Posted on 06/22/2006 8:28:41 AM PDT by Semus Dynnen
Study Says Earth's Temp at 400-Year High Jun 22 11:10 AM US/Eastern
By JOHN HEILPRIN Associated Press Writer
WASHINGTON
The Earth is the hottest it has been in at least 400 years, probably even longer. The National Academy of Sciences, reaching that conclusion in a broad review of scientific work requested by Congress, reported Thursday that the "recent warmth is unprecedented for at least the last 400 years and potentially the last several millennia."
A panel of top climate scientists told lawmakers that the Earth is running a fever and that "human activities are responsible for much of the recent warming." Their 155-page report said average global surface temperatures in the Northern Hemisphere rose about 1 degree during the 20th century.
The report was requested in November by the chairman of the House Science Committee, Rep. Sherwood Boehlert, R-N.Y., to address naysayers who question whether global warming is a major threat.
Last year, when the House Energy and Commerce Committee chairman, Rep. Joe Barton, R-Texas, launched an investigation of three climate scientists, Boehlert said Barton should try to learn from scientists, not intimidate them.
The Bush administration also has maintained that the threat is not severe enough to warrant new pollution controls that the White House says would have cost 5 million Americans their jobs.
Climate scientists Michael Mann, Raymond Bradley and Malcolm Hughes had concluded the Northern Hemisphere was the warmest it has been in 2,000 years. Their research was known as the "hockey-stick" graphic because it compared the sharp curve of the hockey blade to the recent uptick in temperatures and the stick's long shaft to centuries of previous climate stability.
The National Academy scientists concluded that the Mann-Bradley-Hughes research from the late 1990s was "likely" to be true, said John "Mike" Wallace, an atmospheric sciences professor at the University of Washington and a panel member. The conclusions from the '90s research "are very close to being right" and are supported by even more recent data, Wallace said.
The panel looked at how other scientists reconstructed the Earth's temperatures going back thousands of years, before there was data from modern scientific instruments.
For all but the most recent 150 years, the academy scientists relied on "proxy" evidence from tree rings, corals, glaciers and ice cores, cave deposits, ocean and lake sediments, boreholes and other sources. They also examined indirect records such as paintings of glaciers in the Alps.
Combining that information gave the panel "a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years," the academy said.
Overall, the panel agreed that the warming in the last few decades of the 20th century was unprecedented over the last 1,000 years, though relatively warm conditions persisted around the year 1000, followed by a "Little Ice Age" from about 1500 to 1850.
The scientists said they had less confidence in the evidence of temperatures before 1600. But they considered it reliable enough to conclude there were sharp spikes in carbon dioxide and methane, the two major "greenhouse" gases blamed for trapping heat in the atmosphere, beginning in the 20th century, after remaining fairly level for 12,000 years.
Between 1 A.D. and 1850, volcanic eruptions and solar fluctuations were the main causes of changes in greenhouse gas levels. But those temperature changes "were much less pronounced than the warming due to greenhouse gas" levels by pollution since the mid-19th century, it said.
The National Academy of Sciences is a private organization chartered by Congress to advise the government of scientific matters.
oh, they massage the data as they like to serve their agenda
(2003 10 01 )
What do they tell us about the highly-advertised claims of the world's climate alarmists relative to warming-induced droughts and floods?....
Climate alarmists claim that global warming will bring extremes of both floods and droughts to the world, and that the earth is now warmer than it has been in the entire past millennium. If these two claims were correct, we should clearly be seeing wet and dry periods that exceed the worst of the past half-millennium or more. In this extensive and well-calibrated record from the United States, however, we don't. Ergo, something is rotten in more than Denmark:
There is additional evidence, such as the results of examining sedimentary records in lake beds. Those layers of sedimentation permit to identify the seasonal fluctuations in the run-off as well as the total amount of run-off and the historical water levels in our lakes.
Similarly, sedimentation records obtained by examining core samples taken from the sea beds of various oceans permit to establish quite accurately what life existed at the ocean surface and how well it did over the centuries and millennia. Thereby a continuous and accurate record of historical surface sea-temperatures can be determined.
Curiously, and the Kyoto-hype advocates must surely be interested in that (or are they?), the record for the Sargasso Sea shows that the current sea-surface temperature is about half a degree Celsius below the average for the last 3000 years. Moreover, although the sea-surface temperature has recently increased somewhat but not quite reached the 3000-year average, it is rising in perfect synchronicity with the record of solar activity. It has done so before and will do so again.
Just as there were times in the past where it was much colder than it is now, so there were times when our globe was much warmer. The last period of a considerably warmer climate was during the Medieval Optimum, just before the Little Ice Age set in out of which we are climbing just now.
Superstitions, in spite of many voices of reason, brought about the witch hunts as the climate turned colder during the Little Ice Age. (See the paper by historian Wolfgang Behringer: Climatic Change and Witch-Hunting: The Impact of the Little Ice Age on Mentalities)
Superstitions, in spite of many voices of reason, bring us now the witch hunts promoted by the proponents of the Kyoto accord. Such is the power of propaganda.
Full report and data at:( follow the multiple links off this page)
http://www.fathersforlife.org/REA/warming7.htm
I don't wonder why these ocns don't mention that were coming out of an ice age. It doesn't fit their political agenda of abolishing Freedom and grabbing control from the "humans".
See, now, I'd imagine more grapes leads to more wine, more wine leads to more pillaging. And it does. You should see me hitting the yard sales on weekends after a drink or two. It's not pretty.
The criticisms have been well-documented by Stephen McIntyre at the ClimateAudit Web site. There are currently two threads on the subject of the NAS panel report.
NAS Panel - What I’ll Be Looking For
The climate science community of reconstructors is represented by the RealClimate Web site. This Web site was initiated in part due to the Hockey Stick controversy. Their "take" on the NAS Panel report is here:
National Academies Synthesis Report
In the RealClimate commentary, there is a very key quote from the NAS report. I repeat it here, with emphasis:
"Surface temperature reconstructions for periods prior to the industrial era are only one of multiple lines of evidence supporting the conclusion that climatic warming is occurring in response to human activities, and they are not the primary evidence."
There is certainly a lot of back-and-forth debate and discussion in these venues. From my reading, it is clear that the NAS panel made some very telling criticisms of the methodology of the Hockey Stick reconstruction, and these criticisms can probably be directed at several other reconstructions. This will definitely inspire more research.
What wouldn't be good is to interpret criticisms of the methodology of this aspect of climate research (i.e., paleoclimate reconstructions) as indicating that the entire body of data supporting the anthropogenic influence on current and future climate is unreliable or (worse) a hoax. It is reliable, and it's not a hoax.
Become A Pirate To Save The Planet!!
Lets make a documentary to teach everyone the ways of the scurvy dog so our planet will survive!
No, it could have been considerably colder 400 years ago. The correct interpretation is that in the period from now to 400 years ago, it was never (at any time) warmer than it is now.
See post 67.
Friend dirtboy, see post 65.
The work has already begun ...
CO2 is the chief climate change agent in the atmosphere, not SO2. And in a given year, SO2 from volcanoes is about 25% of human emissions (mainly coal burning). In a year with an eruption like Pinatubo or El Chichon, the volcanoes may exceed human emissions, but that doesn't happen very often.
"The scientists say it'll all wash away
But we don't believe anymore
'Cause we've got our recruits
In their green mohair suits
So please show your I.D. at the door"
Parsons/Hillman
Just sorta came to mind!
See post 65.
Milankovitch-cycle driven changes in solar insolation.
See post 65. There is data from multiple sources and analyses that indicates that the current warming trend (since the mid-1970s, to a lesser extent from the 1850s) is at least partly attributable to anthropogenic greenhouse gas emissions.
OK so for that sake of argument let me accept the first premise this means that the earth was as hot as this some 400 to 2000 years + ago... so if you been the hot in the past how do come the conclusion it man-made this time?... what cause it last time?...
First rule of diagnosing a symptom... You ask the question... if it happen before what was the previous cause and/or what is the common factor between then and now
Absolutely true: but the issue of pertinence is how much human activities will influence climate change in this and the following centuries, and particularly how these activities might cause climate to change at a rate faster than most natural processes.
1200 AD was 800 years ago.
They say surface temps only rose 1 degree in 20th century. Is a 1 degree increase that significant and how much of that 1 degree do they estimate is caused by humans vs natural causes?
Note that's 1 deg F, 0.6 deg C. That change is attributed 33-50% to human activities. This is due to the fact that early 20th century temperature increase (1900-1930s) is considered to be about 50% solar driven, 50% human activities. There was a cooler period mid-century (about 0.2 C) attributed to natural variability and perhaps to sulfate aerosols. Since the mid-1970s, the 0.4-0.6 C rise is considered to be primarily due to human activities.
Your statement unfairly characterizes the noted scientific backgrounds of some of the panel members, who most certainly understand natural climate change and variation. Check out Karl Turekian as an example.
Wow! So, how did they arrive at this figure? And why couldn't it be 90/10? And what exactly caused the lack of heat from sunlight for the entire period of the Little Ice Age?
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