Current Temperatures in Context

Start with the following video
from Professor Bob Carter:

Hat tip to Derek Tipp for the video.
Click here to view parts 2, 3 and 4 of that video series.

Note: All information presented in this post is fully cited.
Much of that information comes from directly cited and published peer reviewed science.

If you think current global mean temperatures are unprecedented in any way, think again.

Quoting this source:

"During most of the last 1 billion years the earth had no permanent ice
[as it cycled (NATURALLY) in and out of multi-million year Ice Ages]"

The only reason there is any year round ice anywhere
on this planet is because we are currently in one of the
three coldest Ice Ages in the last 600 million years:

NOTE: Unfortunately, the term “Ice Age” is often used (incorrectly, even by scientists) to refer to a glacial period. Ice Ages last tens to hundreds of millions of years. Glacial periods last tens of thousands of years. Glacial periods only occur during Ice Ages.

The current Ice Age cycle began 30 million years ago.

Some 4 to 5 million years ago, the world cooled enough
for cyclical glacial advances and retreats to begin (again).

The last glacial maximum occurred about 18,000 to 20,000 years ago.
In general, the glaciers have been melting ever since then!

Within the larger context of an ongoing multi-million year Ice Age,
we are currently experiencing one of about 100 perfectly natural,
perfectly normal interglacial warming periods known to have
occurred “in the last 2.5 million years”.

Click here for a discussion of the
impact of Man Made CO2.

Sources for the above chart:

Temperature - The Paleomap Project by Dr. C.R. Scotese,
a PhD geologist at the University of Texas at Arlington.

CO2 - R.A. Berner, 2001 (GEOCARB III), as published in
the American Journal of Science, Vol. 301, February 2001, P.182-204.
The Geocarb III data are found in this file downloaded from this NOAA page.

In the context of the last 10,000 years, there is nothing
even remotely unusual about current temperatures.

41 Years of Temperature Data at Vostok
Click the image to enlarge:

As the next three charts demonstrate, the only unusual thing about the
current interglacial warming period is that it has not yet produced
temperatures as warm as ANY of the previous 4 interglacial warming periods.

The historical temperature proxies in the next three charts are taken directly from peer reviewed data collected from the Vostok Ice Cores.

Note: The 2001 IPCC Third Assessment Report, in a discussion of proxy indicators for temperature, notes that ice core temperature proxies are a "high resolution" proxy allowing temperature determinations down to the "annual or even seasonal" level.

10 Thousand Years of Temperature Data at Vostok
Click the image to enlarge:

140 Thousand Years of Temperature Data at Vostok
Click the image to enlarge:

423 Thousand Years of Temperature Data at Vostok
Click the image to enlarge:

The data used in the above charts are found in:

Current Mean Temperature at Vostok (-55.3C):
British Antarctic Survey - National Environmental Research Council

41 years of recent temperatures at Vostok:
British Antarctic Survey - National Environmental Research Council

Ice Core Data to more than 420,000 years ago:
this file downloaded from this page (Petit et al. 1999 to 3310m).

To verify that the reference point for the Vostok Ice Core study is -55.5C,
click here, then click on “click to view more”.

The Holocene is the name for the current interglacial warming period.

The interglacial warming period which immediately preceded
the Holocene is known as the Eemian.

Some 8,000 years ago, the temperature was 2.06C warmer than
the mean temperature at Vostok at the time of the study (1999)
and 1.86C warmer than the present mean of -55.3C.

But, we can see from the second chart that there were many, MANY times
in the last 10,000 years when the climate was apparently warmer than today!

In this file, ANY number in the rightmost column greater than 0.2 indicates
a temperature which is higher than the current mean.

We can see that the temperature at Vostok was higher
than the current mean as recently as 190 years ago!

The highest known temperature during the Eemian was 3.23C higher than
the mean temperature from 1999 and 3.21C higher than the present mean.

Click here to learn more.