Climate Change Causes and Evidences: Anthropogenic and Natural

Climate change is a phenomenon that pertains to the gradual and sustained alterations in weather patterns and temperatures over an extended period. Although shifts in climate may occur naturally, since the 1800s, human activities have been the primary cause of climate change. This is mainly due to the burning of fossil fuels such as coal, oil, and gas, which has led to an increase in heat-trapping greenhouse gas levels in the Earth’s atmosphere.

Climate Change Causes and Evidence Anthropogenic & Natural Causes
Climate Change Causes and Evidence Anthropogenic & Natural Causes

Human activities that emit greenhouse gases have the effect of enveloping the earth in a blanket, which traps the sun’s heat and leads to a rise in temperatures. Carbon dioxide and methane are examples of greenhouse gas emissions that contribute to climate change.

What are Anthropogenic Causes?

The term “anthropogenic” refers to any phenomena, process, or effect that arises from or is caused by human activities and their impact on the natural environment. The word’s origin is a combination of the Greek words “anthro” meaning human and “genesis” meaning creation or birth.

With the revolution of industries, the use of oil and gasoline has increased enormously. To carry on with regular activities, we depend on the energy of electricity and fuel. Energy has become a part of human life. If you look at your surroundings, you are all surrounded by automobiles, smartphones, and home appliances that rely on energy, and you rely on those accessories. Due to this exploitation of fossil fuels for our lives, we are creating an impact on Earth’s climate. For the past 150 years, Earth’s climate has had an accelerating impact.

Anthropogenic changes refer to alterations in the environment that are caused by human activities. Habitat destruction is the way in which they impact the ecosystem. Anthropogenic changes such as industrialization, pollution, deforestation, urbanization, and building dams have a significant impact on the ecosystem.

The overuse of non-renewable resources, such as fossil fuels, can have a significant negative impact on the ecosystem.

  • Constructing Dams

A dam is a structure built across a stream or river to hold back water. While dams can provide benefits, the negative impacts they create outweigh these benefits.

The construction of dams often results in the displacement of many families from their homes, as well as a significant loss of farmland and forest. Dams are responsible for significant environmental issues such as the emission of greenhouse gases and the loss of aquatic animal species.

  • Urbanization

Urbanization refers to the transformation of natural or rural areas into urban centers, such as cities and towns. Urbanization offers several benefits, including commercialization and employment opportunities. However, it is now posing a threat to the ecosystem.

Urbanization has several negative impacts on the ecosystem, including:

Rapid house construction has led to overcrowding and the development of slums. The infrastructure in these areas is inadequate, resulting in an increase in crime and pollution. Additionally, poor sanitation and housing conditions are prevalent.
Poor nutrition can have negative effects on one’s health and well-being.

  • Invasive Species

Invasive species are non-native organisms that have been introduced to an ecosystem and have the potential to cause harm to the environment, economy, or human health. These species can outcompete native species for resources, disrupt natural food chains, and alter habitats. Invasive species are a major concern for conservationists and environmental managers, as they can have significant impacts on biodiversity and ecosystem function.

An invasive species is a term used to describe an organism that is introduced to a new environment and causes harm by becoming overpopulated. Invasive species possess several characteristics such as fast growth, high dispersal ability, rapid reproduction, and tolerance of a wide range of environments.

  • Overexploitation

Overexploitation refers to the practice of exploiting natural resources at an excessive rate for the purpose of generating profit. There are two types of animal resource depletion: overfishing and overhunting. Overfishing has led to the endangerment of cod, tuna, and swordfish. Passenger pigeons are a prime example of a species that fell victim to overhunting.

GreenHouse Effect

The greenhouse effect is the primary cause of climate change. Certain gases present in the Earth’s atmosphere function similarly to the glass walls of a greenhouse by retaining the sun’s warmth and preventing it from escaping into space, thereby contributing to the phenomenon of global warming.

Although many greenhouse gases occur naturally, human activities are contributing to the increase in concentrations of some of these gases in the atmosphere. Specifically, human activities are responsible for the rise in concentrations of certain greenhouse gases.

Carbon dioxide (CO2), methane, nitrous oxide, and fluorinated gases are all greenhouse gases.
The largest contributor to global warming is the CO2 that is produced by human activities. As of 2020, the concentration of the substance in the atmosphere had increased by 48% compared to its pre-industrial level prior to 1750.

Human activities also emit smaller quantities of other greenhouse gases. Although methane has a shorter atmospheric lifetime, it is a more potent greenhouse gas than CO2. Similar to CO2, nitrous oxide is a greenhouse gas that has a long lifespan and can build up in the atmosphere over a period of decades to centuries.

Pollutants that are not greenhouse gases, such as soot aerosols, have varying impacts on warming and cooling. Additionally, they are linked to other concerns, such as low air quality. It is estimated that natural causes, such as changes in solar radiation or volcanic activity, have contributed less than 0.1°C (plus or minus) to the total warming that occurred between 1890 and 2010.

Anthropogenic Sources of Greenhouse Gases
Anthropogenic Sources of Greenhouse Gases Image Source: geoLibretext]

Human Causes On Climate Changes

  • Human actions, such as the consumption of fossil fuels and the development of land for agricultural and forestry purposes, are also potential contributors to climate change.
  • Since the beginning of the Industrial Revolution, human impacts on the climate system have been steadily growing. Additionally, these actions are detrimental to the ecology because they change the land’s surface and release different toxins into the air. Depending on the net amount of energy entering and leaving the system, this could either warm or chill the climate.
  • Carbon dioxide, classified as a greenhouse gas, is the primary byproduct of the combustion of fossil fuels. Since the beginning of the Industrial Revolution, human activities have had the overall impact of warming the planet’s climate. This warming effect has been driven by carbon dioxide and exacerbated by emissions of other greenhouse gases.

The accumulation of greenhouse gases in the atmosphere has resulted in an intensifying greenhouse effect on the climate. Human-induced augmentation of the greenhouse effect is of primary concern because continued emissions of greenhouse gases have the potential to warm the planet to levels that human civilization has never experienced. This is because the greenhouse effect causes the earth to warm to levels that have never been seen before in the history of human civilization. A change in climate like this could have far-reaching or unanticipated repercussions for the environment, society, and economy.

Transportation

  • Transportation is a significant contributor to global greenhouse gas emissions as it involves the use of cars, trucks, ships, and planes to transport people and goods.
  • The combustion of petroleum-based fuel in engines results in the emission of significant quantities of carbon dioxide into the atmosphere.
  • Passenger cars are responsible for 41% of carbon emissions, and on average, each passenger vehicle emits approximately 4.6 metric tons of carbon dioxide annually.
  • Trucks are the most significant contributors to air pollution on the road. Trucks are known to run almost continuously and primarily rely on diesel fuel. This is the reason why, despite comprising only 4 percent of all vehicles in the United States, they contribute to 23 percent of the total greenhouse gas emissions from transportation.

Electricity Generation

Electricity generation is the process of producing electrical energy from various sources such as fossil fuels, nuclear power, renewable sources like solar, wind, hydro, and geothermal energy. It involves the conversion of mechanical energy, chemical energy, or thermal energy into electrical energy. The generated electricity can then be distributed to homes, businesses, and industries for various purposes.

  • As of 2021, the majority of electricity used in the United States, almost 60 percent, is generated through the combustion of fossil fuels such as coal and natural gas. The electricity sector has heavily invested in dirty energy sources throughout history, which has resulted in it being responsible for approximately 25% of greenhouse gas emissions in the United States. These emissions include carbon dioxide, methane, and nitrous oxide.

However, history is currently undergoing a significant change. With the increasing affordability and ease of development of renewable energy sources such as wind and solar, utilities are increasingly relying on them. The proportion of clean and sustainable energy is increasing annually, leading to a reduction in pollutants that corresponds to this growth.

Although progress is being made, it is not happening at a sufficient pace. In order to prevent the severe consequences of climate change, which scientists warn will occur if the earth’s average temperature rises more than 1.5 degrees Celsius, it is imperative that we make every effort to accelerate the transition from fossil fuels to renewable sources of energy in the electricity industry.

Industry and manufacturing

  • In 2020, factories and facilities that manufacture our goods were accountable for 24 percent of greenhouse gas emissions in the United States. This highlights the significant role they play in contributing to environmental pollution.
  • The majority of industrial emissions are a result of the manufacturing of a limited number of carbon-intensive products, such as basic chemicals, iron and steel, cement and concrete, aluminum, glass, and paper.
  • In order to produce the necessary building blocks for our infrastructure and meet the demands of consumers for a wide range of products, manufacturers must consume significant amounts of energy.
  • Furthermore, older facilities that require efficiency upgrades often release these gases, as well as other harmful forms of air pollution, into the environment.

Improving technology and enforcing pollution regulations are effective ways to enhance efficiency and reduce the carbon footprint of the industrial sector. One alternative approach is to reconsider our attitudes towards consumption, especially with regards to plastics, recycling, and reuse. This way, we can reduce the need for producing excessive amounts of goods.

Major infrastructure projects heavily depend on industries such as cement manufacturing, which is responsible for 7 percent of annual global greenhouse gas emissions. Therefore, policy mandates should utilize the government’s purchasing power to promote cleaner alternatives and ensure that state and federal agencies procure sustainably produced materials for these projects. Accelerating the transition from fossil fuels to renewable energy sources would significantly contribute to reducing the environmental impact of this high-energy sector.

Agriculture

The relationship between soil and climate has been significantly impacted by the emergence of modern, industrialized agriculture. This has resulted in agriculture being responsible for 11 percent of greenhouse gas emissions in the United States in 2020. This industry is known for emitting significant quantities of nitrous oxide and methane, potent gases that are highly efficient at trapping heat.

Agriculture is responsible for almost 75% of the nitrous oxide present in our atmosphere due to the prevalent use of chemical fertilizers and certain crop-management practices that prioritize high yields over soil health. Large-scale industrialized livestock production remains a major contributor to atmospheric methane. This is due to the digestive processes of cattle and other ruminants, which emit methane.

Deforestation

The destruction of the world’s wetlands and the clearcutting of its forests are two more ways that we are increasing the amount of greenhouse gases in the atmosphere. Vegetation and soil have the ability to store carbon by retaining it either at the ground level or underground. By means of logging and other forms of development, we are removing or excavating vegetative biomass and thereby releasing all the carbon it has stored into the atmosphere.

To restore the planet’s carbon sinks, it is necessary to implement government policies that prioritize sustainable practices and encourage changes in consumer behavior.

Oil and gas development

The production and consumption of oil and gas result in emissions throughout every stage of the process. This includes not only when they are burned as fuel, but also from the moment we start drilling a hole in the ground to extract them. The development of fossil fuels is a significant contributor to the release of methane gas, which is known to escape from various oil and gas activities such as drilling, fracking, transportation, and refining.

Although methane is not as abundant as carbon dioxide, it is significantly more effective at trapping heat during the initial 20 years of its emission into the atmosphere. Methane leakage can occur even in abandoned and inoperative wells, which are commonly referred to as “orphaned” wells. There are over 3 million old and defunct wells located throughout the country. In 2018, these wells emitted over 280,000 metric tons of methane.

Buildings

It is not surprising that our buildings, whether they are residential or commercial, emit a significant amount of greenhouse gases considering the amount of time we spend inside them. In 2020, approximately 13 percent of the total emissions in the United States were attributed to activities such as heating, cooling, cooking, operating appliances, and managing other building-wide systems. To make matters worse, on average, approximately 30% of the energy consumed in buildings across the United States is wasted.

Energy efficiency is improving every day, enabling us to accomplish the same or better results with less energy consumption. To reduce emissions in the building sector and make it more affordable for people in all communities to heat, cool, and power their homes, we can implement the highest efficiency standards for new buildings and retrofit existing buildings with the latest technologies. This aligns with the top goal of the environmental justice movement.

Natural Causes of Climate Change

Human activity and the release of greenhouse gases are the primary causes of climate change however, numerous natural causes can also result in alterations to the climate system.

The climate can alternate between warming and cooling due to natural cycles. In addition, there exist natural factors that can cause changes in the climate, which are referred to as “forcings”. Scientific evidence indicates that although natural causes do contribute to climate change, they are not the primary cause.

There are several natural cycles that occur.

Milankovitch cycles refer to the slight changes in Earth’s path and the tilt of its axis as it orbits around the sun. Milankovitch cycles are alterations that impact the quantity of sunlight that reaches the Earth. Changes in temperature on Earth can be caused by this. Nevertheless, it is improbable that the climate changes we are currently witnessing are a result of these cycles, as they occur gradually over tens or hundreds of thousands of years.
The El Niño Southern Oscillation (ENSO) refers to a recurring climate pattern characterized by fluctuations in sea surface temperatures across the Pacific Ocean. During a ‘El Niño’ year, the Earth’s temperature experiences a rise, while in a ‘La Niña’ year, it undergoes a cooling trend. Although these patterns may have a short-term impact on the global temperature (lasting for months or years), they cannot account for the ongoing warming trend that we are currently experiencing.

Natural factors that can contribute to climate change include:

Solar Irridiance

The Earth’s temperature has been impacted by variations in solar irradiance, or the amount of energy emitted by the sun. So far, we have not observed any significant evidence that could alter our climate. An increase in solar energy would cause the Earth’s entire atmosphere to warm up, however, we are only able to observe the warming in the lower layer.

Volcanic Eruptions
Volcanic eruptions can have both positive and negative effects on our climate. Volcanic eruptions generate aerosol particles that have a cooling effect on Earth’s climate. However, they also emit carbon dioxide, which has a warming effect on the planet. Volcanoes are not the primary cause of global warming as they produce 50 times less carbon dioxide than humans do. Cooling, not warming, is the primary effect of volcanic eruptions.

Evidences of Climate change

Detecting climate change through individual experience is essentially impossible. In our day-to-day experiences, we encounter weather phenomena rather than climate patterns. The weather is subject to high localization and can change rapidly over a short period of days or weeks. On the other hand, the climate is regional and undergoes gradual changes over several decades.

Evidence on Global Air temperature

In order to obtain a clear understanding of climate change, it is necessary to refer to long-term records.

  • Direct evidence of a long-term warming trend in global air temperatures can be observed through measures of global air and ocean temperatures over many years.
  • The clear long-term warming trend is not contradicted by the fact that temperatures can vary dramatically from year to year. that global warming represents.
  • It’s important to remember that a brief period of cooler weather in one location does not negate the overall trend of global warming. Therefore, we should not be misled by short-term fluctuations in local weather patterns.
Long-term record of global average temperatures 1850-2021
[Image Source: https://extension.umd.edu]

Evidence on Increment of greenhouse gases

Since the onset of the Industrial Revolution, there has been a significant increase in the atmospheric concentrations of carbon dioxide, methane, and nitrous oxide. The concentration of carbon dioxide has been measured at the Mauna Loa Observatory in Hawaii since 1959. The average concentration of carbon dioxide was 316 parts per million (ppm) in the first year of data available.

Measurements of atmospheric CO2 since 1958
 [Image source: Royalsociety]

As of 2019, the concentration has increased to over 411 ppm. Similar rates of increase have been observed at various other stations across the globe. Since the preindustrial era, there has been a significant rise in the atmospheric concentration of CO2 by more than 40%, methane by over 150%, and nitrous oxide by approximately 20%. Since 1970, over 50% of the rise in CO2 levels has taken place. The warming of Earth is caused by increases in three gases, with CO2 having the greatest impact.

Frequently Asked Questions (FAQ)

Is climate change anthropogenic?

Indeed, climate change is caused by human activities. The rise in carbon dioxide levels in the atmosphere is responsible for climate change. While there are natural sources of carbon dioxide, scientific evidence overwhelmingly indicates that human activities are the primary source of greenhouse gases that contribute to rapid climate change.

What are the human-caused factors that contribute to climate change?

Human activities that contribute to the increase of greenhouse gases in the atmosphere are known as anthropogenic causes of climate change. These activities ultimately result in a rise in global temperatures. The burning of fossil fuels for industry, agriculture, and transportation is the primary human activity that emits greenhouse gases.

Video on Anthropogenic Causes of Climate Change

YouTube video


References

  • https://www.turito.com/learn/biology/anthropogenic-changes-grade-10
  • https://www.nrdc.org/stories/what-are-causes-climate-change#choices
  • https://www.metoffice.gov.uk/weather/climate-change/causes-of-climate-change
  • https://climate.ec.europa.eu/climate-change/causes-climate-change
  • Pachauri, R. K. et al. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. (IPCC, 2014).
  • Dr.A.D.Genio (2008, 09). Separating Natural from Anthropogenic Influences in Twentieth Century Climate Data Record.  http://www.giss.nasa.gov/research/briefs/delgenio_05/
  • https://concernusa.org/news/human-activities-that-cause-climate-change/

About Author

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Jyoti Bashyal

Jyoti Bashyal is a dedicated researcher specializing in computational chemistry, enzyme inhibition, in-vitro analysis, and sustainable chemistry. Alongside her scientific pursuits, she finds immense joy in creative writing, approaching her work with unwavering determination and a positive outlook. With an open mind and a thirst for knowledge, she embraces new opportunities to learn and grow, embodying the spirit of curiosity and continuous self-improvement.

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