Global warming refers to the long-term heating of Earth's climate system observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth's atmosphere. The term is frequently used interchangeably with the term climate change, though the latter refers to both human- and naturally produced warming and the effects it has on our planet.
Climate change is a broader term that encompasses changes in long-term average weather patterns that have come to define Earth's local, regional and global climates. These changes include not just surface temperature increases but also changes in precipitation, sea level rise, and more frequent or intense extreme weather events.
Trends of Global Warming and Climate Change
Scientific data from various sources, including temperature records, glacial retreat, sea-level rise measurements, and changes in extreme weather events, show a clear warming trend. The Intergovernmental Panel on Climate Change (IPCC) reports indicate that each of the last four decades has been successively warmer than any decade that preceded it since 1850. Global average surface temperature has increased by approximately 1.1 °C since the late 19th century.
- Rising Global Temperatures: Long-term temperature records demonstrate a significant upward trend in global average temperatures.
- Ocean Warming: The oceans have absorbed most of the excess heat, leading to ocean warming, which affects marine ecosystems and contributes to thermal expansion.
- Shrinking Ice Sheets and Glaciers: Ice sheets in Greenland and Antarctica are losing mass, and glaciers are retreating almost worldwide.
- Decreased Snow Cover: Snow cover in the Northern Hemisphere has decreased over the last five decades.
- Sea Level Rise: Global mean sea level has been steadily rising due to thermal expansion of water and melting ice.
- Extreme Weather Events: There's an observed increase in the frequency and intensity of extreme weather events such as heatwaves, heavy precipitation, droughts, and tropical cyclones.
Drivers of Global Warming and Greenhouse Gases (GHGs)
The primary drivers of global warming are natural processes and, more significantly, human activities. While natural factors like volcanic eruptions and solar radiation changes can influence climate, the rapid warming observed over the past century is predominantly attributed to anthropogenic (human-caused) emissions of greenhouse gases.
The Greenhouse Effect
The greenhouse effect is a natural process that warms the Earth's surface and atmosphere. Certain gases in the atmosphere trap heat, preventing it from escaping into space, thereby keeping the planet warm enough to sustain life. However, human activities are intensifying this natural effect by releasing additional GHGs, leading to enhanced warming.
Potential of Different Greenhouse Gases (GHGs)
Greenhouse gases differ in their ability to absorb heat and their persistence in the atmosphere. The