Global warming is primarily caused by an increase in the concentration of certain greenhouse gases in the Earth’s atmosphere. These gases trap heat from the sun, preventing it from escaping back into space, a process known as the greenhouse effect. The key factors contributing to global warming include:

1. Carbon Dioxide (CO₂) Emissions

• Burning of Fossil Fuels: The largest source of CO₂ is the burning of fossil fuels like coal, oil, and natural gas for electricity, transportation, and industrial processes.
• Deforestation: Trees absorb CO₂, and when forests are cut down for agriculture, urban development, or logging, less CO₂ is absorbed, and more is released into the atmosphere.

2. Methane (CH₄) Emissions

• Agriculture: Livestock, particularly cattle, produce methane during digestion (enteric fermentation). This is a potent greenhouse gas, about 25 times more effective at trapping heat than CO₂ over a 100-year period.
• Landfills: Organic waste in landfills breaks down anaerobically (without oxygen), releasing methane.
• Oil and Gas Extraction: Methane leaks can occur during the extraction, processing, and transport of natural gas.

3. Nitrous Oxide (N₂O)

• Agricultural Activities: The use of synthetic fertilizers and the management of animal manure contribute to the release of nitrous oxide, which is a potent greenhouse gas.
• Industrial Processes: Nitrous oxide is also released during certain industrial processes, like the production of chemicals.

4. Industrial and Synthetic Greenhouse Gases (F-gases)

• Hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆), and other synthetic gases are used in refrigeration, air conditioning, and various industrial processes. While they are less abundant than CO₂, they are far more effective at trapping heat.

5. Land Use Changes

• Urbanization: As cities grow, they replace forests, grasslands, and wetlands, reducing the natural carbon sinks and increasing the amount of heat-absorbing surfaces (like concrete).
• Agriculture: Large-scale farming, especially of crops like soy and palm oil, can contribute to both deforestation and the release of greenhouse gases from soil degradation and fertilizers.

6. Increase in Energy Use

• As the global population grows and economies expand, the demand for energy increases. Much of this energy is still produced from fossil fuels, which emit greenhouse gases.

7. Feedback Loops

• Melting Ice and Snow: As polar ice caps and glaciers melt due to warming, they reflect less sunlight and absorb more heat (albedo effect), which accelerates warming.
• Permafrost Thawing: Warming causes permafrost in the Arctic to thaw, releasing large amounts of methane and CO₂ that were previously trapped in the frozen soil.

8. Deforestation

• Reduction of Carbon Absorption: Forests play a key role in absorbing CO₂ from the atmosphere. When forests are cleared, not only is this carbon storage capacity reduced, but the act of burning or decomposing trees also releases more CO₂.

Effects

1. Rising Temperatures
   • Global Temperature Increase: The average global temperature has risen by about 1.2°C (2.2°F) since the late 19th century, and this trend is accelerating.
   • Heatwaves: More frequent and intense heatwaves are occurring, particularly in regions that have not traditionally experienced extreme heat.
2. Melting Ice and Rising Sea Levels
   • Polar Ice Melt: The Arctic is warming about twice as fast as the global average. This has led to the melting of glaciers, ice sheets, and permafrost.
   • Rising Sea Levels: Melting ice and the thermal expansion of seawater due to warming contribute to rising sea levels, which threaten coastal communities and ecosystems.
3. Changes in Weather Patterns
   • More Extreme Weather: Global warming contributes to more intense and frequent storms, including hurricanes, typhoons, and cyclones. These storms can cause widespread damage.
   • Shifts in Precipitation: Some regions experience more intense rainfall, leading to flooding, while others face prolonged droughts, particularly in already dry areas.
   • Shifting Seasons: Spring and fall are becoming shorter, and some areas are experiencing earlier springs and later winters, affecting agriculture and ecosystems.
4. Ocean Changes
   • Ocean Warming: Oceans are absorbing much of the excess heat from global warming, which leads to coral bleaching, the disruption of marine life, and changes in fish migration patterns.
   • Acidification: Increased CO₂ levels also lead to higher concentrations of carbonic acid in the oceans, which harms marine organisms like shellfish and corals.
5. Ecosystem Disruptions
   • Biodiversity Loss: Changes in temperature and weather patterns are forcing many species to migrate, and some are unable to adapt fast enough, leading to extinctions.
   • Habitat Destruction: Warming and changing precipitation patterns destroy important habitats, such as wetlands and rainforests, which are vital for biodiversity.
6. Impact on Agriculture
   • Crop Yields: Rising temperatures and unpredictable weather patterns can reduce crop yields and threaten food security, particularly in tropical and subtropical regions.
   • Water Availability: Changes in rainfall and the melting of glaciers (which provide water to rivers) threaten the availability of fresh water for irrigation and drinking.
7. Health Risks
   • Heat-Related Illnesses: More frequent heatwaves increase the risk of heatstroke, dehydration, and other heat-related illnesses.
   • Vector-Borne Diseases: Warmer temperatures allow disease-carrying insects, like mosquitoes, to expand their range, potentially spreading diseases like malaria, dengue, and Zika virus.
   • Air Quality: Warming can worsen air pollution, leading to respiratory problems like asthma and bronchitis.
8. Social and Economic Impacts
   • Displacement: Rising sea levels and extreme weather events can force communities to migrate, creating “climate refugees” and contributing to social and political instability.
   • Economic Costs: Extreme weather events, such as hurricanes, wildfires, and droughts, result in billions of dollars in damage, impacting infrastructure, economies, and insurance industries.

Addressing Global Warming

Mitigating global warming requires reducing greenhouse gas emissions through:

• Transitioning to renewable energy sources (e.g., wind, solar, geothermal).
• Improving energy efficiency in transportation, industry, and homes.
• Adopting carbon capture technologies to remove CO₂ from the atmosphere.
• Promoting sustainable agriculture and forestry to sequester carbon and reduce land-use emissions.
• International agreements like the Paris Agreement, which aims to limit global temperature rise to below 2°C, with efforts to keep it below 1.5°C.