It is easy to confuse the meanings of weather and climate. They are however not the same. While weather is our daily experience with sunshine, rain, wind, snow, hail, or sleet for instance, climate encompasses weather events over a long period of time, including a range of weather events that occur seasonally (George, 2010).
The United Nations Framework Convention on Climate Change (UNFCCC) defines climate change as "a change in climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable periods of time" (UNFCCC,1992). Let's break this down shall we? Climate scientists associate a greater percentage of climate change causes in recent years to anthropogenic activities. However, there are other natural causes of climate change which this blog attempts to elucidate on. The first natural cause of climate change is plate tectonics.
Plate tectonics is a scientific theory that postulates that the earth's lithosphere consists of tectonic plates which slowly move by mere inches annually. Their movement are against, alongside, or away from each other, causing earthquakes, volcanic eruptions, mountain building, and oceanic trench formation. Let’s look at how volcanic eruptions could alter our climate. It is important to note that a portion of incoming solar radiation from the sun is reflected back to space, a portion absorbed by clouds and other particulates, a portion reaching the earth surface. The portion that hits the earth’s surface is re-radiated from the earth surface. Here also a portion is absorbed by greenhouse gases which regulate temperature here on earth, while a portion is sent back to space. Our planet would be downright freezing without naturally occurring greenhouse gases such as carbon dioxide (The Climate Reality Project, 2019).
During a volcanic eruption, particulates (dust, rock, and ash) are released into the atmosphere, impeding the penetration of solar energy from sufficiently reaching plant and animals. This phenomenon would cause the earth to cool rapidly defying plant and animal temperature needs. Frequent massive eruptions could with time alter the climate. Perhaps the most recent cataclysmic volcanic eruption remains Mount Pinatubo's eruption which happened in June 1991. According to the United States Geological Survey (USGS), nearly 20 million tons of sulfur dioxide were injected into the stratosphere in Pinatubo's 1991 eruptions, and dispersal of this gas cloud around the world caused global temperatures to drop temporarily (1991 through 1993) by about 1°F (0.5°C).
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