About our mother Earth?

Question

i). Why do threshold and feedback mechanisms make global warming so scary? ii. If we warm the planet, can we cool it again? iii. What changes could occur in the hydrosphere if the Earth's global temperature increased by 5 degrees C (or 40 degrees F)?

Answer 1

Our planet's temp. is increasing slowly but steadily due to global warming.  This is the result of an increase of the amount of CO2 in our atmosphere, due mostly to the release of CFC's into the atmosphere (have been banned in the U.S. but not worldwide), to car emissions, and in smaller part to deforestation (plants use up CO2 as they undergo the process of photsynthesis).  If we continue to warm our planet, the hydrosphere will, of course, warm up as well, resulting in the melting of the glaciers and polar ice caps (which is already occurring).  This means higher sea levels (flooding along coastlines and the death to coral reef systems, which rely on algae for energy and therefore cannot survive far below water where the algae cannot receive enough sunlight for photosynthesis).  Coral reefs are home to and feeding grounds for much sea life, so this affects them as well.  CO2 has a residence time of 150 years (will stay in the atmosphere that long), so if we completely halt the excess emissions of it, it would take at least 150 years for the planet to down to its pre-global warming temp.