Does the global warming trend exceed historical trends?
Answer:
The trend is different because of the small amount of time it's taken to increase the global temperature over the past few decades.
Here are several plots of reconstructed temperatures over the past 2000 years (note that these are NOT the "hockey stick graph")
http://en.wikipedia.org/wiki/image:2000_...
Here are some over 12,000 years
http://en.wikipedia.org/wiki/image:holoc...
There are large error bars on these, but the average (black line) shows that there likely hasn't been a temperature change as large or rapid as the current on in at least 10,000 years.
From the IPCC report:
"The combined radiative forcing due to increases in carbon dioxide, methane, and nitrous oxide is +2.30 [+2.07 to +2.53] W m–2, and its rate of increase during the industrial era is very likely to have been unprecedented in more than 10,000 years (see Figures SPM.1 and SPM.2). The carbon dioxide radiative forcing increased by 20% from 1995 to 2005, the largest change for any decade in at least the last 200 years."
http://ipcc-wg1.ucar.edu/wg1/report/ar4w...
The aggressiveness of the change will effect tens of millions of people through flooding, drought, famine, disease and extinctions.
No. The warming trend fits historic norms if you look back a million years. During the last million years there have been several ups and downs at regular intervals. The downs were ice ages. We had a down 10,000 years ago and it has been heading up generally since then with a few minor ups and downs on the way. We have just come out of one of those slight downs from the 1970s making the current warming look more obvious. We are actually climbing the warming trend and are about 3/4s of the way up based on the past trends. I am not saying that additional CO2 won't affect it but I doubt it is a significant problem and vastly overstated by those with separate agendas or good intentions without much to substantiate their position IMO.
I think you will see a lot of back pedaling during the next two years. For one thing, more and more evidence is coming to light that the warming trend is slowing (eg Southern Hemisphere cooling, both sea surface temperature and increases in Antarctic ice.) For another, more and more scientists are speaking up, many from the industrial sector - the scientists that actually DO something productive - pointing out the bogus scientific methods used to bolster the anthropogenic global warming argument.
Environmental scientists have always suffered a credibility gap. They can't risk losing all credibility. Eventually they'll come around.
I don't believe it does. Someone is going to probably link a graph that shows a "hockey stick" type graph that tries to show it does, but the problem is most of the scientists (Mann comes to mind here) didn't use proper statistics or subject their work to statistical review when they made that graph. When a highly respected statistician reviewed his work it was shown to be in error.
Statistical significance is not something that is easy to show because you are always subject to an error called bias which is an error that skews your data, such as the fact we don't have accurate measurements from the past, we use things such as ice cores and tree rings to try and reconstruct what the temperature was like.
I have tried pointing out to people about how these are biased, especially the tree rings, and I was personally attacked instead of someone who believes in man-made global warming acknowledging this bias. There are two types of errors that can be made when drawing conclusions from statistics. A type I error states you jumped to a conclusion your data didn't support. And a type II error is one where you said your data is inconclusive when in reality it did show that something really was going on.
So in the case of global warming I believe they have made a type I error. Especially since they use a 90% confidence interval instead of a 95% confidence interval to try and show something is going on. The lower the confidence interval the easier it is to show the trend of man-made global warming is statistically significant.
Not really. Here is an interesting article I found:
http://www.co2science.org/scripts/co2sci...
Yep, it's different. Ten different peer reviewed studies , using different methods, with references (and links) here. The graph stops in 2004. If it went to 2006 it would be even more impressive.
http://www.globalwarmingart.com/wiki/ima...
Another thing that's different. In the past animals and humans could simply migrate where conditions were more favorable. In the modern civilized world, that's not very feasible.
The original "hockey stick" was subject to relatively minor statistical criticism. The National Academy of Sciences reviewed it and found, while the criticism was valid, the basic shape of the hockey stick was correct. The studies I've shown are not the "hockey stick", they were done later and are accepted by the vast majority of the scientific community.
The most recent prior warming cycles were slower in coming. Two were warmer than today, one was close but not warmer.
The shift from the most recent warm period into the next cool period, which in turn preceded the present warm period, occurred very quickly - - at least as quickly as the present warming.
When they downplay the MWP they also downplay the drop from the MWP into the LIA.
They can keep pretending the MWP didn't happen or wasn't warmer but around the world the physical evidence says it was.
I don't think the trends are different in both quality and quantity from previously established warming and cooling cycles.
If you can get your hands on the following article, GSA TODAY, JULY 2003, PG 4-10, you will see in figure 1 that we are not in an extraordinary time of temperature increase (as measured by the proxy of 18-O in calcite shells).
As to why we should be alarmed, I can't rightly say. It would seem that we should wait and see, afterall, we had a cooling spell that ended about 30 years ago, maybe we'll see another cooling spell soon. There are a lot of factors that influence climate, and we just do not know the interconnectedness of all of these factors.
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