General Discussion
Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region ForumsMedieval warming WAS global – new science contradicts IPCC
A proper temperature record for Antarctica is particularly interesting, as it illuminates one of the main debates in global-warming/climate-change: namely, were the so-called Medieval Warm Period and Little Ice Age merely regional, or were they global events? The medieval warmup experienced by northern Europeans from say 900AD to 1250AD seems to have been at least as hot as anything seen in the industrial era. If it was worldwide in extent that would strongly suggest that global warming may just be something that happens from time to time, not something caused by miniscule concentrations of CO2 (the atmosphere is 0.04 per cent CO2 right now; this figure might climb to 0.07 per cent in the medium term).
The oft-mentioned "scientific consensus", based in large part on the work of famous climate-alarmist scientists Michael Mann and Phil Jones and reflected in the statements of the Intergovernmental Panel on Climate Change (IPCC), says that isn't true. The IPCC consensus is that the medieval warming and the "Little Ice Age" which followed it only happened in Europe and maybe some other northern areas. They were local events only, and globally the world was cooler than it is now. The temperature increase seen in the latter half of the 20th century is a new thing caused by humanity's carbon emissions.
Lu and his colleagues' new work, however, indicates that in fact the medieval warm period and little ice age were both felt right down to Antarctica.
http://www.theregister.co.uk/2012/03/23/warm_period_little_ice_age_global/
tabatha
(18,795 posts)"If it was worldwide in extent that would strongly suggest that global warming may just be something that happens from time to time"
All natural phenomena have a scientific basis. This needs to be determined.
CO2 is a greenhouse gas - if there were none in the atmosphere, the planet would be uninhabitable. Approximately 300 ppm is enough to change it from an uninhabitable to a inhabitable one.
The paper may be valid scientifically - however the conclusion drawn in that sentence is not scientific at all.
Well said.
SidDithers
(44,228 posts)Sid
ljm2002
(10,751 posts)Dead give away.
Bohunk68
(1,364 posts)I thought, too.
JBoy
(8,021 posts)In 2010 he was claiming evidence showed that changing energy output from the sun was a major cause of temperature increases on earth.
http://hockeyschtick.blogspot.ca/2010/10/paging-ipcc-much-of-recent-global.html
G_j
(40,370 posts)fascisthunter
(29,381 posts)pscot
(21,024 posts)that a new ice-age is just around the corner.
Boojatta
(12,231 posts)It's a term that is being used:
"United Nations Framework Convention on Climate Change"
http://unfccc.int/2860.php
hootinholler
(26,449 posts)Then it will be so.
mmonk
(52,589 posts)ProdigalJunkMail
(12,017 posts)the scientist who authored the paper come from all around. Instead of trashing the study due to the author of the article...maybe the study has some merits. why does everyone assume the study is done by hacks just because the article is written by one?
sP
Viking12
(6,012 posts)Lewis, along with most other deniers, has a track record of blatant misrepresentation of scientific information. If I can make some time, I'll read the actual piece. I'd bet it does not lead to the types of conclusions made on the serial denier website.
ProdigalJunkMail
(12,017 posts)that the MWP extended to Antarctica...and if there is quantitative data that shows this (and I suspect it would or it would not be in the abstract) then why are people here reacting with such venom?
sP
Viking12
(6,012 posts)Do you know the difference between qualitative and quantitative?
From the article:
"At this stage, the geochemistry of ikaite serves as a qualitative, rather than a quantitative, climatic proxy, because it remains challenging to account for kinetic effects on uptake of ?18O into the carbonate during crystallization and any post-crystallization exchange of ?18Ohydra signal."
ProdigalJunkMail
(12,017 posts)i am not plopping down $40 to be a member so i can read the whole thing...
sP
OnEdit for your addition from the study : Is that the only measure that is in the study? If so, then I guess there IS no quantitative data and we can wait from something more...if it were ever to be forthcoming. My assumption is that there would be more quantitative data deeper into the study...
Viking12
(6,012 posts)It is an interesting paper that identifies the potential of a new paleoclimate proxy. There's much more work to be done before it can be successfully used to infer actual temperatures. It certainly does not contradict previous multiproxy studies as the lying liar from the register asserts.
ProdigalJunkMail
(12,017 posts)were it found to be a valid climate proxy? i would think that it would not be able to be considered valid if it were contradictory to the other accepted proxies.
thanks for the info...quick question though...you copied and pasted some text from 'the article' but i don't see it in the OP posted article. where did it come from? would love to do some more reading when time permits.
sP
Viking12
(6,012 posts)Specifically, the study refers frequently to;
Bentley, M.J., et al., 2009. Mechanisms of Holocene palaeoenvironmental change in the
Antarctic Peninsula region. Holocene 19 (1), 5169.
The authors appear to have made a large leap to infer the MWP signal from the absence of the crystals.
I have access to the article because I have a subscription to ScienceDirect through my employer.
ProdigalJunkMail
(12,017 posts)i thought my reading skills were severely deteriorated beyond my previous assessments
thanks again for the info...very interesting.
sP
Codeine
(25,586 posts)Bandit
(21,475 posts)Core samples have been taken from Antartica and greenland and other Arctic regions for more than a half century now.. At no time in the last six hundred thousand years have Carbon Dioxide concentrations been even half as high as they currently are and they are still spiking...
FarCenter
(19,429 posts)The IPCC basically tried to minimize the Medieval Warm Period, at least in its earlier reports, as being a local European phenomena, and then not very warm at all.
This study shows that the Medieval Warm Period of relatively elevated temperatures extended to Antarctica.
So the problem for global climate modelers is to be able to run climate simulations that reproduce a global MWP, rather than a local minor one.
http://www.sciencedirect.com/science/article/pii/S0012821X12000659
--------------------------------------------------------------------------------
Scientists use rare mineral to correlate past climate events in Europe, Antarctica
http://www.syr.edu/news/articles/2012/ikaite-03-12.html
...
Ikaite crystals incorporate ocean bottom water into their structure as they form. During cooling periods, when ice sheets are expanding, ocean bottom water accumulates heavy oxygen isotopes (oxygen 18). When glaciers melt, fresh water, enriched in light oxygen isotopes (oxygen 16), mixes with the bottom water. The scientists analyzed the ratio of the oxygen isotopes in the hydration water and in the calcium carbonate. They compared the results with climate conditions established in Northern Europe across a 2,000-year time frame. They found a direct correlation between the rise and fall of oxygen 18 in the crystals and the documented warming and cooling periods.
We showed that the Northern European climate events influenced climate conditions in Antarctica, Lu says. More importantly, we are extremely happy to figure out how to get a climate signal out of this peculiar mineral. A new proxy is always welcome when studying past climate changes.
DCBob
(24,689 posts)Most of them show the current warming is more extreme than anything seen in at least 1200 years.
From NOAA..
In summary, it appears that the late 20th and early 21st centuries are likely the warmest period the Earth has seen in at least 1200 years. For a summary of the latest available research on the nature of climate during the "Medieval Warm Period", please see Box 6.4 of the IPCC 2007 Palaeoclimate chapter. To learn more about the "Medieval Warm Period", please read this review published in Climatic Change, written by M.K. Hughes and H.F. Diaz. (Click here for complete review reference). Discussion of the last 2,000 years, including the Medieval Warm Period, and regional patterns and uncertainties, appears in the National Research Council Report titled "Surface Temperature Reconstructions for the Last 2,000 Years", available from the National Academy Press.
http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html
FarCenter
(19,429 posts)From page 28 of:
http://www.grida.no/climate/ipcc_tar/wg1/pdf/WG1_TAR-FRONT.pdf
advance in understanding of temperature change that occurred
over the last millennium, especially from the synthesis of
individual temperature reconstructions. This new detailed
temperature record for the Northern Hemisphere is shown in
Figure 5. The data show a relatively warm period associated
with the 11th to 14th centuries and a relatively cool period
associated with the 15th to 19th centuries in the Northern
Hemisphere. However, evidence does not support these
Medieval Warm Period and Little Ice Age periods, respectively,
as being globally synchronous. As Figure 5 indicates, the
rate and duration of warming of the Northern Hemisphere in
the 20th century appears to have been unprecedented during the
millennium, and it cannot simply be considered as a recovery
from the Little Ice Age of the 15th to 19th centuries.
This was from the 2004 IPCC report. The discussion in 2007 is more complicated and nuanced. See http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch6s6-6.html
Viking12
(6,012 posts)The Register lies about the significance of the article. You parrot those lies.
FarCenter
(19,429 posts)Viking12
(6,012 posts)You haven't read the paper but I have. It says nothing that supports your false assertions. Read the paper and get back to me.
Lydia Leftcoast
(48,217 posts)in the 20th century.
I've heard a theory that says that the sharp drop in global temperatures around 1400 was precipitated by the Black Death, which killed about 1/3 of the population worldwide beginning around 1340.
That meant 1/3 fewer cooking fires, 1/3 fewer heating fires, 1/3 fewer torches or candles being lit, 1/3 fewer industrial processes, 1/3 less carbon dioxide being pumped into the air.
The population of Europe took 200 years to recover its pre-plague size.
The low point of the Little Ice Age is around 1600, or about 200 years after the original drop. The Earth begins warming up gradually.
Then, as Europe and North America begin to industrialize in the nineteenth century, the temperatures start to shoot up.
It's worth thinking about.
FarCenter
(19,429 posts)See link for graph of population of China from 0 to present of current era. http://www.iiasa.ac.at/Research/SRD/ChinaFood/data/pop/pop_21_m.htm
Population collapse after the Song dynasty is a little early for your theory. Also bear in mind that during this period China and India, as well as other parts of Southeast Asia consisted of the bulk of humanity.
The graph is interesting because it gives one an idea of the steady state carrying capacity of China in the pre fossil fuel era (and probably in the post fossil fuel era), i.e. something less than 10% of the current population.
Tikki
(14,559 posts)When the weather is right...
Tikki
intaglio
(8,170 posts)Lewis is a long time climate change denier and a BIG fan of nuclear power.
I note he give no link to the study he is purportedly citing and seems to quote selectively.
The scientists analyzed the ratio of the oxygen isotopes in the hydration water and in the calcium carbonate. They compared the results with climate conditions established in Northern Europe across a 2,000-year time frame. They found a direct correlation between the rise and fall of oxygen 18 in the crystals and the documented warming and cooling periods.
We showed that the Northern European climate events influenced climate conditions in Antarctica, Lu says. More importantly, we are extremely happy to figure out how to get a climate signal out of this peculiar mineral. A new proxy is always welcome when studying past climate changes.
Note that the important parts of this are these quotes
1) We showed that the Northern European climate events influenced climate conditions in Antarctica, it says nothing about Antarctica being warmer just that a North European climate had some undesignated effect upon the Antarctic
2) More importantly, we are extremely happy to figure out how to get a climate signal out of this peculiar mineral. A new proxy is always welcome when studying past climate changes. i.e. there was a detectable signal from an North European event in Antarctica.
Please treat Mr Page with extreme caution because he specialises in deceit, mainly of himself.