Can someone point me in the direction of a statistical study based on the last 10 or more climate cycles...?

Question

that show we are currently experiencing a statistically significant increase in global temperatures in this climate cycle?

I am asking this because I don't believe data from the last 150 years or so is a sufficient time period to show that man-kind has increased the temperature versus natural increases.

I have looked for a few of these studies but was unable to find what I was looking for.

Thanks,

Answer 1

no one was alive to take the statistics down for 9 1/2 of the last 10 cycles...

And for 90% of the last half cycle... no one tried to take down the statistics.

So the data you want does not exist.

What exists is estimations based on very slim amounts of information.

Answer 2

The physical evidence from around the world of what grew where it doesn't grow now and what land and water routes were traveled that are now iced over indicates that it's been warmer for two, and almost as warm as, for at least one, multi-century periods just since the last Ice Age.

The reasons are not 100% understood - in fact the last warm period isn't understood at all.

Before climate change became a political issue this was the unanimous consensus among climatologists. Nobody questioned that the MWP happened or was warmer.

Some proxy models show this period.

Some don't.

The ones that don't are all variations of Mann's model the results of which were published by the UN IPCC in 1998.

Mann's model covers up to the 20th century. The UN superimposed the model-generated estimates from AD 1000 to AD 1900 - a downward slope - upon the measured surface temperatures from 1900-1998 - a sharp upward slope - and called it the Hockey Stick.

But when you update Mann's model with the proxy data from the second half of the 20th century, the sharp warming isn't picked up.....

.....which means the fact that it also doesn't show the MWP as being warmer doesn't mean it wasn't - - it could just be that the model sometimes doesn't pick it up.

But the Hockey Stick is the UN's story and they're sticking to it.

Answer 3

EPICA, GRIP, and GISP are projects that determine past temperature using ice core samples. Here is a link to wiki's report on it.

The data is sufficient to determine the climate at the time. As the snow that form the ice falls, air is trapped. This air is analyzed for various isotopes and other chemical components.
Here is an explanation from wiki:
"Because water molecules containing heavier isotopes exhibit a lower vapor pressure, when the temperature falls, the heavier water molecules will condense faster than the normal water molecules. The relative concentrations of the heavier isotopes in the condensate indicate the temperature of condensation at the time, allowing for ice cores to be used in global temperature reconstruction. In addition to the isotope concentration, the air bubbles trapped in the ice cores allow for measurement of the atmospheric concentrations of trace gases, including greenhouse gases carbon dioxide, methane, and nitrous oxide."

Answer 4

Well, long ago, the temperatures were much higher than they are even today, and that was because the tilt of the earth changed, or something like that, not because of greenhouse gases.

Answer 5

Watch "An Inconvinient Truth". I think that will have the info you're looking for. Very informative movie.

Answer 6

Yes I believe so !!!