Tree-rings prove climate was WARMER in Roman and Medieval times than it is now.

[ALS]

The world has been cooling for 2,000 years

Rob Waugh - DAILYMAIL - July 11, 2012

Rings in fossilised pine trees have proven that the world was much warmer than previously thought - and the earth has been slowly COOLING for 2,000 years.

Measurements stretching back to 138BC prove that the Earth is slowly cooling due to changes in the distance between the Earth and the sun.

The finding may force scientists to rethink current theories of the impact of global warming.

It is the first time that researchers have been able to accurately measure trends in global temperature over the last two millennia.

Over that time, the world has been getting cooler - and previous estimates, used as the basis for current climate science, are wrong.

Their findings demonstrate that this trend involves a cooling of -0.3°C per millennium due to gradual changes to the position of the sun and an increase in the distance between the Earth and the sun.... [Read More]

[PaleMelanesian]

Originally Posted by wikipedia

The warm period became known as the MWP, and the cold period was called the Little Ice Age (LIA). However, this view was questioned by other researchers; the IPCC First Assessment Report of 1990 discussed the "Medieval Warm Period around 1000 AD (which may not have been global) and the Little Ice Age which ended only in the middle to late nineteenth century."[13] The IPCC Third Assessment Report from 2001 summarised research at that time, saying "…current evidence does not support globally synchronous periods of anomalous cold or warmth over this time frame, and the conventional terms of 'Little Ice Age' and 'Medieval Warm Period' appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries".[14] Global temperature records taken from ice cores, tree rings, and lake deposits, have shown that, taken globally, the Earth may have been slightly cooler (by 0.03 degrees Celsius) during the 'Medieval Warm Period' than in the early and mid-20th century.[15] Crowley and Lowery (2000)[16]

[booferama]

"The finding does not change our understanding of the warming power of carbon dioxide. In fact, it shows that human CO2 emissions have interrupted a long cooling period that would ultimately have delivered the next ice age." --New Scientist

[Kurz]

Originally Posted by booferama

"The finding does not change our understanding of the warming power of carbon dioxide. In fact, it shows that human CO2 emissions have interrupted a long cooling period that would ultimately have delivered the next ice age." --New Scientist

Woot Polution Saved Humanity.

[jpleong]

Originally Posted by Kurz

Woot Polution Saved Humanity.

Exactly what I thought when I read that, too. LOL.

JP

[Carcus]

The earth's orbit around the sun is irregular.

The earth wobbles on its axis.



Q: Either of these would obviously have an effect on the earth's surface temperature.... Yet it's almost never talked about. Why?

A: Nobody's figured out a way to seize power or make money off of it ... yet.

[echoman]

Thats intresting because if the past was warmer then the present the arctic would have melted then the world would have cooled enough to refeeze then start to warm up again to get to the point now when it can start to break off ice shelfs and shrink. Come on. Wonder what the ice samples would say?

[worthywads]

Originally Posted by echoman

Thats intresting because if the past was warmer then the present the arctic would have melted then the world would have cooled enough to refeeze then start to warm up again to get to the point now when it can start to break off ice shelfs and shrink. Come on. Wonder what the ice samples would say?

We don't have records on arctic ice, it may have melted. But arctic ice melts every year and it's not causing "refreeze"?

[waltermlee]

In the extreme parts of the north and south poles a layer of ice is laid down for each year and the ice cores taken from those areas do represent a continuous record of the earth's climate. These ice core samples are dated by radioactive isotopes found in each segment of the ice cylinder sample. Within each segment gas and solid/frozen samples of the atmosphere are used to determine the makeup of the the atmosphere at that time. It's pretty elegant system.

Tree-rings of fossilized pine trees are going to be a bit iffy because mineral deposits from the fossilization process can change their chemical nature - the only thing you can be sure of is the age via radioactive isotopes and the growth between each ring (which would allow you to know know favorable the growing environment would be). The maximum lifespan of a pine tree is about 300 years so Dendrochronology based on a pine tree is not a continuous record of the earth's climate. Analysis of fossilized tree rings can only tells which years were favorable or unfavor with respect to growth of which temperature is only one factor in a group of factors - so Tree ring sample data by themselves can't invalidate ice-core sample data.

If anything tree-ring and ice-core sample data should actually support each other with respect to long term climate trends. In the hotly debated climate change - global warming debates - some have suggest scientific fraud and/or flawed methodologies - however, I haven't seen any evidence of data tampering among the global warming studies so far. Ice-core analysis used by global warming advocates are widely accepted because they are repeatable, technically accessible, and the interpretation/analysis of the data is relatively straightforward. What's less clear cut in this debate is the correlation of man's activity and global atmospheric CO2 levels - and whether man can lower the atmosphere's Co2 levels.

[herm]

Originally Posted by waltermlee

- however, I haven't seen any evidence of data tampering among the global warming studies so far.

Try a google search, probably a million hits.