Harvard Study Finds Earth Warmer During Middle Ages

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NOsorrowORshame

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So SUV's and human activity arent destroying the world.....


Middle Ages were warmer than today, say scientists
By Robert Matthews, Science Correspondent
(Filed: 06/04/2003)
DailyTelegraph.co.uk

Claims that man-made pollution is causing "unprecedented" global warming have been seriously undermined by new research which shows that the Earth was warmer during the Middle Ages.

From the outset of the global warming debate in the late 1980s, environmentalists have said that temperatures are rising higher and faster than ever before, leading some scientists to conclude that greenhouse gases from cars and power stations are causing these "record-breaking" global temperatures.

Last year, scientists working for the UK Climate Impacts Programme said that global temperatures were "the hottest since records began" and added: "We are pretty sure that climate change due to human activity is here and it's accelerating."

This announcement followed research published in 1998, when scientists at the Climatic Research Unit at the University of East Anglia declared that the 1990s had been hotter than any other period for 1,000 years.

Such claims have now been sharply contradicted by the most comprehensive study yet of global temperature over the past 1,000 years. A review of more than 240 scientific studies has shown that today's temperatures are neither the warmest over the past millennium, nor are they producing the most extreme weather - in stark contrast to the claims of the environmentalists.

The review, carried out by a team from Harvard University, examined the findings of studies of so-called "temperature proxies" such as tree rings, ice cores and historical accounts which allow scientists to estimate temperatures prevailing at sites around the world.

The findings prove that the world experienced a Medieval Warm Period between the ninth and 14th centuries with global temperatures significantly higher even than today.

They also confirm claims that a Little Ice Age set in around 1300, during which the world cooled dramatically. Since 1900, the world has begun to warm up again - but has still to reach the balmy temperatures of the Middle Ages.

The timing of the end of the Little Ice Age is especially significant, as it implies that the records used by climate scientists date from a time when the Earth was relatively cold, thereby exaggerating the significance of today's temperature rise.

According to the researchers, the evidence confirms suspicions that today's "unprecedented" temperatures are simply the result of examining temperature change over too short a period of time.

The study, about to be published in the journal Energy and Environment, has been welcomed by sceptics of global warming, who say it puts the claims of environmentalists in proper context. Until now, suggestions that the Middle Ages were as warm as the 21st century had been largely anecdotal and were often challenged by believers in man-made global warming.

Dr Philip Stott, the professor emeritus of bio-geography at the University of London, told The Telegraph: "What has been forgotten in all the discussion about global warming is a proper sense of history."

According to Prof Stott, the evidence also undermines doom-laden predictions about the effect of higher global temperatures. "During the Medieval Warm Period, the world was warmer even than today, and history shows that it was a wonderful period of plenty for everyone."

In contrast, said Prof Stott, severe famines and economic collapse followed the onset of the Little Ice Age around 1300. He said: "When the temperature started to drop, harvests failed and England's vine industry died. It makes one wonder why there is so much fear of warmth."

The United Nation's Intergovernmental Panel on Climate Change (IPCC), the official voice of global warming research, has conceded the possibility that today's "record-breaking" temperatures may be at least partly caused by the Earth recovering from a relatively cold period in recent history. While the evidence for entirely natural changes in the Earth's temperature continues to grow, its causes still remain mysterious.

Dr Simon Brown, the climate extremes research manager at the Meteorological Office at Bracknell, said that the present consensus among scientists on the IPCC was that the Medieval Warm Period could not be used to judge the significance of existing warming.

Dr Brown said: "The conclusion that 20th century warming is not unusual relies on the assertion that the Medieval Warm Period was a global phenomenon. This is not the conclusion of IPCC."

He added that there were also doubts about the reliability of temperature proxies such as tree rings: "They are not able to capture the recent warming of the last 50 years," he said
Middle Ages were warmer than today, say scientists Claims that man-made pollution is causing "unprecedented" global warming have been seriously undermined by new research which shows that the Earth was warmer during the Middle Ages.
 
NOsorrowORshame said:
So SUV's and human activity arent destroying the world.....

First off, this isn't new news. I find it intriguing how Harvard can rediscover existing data that they probably just researched differently and pass off as "new." Theories with fluctuating sunspot cycles showed similar data, and, interestingly enough, according to that data, we are heading for a cooler, wetter period around 2020 that will last 320 years (our current warming cycle started in 1700). In other words, the "mysterious" conclusions that the researchers bring up may have to do with the effect of sunspots (more sunspots=more solar intensity & warm periods; less sunspots=less solar intensity & cool periods).

Secondly, I find that to be a logical fallacy. SUVs and human activity *may* still be destroying the world; we will never know whether or not the Earth is supposed to be at this temperature or not naturally.

What this study does tell me is that the Earth was once warmer in a natural state, and that the possibility exists that global warming is all hype. I don't think we should suddenly throw out EPA regulation due to this study.

Melon
 
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Re: Re: Harvard Study Finds Earth Warmer During Middle Ages

melon said:
SUVs and human activity *may* still be destroying the world; we will never know whether or not the Earth is supposed to be at this temperature or not naturally.

Though, given your example of sun spot cycles, it seems like humans have a pretty big ego to think that we can generate global changes on this scale.

I agree with keeping EPA regulations - while humans may not increase the global temperature, we still create a lot of garbage that I don't want to breathe.
 
NOsorrowORshame:

i read some rumours that the first global warming (time of the pharaos) was caused in south america by (estruction of rainforest because of to intense argricultural use) and that this also might have been the reason that these cultures were almost wiped out.

Klaus
 
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This is interesting. I was taught in school that Europe was colder between the years 1300 and 1600. This had a negative effect on crops. For what it's worth I was a medieval history major in school. Generally this cold was really bad news for Europe. Apparently it warmed up after 1600. Why? I don't know.
 
Re: Re: Re: Harvard Study Finds Earth Warmer During Middle Ages

nbcrusader said:

While humans may not increase the global temperature, we still create a lot of garbage that I don't want to breathe.

Exactly.
 
Europe WAS warmer then; they grew grapes in Britain.
As melon said, this is not news.

Problem is, we ARE emitting carbon dioxide faster than can be re-absorbed into the earth, oceans, plants, etc. More carbon dioxide DOES lead to warmer temperatures, and temperatures HAVE been increasing since the industrial era.

One very big factor in global warming is that it's a delayed effect. Even if we totally stopped any type of industrial activity, tilling new land, burning wood, all of it... carbon dioxide would still increase in the atmosphere for years before it started going down. The increases measured now are due to the activity from 50 years ago.

Now, I'm not saying SUVs and that are going to kill us all. Studies show foliage is increasing on plants due to the increased carbon dioxide, and the earth may have stabilization factors that I have never heard of. There's natural fluctuations of temperature I'm not even going to try and get into that are a factor of current and past climate change. Partly because I took that class last year and my notes are at home :)
 
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