Climate Change: The Main Pollutant Culprit

Climate change is the single biggest health threat facing humanity, and air pollution is the leading environmental cause of illness and premature death. While the climate has always varied naturally, the warming observed since the 1950s is too rapid to be explained by natural causes alone. Scientists agree that human activity is the primary driver of climate change, with the burning of fossil fuels being the most impactful human activity. The main pollutant causing climate change is carbon dioxide, which accounted for roughly 79% of the US's total greenhouse gas emissions in 2021. Other greenhouse gases, such as methane, are emitted in smaller quantities but can be more potent.

Carbon dioxide emissions from burning fossil fuels

Carbon dioxide (CO2) emissions from burning fossil fuels are a major contributor to climate change. Fossil fuels include oil, coal, and natural gas. The burning of these fuels for energy production, transportation, and industrial activities releases large amounts of CO2 into the Earth's atmosphere.

In 2023, carbon dioxide emissions from fossil fuels reached record levels, according to estimates from scientists. The continued rise in emissions impedes progress toward limiting global warming. The concentration of carbon dioxide in the atmosphere has increased significantly since the beginning of the industrial era, and it is the primary driver of the planet's rising temperatures.

One of the main sources of carbon dioxide emissions from fossil fuels is the energy sector. Electricity production often relies on burning fossil fuels, especially coal and natural gas. In 2022, 60% of electricity in the US was generated from these sources. As global energy demand increases, so do the carbon dioxide emissions associated with energy production.

The transportation sector is another significant contributor to carbon dioxide emissions from fossil fuels. Over 94% of the fuel used for transportation is petroleum-based, including gasoline and diesel. Cars, trucks, ships, trains, and planes burn these fossil fuels, releasing CO2 into the atmosphere. The transportation sector is the largest source of direct greenhouse gas emissions.

Additionally, industrial activities that burn fossil fuels for energy contribute to carbon dioxide emissions. Certain chemical reactions necessary for producing goods from raw materials also release greenhouse gases. When indirect emissions from electricity use are considered, the industrial sector accounts for an even larger share of carbon dioxide emissions.

The rise in carbon dioxide emissions from burning fossil fuels has severe consequences for the planet. As a greenhouse gas, carbon dioxide traps heat in the Earth's atmosphere, leading to global warming and climate change. This, in turn, causes rising sea levels, more extreme weather events, heat-related health issues, and the increased transmission of infectious diseases.

Methane emissions from oil and gas drilling

Greenhouse gases are the primary driver of climate change. They trap the sun's heat in the Earth's atmosphere, causing global warming. While carbon dioxide (CO2) is the most common greenhouse gas, methane is a more potent greenhouse gas and contributes significantly to climate change.

The oil and gas industry is a major contributor to methane emissions. In 2019, oil and gas operations emitted an estimated 82 million tonnes of methane, split roughly evenly between the two sectors. The most emitting sources produce more than four times the indirect emissions of the least-emitting sources. While there is uncertainty in estimating global methane emissions from oil and gas operations, recent studies suggest that the volume of methane released from these activities in the United States has been significantly underestimated.

Reducing methane emissions from oil and gas drilling is crucial for mitigating climate change. Methane has a shorter atmospheric lifetime than CO2, so reducing methane emissions can have a rapid and significant effect on slowing down climate change. Advanced technologies, such as gas injection and on-site power generation, can help reduce methane emissions from oil and gas production. Improved monitoring and assessment of methane emissions are also necessary to speed up strategic decision-making and innovation in this area.

To address methane emissions from oil and gas drilling, the U.S. Environmental Protection Agency (EPA) has established guidelines for releasing natural gas. These guidelines aim to reduce methane and other harmful air pollutants from the oil and natural gas industry. Additionally, the EPA has added a strong-smelling substance called mercaptan to natural gas so that people can easily detect leaks.

Nitrous oxide emissions from industrial sources

Nitrous oxide is a potent greenhouse gas that remains in the atmosphere for decades to centuries. It is a significant contributor to global warming and climate change. While nitrous oxide occurs naturally, human activities, particularly industrial processes, have significantly increased its concentration in the Earth's atmosphere.

Industrial sources of nitrous oxide emissions include fossil fuel combustion and specific industrial processes. The burning of coal at electric power plants is a major contributor, accounting for 60% of all nitrous oxide emissions from stationary combustion sources. In the United States, industrial sources emitted 11 MMTCO2e of nitrous oxide in 2009, a decrease of 10.8% from 2008. This decrease is attributed to the installation of emissions control technology at adipic acid plants and the closing of a plant without such technology.

The production of adipic acid and nitric acid are the two primary industrial sources of nitrous oxide emissions. Adipic acid is used in the manufacture of nylon fibres and plastics, while nitric acid is a key ingredient in synthetic fertilizers. The oxidation of nitrogen compounds during the production of these acids releases nitrous oxide into the atmosphere.

Additionally, biomass burning, which includes the burning of living and dead vegetation, accounts for 10% of human-caused nitrous oxide emissions. Atmospheric deposition and human sewage also contribute to a smaller extent.

It is important to note that agriculture is the most significant human source of nitrous oxide emissions, with industrialized farming practices and synthetic fertilizer use playing a major role. However, this paragraph focuses specifically on industrial sources, excluding agricultural practices.

Transport emissions from combustion engines

The combustion of fossil fuels is a significant contributor to climate change. Transport emissions from combustion engines are a prime example of this, as the transport sector is heavily reliant on fossil fuels and accounts for a large proportion of global carbon dioxide (CO2) emissions.

Motorised transport on land, sea, and air predominantly relies on combustion engines that run on liquids, natural gas, or fossil fuels like oil. This includes cars, trucks, buses, planes, and ships. In 2018, road travel alone accounted for three-quarters of transport emissions, with passenger vehicles contributing 45.1% and freight trucks contributing 29.4%. Overall, transport accounts for around one-fifth of global CO2 emissions, or 24% when considering only energy-related emissions.

International shipping contributes around 10.6% of transport emissions, while aviation contributes 11.6%. While aviation often receives significant attention in discussions on climate action, long-distance aviation, along with road freight and shipping, will be challenging sectors to decarbonise. The potential for alternative fuels or batteries to power these vehicles is limited by the range and power requirements, as well as the size and weight of the necessary equipment.

To align with net-zero targets, the transport sector must implement policies that encourage a shift to less carbon-intensive travel options and more efficient technologies. This includes promoting walking, cycling, and public transport, as well as the adoption of electric vehicles (EVs). Governments can play a crucial role in this transition by setting sales targets for zero-emission vehicles, providing technical and financial assistance, and sharing best practices across countries.

As transport demand is expected to increase with global population growth and rising incomes, addressing transport emissions from combustion engines is crucial to mitigating climate change. Without concerted efforts to reduce the carbon intensity of transport, this sector will continue to be a significant contributor to global emissions and the associated environmental and health impacts of climate change.

Energy emissions from heating and cooling buildings

Carbon dioxide (CO2) is the main pollutant causing climate change. It accounts for the majority of greenhouse gas emissions, which trap heat in the atmosphere, leading to global warming and climate change. Human activities, such as burning fossil fuels, are the primary contributors to the increased concentration of CO2.

One significant source of CO2 emissions is energy use in buildings, particularly for heating and cooling. According to the World Green Building Council, around 28% of global CO2 emissions originate from building operations. Specifically, 15% of global carbon emissions come from heating and cooling buildings, while another 10% stem from food loss and waste.

In the European Union, the buildings sector is a major contributor to greenhouse gas emissions, accounting for 34% of energy-related emissions in 2022. These emissions arise from the direct use of fossil fuels in buildings, such as oil and gas burned in boilers for heating, and from the production of electricity and heat used in buildings. This includes electricity consumed by water heaters, lighting, electrical devices, and cooling systems.

To address this issue, the EU has implemented initiatives like the European Green Deal and the Renovation Wave, which aim to reduce greenhouse gas emissions and improve energy efficiency in buildings. Between 2005 and 2022, the EU buildings sector achieved a 34% reduction in total greenhouse gas emissions, thanks to higher energy efficiency standards for new buildings and improvements in existing structures.

Additionally, innovative technologies and solutions exist to further enhance energy efficiency and decarbonize heating and cooling systems. For instance, heat recovery methods can be applied creatively to maximize sustainability, as demonstrated by the Energy Hub Aalsmeer project in the Netherlands. By integrating heating and cooling systems, commercial and industrial buildings can significantly reduce their energy consumption and carbon emissions.

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