The concept of global warming and its causes

Global warming refers to the rise in the Earth's average temperature over time, with an increase of approximately 1°C observed over the past century. The period since 1980 has recorded some of the highest temperatures in history, highlighting the ongoing trend of climate change.

Primary causes of global warming

• Increased fossil fuel use - Since the Industrial Revolution, the demand for energy has surged for industrial and domestic purposes. This has led to greater burning of fossil fuels such as coal and oil to meet energy needs.
• Release of greenhouse gases - Burning fossil fuels emits significant amounts of carbon dioxide (CO₂) and methane into the atmosphere. These gases are key contributors to the warming of the planet by trapping heat.

The greenhouse effect and its role in temperature rise

The Earth functions much like a greenhouse, where certain atmospheric gases trap heat, preventing it from escaping back into space. This natural process is essential for maintaining life but becomes problematic when intensified by human activities.

Mechanism of the greenhouse effect

• Incoming solar energy - Energy from the sun reaches the Earth as light, passing through the atmosphere and warming the surface.
• Heat retention - As the Earth's surface radiates this energy back as heat, greenhouse gases like CO₂ in the atmosphere trap it, preventing its escape into space.
• Temperature increase - The accumulation of these gases enhances the greenhouse effect, leading to a rise in global temperatures over time.

The consequences of global warming on sea levels and weather

Global warming has far-reaching effects on the environment, notably impacting sea levels and weather patterns. These changes pose significant risks to ecosystems and human settlements worldwide.

Impacts on sea levels

• Melting ice - Rising temperatures cause ice sheets and glaciers to melt, adding more water to the oceans.
• Rising sea levels - Over the last century, sea levels have increased by about 10-20 cm, with projections estimating a further rise of 0.8-2 metres in the next 100 years.
• Flooding risks - Low-lying regions, such as parts of eastern England, major river deltas like the Nile and Ganges, and numerous global cities, face heightened threats of flooding due to rising seas.

Changes in weather patterns

• Extreme weather events - Global warming contributes to more frequent and intense weather phenomena, including storms and droughts.
• Climate shifts - Long-term changes in climate are possible, such as the northward expansion of arid regions like the Sahara into southern Europe, or warmer conditions in tundra areas making them suitable for agriculture.

Challenges in reducing greenhouse gas emissions

Addressing global warming requires a reduction in greenhouse gas emissions, but this goal faces significant obstacles due to economic, social, and political factors across different regions.

Barriers to emission reduction

• Commitment in developed regions - Countries in Britain and Europe, major consumers of fossil fuels, have pledged to cut emissions to combat climate change.
• Resistance from developing countries - Some less economically developed countries (LEDCs) are reluctant to reduce emissions as it could hinder their economic growth and development pace.
• Concerns of oil-producing nations - States in the Gulf region oppose cuts due to potential declines in income from oil exports, a key component of their economies.
• Hesitation in industrialised nations - Certain more economically developed countries (MEDCs) resist emission reductions, fearing a drop in living standards.