While the earth’s atmosphere allows sunlight to warm up its surface, certain gases including water
vapor, carbon dioxide, and methane act as a barrier against the heat radiating from the earth’s
surface, creating ‘greenhouse effect.’ This is a natural process that allows the earth to have a
properly warm temperature for living. However, the addition of these gases by human activities
worsens the effect, resulting in an increase of 0.6C in the earth’s average temperature within the
last few hundred years (Fig. 5).
CO2 plays major role on this ‘global warming,’ currently known as ‘climate change,’ as it accounts
for 55% of the effect. Meanwhile, 70% of human CO2 emission derives from the fossil fuel
combustion to generate energy. Therefore, the expansion of industry, the increase in global CO2
concentration, and the rising temperature around the world are closely related. Although the
world’s average temperature in the last Ice Age, 18 millennia ago, is only 5C higher than it is
today, it is predicted that a sharp rise of 2.5-4.5C will take place within a few decades.
The effect is aggravated by the discovery of an ‘ozone hole’ over Antarctica caused by
chlorofluorocarbon (CFCs) in 1986. Although it leads to international agreements to reduce CFCs
production, damages may have already been done. It may take centuries for the world to recover.
Together with climate change, the ozone hole could create a huge impact on the environment
within our generation. As imagined in many futuristic movies, seawater could rise by the melting of
polar ice. Ecosystems such as forest systems, coastal wetlands, and agricultural output would all
be affected.