the Eocene
Alexander Cockburn:
It’s a notorious inconvenience for the Greenhousers that data also =
show CO2 concentrations from the Eocene period, 20 million years =
before Henry Ford trundled out his first Model T, 300 to 400 =
percent higher than current concentrations.
Wikipedia http://en.wikipedia.org/wiki/Eocene#Climate:
Marking the start of the Eocene, the planet heated up in one of the =
most rapid (in geologic terms) and extreme global warming events =
recorded in geologic history, called the Paleocene-Eocene Thermal =
Maximum or Initial Eocene Thermal Maximum (PETM or IETM). This was =
an episode of rapid and intense warming (up to 7=B0C at high =
latitudes) that lasted less than 100,000 years [1]. The Thermal =
Maximum provoked a sharp extinction event that distinguishes Eocene =
fauna from the ecosystems of the Paleocene.
The Eocene global climate was perhaps the most homogeneous of the =
Cenozoic; the temperature gradient from equator to pole was only =
half that of today’s, and deep ocean currents were exceptionally =
warm.[2] The polar regions were much warmer than today, perhaps as =
mild as the modern-day Pacific Northwest; temperate forests =
extended right to the poles, while rainy tropical climates extended =
as far north as 45 degrees latitude. The difference was greatest in =
the temperate latitudes; the climate in the tropics however, was =
probably similar to today’s.(Stanley, 508)