2. What is global warming
Global warming is the raise in the temperature of
the atmosphere and the oceans. The
temperature of the planet has increased about
0.6 degrees Celsius since late 19th century
3. Causes
Global warming is caused by either
natural procedures (e.g. solar activity,
release of greenhouse gases from
volcanoes) or human activities (e.g.
fumes , electric power).
4. How that happens
Part of the stratosphere is the ozone layer
which functions like a greenhouse. As it
allows a part of the solar rays to reach the
Earth, there can be life and
evolution,however it prevents some ultraviolet rays to reach the Earth. Due to the
harmful gases that are produced by
human activity, the ozone layer gets
thinner and so the ultra-violet rays ,which
were once stopped, can get through it.
5. The gases which come from industrial activity and
from cars (fumes), create in the lower part of the
atmosphere a thick layer which doesn’t allow the
rays to return to space, increasing the
temperature of the Earth and causing changes in
the climate .