and changes from solid (ice) to gas in sublimation (Water Science School, 2019 b). When water undergoes evaporation and sublimation, the gases escape into the atmosphere and act as a climate feedback, influencing constant change in the earth’s climate (Britannica, 2022). 

How Do F-gases Contribute to Global Warming?

The European Environment Agency (2022) defined F-gases as any artificial gases employed during industrial processes. The industries frequently using these gases include refrigeration, electrification, heating, and air conditioning (Ferreira et al., 2022). When F-gases are used in these sectors, they settle in the atmosphere and thus trap atmospheric heat, leading to global warming (NetRegs, 2020).   

Sectors and Strategies to Prioritized to Reduce GHGs

The United Nations Environment Programme (2020) identified various sectors to consider and how each of them can help reduce GHG emissions:

  1. Energy – the energy sector accounts for about 35% of the total GHG emissions (Intergovernmental Panel on Climate Change (IPPC), 2014). The energy sector can reduce its emissions of GHG by transitioning to renewable energy and improving energy efficiency. The industry can also cut its GHG emissions if governments eliminate policies enhancing the growth of the fossil fuel industry. Finally, replacing private car travel with other activities such as walking, cycling, or public transport can also help the sector to minimise its GHG emissions. By applying these, the energy sector can cut 12.5 gigatonnes (Gt) of GHG emissions yearly.
  2. Industry – the industry sector contributes approximately 21% to global GHG emissions (IPPC, 2014). The industry sector can minimize GHG emissions by promoting energy efficiency standards and implementing policies to prioritise them. The industry can also reduce GHG emissions by enhancing efficient and renewable heating and cooling systems. Carbon pricing and the provision of incentives and mandates to lower GHG emissions are also relevant to cut down the sector’s emissions of GHG. However, the industry sector can reduce emissions by 7.3 Gt annually if the abovementioned strategies are followed.
  3. Agriculture, Food, and Waste – agriculture and agriculture-related activities account for about 24% of the total GHG emissions (IPPC, 2014). However, agriculture and agriculture-related activities can reduce GHG emissions by encouraging sustainable and climate-smart agriculture activities. GHG emissions generated from agriculture and agriculture-related activities can be minimised by collaborating with producers and consumers to realise their food choices and reduce food loss waste in the food supply chain. Finally, aligning climate goals and national diet recommendations can also help reduce GHG emissions from agriculture and agriculture-related activities. By doing these, agriculture and agriculture-related activities will cut 14.6 Gt yearly.
  4. Transport – about 14% of the total GHG emissions come from transportation (IPPC, 2014). The transport industry can minimise GHG emissions by replacing private and public transport with electric vehicles. The sector can also reduce the emissions of GHG by encouraging walk and cycling among individuals. Finally, creating safe spaces using non-motorized transport can minimise GHG emissions in the transport industry. However, the transport sector can cut 4.7 Gt of GHG annually by employing these strategies.
  1. Building and Cities – buildings and cities account for about 6% of the total GHG emissions (IPPC, 2014). However, buildings and cities can reduce the emissions of GHG by modernising public facilities. GHG emissions from buildings and cities can also be minimised by constructing homes, offices, roads, and other places using carbon-neutral structures and linking rural and urban producers and consumers by investing in physical and market infrastructure. By implementing these strategies, buildings and cities can cut 5.9 Gt of GHG emissions annually. 

Conclusion

The study above assessed why it is significant to mitigate the emissions of GHGs to achieve some of the set climate goals by 2030. From the research, climate change relies on GHGs, generated mainly by human activities, and without those GHGs, climate change would have been regarded as a regular event, like in the 1700s. However, with current population growth stimulating various actions, it would be hard for climate change to occur at its average level. Hence, sectors such as energy, industry, agriculture, food and waste, transportation, and building and cities should play their parts in mitigating the GHGs they generate daily, as they are responsible for almost every GHG, from CO2 to F-gases. If these industries fail to address global warming, a severe global problem, the world will continue experiencing floods, mudslides, drought, and other climate-related disasters.

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