The Present Day
Currently, we are in an icehouse climate state. About 34 million years ago, we started our icehouse state, as ice sheets began to form in Antarctica; the ice sheets in the Arctic didn’t start forming until 2 million years ago. Some processes that may have led to our current icehouse may be connected to the development of the Himalayan Mountains and the opening of the Drake Passage between South America and Antarctica. Scientists have been attempting to compare the past transitions between icehouse and greenhouse, and vice versa to understand where our planet is now heading.
Without the human influence on the greenhouse gas concentration we would be heading back towards a glacial period. Predicted changes in orbital forcing suggest that in absence of human-made global warming the next glacial period would begin at least 50,000 years from now (see Milankovitch cycles).
But due to the ongoing anthopogenic climate change we are heading now towards a greenhouse Earth period. Permanent ice is actually a rare phenomenon in the history of the Earth, occurring only during the 20% of the time that the planet is under an icehouse effect.
Read more about this topic: Greenhouse And Icehouse Earth
Famous quotes containing the words present and/or day:
“I will venture to affirm, that the three seasons wherein our corn has miscarried did no more contribute to our present misery, than one spoonful of water thrown upon a rat already drowned would contribute to his death; and that the present plentiful harvest, although it should be followed by a dozen ensuing, would no more restore us, than it would the rat aforesaid to put him near the fire, which might indeed warm his fur-coat, but never bring him back to life.”
—Jonathan Swift (1667–1745)
“To get time for civic work, for exercise, for neighborhood projects, reading or meditation, or just plain time to themselves, mothers need to hold out against the fairly recent but surprisingly entrenched myth that “good mothers” are constantly with their children. They will have to speak out at last about the demoralizing effect of spending day after day with small children, no matter how much they love them.”
—Wendy Coppedge Sanford. Ourselves and Our Children, by Boston Women’s Health Book Collective, introduction (1978)