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The First Solar Cell
The first solar cell was created by American inventor Charles Fritts. It was made from selenium, a gray crystalline nonmetal with semi-conductive properties. He created this solar cell to hopefully compete with Thomas Edison's coal-fired power plants but deemed unsuccessful since his cells weren't very efficient at converting solar energy to electricity, at 1% efficiency. This invention influenced the creation of the first practical solar cell later on. -
Proof that temperatures are rising globally
Backtracking a bit, in 1896, a Swedish scientist named Svante Arrhenius first predicted that CO2 levels in the atmosphere could alter the surface temperature through the greenhouse effect. But in 1938, a person named Guy Callendar proved Arrhenius' thesis as he connected CO2 increases in the atmosphere to global warming. Fast forward today, CO2 levels are now higher than ever as seen in Earth's documented history. -
The First Practical Solar Cell is Born
Instead of using selenium, silicon was used to produce these solar cells, and it proved to be efficient, as these cells were capable of converting up to 6% of solar energy into electricity, as opposed to earlier concepts converting only less than 1%. This was a huge breakthrough for solar technologies. -
The Ozone Hole Discovery
This hole in the ozone layer, which protects us from solar radiation, was discovered by scientists from the British Antarctic Survey (BAS). After discovering that CFCs were the main culprit of the depletion, several politicians and scientists took action to control or completely ban the use of these CFCs and other chemicals. This event shows how sensitive Earth is to human activities. -
Paris Agreement
The Paris Agreement is a legally binding international treaty on climate change and was signed on April 22nd, 2016 by 175 parties. The goal of this treaty is to slow down the rise of global temperatures, keeping rising levels below 2 degrees celsius.