|
Post by socold on May 25, 2009 17:19:56 GMT
This isn't about predicting a specific event, it's about the models not showing an ever upward year-by-year temperature rise. Some ten year periods in the models show cooling or flat. There is noise over the trend. 10 years is not enough to guarantee what you are seeing is trend rather than noise. But strangely enough, there have been quite a few predictions the last 10 years by "experts" that we would see a new global temperature record this year or that year. Obviously, you cannot claim that anyone expected this prolonged pause in warming - which should perhaps give us pause before swallowing all of their predictions for the future. Some records have seen a global temperature record set in the last 10 years. In fact only HadCrut and the satellite records have not. Not expecting something doesn't mean it cannot happen. If a record warm year in 10 years has 90% chance then of course experts will tell us that a record warm year is likely in the next 10 years. Just because it doesn't happen doesn't prove them wrong.
|
|
|
Post by socold on May 25, 2009 17:20:34 GMT
Some sceptics argue that a few ppm of CO2 can't possibly be important. Others argue that CO2 is so potent that all of its affect has already been "used up". Strange. The 5 inch mesh analogy is probably slightly more inappropriate given that CO2 does indeed effectively absorb the radiation around its spectral lines. Every 100ppm of CO2 would make up about a metre thickness of CO2 if you compressed it all down to the surface at surface temperature and pressure. If each 100ppm is a coat, we had 3 coats, we've got a fourth and are currently starting to add a 5th. Yes it has less effect than the others, but I have worn 5 or 6 layers when camping or walking in -10 to -20C temperatures. Why haven't we seen any acceleration in the warming trend the past 100 years? When will these "extra layers" kick in? Why assume extra layers cause an acceleration?
|
|
|
Post by tacoman25 on May 26, 2009 2:01:27 GMT
But strangely enough, there have been quite a few predictions the last 10 years by "experts" that we would see a new global temperature record this year or that year. Obviously, you cannot claim that anyone expected this prolonged pause in warming - which should perhaps give us pause before swallowing all of their predictions for the future. Some records have seen a global temperature record set in the last 10 years. In fact only HadCrut and the satellite records have not. Not expecting something doesn't mean it cannot happen. If a record warm year in 10 years has 90% chance then of course experts will tell us that a record warm year is likely in the next 10 years. Just because it doesn't happen doesn't prove them wrong. GISS/NOAA use the same data source, and they were the only ones showing 2005 warmer than 1998. All other temperature sources, RSS, UAH, and HadCRU, did not have 2005 even close to 1998. Therfore, objectively, one has to consider the NOAA/GISS data to be the outlier. If you look at most previous record years, all sources agreed on them, or at least were very close. Therefore, 1998 must remains the last true record year. And you completely missed my point, anyway. The point was that nothing is as certain as the "experts" make it sounds sometimes.
|
|
|
Post by tacoman25 on May 26, 2009 2:01:57 GMT
Why haven't we seen any acceleration in the warming trend the past 100 years? When will these "extra layers" kick in? Why assume extra layers cause an acceleration? I don't assume that. The models do.
|
|
|
Post by icefisher on May 26, 2009 2:15:10 GMT
Why assume extra layers cause an acceleration? I don't assume that. The models do. Perhaps CO2's GH radiative abilities are already fully saturated.
|
|
|
Post by kenfeldman on May 26, 2009 4:52:56 GMT
I don't assume that. The models do. Perhaps CO2's GH radiative abilities are already fully saturated. That was proposed over a hundred years ago, in response to Arrhenius' hypothesis of AGW. It was shown to be false in the 1950s. Do try to keep up with the current millenium please.
|
|
|
Post by tacoman25 on May 26, 2009 6:10:04 GMT
Perhaps CO2's GH radiative abilities are already fully saturated. That was proposed over a hundred years ago, in response to Arrhenius' hypothesis of AGW. It was shown to be false in the 1950s. Do try to keep up with the current millenium please. There has been no global warming this millenium. Perhaps you should keep up with the times?
|
|
|
Post by woodstove on May 26, 2009 15:33:27 GMT
It is a shame that time travel is not possible. If it were, we could gather up Arrhenius (who, by the way, said that AGW could easily be a good thing), Ken, socold, glc, Steve, and any other AGWers and have them look around at the thriving biosphere during the Holocene Optimum. After taking in the warmer temperatures than today and the shrunken glaciers, one wonders whether they would dare speak of dangerous AGW again.
The Holocene Optimum, contrary to your suggestions, Steve, was real and worldwide:
Excerpt from one of the dozens of papers confirming same (by Zheng Zhuo1, Yuan Baoyin2, Nicole Petit-Maire3); paper is entitled Paleoenvironments in China during the Last Glacial Maximum and the Holocene Optimum:
"The data of Holocene recognized a warm period (ca. 9,000-6,000 yr BP) that the temperature estimates were generally 2-4 degrees Celsius higher than nowadays. The rise of sea level resulted in great changes of the coastal environment in eastern China. Due to the warm climate, glaciers largely retreated and even disappeared in the eastern part. The permafrost was located to the North of the current limit. Desert and loess greatly reduced and the highest lake level was found mostly during 9,000-5,000 yr BP. The boreal conifers were to the north of the present locations, and many steppe areas were covered with forested formations."
|
|
|
Post by kenfeldman on May 26, 2009 15:54:36 GMT
That was proposed over a hundred years ago, in response to Arrhenius' hypothesis of AGW. It was shown to be false in the 1950s. Do try to keep up with the current millenium please. There has been no global warming this millenium. Perhaps you should keep up with the times? Every year in the 21st century has been warmer than every year in the 19th and 20th centuries with the exception of 1998. Perhaps you should investigate the facts before you just repeat denialist myths.
|
|
|
Post by glc on May 26, 2009 16:32:29 GMT
Every year in the 21st century has been warmer than every year in the 19th and 20th centuries with the exception of 1998.
Perhaps you should investigate the facts before you just repeat denialist myths.
To be fair your statement and Tacoman25's "no 21st century warming" statement could both be true. In fact they both probably are, though Tacoman might need to define when the start of the 21st century occurred.
|
|
|
Post by kenfeldman on May 26, 2009 17:01:21 GMT
Every year in the 21st century has been warmer than every year in the 19th and 20th centuries with the exception of 1998.
Perhaps you should investigate the facts before you just repeat denialist myths. To be fair your statement and Tacoman25's "no 21st century warming" statement could both be true. In fact they both probably are, though Tacoman might need to define when the start of the 21st century occurred. There was no year 0, so the 21st century started on January 1, 2001. Take a look at that graph. Every point from 2001 to 2008 is higher than every other year on the graph with the exception of 1998. This is what the denialists mean by "no global warming"? I find it interesting that on this website, which is devoted to solar cycle 24, people forget that we are currently in a solar minimum, which which started in 2006 with the first spotless day since the last minimum. 2008 saw very little solar activity and a pretty deep La Nina, which should indicate cooling. Compare the temps for 1996, the minimum between SCs 22 and 23, with 2008, our current minimum: 1996 Anamoly 0.29 C 2008 Anamoly 0.44 C So 2008 is 0.15 C warmer than the year of the previous solar minimum, even though there was a La Nina event in 2008. While looking at La Nina years, we had a pretty deep La Nina in 1999 and 2000. Let's look at the global temperature anamolies: 1999 Anamoly 0.32 C 2000 Anamoly 0.33 C 2008 Anamoly 0.44 C So coming off the huge El Nino of 1997-98 (1998 anamoly 0.57) the globe cooled for two years and then the warming took off. Anamolies in 2002 through 2007 were all above 0.50, which is more than 0.1 degrees C higher than any other year than 1998. 2005 was the warmest year on record, with an anomoly of 0.62 C, 0.05 C higher than 1998. That's the record of "no warming" the denialists want you to believe. Don't be deceived.
|
|
|
Post by jimcripwell on May 26, 2009 17:06:03 GMT
glc writes "To be fair your statement and Tacoman25's "no 21st century warming" statement could both be true. In fact they both probably are, though Tacoman might need to define when the start of the 21st century occurred. "
Both statements are true. The difference is in the tense used. kenfeldman is correct that global temperatures have risen (past tense). Tacoman is right that global temperatures are now falling (present tense). As I have pointed out many times, when you have a warming period followed by a cooling perion, then the cooling period starts at the maximum of the warming period. World temperatures seem to have passed through a shallow maximum, probably around 2005. So, while temperatures are still high by historic standards, they are now falling. Whether they will go on falling is an entirely different matter. What matters is which statement is the more important; that temperatures are still high by historic standards, or that they are now falling. I believe the latter is far more important than the former.
|
|
|
Post by jimcripwell on May 26, 2009 17:51:19 GMT
Let me expand on my last post. I apologise for not being able to post nice graphs from my computer. But here is an experiement that anyone with a reasonable amount of scientific knowledge can carry out. Take any one of the 5 data sets that report global temperatures on a monthly basis. Or take all 5. Actually the GISS data that kenfeldman has quoted would be an excellent choice. Start the data many years ago; say at least 30 years ago. Carry out a non-linear least squares regression analysis on the data stopping at several different years, or if you use monthly data, several different months. Each year, or month, note the slope of the temperature/time graph at the last point of the curve. For the GISS data set, you will find this slope is positive (rising temperatures) for all years after 2000 up to 2006. I am guessing, as I have not got the actual data, but for 2007, the slope becomes neutral. In 2008, the slope went negative, and taking a reasonable value for what is happening in 2009, 2009, will almost certainly be negative. What this sort of analysis does not do, of course, is give any idea of what is going to happen in the future. That is an entirely different story. If you use the other data sets, what you will find is that the first year of negative slopes occurs earlier than with the GISS data.
|
|
|
Post by glc on May 26, 2009 18:26:10 GMT
That's the record of "no warming" the denialists want you to believe. Don't be deceived.
Looking at the plot in your post, it's clear that you could have made the same point you're making now in the 1940s. In fact it could be argued that the recent warming trend is just a continuation of the 1910-45 warming trend. The trends are very similar. But CO2 concentrations in 1910 were not that much different to what they were in pre-industrial times - so what caused the warming?
It occurs to me that if we don't know what caused the warming then how can we be sure what caused the warming since 1975. We need to do a bit of "detection and attribution" here.
|
|
|
Post by woodstove on May 26, 2009 19:04:25 GMT
GLC writes: "It occurs to me that if we don't know what caused the warming then how can we be sure what caused the warming since 1975. We need to do a bit of 'detection and attribution' here."
Perhaps you would like to detect and attribute whatever may have forced the warming during the Holocene Optimum?
Just wondering what might have caused the substantial cooling since then.
|
|