It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Thank you.
Some features of ATS will be disabled while you continue to use an ad-blocker.
(visit the link for the full news article)
A study from NASA’s Goddard Space Flight Center in Greenbelt, Maryland looking at climate data over the past century has concluded that solar variation has made a significant impact on the Earth's climate. The report concludes that evidence for climate changes based on solar radiation can be traced back as far as the Industrial Revolution.
Oceanic Influences on Recent Continental Warming
GILBERT P. COMPO
PRASHANT D. SARDESHMUKH
Climate Diagnostics Center,
Cooperative Institute for Research in Environmental Sciences,
University of Colorado, and
Physical Sciences Division, Earth System Research Laboratory,
National Oceanic and Atmospheric Administration
325 Broadway R/PSD1
Boulder CO 80305-3328
[email protected]
(303) 497-6115
(303) 497-6449
Citation:
Compo, G.P., and P.D. Sardeshmukh, 2008: Oceanic influences on recent continental warming. Climate
Dynamics, doi: 10.1007/s00382-008-0448-9.
This article is published by Springer-Verlag. This author-created version is distributed courtesy of Springer-Verlag.
The original publication is available from www.springerlink.com at
www.springerlink.com...
Abstract
Evidence is presented that the recent worldwide land warming has occurred largely in response to a worldwide warming of the oceans rather than as a direct response to increasing greenhouse gases (GHGs) over land.
Atmospheric model simulations of the last half-century with prescribed observed ocean temperature changes, but without prescribed GHG changes, account for most of the land warming. The oceanic influence has occurred through hydrodynamic-radiative teleconnections, primarily by moistening and warming the air over land and increasing the downward longwave radiation at the surface. The oceans may themselves have warmed from a combination of natural and anthropogenic influences.
Originally posted by Annee
I would like to believe NASA is above being bought.
I don't.
Current warmth seems to be occurring nearly everywhere at the same time and is largest at high latitudes in the Northern Hemisphere. Over the last 50 years, the largest annual and seasonal warmings have occurred in Alaska, Siberia and the Antarctic Peninsula. Most ocean areas have warmed. Because these areas are remote and far away from major cities, it is clear to climatologists that the warming is not due to the influence of pollution from urban areas.
Originally posted by drwizardphd
..............
The changes we are seeing now, for example, are considerably more severe than those recorded during the Medieval Warming Period. They are also being brought on more suddenly, and most scientists attribute that to man..................
Originally posted by ElectricUniverse
Oh boy...sorry but not true. There are "peer-reviewed" research papers from ALL over the world that show that the warming during the Medieval Warm period was worse than that of the late 20th century, or the beginning of the 21st century.
The various studies differ in methodology, and in the underlying paleoclimate proxy data utilized, but all reconstruct the same basic pattern of cool "Little Ice Age", warmer "Medieval Warm Period", and still warmer late 20th and 21st century temperatures.
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.
As the US National Oceanographic and Atmospheric Administration (Noaa) puts it: "The idea of a global or hemispheric Mediaeval Warm Period that was warmer than today has turned out to be incorrect". Additionally, although the Arctic was warmer in the 1930s than in the following few decades, it is now warmer still.
Glacial geological evidence for the medieval warm period
Journal Climatic Change
Publisher Springer Netherlands
ISSN 0165-0009 (Print) 1573-1480 (Online)
Issue Volume 26, Numbers 2-3 / March, 1994
DOI 10.1007/BF01092411
Pages 143-169
Subject Collection Earth and Environmental Science
SpringerLink Date Monday, February 07, 2005
Jean M. Grove1 and Roy Switsur2
(1) Girton College, Cambridge, U.K.
(2) Wolfson College, Cambridge, U.K.
Received: 22 September 1992 Revised: 12 October 1993
Abstract It is hypothesised that the Medieval Warm Period was preceded and followed by periods of moraine deposition associated with glacier expansion. Improvements in the methodology of radiocarbon calibration make it possible to convert radiocarbon ages to calendar dates with greater precision than was previously possible. Dating of organic material closely associated with moraines in many montane regions has reached the point where it is possible to survey available information concerning the timing of the medieval warm period. The results suggest that it was a global event occurring between about 900 and 1250 A.D., possibly interrupted by a minor readvance of ice between about 1050 and 1150 A.D.
CfA Press Release
Release No.: 03-10
For Release: March 31, 2003
20th Century Climate Not So Hot
Cambridge, MA - A review of more than 200 climate studies led by researchers at the Harvard-Smithsonian Center for Astrophysics has determined that the 20th century is neither the warmest century nor the century with the most extreme weather of the past 1000 years. The review also confirmed that the Medieval Warm Period of 800 to 1300 A.D. and the Little Ice Age of 1300 to 1900 A.D. were worldwide phenomena not limited to the European and North American continents. While 20th century temperatures are much higher than in the Little Ice Age period, many parts of the world show the medieval warmth to be greater than that of the 20th century.
P. D. Tyson, W. Karlén, K. Holmgren and G. A. Heiss (in press) The Little Ice Age and Medieval Warming in South Africa. South African Journal of Science.
--------------------------------------------------------------------------------
The Little Ice Age and Medieval Warming in South Africa
P. D. Tyson1, W. Karlén2, K. Holmgren2 and G. A. Heiss3.
1Climatology Research Group, University of the Witwatersrand
2Department of Physical Geography, Stockholm University
3Geomar, Wischhofstr. 1-3, 24148 Kiel, Germany; present address: German Advisory Council on Global Change (WBGU), P.O. Box 120161, 27515 Bremerhaven, Germany, E-mail: [email protected]
Abstract
The Little Ice Age, from around 1300 to 1800, and medieval warming, from before 1000 to around 1300 in South Africa, are shown to be distinctive features of the regional climate of the last millennium. The proxy climate record has been constituted from oxygen and carbon isotope and colour density data obtained from a well-dated stalagmite derived from Cold Air Cave in the Makapansgat Valley.
The climate of the interior of South Africa was around 1oC cooler in the Little Ice Age and may have been over 3°C higher than at present during the extremes of the medieval warm period. It was variable throughout the millennium, but considerably more so during the warming of the eleventh to thirteenth centuries. Extreme events in the record show distinct teleconnections with similar events in other parts of the world, in both the northern and southern hemispheres. The lowest temperature events recorded during the Little Ice Age in South Africa are shown to be coeval with the Maunder and Sporer Minima in solar irradiance. The medieval warming is shown to have been coincided with the cosmogenic 10Be and 14C isotopic maxima recorded in tree rings elsewhere in the world during the Medieval Maximum in solar radiation.
Medieval climate warming and aridity as indicated by multiproxy evidence from the Kola Peninsula, Russia
K.V Kremenetski, a, b, , T Boettgerc, 1, , G.M MacDonalda, 2, , T Vaschalovad, 3, L Sulerzhitskye, 4 and A Hillerf,
aDepartment of Geography, University of California, 1255 Bunche Hall, Los Angeles, CA 90095 1524, USA
bInstitute of Geography, Russian Academy of Sciences, Moscow, Russia
cUFZ Centre for Environmental Research Leipzig–Halle, Germany
dMoscow State University, Moscow, Russia
eGeological Institute, Russian Academy of Sciences, Moscow, Russia
fInstitute of Interdisciplinary Isotope Research, Leipzig, Germany
Received 16 January 2003; accepted 5 February 2004. Available online 23 April 2004.
Abstract
Data obtained from the low-elevation Khibiny Mountains (ca. 67–68°N; 33–34°E) on the Kola Peninsula, northwest Russia, indicate a period of exceptionally warm and dry conditions commenced at ca. AD 600 and was most pronounced between ca. AD 1000 and 1200. Warmer summer temperatures during this period (coeval with the ‘Medieval Warm Period’ observed in other parts of Europe) are evident in a 100–140 m upward shift in the pine (Pinus sylvestris L.) limit in the Khibiny Mountains. On average, the cellulose of pine trees that grew between ca. AD 1000 and 1300 is enriched by δ13C values of around 1‰ compared to the modern trees from the region, further suggesting warmer summer climate than at present. The Medieval Warm Period was also accompanied by a steady decline in avalanche activity and the resulting formation of soils on the current avalanche cones in the Khibiny Mountains, suggesting lower winter precipitation and thinner snow cover. Lower precipitation is also evident by currently submerged tree stumps dating to the medieval period that indicate lower lake levels on the Kola Peninsula. In the middle of the peninsula at about AD 1000, the level of small closed-basin lakes was 1 m lower than the modern time at some sites. Drier conditions may be attributable to decreased cyclonic activity. The medieval warm and dry episode was followed at ca. AD 1300 by the development of a colder climate with increased precipitation resulting in a decline in the alpine pine limits, increased avalanche activity, and higher lake levels. That phase corresponds to the modern aeolian episode reconstructed in subarctic Finland. Our results indicate that the Medieval Warm Period on the Kola Peninsula experienced notably warm and dry conditions. Hence, this period of warming extends to northwestern Russia as well as other parts of Europe.
Evidence for the existence of the medieval warm period in China
Journal Climatic Change
Publisher Springer Netherlands
ISSN 0165-0009 (Print) 1573-1480 (Online)
Issue Volume 26, Numbers 2-3 / March, 1994
DOI 10.1007/BF01092419
Pages 289-297
Subject Collection Earth and Environmental Science
SpringerLink Date Monday, February 07, 2005
De'Er Zhang1
(1) Chinese Academy of Meteorological Sciences, Baishiqiaolu No. 46, 100081 Beijing, China
Abstract The collected documentary records of the cultivation of citrus trees andBoehmeria nivea (a perennial herb) have been used to produce distribution maps of these plants for the eighth, twelfth and thirteenth centuries A.D. The northern boundary of citrus andBoehmeria nivea cultivation in the thirteenth century lay to the north of the modern distribution. During the last 1000 years, the thirteenth-century boundary was the northernmost. This indicates that this was the warmest time in that period. On the basis of knowledge of the climatic conditions required for planting these species, it can be estimated that the annual mean temperature in south Henan Province in the thirteenth century was 0.9 –1.0° C higher than at present. A new set of data for the latest snowfall date in Hangzhou from A.D. 1131 to 1264 indicates that this cannot be considered a cold period, as previously believed.
Paper No. 9-4
Presentation Time: 8:30 AM-5:30 PM
TREE RING EVIDENCE FOR A MEDIEVAL WARM PERIOD IN COLUMBIA BAY, ALASKA
BRADY, Kristina L.1, WILES, Gregory C.1, D'ARRIGO, Rosanne2, and CALKIN, Parker E.3, (1) Geology, The College of Wooster, Wooster, OH 44691, [email protected], (2) Tree ring Lab, Lamont-Doherty Earth Observatory, Palisades, NY 10964, (3) Institute of Arctic and Alpine Research, Univ of Colorado, Boulder, CO 80309
Recent dendroclimatic compilations from Northern Hemisphere temperature-sensitive tree-ring sites support a Medieval Warm Period (MWP) spanning parts of the 8th through 12th centuries AD. A newly-compiled, well-replicated ring-width chronology from Columbia Bay is a record of temperature variation along the maritime southern Alaskan coast and now spans the MWP (AD 774-2000). Over the past two decades the tidewater Columbia Glacier has experienced catastrophic retreat exposing almost 15 km of fjord. The ring-width record here is assembled from living trees and subfossil wood killed by a steady, millennium long glacial advance of the iceberg calving Columbia Glacier margin.
Preliminary dendroclimatic results using Regional Curve Standardization (RCS) techniques to extract a low-frequency climate signal suggest that the multiple decades centered on AD 1050 were warmer relative to the following centuries spanning the Little Ice Age. This warming is consistent with the reconstructed glacial record for the region that shows retracted ice margins during this time.
Cordilleran Section - 99th Annual (April 1–3, 2003)
General Information for this Meeting
Session No. 9--Booth# 40
Undergraduate Research Session (Posters)
Hotel NH Krystal: La Capilla
8:30 AM-5:30 PM, Tuesday, April 1, 2003
--------------------------------------------------------------------------------
© Copyright 2003 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.
Evidence for Climate Variations Induced by the Solar Cycle
William Bruckman1, Elio Ramos2
Department of Physics and Electronics1 and Department of Mathematics2
University of Puerto Rico at Humacao
CUH Station
100 Route 908
Humacao PR 00791-4300
Abstract
We argue that the solar activity cycle induce periodic variations in rain-snow precipitation and sea-air temperatures, that cause mean sea level oscillations. We present observational evidence in favor of the above hypothesis, starting with a brief historical background of studies of solar cycle influence on climate. The evidence indicate that the Solar and Cosmic rays cycles are correlated with changes in temperature and precipitation. We analyzed data for the monthly mean sea level at San Juan and Magueyes Island in Puerto Rico, seeking correlations between sea level fluctuations and solar, cosmic rays and temperature cycles. Our analysis suggest that a solar activity cycle minimum (cosmic ray intensity maximum) correlates with lower than average temperatures and mean sea levels. We discussed, as a posible explanation of the above correlations, that the solar and cosmic rays cycles could cause larger than average accumulation of continental water and snow with lower temperatures contracting the oceans, thus implying lower mean sea levels. If this is the case, we predict that lower than average temperatures and mean sea levels will occur around the year 2009,with a delay of about 2 year after the 2007 solar activity minimum.