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Global warming - How Do We Know It Happens?
Credit to OTOP
Global warming is something we know for a fact. Yes, but how do we know it? Or better – how do scientists who inform us about it know it?
Firstly, temperatures are taken and compared over a period of at least several decades. For example, they are measured below (down to half mile deep) and above the surface of oceans. Warmer water changes marine life, which may affect lives of fishermen. Warmer air above the ocean means that water evaporates at a faster rate and precipitation tends to get heavier. The temperature of the surface of water also rises, resulting in frequent cyclones and hurricanes. The increase in average temperatures above the land leads to heat waves and droughts becoming more common. We live in the lowest layer of the atmosphere, which has also got warmer. It is where greenhouse gases accumulate, trapping the heat that comes from the Earth.
Global warming can also be observed by comparing the current state of glaciers with old paintings and photographs. They are definitely melting. Snow that lingers high in the mountains long after the winter is gone covers smaller areas than before and disappears faster. As a consequence, the environment receives less water. Arctic sea ice also shrinks and becomes thinner. New shipping routes can be established and oil resources, which have so far been inaccessible, exploited; this will, however, inevitably upset the balance of nature.
These phenomena affect birds as well. Scientists have recently observed that emperor penguins, which live in the Antarctic and spend breeding season on thin sea ice where they can easily access water, have to relocate to floating ice shelves, climbing their steep walls which can be as much as 100 ft high. They have to do that because sea ice forms even one month later than before.