Climate change is defined as a change in climate that persists over a sustained period of time. The World Meteorological Organization defines this time period as 30 years.
The Intergovernmental Panel on Climate Change (IPCC) in 2003 stated that “there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities”. These changes have led to the emergence of large-scale environmental hazards to human health, such as extreme weather, ozone depletion, loss of biodiversity, stresses to food-producing systems and the global spread of infectious diseases.
The Greenhouse Effect
The earth’s temperature is a balancing act between the energy entering the earth’s planet system and the energy leaving it. When the earth absorb energy coming from the sun there is increase in temperature while there is a drop in temperature when the energy is reflected back into space. Many factors influence the earth’s energy balance. These include changes in greenhouse effect, variation in sun’s energy reaching the earth and changes in reflectivity of the earth’s atmosphere and surface.
When sunlight reaches Earth’s surface, it can either be reflected back into space or absorbed by Earth. Once absorbed, the planet releases some of the energy back into the atmosphere as heat. Greenhouse gases (GHGs) like water vapor (H2O), carbon dioxide (CO2), and methane (CH4) absorb energy, slowing or preventing the loss of heat to space. In this way, GHGs act like a blanket, trapping heat and warming the earth thereby making Earth warmer than it would otherwise be. This process is commonly known as the “greenhouse effect”. Since the Industrial Revolution began around 1750, human activities have substantially increased the amount of greenhouse gases in the atmosphere. The increased amount of gases which absorb heat, has directly lead to more heat being retained in the atmosphere and thus an increase in global average surface
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