20,000 years ago there was 300-500 feet of ice over Boston and New York. The coastlines used to extend out to the continental shelf. There used to be a landbridge to Russia, likely how humans migrated to the Americas from Asia.
If you go further back there used to be an inland sea in the middle of the United States.
Global warming and cooling has been going on for billions of years and will continue to do so until the sun eventually turns the Earth into a piece of charcoal when it turns into a red giant star.
Another great way to put it. If the history of the planet is The Empire State Building, human history is represented by a postage stamp stuck on the building. Human influence on the global planet is still marginal at best.
also, FYI to gore
NYC and Boston was under a glacial ice sheet 300 feet thick 50,000 years ago.
http://www.nycgovparks.org/sub_your_park/historical_signs/hs_historical_sign.php?id=12325
GLACIERS IN NEW YORK CITY - INWOOD HILL PARK
Inwood Hill Park
Inwood Hill Park now contains the last natural forest and salt marsh in Manhattan, but the land once lay beneath a huge sheet of moving ice. The most recent ice age began about 1.5 million years ago, at the advent of the Pleistocene Era, and lasted until around 10,000 years ago. At the beginning of the Pleistocene, global temperatures dropped dramatically. Huge masses of snow and ice formed in the Arctic, sometimes as thick as two miles. The tremendous weight and pressure of the ice sheet caused the snow underneath to solidify, providing a surface on which glaciers could travel. During the Pleistocene Epoch, there were four glacial advances - the most recent being the Wisconsin ice sheet, which had the greatest impact on the land beneath New York City.
The Wisconsin ice sheet began its southward journey from the Arctic around 100,000 years ago, reaching what is now New York roughly 50,000 years later. By this time, it had lost some of its bulk, although it was still 300 feet thick and stretched from Massachusetts to Montana. As the glacier moved through this region, it deepened the bed of the Hudson River, carved out such geologic features as the Great Lakes and the Finger Lakes basins, and left its mark on the Adirondack mountains. The glacier also deposited tons of gravel and pebbles, moving boulders from the Palisades to Central Park, plowing up topsoil, leveling the earth, and filling in depressed areas with glacial till. This glacial activity sculpted the characteristic terrain of Inwood Hill Park, with its dramatic caves, valleys, and ridges.
http://www.geotimes.org/feb06/Travels0206.html
What the exhibits won't tell you is that the Puritans settled at the base of Beacon Hill because it is made of stratified sand from a glacial outwash channel. The layered deposits allow groundwater to flow and pool at the base, where the settlers could collect it for drinking water. King's Chapel is built of 450-million-year-old Quincy Granite, which formed when an island the size of Japan collided with the island that carried Boston-to-be, long before it was part of North America. Bunker Hill is a drumlin: a streamlined hill of compacted glacial debris, shaped by a retreating glacier.
From the Prudential Building, most of what you see below you is glacial debris. The Wisconsin Ice Sheet, the last glacier to blanket New England, retreated about 16,000 years ago, leaving in its wake boulders and gravel it had carried down from the North, and forming Cape Cod and the islands of Martha's Vineyard and Nantucket. Around Boston, the glacier left dozens of drumlins and "kettles" (bowl-shaped hollows created when glaciers melt), which form most of the ponds of the city's "Emerald Necklace," one of the oldest series of parks and parkways in the United States that are worth a visit unto themselves