Your Daily Facts about Global Warming
# The Earth was formed about 4,540,000,000 years ago.# In the beginning, the Earth's atmosphere contained very little oxygen (less than 1% oxygen pressure).# Early plants started to develop more than 2 billion years ago, probably about 2,700,000,000.# Through photosynthesis, plants uptake carbon dioxide into the biosphere as organic matter, and release oxygen as a byproduct.# Through geologic time, oxygen accumulated gradually in the atmosphere, reaching a value of about 21% of atmospheric gases