How much hotter than now did the last global warming get?

Question

And how long did it last?

Answer 1

Well this depends on what you mean by "the last global warming." We don't know of any previous man-made global warming, and it's difficult to compare man-made global warming  with natural weather cycles and periods of warming or cooling. Earth's atmosphere has often been effected greatly by the species it harbors; for example, strictly speaking, Earth does not 'naturally' have an oxygen atmosphere. After its formation its atmosphere was made up largely of chemicals that would be toxic to us; only the proliferation of plant life has created free oxygen and made the Earth livable for us today.

That being said, there are a LOT of known instances of temperature fluctuation, ranging from almost imperceptibly mild to catastrophic. There have been several 'mini warmings' or 'mini coolings' of just a few degrees that lasted just a few years, some of which have been attributed to cycles of the sun and some of which have been attributed to volcanic occurrences that spewed lots of ash in the air to block sunlight or greenhouse gases to trap heat. Volcanoes are nature's source of greenhouse gases; the most terrifying case of greenhouse gas-related global warming resulted in the Permian extinction; the planet's temperatures rose 60% over the course of a few million years, and 90% of all life on Earth died off. That is a sobering reminder for us, since we have thus far made only a tiny change in the Earth's climate, but the change has happened frighteningly fast on a geologic time scale. It is doubtful that any affect we have will reach Permian levels, but if trends in the increase of greenhouse gas pollution continue unabated, we could definitely over the course of centuries do some serious damage to the climate around which our civilizations were built.

Answer 2

The last global warming was when the earth was covered with volcano lava

Answer 3

Global warming is not uncommon in the last 11,500 years. There has been quite a few warm periods that were warmer than the present. Here are a couple of graphs from the Vostok ice cores:

http://www.socialtext.net/data/workspace...

http://www.socialtext.net/data/workspace...

Answer 4

It wasn't. There was a warming period much warmer than the current one about 300,000 years ago though. But that has nothing to do with the current one. The question for the current warming is "what is the cause?" or "is it natural?".

Answer 5

There wasn't a "last one".

Global warming is a popular name for the recent warming of the climate, caused mostly by man.  That has NEVER happened before.

The temperatures are warmer now than they've been for over a thousand years.  Proof here:

http://dels.nas.edu/globalchange/

Answer 6

global warming is a constant thing....