Global Warming
From Halbeeg, the open encyclopedia · Af-Soomaali
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Global warming is the sustained increase in average temperature of the atmosphere and oceans of the Earth over a long period. Temperature measurements are gathered from stations on land, ships, ocean buoys, and satellites. The method is to compare annual temperature against a chosen reference period, for example the pre-industrial centuries.
The term is often used interchangeably with "climate change," but the two are not the same. Global warming refers specifically to the rise in temperature; climate change encompasses changes in rainfall, wind patterns, sea level, and extreme events.
The greenhouse effect mechanism
Sunlight reaches the Earth. The Earth absorbs part of it and then reflects back infrared radiation. Certain gases in the atmosphere—such as carbon dioxide (CO2), methane, and water vapor—trap some of this radiation and redirect it back to the Earth. This is known as the greenhouse effect. As the concentration of these gases increases, the trapped heat increases.
Sources of gas increase
The largest source of rising CO2 is the burning of fossil fuels—coal, oil, and natural gas—for energy, industry, and transport. Deforestation also contributes, as it reduces the capacity of trees to absorb CO2, as do cement factories. Methane comes from livestock, rice paddies, waste, and gas extraction.
Observed effects
Documented changes include Arctic sea ice shrinkage, melting of mountain glaciers, rising sea level (from water thermal expansion and melting ice), and shifts in rainfall patterns. Intense heat waves and droughts are often linked to these changes. The Horn of Africa is affected by shifts in the Gu (spring) and Deyr (autumn) rainfall seasons, with consequences for pastoralism and agriculture.
Policy responses
Two types of action exist: mitigation and adaptation. Mitigation relies on renewable energy, improved energy efficiency, and forest conservation. Adaptation involves building sea defenses, developing drought-resistant crops, and establishing early warning systems. International agreements signed by states set mitigation targets.