What does the tree ring record show?

Question

Do you think it is good science to create the hockey stick chart using different sets of data? The first section is from tree ring data that shows a cooling trend. The last section is from thermometers in urban areas and shows a sharp increase in temperatures. Is this good science? Did this go through peer review? What would that chart look like if it used only tree ring data?

The chart is from the 2001 IPCC report.
http://www.grida.no/climate/ipcc_tar/wg1/figspm-1.htm

Answer 1

It could show an increase in rain ,or sun ,and it might mean the CO2 was very high . The CO2 will increas growth as much as fertilizer.

Answer 2

There are a vast number of 'hockey stick' charts - many, many millions of them. I'm guessing you're referring to the one used by Al Gore in his movie. The primary data source for this was ice core analysis based on the CO2 record extracted from the Concordia and Vostok ice core samples. These give us a temperature record that extends back nearly 750,000 years.

Dendrology (tree rings) can give us a record stretching back only a few thousand years. By taking enough samples from across the planet we can produce a reasonably accurate graph of past temperatures but there are other factors that affect the dendrological record so it's not the most reliable method of calculating historical temperatures.

It's a popular misconception that recent temperature records are obtained from thermometers in urban areas. For the last 30 years temperatures have been recorded using satellite telemetry which measures the temperature everywhere across the surface of the globe. Ground stations are often at locations away from urban areas such as airports and observatories and they also include data from weather ships, planes and baloons - again, well away from urban areas.

If the chart used only tree ring data it would look similar, just as it would were it based solely on ice core CO2 analysis, oxygen isotope analysis, sedimentary analysis, oceanographic or hydrological records etc. Whichever way the graph is produced it shows the same overall trends but by comparing the numerous sets of data a more accurate representation can be produced. This is what a good scientist will do, rather than use a single data set many different ones will be obtained for comparision and identification of anomolies.

Answer 3

Scientists have to work with the data that they can get. And unless you've got atime machine so you can go back and take direct measurements, this is one of the best methods.

Yes--papers like this are peer reviewed.

Here's how this particular method works. We have reliable and accurate records --using thermometers--of temperatures back for about two centures. The "tree ring scale" was created using those figures--measuiring ring width against known temperatures.

So--you could use a scale that is entirely tree ring data--and it would show exactly the same thing it does, because the "tree ring scale is derived from the thermometer readings in the first place . Every scientist knows this--and in a situation like this, its common to use the istrument-derived readigs where their available, simply for convenience.

Granted, the detailed explanation I just gave isn't usually explicitly stated. Thats because scientists aren't going to waste reader's time repeating stuff others already know--any more than a sports announcer isgoing to repeat the rules of baseball during each and every game. The assumption in either case is that the audience already knows the basics.

Answer 4

Data showing a warming trend is no surprise. Urban areas are warmer than rural. Check out www.surfacestations.org to see how the Global Warming Cult relies on temperature sensors located next to air conditioner hot air vents to prove their points and are at a loss when satellite temperature readings show very little change.

Answer 5

On top of that the proxy models don't pick up the late 20th century warming - not only is the hockey stick two separate sets of data plastered one before the other, but if you continued the first data set, it wouldn't agree with the second.

Answer 6

The age of the tree.

Answer 7

Look up paleoclimate and proxy data.

Answer 8

Blah blah blah data blah blah blah.

Where is this data exactly? You have not provided a link.