Slashdot Mirror
20th Century Warmest In 1200 Years
gcranston writes "Research from the University of East Anglia in Norwich, U.K. shows that the 20th century was the warmest for the northern hemisphere since approximately 800AD. Historical climate data were calculated from weather 'proxies' such as tree rings, ice cores, and seashells from Europe, Asia, and North America, and attempted to address the shortcomings of earlier studies. The findings support the argument for global warming as a result of human interference rather than natural climate change."
The article doesn't say what happened in the 8th century, just that tree rings don't reliably go back any farther. They must be using only specific species of trees, though, because there there are several species of living trees that are much, much older. Do their rings not reflect temperature, too?
The article contains almost no technical data, but it does say there have been been conflicting results:
"In 2003, a team led by researchers from the Harvard-Smithsonian Center for Astrophysics announced that it believed the 20th century wasn't the warmest, nor the one with the most extreme weather of the past 1,000 years.
"But this research has been criticized for its selection of the indicators used to estimate historic temperatures, among other problems."
The article doesn't say what indicators the Harvard-Smithsonian group used, just that they think their indicators are better.
The problem here, fundamentally, is too many science-types go to unending lengths using bad science and bad use of statistics to prove themselves right. This conversation constantly degenrates into two uninformed groups of people spouting completely false nonsense at each other based entirely on a misuse of statistics. Even in this slashdot thread you will see people getting modded up for citing (incorrectly) correlative evidence as causitive evidence.
The fundamental issue here is correlation. Good climatologists are at war with correlation implying causality. They are unable to produce proper control experiments, so no matter how convincing their results, it's able to be dismissed by others. No good science should look at correlative evidence (as you have stated plenty) and draw conclusions. Guess what, since 1980, Jupiter has seen a HUGE increase in the number of comet strikes of the previous decades. But we can't pin that on global warming.
The fundamental question is how much has humanity effected the global warming of this planet. Just showing that it is warming is completely and totally irrelevant. The important scientific question, and the one most difficult to answer, is how much humans have contributed. The methods whereby CO2 heats up a planet are fairly well understood, and no one with a sane state of mind can deny that humanity has made things worse. The scientific debate remains to what degree. Slashdot karma-whores can continually abuse the general lack of statistical know-how by stating "look how much warmer it is now!" and get modded up. The fact of the matter is using the metric of "difference in temperature in time" is completely and utterly meaningless in a debate about humanity's contribution to global warming.
And we don't even need to get into the ridiciously horrible statistical fallacies possible when one begins using "extremes" and "records" as a basis for drawing conclusions.
So here we are again, another long rant from two sides of an argument where those arguing are not in possesion of most of the facts.
It always amazes me that these two sides will get into bitter feuds over this subject and no one seems to want to put it in any context. For me what it comes down to is this: we can spend a lot of money, time, and research trying to find out if we are a contributing factor to global warming, only to discover it may be too late, or we can spend even more money, time, and research trying to change the way we interact with the atmosphere. And in the end if those who claim that global warming is impacted by humans are right and we listened to them then we are on our way to fixing it and have a cleaner environment for the future. If they are wrong and we listened to them we still have a cleaner environment and we might just find that all those chemicals we were pumping into the atmosphere had other effects which would then be limited. If, on the other hand we don't listen to them and they are right then we have to learn to live in a new world climate and deal with the vast ammounts of crap we have been pumping into the atmosphere for centuries.
What it comes down to, for me, is this: do we want to risk the global climate on this? Is it worth the piece of mind to know that what happens is out of our control instead of our fault?