Posted on 09/26/2006 7:30:57 AM PDT by cogitator
A new study by NASA scientists finds that the world's temperature is reaching a level that has not been seen in thousands of years.
The study, led by James Hansen of NASA's Goddard Institute for Space Studies, N.Y., along with scientists from other organizations concludes that, because of a rapid warming trend over the past 30 years, the Earth is now reaching and passing through the warmest levels in the current interglacial period, which has lasted nearly 12,000 years. An "interglacial period" is a time in the Earth's history when the area of Earth covered by glaciers was similar or smaller than at the present time. Recent warming is forcing species of plants and animals to move toward the north and south poles.
The study used temperatures around the world taken during the last century. Scientists concluded that these data showed the Earth has been warming at the remarkably rapid rate of approximately 0.36° Fahrenheit (0.2° Celsius) per decade for the past 30 years.
"This evidence implies that we are getting close to dangerous levels of human-made pollution," said Hansen. In recent decades, human-made greenhouse gases have become the largest climate change factor. Greenhouse gases trap heat in the Earth's atmosphere and warm the surface. Some greenhouse gases, which include water vapor, carbon dioxide, methane, nitrous oxide, and ozone, occur naturally, while others are due to human activities.
The study notes that the world's warming is greatest at high latitudes of the Northern Hemisphere, and it is larger over land than over ocean areas. The enhanced warming at high latitudes is attributed to effects of ice and snow. As the Earth warms, snow and ice melt, uncovering darker surfaces that absorb more sunlight and increase warming, a process called a positive feedback. Warming is less over ocean than over land because of the great heat capacity of the deep-mixing ocean, which causes warming to occur more slowly there.
Hansen and his colleagues in New York collaborated with David Lea and Martin Medina-Elizade of UCSB to obtain comparisons of recent temperatures with the history of the Earth over the past million years. The California researchers obtained a record of tropical ocean surface temperatures from the magnesium content in the shells of microscopic sea surface animals, as recorded in ocean sediments.
One of the findings from this collaboration is that the Western Equatorial Pacific and Indian Oceans are now as warm as, or warmer than, at any prior time in the Holocene. The Holocene is the relatively warm period that has existed for almost 12,000 years, since the end of the last major ice age. The Western Pacific and Indian Oceans are important because, as these researchers show, temperature change there is indicative of global temperature change. Therefore, by inference, the world as a whole is now as warm as, or warmer than, at any time in the Holocene.
According to Lea, "The Western Pacific is important for another reason, too: it is a major source of heat for the world's oceans and for the global atmosphere."
In contrast to the Western Pacific, the researchers find that the Eastern Pacific Ocean has not shown an equal magnitude of warming. They explain the lesser warming in the East Pacific Ocean, near South America, as being due to the fact this region is kept cool by upwelling, rising of deeper colder water to shallower depths. The deep ocean layers have not yet been affected much by human-made warming.
Hansen and his colleagues suggest that the increased temperature difference between the Western and Eastern Pacific may boost the likelihood of strong El Ninos, such as those of 1983 and 1998. An El Nino is an event that typically occurs every several years when the warm surface waters in the West Pacific slosh eastward toward South America, in the process altering weather patterns around the world.
The most important result found by these researchers is that the warming in recent decades has brought global temperature to a level within about one degree Celsius (1.8°F) of the maximum temperature of the past million years. According to Hansen, "That means that further global warming of 1 degree Celsius defines a critical level. If warming is kept less than that, effects of global warming may be relatively manageable. During the warmest interglacial periods the Earth was reasonably similar to today. But if further global warming reaches 2 or 3 degrees Celsius, we will likely see changes that make Earth a different planet than the one we know. The last time it was that warm was in the middle Pliocene, about three million years ago, when sea level was estimated to have been about 25 meters (80 feet) higher than today."
Global warming is already beginning to have noticeable effects in nature. Plants and animals can survive only within certain climatic zones, so with the warming of recent decades many of them are beginning to migrate poleward. A study that appeared in Nature Magazine in 2003 found that 1700 plant, animal and insect species moved poleward at an average rate of 6 kilometers (about 4 miles) per decade in the last half of the 20th century.
That migration rate is not fast enough to keep up with the current rate of movement of a given temperature zone, which has reached about 40 kilometers (about 25 miles) per decade in the period 1975 to 2005. "Rapid movement of climatic zones is going to be another stress on wildlife," according to Hansen. "It adds to the stress of habitat loss due to human developments. If we do not slow down the rate of global warming, many species are likely to become extinct. In effect we are pushing them off the planet."
The linked press release includes images with captions. I did not include them in this posting.
** ping **
Exactly.
Thousands of years ago there were no SUVs to blame.
Oh my God, that's a little over 1 degree in 30 years. I thought it was hot in here. Hey is that a triceratops? Forget about the Muzzies who want to kill us. What are we going to do when the dinosaurs return? Panic now, before it's too late!!!
Or, there is this story:
Earth Headed for Warmest Temps in a Million Yearsl
Drive-by climatologists. They just want their name in the paper.
"at any prior time in the Holocene"
So things have been getting warmer since the end of the last Ice Age.
Will they get warmer yet as the Milankovitch cycle continues?
The weather is more the way it is today than it has ever been before.
Can Someone link me to one or two articles that take the point of view there is no global warming or at least not caused by us humans or SUVs. My daughter is in college and is reading Al Gore's book. I want to send her other points of view. It won't help but a least I will give it a try.
"State of Fear" by Michael Crichton
"Skeptical Environmentalist: Measuring the Real State of the World" by Bjorn Lomborg, Bjern Lomberg
So many points to discuss....I'll just pick one.
A specices (as a whole) moved poleward by a total of 20 miles in the past 50 years? How would you go about measuring something like that? And, how would it be relevant?
More Global Warming nonsense. James Hansen, irregardless of his credentials, is one of the larger Chicken Littles out there.
So? We have been comming out of an Ice Age for what 10-12,000 years. It would only be natural for warming to be the highest in thousands of years. If you look at the big picture as I have seen on some graph's this is nothing.
I wonder sometimes whether scientists or eco-warriors have ever heard of The Milankovitch Cycles.
According to the three cycles the northern Hemisphere currently should be due to return to glacial levels, ice core sediments also show that a warming spike was reached just before previous glacial epochs took hold.
Heard that NASA guy again this morning pushing his retired-guy agenda. Kind of reminds one of retired guys who appear on the Art Bell Show with their tales of captured UFOs in the mountains.
Also the most misleading result. They are comparing precise measurements from the present with very imprecise and smoothed measurements from the past. All the spikes like the one of the last 30 years disappear when the temperature proxy only takes measurements every century or 1000 years and averages decades or centuries worth of variation into that measurement.
yea, but which Bush family member was in office?
And what was Haliburton doing @ the time!?!?
Hansen is supposed to be taken seriously because he converted to global warming alarmist after looking at the data as a skeptical scientist. It's easily seen to be BS when looking at his statements about climate zones moving and stress. He obviously knows nothing about the science, just wants to sound an alarm.
His tone of voice is exactly what grandfathers develop from explaining to grandkids why grass is green and the sky is blue and where the world came from even though the kids world extends to the street in front of their house and the bus ride to school. It is the 'I am being sincere' tone. All the senior Art Bell guests have that tone.
Between 1960 and 1963, if you looked up the temperature at Tyndall AFB on a given day, there is a high probability that I was the guy reading the thermometer; our temperature shelter was located on a hangar roof which housed the observation tower directly across from the ATC tower between the runways.
Most stations were located at approximately 6 feet above ground level for convenience and standardization.
We switched to electronic devices in 1962 and no longer made the trip down the steps to read the old mercury thermometers.
Since then most of the gauges have been automated and the majority worldwide now are largely unmanned.
There are a host of variables also subject to modernization that are largely smoothed by the sheer numbers of observation points all using instruments that are rarely calibrated.
Thirty years is but a blink in the eye of time.
Michael Crichton's State of Confusion
Michael Crichton’s State of Confusion II: Return of the Science
And it's been a relatively stable interglacial climate up until now, too.
0.2 C in 30 years is 1/3 of the total global temperature increase (approximately) from 1900-2000.
And that approach won't work. What is needed is increased efficiency with existing energy technology and new energy sources (as well as upgrades to existing and proven technologies, like nuclear power).
Well, the problem is that this particular interglacial didn't seem particularly influenced by Milankovitch forcing, and therefore has exhibited very stable temperatures. So the only real forcing that might cause (and appears to be causing) increasing temperatures is increasing greenhouse gas concentrations in the atmosphere.
There are many indications that the current warming trend is not due to natural variation (primarily).
Conclusion: Changing human activity will stop global warming.
Hansen is actually a believer in alternate energy and new technology as the best way to address the situation.
Conclusion: Prudence demands implementing this change immediately.
Hansen has expressed the viewpoint that humanity, collectively, has a decade or so to start doing something substantial about global warming or irreversible changes with the potential to induce significant-to-severe climate alteration in the future will become much more probable.
In fact, ice core drillings have indicated that the earth has been warmer as well as cooler than it is now a number of times in the past without catastrophe.
Define "catastrophe" in this context. For the glacial-interglacial era, there have only been a few short periods during prior interglacials that were slightly warmer than now -- without the higher CO2 concentrations in the atmosphere that will contribute to even higher temperatures. So the Earth may be on the verge of entering an unprecedented climate state.
A paper published in Science indicated that the expected next entry into a glacial epoch, based on Milankovitch forcing, is 50,000 years or so off.
"More recent work by Berger and Loutre suggests that the current warm climate may last another 50,000 years." Citation: Berger A, Loutre MF (2002). "Climate: An exceptionally long interglacial ahead?". Science 297 (5585): 1287-1288.DOI:10.1126/science.1076120.
I agree and I think that this was done to attract attention. The more immediate concern is the 0.2 C rise in the past 30 years. If you are going to compare to temperatures over the whole past million years, you have to address the time-scale of various forms of variability.
"This evidence implies that we are getting close to dangerous levels of human-made pollution," said Hansen. In recent decades, human-made greenhouse gases have become the largest climate change factor. Greenhouse gases trap heat in the Earth's atmosphere and warm the surface. Some greenhouse gases, which include water vapor, carbon dioxide, methane, nitrous oxide, and ozone, occur naturally, while others are due to human activities."
Contradictions that produce false claims: (a)"human-made greenhouse gases have become the largest climate change factor"; (b)"greenhouse gases which include water vapor, carbon dioxide, methane, nitrous oxide and ozone, while others are due to human activities"; however (c)water vapor is the largest component of "greenhouse gases" responsible for climate change and (d)most atmospheric water vapor is not "human made" and humans have almost zero ability to control it. See: http://www.geocraft.com/WVFossils/greenhouse_data.html
"The study notes that the world's warming is greatest at high latitudes of the Northern Hemisphere, and it is larger over land than over ocean areas. The enhanced warming at high latitudes is attributed to effects of ice and snow. As the Earth warms, snow and ice melt, uncovering darker surfaces that absorb more sunlight and increase warming, a process called a positive feedback. Warming is less over ocean than over land because of the great heat capacity of the deep-mixing ocean, which causes warming to occur more slowly there."
The above statement is not science or it is terribly bad communication. The atmosphere and the oceans circulate any and all earth warming or cooling. Yes, there are temperature differences, due to the specifics of a particular location such as latitude (closer to the poles or closer to the equator), altitude (elevation above sea level), path of prevailing jet-stream and trade wind patterns and other factors. But, the description in the preceding paragraph is a description of affects, not causes. The northern latitudes are not "warming" because the snow and ice are melting, exposing more land. The snow and ice are melting because it is warming there. The heat that is absorbed does contribute to warming ground temperatures, but it does not contribute immensely to warmer atmospheric temperatures and would cease to be a factor if (and when) atmospheric temperatures drop.
What has actually been observed in the northernmost latitudes is areas of snow and ice melt nearest the oceans (like Greenland and Antarctica) which has (a)reduced glaciers at the waters edge and melted snow nearest the oceans, and (b)produced greater local water vapor which when meeting the atmosphere has produced greater snow fall, which has produced much deeper and denser snow packs inland, which in affect is (c)building the makings of the next phase of glacial expansion when the warming cycle recedes again.
"The California researchers obtained a record of tropical ocean surface temperatures from the magnesium content in the shells of microscopic sea surface animals, as recorded in ocean sediments......One of the findings .........is that the Western Equatorial Pacific and Indian Oceans are now as warm as, or warmer than, at any prior time in the Holocene" - the Holocene is our current "relatively warm period that has existed for almost 12,000 years, since the end of the last major ice age. The Western Pacific and Indian Oceans are important because, as these researchers show, temperature change there is indicative of global temperature change."
Here where the science is slipping up. The oceans cover 2/3 of the earth. What happens in and under the oceans and between the oceans and the atmosphere is 2/3 of the climate story but probably less than 10% of the known data. Why? The earth, through its molten core, its magnetic field, its tectonic activity (shifting plates of land sliding around the earth) is a huge heat generator and dispenser. Most of that heat, from earthquakes, to volcanoes and millions of fissures, from tiny to immense, is dispensed under the oceans, absorbed by ocean water and transported to the atmosphere (and back) in the form of water vapor. Which, the link above has already told you is more dense lately, and the largest contributor to "global warming". And yet, that activity is not constant in its severity or its distribution. And, this part of the science is the weakest part in terms of data to represent this activity.
http://www.sciencedaily.com/releases/2006/07/060727180622.htm
http://www.mpg.de/english/illustrationsDocumentation/documentation/pressReleases/2003/pressRelease20030718/index.html
"According to Lea, 'The Western Pacific is important for another reason, too: it is a major source of heat for the world's oceans and for the global atmosphere." In contrast to the Western Pacific, the researchers find that the Eastern Pacific Ocean has not shown an equal magnitude of warming. They explain the lesser warming in the East Pacific Ocean, near South America, as being due to the fact this region is kept cool by upwelling, rising of deeper colder water to shallower depths. The deep ocean layers have not yet been affected much by human-made warming.
And yet that explanation should also hold true for the northeastern Pacific, but it does not, because it is warmer than the eastern Pacific in the south and warmer than the western Pacific. Since the water and atmospheric flows are generally west to east (caused by the earth's rotation), what is under the middle of the northern Pacific that makes it warmer, and thus increases the northern Pacific's contribution of water vapor - the largest green house gas?
Water vapour: feedback or forcing?
What happens in and under the oceans and between the oceans and the atmosphere is 2/3 of the climate story but probably less than 10% of the known data. Why? The earth, through its molten core, its magnetic field, its tectonic activity (shifting plates of land sliding around the earth) is a huge heat generator and dispenser. Most of that heat, from earthquakes, to volcanoes and millions of fissures, from tiny to immense, is dispensed under the oceans, absorbed by ocean water and transported to the atmosphere (and back) in the form of water vapor.
The temperature of the global water column (from 0-3,000 meters) has been measured at numerous points around the world. A compilation of this data (by Levitus) indicated a clear warming of the water column, with most of the warming at the surface and just a little penetrating to depth, as would be expected. Heat from volcanic sources is negligible as a contribution to warming or the water vapor "budget".
And yet that explanation should also hold true for the northeastern Pacific, but it does not, because it is warmer than the eastern Pacific in the south and warmer than the western Pacific. Since the water and atmospheric flows are generally west to east (caused by the earth's rotation), what is under the middle of the northern Pacific that makes it warmer, and thus increases the northern Pacific's contribution of water vapor - the largest green house gas?
There isn't a lot of upwelling in the northeastern Pacific. There's a little on the PacNW and California coast, but not nearly as much as the Peru Upwelling.
And 30 years is about 1/3 of the time between 1900 and 2000. Your point?
Temperatures are simply returning to the norm they were at 1000 years ago before the Little Ice Age. One study of the Milankovitch cycles by Berger and Loutre predicts the current warm climate may last another 50,000 years.
Your point is incorrect.
Attribution of recent climate change
A quote from one of the many cited articles: "A recent paper (Estimation of natural and anthropogenic contributions to twentieth century temperature change, Tett SFB et al., JGR 2002), says that "Our analysis suggests that the early twentieth century warming can best be explained by a combination of warming due to increases in greenhouse gases and natural forcing, some cooling due to other anthropogenic forcings, and a substantial, but not implausible, contribution from internal variability. In the second half of the century we find that the warming is largely caused by changes in greenhouse gases, with changes in sulphates and, perhaps, volcanic aerosol offsetting approximately one third of the warming."
If the global temperatures at any time prior to the industrial revolution were ever equal to, or warmer than the present, then there are obviously natural mechanisms which were responsible for that increase and could be so, again, in the present.
"Could be responsible" does not mean that they are responsible. Please read the link that I provided. The scientists have assessed the contributions of natural factors and the assessment indicates that natural factors are insufficient to produce the major part of the observed warming trend.
The climate has been stable my Arse. Climate has always had its fluctuations. Did you forget about the Little Ice Age? Also, Greenland was much warmer back when the Viking settled there than it is now.
The current interglacial is the blue zone starting about 10,000 years BP. It's fairly obvious from this chart that the interglacial temperature pattern was "spikier" in the previous interglacials than the current one. (And if this data is believed, then it appears that the peak temperatures of previous interglacials were somewhat higher than present, so I don't know if Hansen is taking a more global view. This is, after all, ultimately representative primarily of Antarctic temperatures with an overlying global pattern).
Anyway, go to this article:
and read the "Present Conditions" section. If you're really intrigued, you may want to try and get the Berger and Loutre paper, reference 8. This was an important paper and I wish it was available for free online, but I can't find it anywhere.
No. The Holocene climate is very stable compared to other interglacials. See the chart in the post above this one.
And 30 years is about 1/3 of the time between 1900 and 2000. Your point?
Point one: I make mistakes. Point two: The trend is 0.2 C per decade, so 0.2 C in 10 years is 1/3 of the total global temperature increase in the 20th century. Or, to put it another way, 0.6 C in the past 30 years is approximately the same increase in global temperature observed in the 20th century.
....and that makes perfect sense. If the global temperature rose 0.6 C in 100 years, then it would rise 0.2 C in 33 1/3 years. So it's increased that much in 30 years instead of 33 1/3 years, I don't see that as significant.
This evidence indicates somebody's got an agenda.
The trend is currently +0.2 C per decade: 2.0 C in 100 years.
The previous interglacials could be more described "up-up-up-peak-down-flat-down-down" into the next glacial period. The current interglacial would be described "up-up-up-bounce(Younger Dryas)-flat" and flat is where we are now. The flat section is considerably longer than for the previous interglacials.
I admit that I don't know exactly how the end of a glacial period and the beginning of an interglacial period is defined (except for the Holocene). I don't think that end of the glacial period is defined as the point when global temeperatures start to increase; it's probably defined by the recession of the continental ice sheets.
Thanks for good info, cogitator.
Glad it was informative.
All we have to do to cool things off is what they did back then to start the Little Ice Age - ban SUV's and limit industrial hydrocarbons. :-))
"The temperature of the global water column (from 0-3,000 meters) has been measured at numerous points around the world. A compilation of this data (by Levitus) indicated a clear warming of the water column, with most of the warming at the surface and just a little penetrating to depth, as would be expected. Heat from volcanic sources is negligible as a contribution to warming or the water vapor "budget"."
"measured at numerous points around the world".
From what I have seen the data is too anecdotal and not consistently systematic, nor systematically collected at a sufficient number of locations and depths on a onsistent and ongoing basis for a long enough period of time.
"Heat from volcanic sources is negligible as a contribution to warming or the water vapor 'budget'"
No reliable studies have ever (1)identified all the under-the-ocean heat sources from tectonic and volcanic activity or (2)systematically measured their heat output, making your statement, and statemenst like it, a guess, because the data to make that statement is nothing other than data no one has, and thus it is dismissed as "negligible", where the failure to acknowledge the lack of relevant data on this issue is what is negligent.
Anybody who is reasonably facile with mathematics can tell you that a model is only useful in its predictive power if it can be retroactively applied to past conditions and produce “predictions” that, in fact, “mirror” the observations of that past time frame.
Such as like this:
http://www.grida.no/climate/ipcc_tar/wg1/450.htm#fig127
Caption: Global mean surface temperature anomalies relative to the 1880 to 1920 mean from the instrumental record compared with ensembles of four simulations with a coupled ocean-atmosphere climate model (from Stott et al., 2000b; Tett et al., 2000) forced (a) with solar and volcanic forcing only, (b) with anthropogenic forcing including well mixed greenhouse gases, changes in stratospheric and tropospheric ozone and the direct and indirect effects of sulphate aerosols, and (c) with all forcings, both natural and anthropogenic. The thick line shows the instrumental data while the thin lines show the individual model simulations in the ensemble of four members. Note that the data are annual mean values. The model data are only sampled at the locations where there are observations. The changes in sulphate aerosol are calculated interactively, and changes in tropospheric ozone were calculated offline using a chemical transport model. Changes in cloud brightness (the first indirect effect of sulphate aerosols) were calculated by an offline simulation (Jones et al., 1999) and included in the model. The changes in stratospheric ozone were based on observations. The volcanic forcing was based on the data of Sato et al. (1993) and the solar forcing on Lean et al. (1995), updated to 1997. The net anthropogenic forcing at 1990 was 1.0 Wm-2 including a net cooling of 1.0 Wm-2 due to sulphate aerosols. The net natural forcing for 1990 relative to 1860 was 0.5 Wm-2 , and for 1992 was a net cooling of 2.0 Wm-2 due to Mt. Pinatubo. Other models forced with anthropogenic forcing give similar results to those shown in b (see Chapter 8, Section 8.6.1, Figure 8.15; Hasselmann et al., 1995; Mitchell et al., 1995b; Haywood et al., 1997; Boer et al., 2000a; Knutson et al., 2000).
For that matter, we do not have any statistically valid, data observation compilations of the amount and compositions of gases put into the earth’s atmosphere by volcanic activity, let alone the total amount of such activity, more than a century ago. We do know from very limited observations that a single volcano can potentially “belch” more greenhouse gases and other, erstwhile, pollutant gases into the atmosphere in a single eruption than any possible industrial contribution.
Totally wrong. While volcanoes are a significant contributor of SO2 (particularly big eruptions), SO2 is not a greenhouse gas and actually would cause a cooling effect. Volcanoes are not a signficant source of CO2 or any other greenhouse gas compared to current anthropogenic production.
Gases: Man versus the Volcanoes
Volcanic Gases and their Effects
We have no data on the so-called, “ozone hole” over Antarctica prior to the satellite age nor do we have unquestioned explanations as to that phenomenon’s recently observed variations, let alone its driving mechanism.
Incorrect again. The ozone hole was discovered by ground-based measurements of ozone (Dobson unit decline) made by the British Antarctic Survey; in fact, when the ozone monitoring sensors on satellites first detected the hole, it was thought that the measurements were erroneous and the ground-based measurements had to be consulted to confirm what the satellites were observing.
Simple statistical analysis of the variations that are postulated to have occurred in the past based upon observations of ice core drillings and ocean core samples, etc., reveal that the currently observed changes are not outside the expected range of natural variation.
That's a specious ["have a false look of truth or genuiness"] argument. Even if the observed changes are not out of the full range of natural variation, their relevant aspect is the climate context in which the observed changes are occurring. If natural causes cannot be identified for the observed changes, then at least part of what is happening is not natural variation. Therefore, it is relevant to try to determine if the non-natural causes have the potential to push the climate system beyond the range of natural variation -- and this indeed is the concern of the climate science community.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.