Wednesday, July 23, 2014

New paper finds 23% of warming in Europe since 1980 due to clean air laws reducing sulfur dioxide

A paper published today in Geophysical Research Letters finds that clean air laws which greatly reduced sulfur dioxide emissions explain 81% of the "brightening" of sunshine and 23% of the surface warming in Europe since 1980. However, the authors note "this phenomenon is however hardly reproduced by global and regional climate models." 

According to the paper, 
"observed surface solar radiation, as well as land and sea surface temperature spatio-temporal variations over the Euro-Mediterranean region are only reproduced when simulations include the realistic aerosol variations" which the authors state are "however hardly reproduced by global and regional climate models"
"Global brightening" is a well-known global phenomenon which may partially be due to clean air laws reducing sulfate and black carbon aerosols, as well as natural changes in cloud cover. "Global brightening" and "global dimming" show high correlation with global temperatures, yet as this paper notes are "hardly reproduced" by climate models. Another of many highly important variables including ocean oscillationssolar amplification mechanisms, convection, clouds, etc., etc. which climate models do not adequately simulate.

Note: Sulfur dioxide is an actual air pollutant, unlike harmless, essential, & beneficial carbon dioxide, despite the widespread scaremongering propaganda labelling CO2 as "carbon pollution"

Contribution of anthropogenic sulfate aerosols to the changing Euro-Mediterranean climate since 1980

Pierre Nabat et al

Since the 1980s anthropogenic aerosols have been considerably reduced in Europe and the Mediterranean area. This decrease is often considered as the likely cause of the brightening effect observed over the same period. This phenomenon is however hardly reproduced by global and regional climate models. Here we use an original approach based on reanalysis-driven coupled regional climate system modelling, to show that aerosol changes explain 81 ± 16 per cent of the brightening and 23 ± 5 per cent of the surface warming simulated for the period 1980–2012 over Europe. The direct aerosol effect is found to dominate in the magnitude of the simulated brightening. The comparison between regional simulations and homogenized ground-based observations reveals that observed surface solar radiation, as well as land and sea surface temperature spatio-temporal variations over the Euro-Mediterranean region are only reproduced when simulations include the realistic aerosol variations.

New excuse for the 'pause': Negative phase of the natural Interdecadal Pacific Oscillation

Matthew "say anything" England is back with a new paper which offers yet another excuse for the 17+ year pause in global warming: the negative phase of the natural Interdecadal Pacific Oscillation (IPO)  [excuse #14 by my count]. 

The paper comes hot on the heels of another paper by England et al claiming that the 'pause' was due to an entirely different mechanism of strengthened Pacific trade winds, but which was readily debunked by skeptics and apparently not even believed by England himself anymore as he now claims
"We further demonstrate that most non-volcanic hiatuses across CMIP5 models are associated with enhanced cooling in the equatorial Pacific linked to the transition to a negative [Interdecadal Pacific Oscillation] IPO phase."
The natural IPO is a close cousin of the ~60 year Pacific Decadal Oscillation, but with a cycle of 15–30 years, and affects both the North and South Pacific.

England et al boldly claims using the same climate models that did not predict the current pause of almost 18 years that after 2030, no more decadal 'pauses' of global warming will occur, stating, 
Under high rates of greenhouse gas emissions there is little chance of a hiatus decade occurring beyond 2030, even in the event of a large volcanic eruption. 
More circular reasoning from climate scientists that models which utterly failed to simulate the current 'pause' can be used to simulate the probability of a 'pause' in the future. Not to mention, CMIP model projections have already been falsified at confidence levels of 95-98+%. 

As noted by Dr. Roy Spencer,
"...they can’t ignore our arguments any longer. For many years we had been hearing from the “scientific consensus” side that natural climate change is nowhere near as strong as human-caused warming…yet the lack of surface warming in 17 years has forced those same scientists to now invoke natural climate change to supposedly cancel out the expected human-caused warming!
C’mon guys. You can’t have it both ways! They fail to see that a climate system capable of cancelling out warming with natural cooling is also capable of causing natural warming in the first place."

Drivers of decadal hiatus periods in the 20th and 21st Centuries

Nicola Maher, Alexander Sen Gupta, Matthew H. England

The latest generation of climate model simulations are used to investigate the occurrence of hiatus periods in global surface air temperature in the past and under two future warming scenarios. Hiatus periods are identified in three categories, (i) those due to volcanic eruptions, (ii) those associated with negative phases of the Interdecadal Pacific Oscillation (IPO) and (iii) those affected by anthropogenically released aerosols in the mid 20th Century. The likelihood of future hiatus periods is found to be sensitive to the rate of change of anthropogenic forcing. Under high rates of greenhouse gas emissions there is little chance of a hiatus decade occurring beyond 2030, even in the event of a large volcanic eruption. We further demonstrate that most non-volcanic hiatuses across CMIP5 models are associated with enhanced cooling in the equatorial Pacific linked to the transition to a negative IPO phase.

New paper finds climate models unable to simulate the Holocene Climate Optimum & subsequent cooling

A paper under discussion for Climate of the Past finds climate models are unable to simulate the mid-Holocene Climate Optimum from ~4-6 thousand years ago when global temperatures were naturally 2-3C higher than the present. The models are also unable to simulate the gradual cooling from the Holocene Climate Optimum to the Little Ice Age and pre-industrial temperatures.

According to the authors,
"The model does not capture the mid-Holocene "thermal maximum" and gradual cooling to pre-industrial global temperature found in the data."
If climate models are unable to simulate the Holocene Climate Optimum, Roman Warm Period, Dark Ages Cold Period, Medieval Warm Period, and little Little Ice Age over the past 4,000 years, how can they possibly be relied upon to simulate the Current Warm Period or to distinguish natural variability from anthropogenic?


Clim. Past Discuss., 10, 2925-2978, 2014
www.clim-past-discuss.net/10/2925/2014/
doi:10.5194/cpd-10-2925-2014

Global climate simulations at 3000 year intervals for the last 21 000 years with the GENMOM coupled atmosphere–ocean model


J. R. Alder and S. W. Hostetler
US Geological Survey, College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, United States
Abstract. We apply GENMOM, a coupled atmosphere–ocean climate model, to simulate eight equilibrium "time-segments" at 3000 yr intervals for the past 21 000 years forced by changes in Earth-Sun geometry, atmospheric greenhouse gases (GHGs), continental ice sheets and sea level. Simulated global cooling during the Last Glacial Maximum (LGM) is 3.8 °C and the rate of post-glacial warming is in overall agreement with recently published temperature reconstructions. The greatest rate of warming occurs between 15 and 12 ka (2.4 °C over land, 0.7 °C over oceans and 1.4 °C globally) in response to changes in radiative forcing from the diminished extent of the Northern Hemisphere (NH) ice sheets and increases in GHGs and NH summer insolation. The modeled LGM and 6 ka temperature and precipitation climatologies are generally consistent with proxy reconstructions, the PMIP2 and PMIP3 simulations, and other paleoclimate data-model analyses. The model does not capture the mid-Holocene "thermal maximum" and gradual cooling to pre-industrial global temperature found in the data. Simulated monsoonal precipitation in North Africa peaks between 12 and 9 ka at values ~ 50% greater than those of the PI, and Indian monsoonal precipitation peaks at 12 and 9 ka at values ~ 45% greater than the PI. GENMOM captures the reconstructed LGM extent of NH and Southern Hemisphere (SH) sea ice. The simulated present-day Antarctica Circumpolar Current (ACC) is ~ 48% weaker than observed (62 vs. 119 Sv). The simulated present-day Atlantic Meridional Overturning Circulation (AMOC) of 19.3 ± 1.4 Sv on the Bermuda Rise (33° N) is comparable with the observed value of 17.4 Sv. AMOC at 33° N is reduced by ~ 15% during the LGM, and the largest post-glacial increase (~ 11%) occurs, unforced, during the 15 ka time slice.

Tuesday, July 22, 2014

The large increase in Antarctic sea ice since 2002 is real

A new paper is being spun by warmists as debunking the recent record highs in Antarctic sea ice. According to the authors, a change in satellite sensors in December 1991 led to a "significant error" in either the data prior to 12/91 or the data after 12/91, but they don't know which one. It's also curious that this "significant error" occurred 23 years ago, but was not found until Antarctic sea ice hit all-time record highs, and that they don't know whether the data since 12/91 is erroneous or not. 

Color me skeptical, but the alleged step-change in data in 12/91 shown at the red arrow below is not apparent from the data, which shows little to no change in trend from 1979 to 2001. The increasing trend began around 2002, around the same time as global cooling. Regardless of attempts to soften the huge blow to warmism, the sensor and processing algorithm have not changed since 12/91 and thus the recent increasing trend in Antarctic sea ice since ~2002 is real. 



Is Antarctic sea ice cover really setting record highs? Processing errors may be confusing the matter



Date: July 22, 2014

Source: European Geosciences Union (EGU)

Summary: Antarctic sea ice may not be expanding as fast as previously thought, new research suggests. A team of scientists say much of the increase measured for Southern Hemisphere sea ice could be due to a processing error in the satellite data. "This implies that the Antarctic sea ice trends reported in the 2007 and 2013 assessment reports from the Intergovernmental Panel on Climate Change can't both be correct: our findings show that the data used in one of the reports contains a significant error. But we have not yet been able to identify which one contains the error," says the study's lead-author.

New research suggests that Antarctic sea ice may not be expanding as fast as previously thought. A team of scientists say much of the increase measured for Southern Hemisphere sea ice could be due to a processing error in the satellite data. The findings are published today inThe Cryosphere, a journal of the European Geosciences Union (EGU).

Arctic sea ice is retreating at a dramatic rate. In contrast, satellite observations suggest that sea ice cover in the Antarctic is expanding -- albeit at a moderate rate -- and that sea ice extent has reached record highs in recent years. What's causing Southern Hemisphere sea ice cover to increase in a warming world has puzzled scientists since the trend was first spotted. Now, a team of researchers has suggested that much of the measured expansion may be due to an error, not previously documented, in the way satellite data was processed.

"This implies that the Antarctic sea ice trends reported in the IPCC's AR4 and AR5 [the 2007 and 2013 assessment reports from the Intergovernmental Panel on Climate Change] can't both be correct: our findings show that the data used in one of the reports contains a significant error. But we have not yet been able to identify which one contains the error," says lead-author Ian Eisenman of the Scripps Institution of Oceanography at University of California San Diego in the US.

Reflecting the scientific literature at the time, the AR4 reported that Antarctic sea ice cover remained more or less constant between 1979 and 2005. On the other hand, recent literature and the AR5 indicate that, between 1979 and 2012, Southern Hemisphere sea ice extent increased at a rate of about 16.5 thousand square kilometres per year. Scientists assumed the difference to be a result of adding several more years to the observational record.

"But when we looked at how the numbers reported for the trend had changed, and we looked at the time series of Antarctic sea ice extent, it didn't look right," says Eisenman, who set out to figure out what was wrong.

Scientists have used satellite data to measure sea ice cover for 35 years. But the data doesn't come from a single instrument, orbiting on a single satellite throughout this period. Instead, researchers splice together observations from different instruments flown on a number of different satellites. They then use an algorithm -- the most prevalent being the Bootstrap algorithm -- and further processing to estimate sea ice cover from these data.

In the study published in The Cryosphere, Eisenman and collaborators compare two datasets for sea ice measurements. The most recent one, the source of AR5 conclusions, was generated using a version of Bootstrap updated in 2007, while the other, used in AR4 research, is the result of an older version of the algorithm.

The researchers found a difference between the two datasets related to a transition in satellite sensors in December 1991, and the way the data collected by the two instruments was calibrated. "It appears that one of the records did this calibration incorrectly, introducing a step-like change in December 1991 that was big enough to have a large influence on the long-term trend," explains Eisenman.

"You'd think it would be easy to see which record has this spurious jump in December 1991, but there's so much natural variability in the record -- so much 'noise' from one month to the next -- that it's not readily apparent which record contains the jump. When we subtract one record from the other, though, we remove most of this noise, and the step-like change in December 1991 becomes very clear."

With the exception of the longer time period covered by the most recent dataset, the two records were thought to be nearly identical. But, by comparing the datasets and calculating Antarctic sea ice extent for each of them, the team found that there was a stark difference between the two records, with the current one giving larger rates of sea ice expansion than the old one in any given period.

If the error is in the current dataset, the results could contribute to an unexpected resolution for the Antarctic sea ice cover enigma.


Journal Reference:
I. Eisenman, W. N. Meier, J. R. Norris. A spurious jump in the satellite record: has Antarctic sea ice expansion been overestimated? The Cryosphere, 2014; 8 (4): 1289 DOI: 10.5194/tc-8-1289-2014

New poster claims Exxon is the biggest climate 'contrarian'

The climate alarmists on Twitter are in a fuss today about a new chart by Dr. Joanna Boehnert, a "visiting fellow" at the "Cooperative Institute for Research in Environmental Sciences" at the U. of Colorado, which claims to "map" climate communication from "neoliberalism" to "contrarian" and "climate science" to "climate justice."

According to the chart, Exxon-Mobile (the big red circle in the upper right) is the biggest "contrarian" "climate justice actor," demonstrably false as Exxon-Mobile hasn't given anything to climate think-tank organizations for many years, while donating many millions to climate alarmist organizations. It's more of the same false meme repeated over and over by warmists that climate skeptics are funded by the oil industry, disproven time and again.

Reading the fine print on Dr. Boehnert's blog, she admits "the size of the circles and their positions are all speculative," i.e. not based upon any objective data whatsoever. Good enough for alarmist work. 


The "map" is rather amusing, giving circles to "Skeptical Science", but not WUWT or Climate Depot which have much higher traffic, gives circles to Bill McKibben and Michael Mann, but not Anthony Watts or Steve McIntyre, etc. etc., have a look:



from Dr. Beohnert's blog:


Mapping Climate Communication, new posters July 2014


Network of Actors, USA and UK Based Organizations and Individuals.  Version 1. July 2014
The poster illustrates relationships between prominent actors and major organizations participating in climate communication. These include: science institutions, media organizations, think tanks, government departments, non-governmental organization (NGOs) and individuals – along with some of the more significant funders. Actors are situated within four discursive realms: climate science; counter-movements (contrarianism); ecological modernization (often neoliberalism); and social movements (climate justice). These four discourses are mapped on a framework wherein actors are colour-coded according to where they are situated. In this first version the colour, the size of the circles and their positions are all speculative. Subsequent versions will use different methods for plotting the actors and linking the nodes.

New paper finds another non-hockey-stick in Romania

A paper published today in Climate of the Past finds another non-hockey-stick in Romania, with temperatures higher for hundreds of years during the mid-Holocene Climate Optimum, Roman Warm Period, and Medieval Warm Period in comparison to the end of the record in the mid-20th century. 

Interestingly, the d13C proxy for CO2 levels is also found to be higher during the mid-Holocene Climate Optimum, and between the Roman and Medieval Warm periods in comparison to the end of the record in the mid-20th century. The proxy is obtained from stalagmites and thus reflects CO2 levels present within the cave studied. 

The paper adds to over 1000 other peer-reviewed papers finding non-hockey-sticks worldwide. 

Top graph of d18O is a proxy for precipitation and temperature. Bottom graph d13C is a proxy of CO2 levels. Horizontal axis is thousands of years before the present. 

Clim. Past, 10, 1363-1380, 2014
www.clim-past.net/10/1363/2014/
doi:10.5194/cp-10-1363-2014

Constraining Holocene hydrological changes in the Carpathian–Balkan region using speleothem δ18O and pollen-based temperature reconstructions
V. Drăguşin1,2,3, M. Staubwasser3, D. L. Hoffmann4, V. Ersek5,6, B. P. Onac7,8, and D. Veres8
1Emil Racoviţă Institute of Speleology, Romanian Academy, Frumoasă 31, 010986, Bucharest, Romania
2Department of Geology, Babeş-Bolyai University, Kogălniceanu 1, 400084, Cluj-Napoca, Romania
3Institute of Geology and Mineralogy, University of Cologne, Greinstrasse 4–6, 50939, Cologne, Germany
4National Research Centre for Human Evolution, Paseo Sierra de Atapuerca, s/n, 09002 Burgos, Spain
5Department of Geography, Northumbria University, Ellison Building, NE1 8ST, Newcastle upon Tyne, UK
6Department of Earth Sciences, University of Oxford, South Parks Rd, OX1 3AN, Oxford, UK
7School of Geosciences, University of South Florida, 4202 E. Fowler Ave., NES 107, FL 33620, Tampa, USA
8Institute of Speleology, Romanian Academy, Clinicilor 5, 400006, Cluj-Napoca, Romania

Abstract. Here we present a speleothem isotope record (POM2) from Ascunsă Cave (Romania) that provides new data on past climate changes in the Carpathian–Balkan region from 8.2 ka until the present. This paper describes an approach to constrain the effect of temperature changes on calcite δ18O values in stalagmite POM2 over the course of the middle Holocene (6–4 ka), and across the 8.2 and 3.2 ka rapid climate change events. Independent pollen temperature reconstructions are used to this purpose. The approach combines the temperature-dependent isotope fractionation of rain water during condensation and fractionation resulting from calcite precipitation at the given cave temperature. The only prior assumptions are that pollen-derived average annual temperature reflects average cave temperature, and that pollen-derived coldest and warmest month temperatures reflect the range of condensation temperatures of rain above the cave site. This approach constrains a range of values between which speleothem δ18O changes should be found if controlled only by surface temperature variations at the cave site. Deviations of the change in δ18Ocspel values from the calculated temperature-constrained range of change are interpreted towards large-scale variability of climate–hydrology.

Following this approach, we show that an additional ∼0.6‰ enrichment of δ18Oc in the POM2 stalagmite was caused by changing hydrological patterns in SW Romania across the middle Holocene, most likely comprising local evaporation from the soil and an increase in Mediterranean moisture δ18O. Further, by extending the calculations to other speleothem records from around the entire Mediterranean basin, it appears that all eastern Mediterranean speleothems recorded a similar isotopic enrichment due to changing hydrology, whereas all changes recorded in speleothems from the western Mediterranean are fully explained by temperature variation alone. This highlights a different hydrological evolution between the two sides of the Mediterranean.

Our results also demonstrate that during the 8.2 ka event, POM2 stable isotope data essentially fit the temperature-constrained isotopic variability. In the case of the 3.2 ka event, an additional climate-related hydrological factor is more evident. This implies a different rainfall pattern in the Southern Carpathian region during this event at the end of the Bronze Age.

US Naval Research Lab models atmospheric temperatures without using CO2

Interesting, the US Naval Research Laboratory's empirical, global model of the Earth’s atmospheric temperature profile from ground to space is based only upon atmospheric mass densities, solar flux, and molecular composition sans CO2, with no input or consideration of CO2 levels or CO2 'radiative forcing'. Could it possibly be that atmospheric mass, pressure, gravity and solar flux determine the temperature profile of the atmosphere, not radiative forcing from CO2?

Reblogged from Malaga Bay:

Atmospheric Science: US Standard Atmosphere 1962

A sad example of the Mushroom Management that is endemic in Wikipedia is the breathtaking inclusion of a diagram [in their Atmosphere of Earth article] based upon the 1962 US Standard Atmosphere.
Evidently, Wikipedia thinks Atmospheric Science hasn’t advanced in the last 52 years.
Wikipedia Atmosphere of Earth
US_standard_atmosphere_1962
However, 1962 was a long time ago.
1962 saw the Beatles release their first single in the United Kingdom. 
1962 saw the arrival of the trijet airliner.
1962 saw John Glenn orbit the Earth three times.
1962 saw Europe still enjoying black and white television.
Scrolling down the Atmosphere of Earth article we find that Wikipedia has included a graph from the NRLMSISE-00 standard atmosphere model.
NRLMSISE-00 standard atmosphere - portrait
Temperature and mass density against altitude from the NRLMSISE-00 standard atmosphere model (the eight dotted lines in each “decade” are at the eight cubes 8, 27, 64, …, 729)
NRLMSISE-00 is apparently a model of the “Earth’s atmosphere from ground to space” developed by the US Naval Research Laboratory.
NRLMSISE-00 is an empirical, global model of the Earth’s atmosphere from ground to space. It models the temperatures and densities of the atmosphere’s components. A primary use of this model is to aid predictions of satellite orbital decay due to atmospheric drag. This model has also been used by astronomers to calculate the mass of air between telescopes and laser beams in order to assess the impact of laser guide stars on the non-lasing telescopes.
The model, developed by Mike Picone, Alan Hedin, and Doug Drob, is based on the earlier models MSIS-86 and MSISE-90, but updated with actual satellite drag data. It also predicts anomalous oxygen.
NRL stands for the US Naval Research Laboratory.
MSIS stands for Mass Spectrometer and Incoherent Scatter Radar respectively, the two primary data sources for development of earlier versions of the model.
E indicates that the model extends from the ground through exosphere and 00 is the year of release.
Although NRLMSISE-00 can model the Earth’s atmosphere from ground to space Wikipedia only manages to provide a graph detailing the first 150 kilometres of the atmosphere.
Additionally, the example NRLMSISE-00 graph is not directly comparable with the 1962 US Standard Atmosphere because tucked away on the associated image page we learn that the NRLMSISE-00 graph was produced using the following parameters:
Day = 172
UT(Sec) = 29000
Geodetic Latitude(Deg) = 60
Geodetic Longitude(Deg) = 120
Local Apparent Solar Time(Hrs) = 16
81 day Average of F10.7 Flux = 150
Daily F10.7 Flux for Previous Day = 150
AP=Magnetic Index (Daily) = 4

On the positive side these parameters provide a wonderful insight into what the mainstream currently believe controls the density and temperature profiles of the Earth’s atmosphere.
Intriguingly, the NRLMSISE-00 model doesn’t have a parameter for CO2.
An additional bonus is that the Wikipedia article relating to the U.S. Standard Atmosphere provides a graphic detailing the “composition by volume of Earth’s atmosphere” [excluding water vapour] which is more comprehensive than the table provided by Wikipedia in their Atmosphere of Earth article.
Atmospheric_composition_Langley
Furthermore, this Wikipedia article also provides a link to the 1976 version of the U.S. Standard Atmosphere…
Added: see also the model documentation here, which shows assumptions for the molecular composition of the atmosphere including O3, N2O, O2, Ar, H2O, and N2, but no mention of CO2 anywhere. 

New paper finds transient climate sensitivity to doubled CO2 levels is only about 1C

A new paper published in Ecological Modelling finds climate sensitivity to doubled CO2 concentrations is significantly lower than estimates from the IPCC and climate models which "utilize uncertain historical data and make various assumptions about forcings." The author instead uses a 'minimal model' with the fewest possible assumptions and least data uncertainty to derive a transient climate sensitivity of only 1.093C:
"A minimal model was used that has the fewest possible assumptions and the least data uncertainty. Using only the historical surface temperature record, the periodic temperature oscillations often associated with the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation were estimated and subtracted from the surface temperature data, leaving a linear warming trend identified as an anthropogenic signal. This estimated rate of warming was related to the fraction of a log CO2 doubling from 1959 to 2013 to give an estimated transient sensitivity of 1.093 °C (0.96–1.23 °C 95% confidence limits) and equilibrium climate sensitivity of 1.99 °C (1.75–2.23 °C). It is argued that higher estimates derived from climate models are incorrect because they disagree with empirical estimates."
Otto et al find equilibrium climate sensitivity [over the next several centuries] is only ~1.3 times greater than transient climate sensitivity, thus the estimate of 1.093C transient sensitivity could be associated with as little as 1.4C equilibrium sensitivity, less than half of the implied IPCC central estimate in AR5 of ~3.3C.

Moreover, this paper does not assume any solar forcing or solar amplification mechanisms. The integral of solar activity plus ocean oscillations explain ~95% of global temperature change over the past 400 years. Including potential solar forcing into the 'minimal model' could substantially reduce estimated climate sensitivity to CO2 to a much greater extent. 

Empirical estimates of climate sensitivity are highly uncertain.
Anthropogenic warming was estimated by signal decomposition.
Warming and forcing were equated in the time domain to obtain sensitivity.
Estimated sensitivity is 1.093 °C (transient) and 1.99 °C (equilibrium).
Empirical study sensitivity estimates fall below those based on GCMs [Global Circulation Models].

Abstract

Climate sensitivity summarizes the net effect of a change in forcing on Earth's surface temperature. Estimates based on energy balance calculations give generally lower values for sensitivity (< 2 °C per doubling of forcing) than those based on general circulation models, but utilize uncertain historical data and make various assumptions about forcings. A minimal model was used that has the fewest possible assumptions and the least data uncertainty. Using only the historical surface temperature record, the periodic temperature oscillations often associated with the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation were estimated and subtracted from the surface temperature data, leaving a linear warming trend identified as an anthropogenic signal. This estimated rate of warming was related to the fraction of a log CO2 doubling from 1959 to 2013 to give an estimated transient sensitivity of 1.093 °C (0.96–1.23 °C 95% confidence limits) and equilibrium climate sensitivity of 1.99 °C (1.75–2.23 °C). It is argued that higher estimates derived from climate models are incorrect because they disagree with empirical estimates.


Monday, July 21, 2014

New paper finds a decrease of sunshine in Iran since 2000. A cause of the 'pause'?

A paper published today in the International Journal of Climatology finds dimming of sunshine occurred in Iran from the early 1960's to late 1970's [during the 1970's ice age scare], followed by sunshine brightening from the early 1980's through the end of the 20th century [in alignment with global warming], and a renewed dimming during the 2000's [in alignment with the 'pause' of global warming]. 

According to the authors,
"The annual sunshine duration mean time series shows a decrease from the early 1960s to the late 1970s, in line with the widespread dimming of surface solar radiation observed during this period. By the early 1980s, there is an increase in sunshine through the end of the 20th century, aligning with a well-known and well-documented brightening period. In addition, a renewed dimming is observed during the 2000s, with a sharp drop in 2009."
Many other peer-reviewed papers have documented "global dimming" and "global brightening" observed worldwide during these same approximate periods, and which correlate remarkably well to global temperature changes. Sunshine [solar radiation which reaches the surface after clouds/aerosols] is much better correlated to global temperature changes than CO2 levels [of which only 15 ppm or 0.0015% of the atmosphere is from burning of fossil fuels]. 



New evidence on the dimming/brightening phenomenon and decreasing diurnal temperature range in Iran (1961–2009)

Fatemeh Rahimzadeh et al

For a better understanding of multidecadal climate change, as well as for the production of solar power, there is a growing need for knowledge of the trends in incident sunlight at the Earth's surface, but a lack of a long-term sunlight time series dictates that a proxy measure is needed. In this study, variations of sunshine duration and diurnal temperature range (DTR) are used as proxies for surface solar radiation. Annual and seasonal composites of both variables from 29 stations are analyzed from 1961 through 2009 across the different types of climates of Iran. The annual sunshine duration mean time series shows a decrease from the early 1960s to the late 1970s, in line with the widespread dimming of surface solar radiation observed during this period. By the early 1980s, there is an increase in sunshine through the end of the 20th century, aligning with a well-known and well-documented brightening period. In addition, a renewed dimming is observed during the 2000s, with a sharp drop in 2009. A linear trend estimated over the 1961–2009 period was not found to be statistically significant. However, the annual DTR [daily temperature range] time series shows a widespread and statistically significant decrease since the 1960s, although the series ends without relevant variations after the 1990s. An agreement in the interannual variability of sunshine and DTR is observed except for the summer season. On decadal time scales, only the spring DTR series shows a partial agreement with sunshine series. Nevertheless, the recent leveling off in the DTR series supports a transition in the radiative regime.

Sunday, July 20, 2014

New paper unexpectedly finds diverging trends in global temperature & radiative imbalance from greenhouse gases

Unsettled science:

A new paper published in Geophysical Research Letters finds that the radiative imbalance from greenhouse gases at the top of the atmosphere has increased over the past 27 years while the rate of global warming has unexpectedly decreased or 'paused' over the past 15+ years.

This finding contradicts expectations from AGW theory of increased 'heat trapping' from increased greenhouse gases. However, the finding is consistent with radiosonde observations showing that outgoing longwave radiation to space from greenhouse gases has unexpectedly increased rather than decreased over the past 62 years, inconsistent with more heat being "trapped" in the mid-upper troposphere. 


According to the authors, the radiative imbalance from 1985-1999 was less than from 2000-2012 during the 'pause' in global surface temperatures. 
"Over the 1985-1999 period mean N [radiative imbalance] (0.34 ± 0.67 WM–2) is lower than for the 2000-2012 period (0.62 ± 0.43 WM–2, uncertainties at 90% confidence level) despite the slower rate of surface temperature rise since 2000."
The authors find that the radiative imbalance at the top of the atmosphere is correlated to natural variability including ENSO and volcanic eruptions:
"While the precise magnitude of [radiative imbalance] remains uncertain, the reconstruction captures interannual variability which is dominated by the eruption of Mt. Pinatubo in 1991 and the El Niño Southern Oscillation."

However, Willis Eschenbach has shown radiative imbalances at the top of the atmosphere from the Pinatubo eruption have had essentially no effect on surface temperatures, which is observational evidence that emergent thermodynamic phenomena control temperature and the climate, rather than radiative imbalance from greenhouse gases at the top of the atmosphere.


Changes in global net radiative imbalance 1985-2012

Richard P. Allan, et al


Abstract

Combining satellite data, atmospheric reanalyses and climate model simulations, variability in the net downward radiative flux imbalance at the top of Earth's atmosphere (N) is reconstructed and linked to recent climate change. Over the 1985-1999 period mean N (0.34 ± 0.67 WM–2) is lower than for the 2000-2012 period (0.62 ± 0.43 WM–2, uncertainties at 90% confidence level) despite the slower rate of surface temperature rise since 2000. While the precise magnitude of N remains uncertain, the reconstruction captures interannual variability which is dominated by the eruption of Mt. Pinatubo in 1991 and the El Niño Southern Oscillation. Monthly deseasonalized interannual variability in N generated by an ensemble of 9 climate model simulations using prescribed sea surface temperature and radiative forcings and from the satellite-based reconstruction is significantly correlated (r ∼ 0.6) over the 1985-2012 period.

New paper finds significantly more solar & less greenhouse gas climate forcing than IPCC claims over past 120 years

A new paper published in the Journal of Geophysical Research Atmospheres finds the change in shortwave forcing from the Sun [0.76 W/m2 per decade] exceeded that of longwave forcing from greenhouse gases [0.64 W/m2 per decade] over the past 120 years in Potsdam, Germany, one of the few worldwide sites with sufficient long-term observations. The authors find water vapor alone was responsible for 3/4 of this change in longwave forcing, with only 25% of the longwave forcing [0.16W/m2 per decade, total 1.92 W/m2 over 120 years] attributable to all man-made greenhouse gases including CO2. 

In contrast, the IPCC claims CO2, methane, nitrous oxide, and other man-made greenhouse gases have produced a total ~2.7 W/m2 in longwave forcing since pre-industrial times, i.e. about 29% more radiative forcing than found by the long-term observations in this new paper. The shortwave forcing from the Sun after albedo/aerosols was +9.12 W/m2 over the 120 years, 9.7 times more than the IPCC claim of negative 1.05 W/m2 forcing from the Sun + aerosols since pre-industrial times. 


According to the authors,
"Three-quarters of the increase in the long-wave flux was due to changes in the water content of the lower atmosphere; the remainder was attributed to increases in CO2 and other anthropogenic, radiatively active gases. Over the period radiative forcing in the short-wave flux slightly exceeded that in the long-wave but its effect on air temperature was much less as the climate sensitivity to atmospheric radiation, 0.187 °C per Wm−2, was three times greater than to short-wave global radiation. This anomalous finding, similar to that previously reported at two coastal sites, awaits explanation..."
This "anomalous finding" is quite a paradox, since "for [climate sensitivity] to be useful, the measure must be independent of the nature of the forcing (e.g. from greenhouse gases or solar variation)." Potential reasons for this anomaly include assumptions made to calculate longwave forcing [which was not directly measured] on the basis of pressure & humidity, and questionable blackbody assumptions. 
In addition, the authors find no indication of a trend in precipitation amount or variability over the past 120 years, in contrast to alarmist claims.

The authors attribute the significant increase in specific humidity to a reduction in cloud cover and/or pollution [black carbon]:
"The significant increase in specific humidity measured at Potsdam in the early 1980's (Fig. 3) which amplified the down-welling long-wave flux, indicates an increased frequency of warmer, moister air masses reaching the region. The significant increase in global radiation measured at the same time (Fig. 3) indicates a reduction in cloud cover and/or pollution." 
And find, "low levels of solar activity promote frequent and persistent atmospheric blocking events in the eastern North Atlantic which modify the flow of Westerly winds leading to an increased frequency of cold winters in Europe" [and the US], i.e. ascribing jet stream dips and the polar vortex to solar activity, not global warming as alarmists have claimed. 
"Changes in circulation patterns over Europe have been shown to occur on both decadal and centennial time periods. Over the 1958 to 1998 period an increase in the frequency of anti-cyclonic circulation patterns in winter took place between the late 1960's and the early 1990's followed by a decline and a sharp increase in persistence (mean residence time) of allcirculation types in winter around 1990 and of anti-cyclonic types in summer during the 1990's (Kysely and Huth, 2006). On a millennial time scale proxy measures were used toreconstruct the temperature and salinity conditions in the North Atlantic with a sub decadal resolution over the 818 to 1780 period. The variations found were highly correlated with those in climate simulated over the past millennium and in total solar irradiance. Simulations of the changes in atmospheric circulation over this period indicated that low levels of solar activity promote frequent and persistent atmospheric blocking events in the eastern North Atlantic which modify the flow of Westerly winds leading to an increased frequency of cold winters in Europe (Moffa-Sanchez et al, 2014)."

Radiative forcing and temperature change at Potsdam between 1893 and 2012 


Gerald Stanhill and Ori Ahiman

Abstract

Radiative forcing in both the short and long-wave lengths reaching the Earth's surface accounted for more than 80% of the inter-annual variations in the mean yearly temperatures measured at Potsdam, Germany during the last 120 years. Three-quarters of the increase in the long-wave flux was due to changes in the water content of the lower atmosphere; the remainder was attributed to increases in CO2 and other anthropogenic, radiatively active gases. Over the period radiative forcing in the short-wave flux slightly exceeded that in the long-wave but its effect on air temperature was much less as the climate sensitivity to atmospheric radiation, 0.187 °C per Wm−2, was three times greater than to short-wave global radiation. This anomalous finding, similar to that previously reported at two coastal sites, awaits explanation as does the complex interaction existing between radiative forcing and advection [horizontal movement of air] in determining temperature change.

New paper finds Asian aerosols are not a valid excuse for the 'pause' in global warming

A new paper published in Geophysical Research Letters finds that Asian aerosol emissions do not explain the hiatus in global temperature over the past 15+ years. Chinese/Asian aerosols are one of the 12+ excuses for the 'pause' or 'hiatus' in global warming that have appeared in the scientific literature. According to the authors, the net global effects of changes in sulfate and black carbon aerosols over the past 15 years increased radiative forcing, which would increase rather than decrease warming. 

According to the authors,
"Increases in Asian aerosol emissions have been suggested as one possible reason for the hiatus in global temperature increase during the past 15 years.  
We find that the increased Asian emissions have had very little regional or global effects, while the emission reductions in Europe and the U.S. have caused a positive radiative forcing. 
In Asia, the Black Carbon warming due to sunlight absorption has largely offset the cooling caused by sulphate aerosols. Asian Black Carbon concentrations have increased by a nearly constant fraction at all altitudes, and thus, they warm the atmosphere also in cloudy conditions."
Of course, this would suggest that natural variability overwhelms any effect of mankind from either aerosols or greenhouse gases upon climate. Climate alarmists "fail to see that a climate system capable of cancelling out warming with natural cooling is also capable of causing natural warming in the first place."

Climate impacts of changing aerosol emissions since 1996

T. Kühn et al

Increases in Asian aerosol emissions have been suggested as one possible reason for the hiatus in global temperature increase during the past 15 years. We study the effect of sulphur and black carbon (BC) emission changes between 1996 and 2010 on the global energy balance. We find that the increased Asian emissions have had very little regional or global effects, while the emission reductions in Europe and the U.S. have caused a positive radiative forcing. In our simulations, the global-mean aerosol direct radiative effect changes by 0.06 W/m2 during 1996 to 2010, while the effective radiative forcing (ERF) is 0.42 W/m2. The rather large ERF arises mainly from changes in cloudiness, especially in Europe. In Asia, the BC warming due to sunlight absorption has largely offset the cooling caused by sulphate aerosols. Asian BC concentrations have increased by a nearly constant fraction at all altitudes, and thus, they warm the atmosphere also in cloudy conditions.

Friday, July 18, 2014

WSJ: 'Aussies hated having their energy prices raised so elites could feel good about themselves'

Tony Abbott's Leadership Lesson

By MARY KISSEL
July 18, 2014 12:32 p.m. ET   THE WALL STREET JOURNAL

Australian Prime Minister Tony Abbott fulfilled a major campaign pledge Thursday when his government voted to repeal the country's carbon tax, provoking wailing from the political left and green groups about climate Armageddon. The smarter analysis is that Mr. Abbott proved that conviction politicians are rewarded when their ideas have economic merit—and are clearly explained—to the electorate. Republicans should take note.

Australia's conservative Liberal Party started to embrace the questionable science of man-made climate change under former Prime Minister John Howard, and the trend continued after the Liberals lost the 2007 national election. Opposition leader Malcolm Turnbull, a wealthy banker who hails from one of Sydney's toniest suburbs, had the Liberals endorse the Labor government's carbon-tax proposal. Predictably, the Liberals went nowhere in the polls.

Ordinary Aussies, as it turns out, hated the idea of having their energy prices raised so that elites in Melbourne and other urban centers could feel good about themselves. (Australians already pay some of the highest energy prices in the developed world.) Mr. Abbott understood that sentiment and challenged Mr. Turnbull in December 2010 for the party leadership—and won by a single vote. The same day, he declared the carbon tax "a great big tax to create a great big slush fund to provide politicized handouts, run by giant bureaucracy." No nuance there.

Mr. Abbott spent the next two years touring the country and patiently explaining, at every opportunity, why it would be economic suicide for Australia, which accounts for 1.2% of the world's carbon emissions, to self-impose an energy tax that would do nothing to help "save the planet" and would slow economic growth. He also questioned climate science, as have prominent scientists at Princeton, MIT and elsewhere. The Labor Party ridiculed him for his stance, as did local media worthies like Peter Hatcher, Michelle Grattan and Laurie Oakes.

But Mr. Abbott stuck to his guns. In 2010 he took the Liberal Party to the polls on a pledge to "axe the tax" and would've become prime minister that year, had a few rural politicians not bucked the popular vote in their constituencies and thrown their support to the Labor Party. Last year Mr. Abbott finally did ride to victory—by a landslide—touting the very same message. His government immediately laid the groundwork to repeal the tax, which was sealed by the Senate vote Thursday.

Many Republicans in this country have bought into the idea that the American public is so fed up with President Obama's lousy economic record, bureaucratic scandals (VA, IRS, HHS) and failing foreign policy that they don't have to outline any serious ideas of their own before the November mid-term elections. Mr. Abbott shows what can be accomplished when a politician has a clear idea about policy, explains it, and has the courage to fight elections to get a popular mandate to implement it. As they say Down Under, "Good on ya, Tony."

Thursday, July 17, 2014

Paper predicts increased precipitation in Antarctica will slow sea level rise by > 1 mm/yr

Comment by Frank Walters, elevated to a post:

I found an interesting paper: Antarctic precipitation and climate-change predictions: horizontal resolution and margin vs plateau issues, by C. GENTHON, G. KRINNER, H. CASTEBRUNET (Annals of Glaciology 50 2009)

The paper suggests that the INCREASE in snow and ice on the margins of Antarctica may cause the rate of rise in global sea level to be 1 mm per year LESS than the rate of rise otherwise expected..

The increase in sea ice can be linked to increase in precipitation on the margins of Antarctica. This is what one would expect intuitively, since the melting of the grounded coastal ice in accompanied by an endothermic process that causes refreezing as sea ice.

A buildup of snow on top of the glacier adds weight and causes strain within the ice (shear) and thus increases the amount of ice moving down slope and calving from the seaward margin of the grounded ice.

What needs to be explained is the increase in precipitation over the margins of Antarctica.

Since the interior of the continent is a desert, snowfall on the plateau can be ignored.


Full paper available here:

Antarctic precipitation and climate-change predictions: horizontal resolution and margin vs plateau issues

C. GENTHON, G. KRINNER, H. CASTEBRUNET

ABSTRACT. All climate models participating in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, as made available by the Program for Climate Model Diagnosis and Intercomparison (PCMDI) as the Coupled Model Intercomparison Project 3 (CMIP3) archive, predict a significant surface warming of Antarctica by the end of the 21st century under a moderate (SRESA1B) greenhouse-gas scenario. All models but one predict a concurrent precipitation increase but with a large scatter of results. The models with finer horizontal resolution tend to predict a larger precipitation increase. Because modeled Antarctic surface mass balance is known to be sensitive to horizontal resolution, extrapolating predictions from the different models with respect to model resolution may provide simple yet better multi-model estimates of Antarctic precipitation change than mere averaging or even more complex approaches. Using such extrapolation, a conservative estimate of the predicted precipitation increase at the end of the 21st century is +30 kg m–2 a–1 on the grounded ice sheet, corresponding to a > 1mm a–1 sea-level rise [i.e. equivalent to 1 mm less sea level rise & acting as a negative feedback]. About three-quarters of this rise originates from the marginal regions of the Antarctic ice sheet with surface elevation below 2250 m. This is where field programs are most urgently needed to better understand and monitor accumulation at the surface of Antarctica, and to improve and verify prediction models.

New paper finds Medieval Warm Period was global & significantly warmer than the present, rejects Mann's hockey stick

A new paper examines 258 worldwide temperature proxy datasets and finds "the Medieval Warm Period was a global phenomenon significantly warmer than the recent warm period." The paper also corroborates other papers including by McIntyre, McKitrick, Soon, Baliunas, et al, refuting Michael Mann's erroneous statistical methods which generate hockey sticks from random numbers, among other atrocities.

Excerpt from the conclusion:
"temperature breaks and peaks are centered within the Middle Ages so that, given the large geographical scope covered by the available data, we may conclude that the Medieval Warm Period was a global phenomenon significantly warmer than the recent warm period"

Testing the hockey-stick hypothesis by statistical analyses of a large dataset of proxy records

Guido Travaglini

Abstract

This paper is a statistical time-series investigation addressed at testing the anthropogenic climate change hypothesis known as the “hockey-stick”. The time-series components of a select batch of 258 long-term yearly Climate Change Proxies (CCP) included in 19 paleoclimate datasets, all of which running back as far as the year 2192 B.C., are reconstructed by means of univariate Bayesian Calibration. The instrumental temperature record utilized is the Global Best Estimated Anomaly (BEA) of the HADCRUT4 time series readings available yearly for the period 1850-2010. After performing appropriate data transformations, Ordinary Least Squares parameter estimates are obtained, and subsequently simulated by means of multi-draw Gibbs sampling for each year of the
pre-1850 period. The ensuing Time-Varying Parameter sequence is utilized to produce high-resolution calibrated estimates of the CCP series, merged with BEA to yield Millennial-scale Time Series (MTS). Finally, the MTS are individually tested for temperature single break date and multiple peak dates. As a result, the estimated temperature breaks and peaks suggest widespread rejection of the hockey-stick hypothesis since they are mostly centered in the Medieval Warm Period.

WSJ: Australia's Carbon Tax Message: Climate absolutists have a problem- democracy

Australia's Carbon Tax Message
Tony Abbott shows that climate absolutists have a problem: democracy.

July 17, 2014 12:56 p.m. ET

Tony Abbott scored a big win Thursday when the Senate repealed Australia's carbon tax, fulfilling the Prime Minister's most prominent promise from last year's election. The global intelligentsia is now making Mr. Abbott public climate enemy number one, but he deserves applause for honoring his campaign pledge and removing a burden on the Australian economy. As the first developed nation to rebel against the cost of climate scare-mongering, Australia could start a trend that has greens worried.

Mr. Abbott's Liberal Party doesn't control the Senate and so had to enlist the support of Clive Palmer, a colorful entrepreneur-turned-politician whose Palmer United Party holds three seats. Mr. Palmer generally turned the debate into a circus that included an appearance by Al Gore, who somehow was led to believe that repealing the tax would lead to a cap-and-trade scheme.

This made it possible for most of the world's media to ignore the reason the tax had to go: The public hates it. Somehow Australians don't buy the argument of Greens party leader Christine Milne that without a carbon tax the country will become "a global pariah."

Five years ago Australia was in the vanguard of the anticarbon crusade. As Tom Switzer writes nearby, Labor Prime Minister Kevin Rudd set out to pass a cap-and-trade scheme in 2009, but failed to strike a deal with an opposition leadership then ready to support it. When the rest of the world then declined to sign up to expensive carbon-reduction measures at the Copenhagen summit that December, Mr. Rudd looked even more foolish.

Two defeats in the Senate paved the way for a leadership challenge in 2010 by Julia Gillard, who promised not to impose a carbon tax. But Ms. Gillard still lost seats in parliament, and at the behest of her coalition partners in the Greens the new Prime Minister reneged and pressed ahead with the unpopular levy of A$23 (US$21.54) per ton of carbon. That further weakened the Labor Party and set up Mr. Abbott to win election last year on a platform of repeal.

The government's own figures estimate the tax added A$9.90 to the average household's weekly power bill. The burden to industry has been even greater, exacerbating Australia's loss of competitiveness in manufacturing. The tax was due to increase to A$25.40 on July 1, and then become a cap-and-trade scheme in 2015. In Europe the spot price for carbon hovers around A$7 (€5) per ton.

Some economists we respect support a carbon tax as the most transparent and efficient way to impose a cost on fossil-fuel production. And such a levy might make economic sense if it replaced entirely another kind of tax—say, the personal income tax. But in practice as in Australia, it always becomes an additional tax that puts more of the private economy under political control.

Mr. Abbott's views reflect those of a public that cares about environmental matters but not at the expense of reducing economic growth. Australians also don't want to bear inordinate costs for carbon reduction when they produce only 1.2% of the world's emissions. The climate dogmatists denounce anyone who disagrees as "deniers" or worse, but Australia's vote shows that the real obstacle to their dreams of controlling more of the world's economy is democratic consent.

New paper finds a 'striking mismatch' between data & models for the present & last interglacial

More of the daily dose of bad news for climate models: 

A paper published today in Quaternary Science Reviews finds climate models are unable to reproduce the known climate change of Greenland and the Southern Hemisphere during the present and last interglacial periods. The authors attribute these major problems to either an incorrect balance of feedbacks, or to unknown mechanisms not included in the models, stating, 
"the model-data mismatch in mid and high Southern Hemisphere latitudes implies that none of the models is able to resolve the correct balance of these feedbacks, or, alternatively, that interglacial Southern Hemisphere temperature trends are driven by mechanisms which are not included in the transient simulations, such as changes in the Antarctic ice sheet or meltwater-induced changes in the overturning circulation.
"the strong LIG [Last InterGlacial] cooling trend reconstructed from Greenland ice cores that is not simulated by any of the models. A striking model-data mismatch is found for both the PIG [Present InterGlacial] and the LIG [Last InterGlacial] over large parts of the mid-to-high latitudes of the Southern Hemisphere where the data depicts negative temperature trends that are not in agreement with near zero trends in the simulations."

First model-data comparison of interglacial multi-millennial temperature trends.
Relation between Present and Last Interglacial insolation and NH temperature trends.
Multi-millennial temperature trends consistent between models and data for NH, mismatch for SH.

Abstract

Though primarily driven by insolation changes associated with well-known variations in Earth's astronomical parameters, the response of the climate system during interglacials includes a diversity of feedbacks involving the atmosphere, ocean, sea ice, vegetation and land ice. A thorough multi-model-data comparison is essential to assess the ability of climate models to resolve interglacial temperature trends and to help in understanding the recorded climatic signal and the underlying climate dynamics. We present the first multi-model-data comparison of transient millennial-scale temperature changes through two intervals of the Present Interglacial (PIG; 8–1.2 ka) and the Last Interglacial (LIG; 123–116.2 ka) periods. We include temperature trends simulated by 9 different climate models, alkenone-based temperature reconstructions from 117 globally distributed locations (about 45% of them within the LIG) and 12 ice-core-based temperature trends from Greenland and Antarctica (50% of them within the LIG). The definitions of these specific interglacial intervals enable a consistent inter-comparison of the two intervals because both are characterised by minor changes in atmospheric greenhouse gas concentrations and more importantly by insolation trends that show clear similarities.
Our analysis shows that in general the reconstructed PIG and LIG Northern Hemisphere mid-to-high latitude cooling compares well with multi-model, mean-temperature trends for the warmest months and that these cooling trends reflect a linear response to the warmest-month insolation decrease over the interglacial intervals. The most notable exception is the strong LIG [Last InterGlacial] cooling trend reconstructed from Greenland ice cores that is not simulated by any of the models. A striking model-data mismatch is found for both the PIG [Present InterGlacial] and the LIG [Last InterGlacial] over large parts of the mid-to-high latitudes of the Southern Hemisphere where the data depicts negative temperature trends that are not in agreement with near zero trends in the simulations. In this area, the positive local summer insolation trend is counteracted in climate models by an enhancement of the Southern Ocean summer sea-ice cover and/or an increase in Southern Ocean upwelling. If the general picture emerging from reconstructions is realistic, then the model-data mismatch in mid and high Southern Hemisphere latitudes implies that none of the models is able to resolve the correct balance of these feedbacks, or, alternatively, that interglacial Southern Hemisphere temperature trends are driven by mechanisms which are not included in the transient simulations, such as changes in the Antarctic ice sheet or meltwater-induced changes in the overturning circulation.