Can you dispute this? Global warming?

Question

Tree rings show Earth was warm 800 years ago

WASHINGTON (AP) — an unusually warm period a millennium ago may have been part of a natural planetary cycle, say researchers who studied tree rings.
The study, appearing in the March 21 issue of the journal Science, analyzed ancient tree rings from 14 sites on three continents in the northern hemisphere and concluded that temperatures in an era known as the Medieval Warm Period some 800 to 1,000 years ago closely matched the warming trend of the 20th century.
In recent years, many climate scientists have said an unprecedented warming spell that began last century and continues is caused by an enhanced greenhouse effect. While the natural greenhouse effect keeps the Earth at a liveable temperature, the enhanced greenhouse effect is blamed on an increase in the atmosphere of gases, principally carbon dioxide, from the burning of fossil fuels.
The tree-ring study gives another perspective on Earth's natural cycles; said Edward Cook of the Lamont-Doherty Earth Observatory in Palisades, N.Y. Cook is co-author of the study with Jan Esper and Fritz Schweingruber of the Swiss Federal Research Institute.
Cook said the study shows the Earth to be "capable of rapid changes and long periods of above average warmth on its own without enhanced greenhouse warming caused by human activities.
"We don't use this as a refutation of greenhouse warming," said Cook. "But it does show that there are processes within the Earth's natural climate system that produce large changes that might be viewed as comparable to what we have seen in the 20th century."
Cook said the study found that, based on the growth of rings in the trunks of trees that lived hundreds of years ago; the temperatures during the Medieval Warm Period were about equal to the warming trend that started in the 20th century.
"Greenhouse gases (added to the atmosphere by humans) were not a factor back in the Medieval Warm Period," said Cook.
The Intergovernmental Panel on Climate Change, an international group, has predicted that the current warming trend will continue deep into the 21st century, with average temperatures rising by from 2.5 and 10 degrees.
Cook said data used in the climate change panel's calculation is based on a model that compared the preindustral age climate with the climate of the 20th century. The model did not include a Medieval Warm Period. Including data from that era could change the calculations, Cook said.
"The Medieval Warm Period is in some sense comparable up to 1990 in the 20th century," said Cook. "But that does not say that the 20th century hasn't been perturbed by greenhouse gases. The real challenge is to factor out the natural variability from" manmade causes of global warming.
Cook said the panel's temperature warming prediction could be correct. Based on the new tree-ring data, however, he said the warming could be in the lower part of the temperature range forecast by the group.
Keith Briffa and Timothy Osborn, climate scientists at the University of East Anglia in Britain, said the study by Cook and his colleagues "provides evidence for greater climate swings in the last 1,000 years than has yet been generally accepted."
In a commentary in Science, Briffa and Osborn said a need exists for more such independent studies to refine predictions for global warming in this century.
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Copyright 2002 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Answer 1

Having studied climate change and global warming for 20 years it would be extremely easy for me to rip the entire article apart sentence for sentence.

The article is based on dendrological analysis indicating the warming of the world 800 to 1000 years ago might be comparable to that of the 20th century.

The only significant warming during the time in question occurred between approx 1130 and 1160. A thirty year period in which the earth's average temperature rose by about 0.2 degrees Celsius. In the last 30 years the world's temperature has risen by about 0.7 degrees (three and a half times as fast). What's more, the rate of rise is faster than is ever known to have occurred and the world is now the warmest it's been for 130,000 years and is rising fast.

Read the article carefully - references to historical evidence are vague and full of uncertainties - maybe, indicates, might. There is no such ambiguity when referring to modern day events and the article specifically states that there are manmade causes of global warming.

I wouldn't rely on this as evidence that global warming isn't happening as it's riddled with inaccuracies, misinformation and exaggeration.

Answer 2

I can dispute it. Yes, the planet has gone through wild swings in the past. Due to those swings there have been large mass extinctions - at times it has been estimated over 95% of species were wiped out. During the last ice age scientists believe humans nearly became extinct, with only perhaps a few thousand remaining at one time. Climate swings are not a good thing for those living on the planet.

Next. Yes, there are global swings. Things such as volcanic eruptions, solar activity, or wobbles in the earth's motion can affect the temperature. However, when you add on top of that a bias because of human activity you make a cataclysmic change that much more likely. There is nothing we can do about volcanos. We can do something about the man-made contribution.

I had not seen this article. To me it looks like a lot of what the author said is taken out of context - yes, there are natural climate swings, yes, science cannot accurately predict the exact contribution of the man-made influence. But the debate about existence of human contribution to global warming is pretty much over - almost no knowledgeable person denies it exists, though the extent is still disputed. (even President Bush, a long-time naysayer with strong economic interests in the status quo, has admitted that it is real and needs to be addressed.)

Even this article says so - he says his model is that the change is towards the lower end of the range given by the Intergovernmental Panel on Climate Change, not that they are wrong. He says earth has changed before, which no one disputes, and is 100% irrelevant to our present situation. "Greenhouse gases (added to the atmosphere by humans) were not a factor back in the Medieval Warm Period"? A total nonsequitor. Of course they weren't. Greenhouse gases (added to the atmosphere by humans) were not a factor in the overheating of Venus either. So what?

In fact, at this point I consider deniers in the same position as all those who denied for years that smoking could be harmful. At best they are ignorant and naive, at worst intentionally prostituting their names for profit. The science and the debate has moved on to what can, or should, be done about it. I suggest you do too, or else you will find yourself increasingly irrelevent.

Answer 3

At some point everyone has to stop looking for excuses and start looking for solutions, don't they?
The question is not whether there have been warm periods in the past. Of course there have been. But they've never gotten as warm as quickly as our current swing. And 1000 years ago you and your little tribe could pack up and migrate somewhere else. What are all you smart asses who try so hard to deny global warming going to do if our largest agricultural areas turn to desert?
Yes, warming has occured before and whole tribes in the American southwest disappeared when their once fertile land dried up. Even if this is part of a natural cycle, we are clearly making it worse and we don't have anywhere else to move to. It's time to start trying to solve the problem rather than clinging desperately to any scrap you can find in hopes of continuing your fantasy that the problem doesn't exist

Answer 4

You are forgetting just one important factor.You have not mentioned ocean warming,which has increased 2.5 deg.Researchers have studied a extinct beetle and how it's body changed color according to the temp.Long story short they believe the earth pulsates which makes the earth hot for longer periods for and cold for shorter periods until it reaches a point.Then it reverses that effect until reaching an ice age.

Answer 5

Thanks for the info. If I hear one more thing about global warming in the "negative" form I think I will scream. I have sisters that talk about it all the time... my husband does... gooooodness.. move on... This planet is going to stand as long as God wants it to.. no less.. no more. Let's move on.... if we want to "save" the earth they should let us have biofuel (made from veggies ~ safe for the environment).. quit shipping stuff to outer space (do you ever notice how they are NEVER to blame for polution??) have windmills to produce electric, and make the other lightbulbs more affordable.

Answer 6

"Global Warming" is just part of the cycles the earth goes through! i.e. the extremely cold temperature in Europe many years ago!

Answer 7

Since Im to lazy to read this i am just going to say the truth. GLOBAL WARMING DOES NOT EXIST. And most "Enviormentalist" dont even know what they're talking about. At a rally their group leader signed a petition banning dicarbon monoxide a.k.a. water.