Human Activities And Global Warming's Pollution Sources

Global warming is caused by an increase in the concentration of certain gases in the Earth's atmosphere, which act like the glass in a greenhouse, trapping the sun's heat and preventing it from escaping back into space. This phenomenon is known as the greenhouse effect. While some amount of greenhouse gases occur naturally, human activities have significantly increased their concentration, leading to the current era of global warming. The burning of fossil fuels, such as coal, oil, and natural gas, is a major contributor to this increase, with the transportation, manufacturing, and electricity production sectors being the largest emitters. Deforestation and agricultural practices also play a significant role, releasing carbon dioxide and methane into the atmosphere. Additionally, certain industrial chemicals, such as fluorinated gases and nitrous oxide, have a potent warming effect, further exacerbating global warming.

Deforestation and agriculture

The link between deforestation and agriculture is clear, and the latter is responsible for a large proportion of greenhouse gas emissions. The global food system is responsible for 17 billion metric tons of carbon dioxide equivalent or 31% of human-made greenhouse gas emissions in 2019, according to the United Nations' Food and Agriculture Organization (FAO). This includes emissions related to farming and land use, producing crops and livestock, household food consumption and waste, and energy used in farm and food processing and transportation.

Livestock is one of the biggest contributors to emissions within the global food system, with global livestock production generating around 14.5% of all anthropogenic GHG emissions, according to FAO. Cattle are responsible for 65% of those emissions, largely in the form of methane from burping. Food waste is another major issue, generating half of all global food system emissions, including the energy used to produce and transport food, and the methane formed when food rots in landfill.

Agriculture and food production are associated with carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), the three largest individual contributors to global warming. While direct agricultural emissions are usually dominated by CH4 and N2O, CO2 emissions are harder to quantify due to the distinct processes through which they are generated and the difficulty in applying uniform accounting methods. However, it is important to note that CO2 is by far the main contributor to anthropogenic global warming.

To address these issues, policymakers have developed the 'Reducing Emissions from Deforestation and Degradation' (REDD) programme, which provides financial incentives to governments, agribusinesses, and communities to maintain and possibly increase forest cover. REDD+ includes incentives for countries, communities, and individual landowners to slow deforestation and promote reforestation and sustainable forest management. While REDD+ has the potential to reduce CO2 emissions, it also faces challenges, including the difficulty of monitoring and measuring deforestation rates, and concerns about foreign interference in land use policies.

Fossil fuels

The burning of fossil fuels for energy production and transportation is a significant contributor to carbon dioxide emissions. Transportation, such as cars, trucks, ships, and planes, relies on fossil fuels and is a major source of greenhouse gas emissions, particularly carbon dioxide. Additionally, the manufacturing industry uses fossil fuels to run machines and produce materials like plastics, further contributing to emissions.

The concentration of carbon dioxide in the atmosphere has significantly increased since the beginning of the industrial era. According to scientists, carbon dioxide emissions from fossil fuels reached record levels in 2023, impeding progress toward limiting global warming. The rise in heat-trapping greenhouse gases is the main reason for the planet's rising temperatures. As a result, the global surface temperature in 2023 was 1.2 degrees Celsius warmer than the average for NASA's baseline period (1951-1980), making it the hottest year on record.

The impact of global warming due to fossil fuel emissions is widespread. It leads to rising global surface temperatures, more frequent and intense heat waves, and destructive storms. Global warming also exacerbates water scarcity, leading to agricultural and ecological droughts, threatening food security. Additionally, the warming ocean contributes to the intensity of tropical storms, cyclones, hurricanes, and typhoons.

To address the issue of global warming caused by fossil fuels, there is a growing consensus on the need to transition to renewable energy sources. The Intergovernmental Panel on Climate Change (IPCC) has warned that fossil fuel emissions must be halved within a certain timeframe to limit global warming to a specific temperature increase. This transition to renewable energy sources is crucial to mitigate the devastating effects of global warming on the planet and humanity.

Transportation

In the United States, the transportation sector is the largest source of greenhouse gas emissions, accounting for about 28% of total US greenhouse gas emissions. This makes it an even more significant contributor than the electric power sector. CO2 emissions from transportation have been on the rise, and they represent almost all of the global warming potential of greenhouse gas emissions from this sector. The burning of fossil fuels by vehicles is a major cause of these emissions, as most cars, trucks, ships, and planes run on fossil fuels such as coal, oil, gasoline, or natural gas.

The demand for transportation services is relatively insensitive to the price of such services, which makes reducing emissions in this sector challenging. However, there are efforts to address this issue. The US Environmental Protection Agency (EPA) has been taking action to reduce greenhouse gas emissions from transportation. They have implemented joint rule-making with the Department of Transportation (DOT) to set emissions and fuel economy standards for large sources of greenhouse gases in the transportation sector. The EPA also provides resources to help consumers make environmentally conscious choices when purchasing vehicles. Their Green Vehicle Guide and fueleconomy.gov website offer information on vehicles' fuel economy and emissions, while the SmartWay light-duty program identifies the top-performing vehicles in terms of fuel economy and emissions.

Reducing emissions in the transportation sector is crucial because, unlike in other sectors, reductions here are unlikely to be offset by corresponding increases in other countries. Therefore, addressing transportation emissions is a critical component of global efforts to limit global warming and mitigate its devastating impacts on our planet, economy, health, and ways of life.

Manufacturing

The manufacturing industry is one of the largest contributors to greenhouse gas emissions worldwide. The machines used in the manufacturing process often run on coal, oil, or gas, and some materials, like plastics, are made from chemicals sourced from fossil fuels. The burning of fossil fuels releases carbon dioxide (CO2), a vital component of the atmosphere, into the air as a greenhouse gas.

In 2021, the manufacturing sector was responsible for 12% of US greenhouse gas emissions, with about 75% of those emissions coming from burning fuel to create heat, and the rest being by-products of industrial processes that transform materials into products. Most emissions in the manufacturing sector come from the chemical and refining industries. In Europe, the industry emits an annual total of 880 million tonnes of carbon dioxide equivalents, making it one of the largest emitters of greenhouse gases on the continent.

Changes in economic output and industries' emissions intensity are the two primary factors contributing to changes in manufacturing emissions. While changes in output between 2002 and 2019 would have increased emissions, a much larger change in emissions intensity caused total emissions from manufacturing to decrease.

To reduce emissions, the manufacturing industry must improve resource efficiency, reduce its reliance on fossil fuels, recycle components, and adopt more environmental design practices. The circular economy, which promotes sustainable manufacturing, is the foundation of this. Remanufacturing and the recycling of components are two vital ways to make manufacturing more sustainable.

Some companies have committed to initiatives such as the Science Based Targets initiative, which calls for real action to limit global warming, and the Business Ambition for 1.5˚C goal, which targets a net-zero greenhouse gas value chain by 2050.

Energy production

The burning of coal, in particular, is highly polluting as it emits not only CO2 but also other harmful substances such as nitrogen oxide, sulfur dioxide, and particulate matter, all of which can have detrimental effects on both the environment and human health. Oil and natural gas combustion also contribute to global warming, especially when these fuels are used for transportation, as the burning of gasoline and diesel fuel in vehicles releases a substantial amount of CO2 and other pollutants.

To mitigate the impact of energy production on global warming, a transition to cleaner and renewable energy sources is essential. This includes harnessing energy from the sun, wind, geothermal heat, and hydropower, all of which produce little to no direct greenhouse gas emissions. Many countries are already embracing this shift, investing in renewable energy infrastructure and phasing out fossil fuels. For example, solar and wind power are rapidly growing in capacity, providing an increasingly significant proportion of the world's electricity needs.

Additionally, improving energy efficiency can also help reduce the demand for energy and, consequently, lower emissions. This includes implementing energy-efficient practices and technologies in buildings, industry, and transportation, such as better insulation, more efficient appliances, and the development of electric vehicles. By reducing the amount of energy required to perform the same tasks, we can decrease the need for energy production and, thus, lower the emissions associated with it.

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