What are the human causes of climate change?

Introduction

Human activities have significantly increased the concentration of greenhouse gases in the Earth’s atmosphere, leading to the enhanced greenhouse effect and global warming. This page explores how industries, transport, energy production, and farming contribute to greenhouse gas emissions, specifically carbon dioxide (CO2) and methane (CH4).

The Greenhouse Effect

The greenhouse effect is a natural process where certain gases in the Earth’s atmosphere trap heat, keeping the planet warm enough to support life. These gases, including carbon dioxide, methane, water vapour, and nitrous oxide, allow sunlight to enter the atmosphere but prevent some of the heat from escaping back into space.

The Enhanced Greenhouse Effect

The enhanced greenhouse effect refers to the increase in Earth’s average temperature due to higher concentrations of greenhouse gases resulting from human activities. This leads to global warming, which causes changes in weather patterns, sea level rise, and various other environmental impacts.

Human Activities Producing Greenhouse Gases

1. Industry
   • Carbon Dioxide (CO2): Industrial activities, such as manufacturing and chemical production, release significant amounts of CO2. The burning of fossil fuels (coal, oil, and natural gas) in factories for energy and raw material processing is a major source of emissions.
   • Methane (CH4): Some industrial processes, including oil refining and the production of certain chemicals, release methane.
2. Transport
   • Carbon Dioxide (CO2): Transport is a major source of CO2 emissions, primarily from the combustion of petrol and diesel in cars, trucks, ships, and aeroplanes. The rapid increase in vehicle numbers and air travel has led to higher emissions.
   • Methane (CH4): Methane emissions from transport are less significant but can occur from fuel extraction, production, and distribution processes, particularly with natural gas vehicles.
3. Energy Production
   • Carbon Dioxide (CO2): Energy production is the largest source of CO2 emissions. The burning of fossil fuels for electricity and heat generation releases vast amounts of CO2. Coal-fired power plants are particularly notorious for their high emissions.
   • Methane (CH4): Methane is emitted during the extraction, processing, and distribution of fossil fuels, especially natural gas. Leaks from natural gas infrastructure and flaring of gas during oil extraction contribute to methane emissions.
4. Farming
   • Methane (CH4): Agriculture is a significant source of methane emissions, primarily from enteric fermentation in ruminant animals like cows and sheep. Methane is also produced from the decomposition of organic matter in rice paddies and manure management.
   • Carbon Dioxide (CO2): Farming practices contribute to CO2 emissions through the use of fossil fuel-powered machinery, deforestation for agricultural expansion, and soil management practices that release carbon stored in the soil.

The Impact of Greenhouse Gases

• Carbon Dioxide (CO2): CO2 is the most abundant greenhouse gas emitted by human activities. It has a long atmospheric lifetime, meaning it accumulates over time, leading to prolonged warming effects. Increased CO2 levels enhance the greenhouse effect, trapping more heat in the atmosphere and raising global temperatures.
• Methane (CH4): Although methane is present in smaller quantities compared to CO2, it is much more effective at trapping heat in the short term. Over a 20-year period, methane has about 84-87 times more warming potential than CO2. Therefore, even small increases in methane emissions can have significant impacts on global warming.