Saturday, August 23, 2014

New paper finds large volcanic eruptions only cause 3-5 years of cooling; Hansen claims 20+ years

A paper published today in Global and Planetary Change reconstructs winter temperatures from 1500-1980 in Western North America and find large volcanic eruptions are followed by 
  • A clear and robust La Niña-like [cooling] response occurs in years 3-5 after eruption
  • Results argue against [prior claim] that later La Niña requires early El Niño response
  • Later La Niña-like response is consistent with restored heat balance after ~ 2 years
The findings contradict claims by James Hansen et al that the 18 year "pause" of global warming is due to a 23 year very long delayed cooling effect from the 1991 Mt. Pinatubo volcanic eruption. 

Hansen's very-delayed cooling effect from volcanic eruptions + solar minimum hypothesis has been added to the updated list as excuse #39 for the 18 year "pause" in global warming.


Note also, decreased cooling effect from volcanic aerosols implies lower warming effect/climate sensitivity to CO2.








Western N. America winter temperature reconstructions clearly detect ENSO patterns
Early post-volcanic El Niño-like response is conditional on eruptions evaluated
Clear and robust La Niña-like response occurs in years 3-5 after eruption
Results argue against hypothesis that later La Niña requires early El Niño response
Later La Niña-like response is consistent with restored heat balance after ~ 2 years

Abstract

February-March temperature reconstructions in western North America from 1500-1980 CE are used to evaluate, from a regional perspective, the hypothesis that radiative forcing by large tropical volcanic eruptions induces a tendency in the climate system towards an early post-event El Niño (EN) response followed by a delayed La Niña (LN) response. Post-event spatial composites using superposed epoch analysis (SEA) detect indications for an EN-like pattern in post-event Years 1-2; this result, however, is sensitive to the set of eruptions evaluated. Highly significant LN-like patterns are also observed for two eruptions during Year 1. In contrast, a clear and unique LN-like response is found in both eruption sets during Years 3-5; Year 3 in particular represents the time of strongest post-event response. No significant EN-like patterns occur during these years. The relative homogeneity of the SEA response for each post-event year is evaluated in terms of the ratio of the amplitude of the SEA composite to its standard deviation across the eruption events. In relation to the same metric determined from random-event-year SEAs, these signal-to-noise ratios are most highly significant in the portions of the domain with the strongest anomalies in Years 1-5, especially Year 3. The signal-to-noise ratios tend toward uniformly low and insignificant values beyond the first half-decade after the eruption, indicating generally reduced coherence across events. In relation to the larger-scale circulation, post-eruption 500 mb February-March geopotential height composites from the 20th Century Reanalysis show ENSO-type features that are largely consistent with the SEA results from the primary eruption set during Years 1-2, but are inconsistent with the EN-like pattern exhibited by the second eruption set during this time. In Year 3, the pressure composite over North America and the adjacent Pacific and Atlantic is strongly LN-like, consistent with all SEA results; similarly, weakening coherence across events as time progresses beyond Year 3 is also consistent with more variable pressure composites noted after that time. The relatively robust character of the delayed LN-like response is evaluated in terms of the dynamic rebound of the climate system towards its initial energy balance as the radiative impact of immediate post-eruption aerosol cooling dissipates. The LN-like SEA temperature response in Years 3-5 exhibits a slight shift of its southern warm anomaly to the north and west relative to pure composite LN conditions, which is detected as a specifically post-eruption feature in the region.

Friday, August 22, 2014

WSJ: Spontaneous Solar Combustion. Will green activists feel cognitive dissonance for turning on renewable energy?

Spontaneous Solar Combustion

Can we please see your Avian and Bat Monitoring Plan?

Aug. 22, 2014 6:42 p.m. ET  THE WALL STREET JOURNAL

The sprawling Ivanpah solar power station in the Mojave Desert probably never would have been built without environmental activists and the subsidies and mandates they created, so there's more than a little irony that BrightSource Energy, Google and another clean-tech utility are now getting an education in the green opposition that bedevils other American businesses. Lobbies like the Sierra Club and Audubon Society are turning on solar farms for avian mass murder.

Ivahpah's solar thermal technology uses 300,000 giant computer-controlled mirrors spread over 3,500 acres to follow the sun and concentrate energy on water towers, where boiler turbines generate electricity. The problem with this $2.2 billion feat of engineering is that birds that fly into the 800 degrees Fahrenheit rays sometimes singe or catch fire in midair. Plant workers call them "streamers" after the trail of smoke that follows the carcasses to the ground after they ignite, according to a recent Associated Press investigation.



The Ivanpah Solar ElectirIc Generating System in Primm, Nev.

The Center for Biological Diversity speculates that Ivanpah will kill 28,000 birds a year. In a study earlier this year, the U.S. Fish and Wildlife Service's forensics laboratory calls the apparatus a "mega-trap" for insects, swallows, road runners, hawks and even monarch butterflies, "creating an entire food chain vulnerable to injury and death."

The Biological Diversity folks are suing to force solar farms to install lights or noise alert warnings to encourage wildlife to adopt a different flight path. Some California legislators are accidentally sensible and want to ban plants like Ivanpah, which sounds like a deal for birds and taxpayers.

We got a no-irony-intended email from a lobbyist friend working for BrightSource on Thursday explaining "avian fatalities"—the plant's actual year-to-date body count is all of 321 in total, and only 133 of them related to so-called "solar flux"—and Ivanpah's Avian and Bat Monitoring and Management Plan. The company notes that as many as 3.7 billion birds each year are killed by cats and 980 million by crashing into walls.

This green-on-green showdown exquisitely captures the reason that the America that built the Hoover Dam in five years now has so much trouble building those "infrastructure" projects everybody in Washington and Sacramento claim to favor. Environmental review and permitting are often dragged out a decade or longer across a slew of lawsuits and federal and state agencies. Ivanpah was required to spend $34 million on a "Head Start" nursery for desert tortoises. Really.

So it is that the same beau monde activists who think the Keystone XL pipeline is a threat to civilization are now turning on non-fossil fuel power too. Maybe this time they'll feel cognitive dissonance, but then they never do.

Ocean 'acidification' alarmists at work

A comment today on a prior post "New paper finds no evidence of ocean 'acidification' in upper Santa Monica Bay" claimed that collection of additional data since the paper was published does show "a statistically significant trend in surface pH, calculated from additional data which extended to 2013. The pH values in the top meter had been decreasing by about 0.003 per year.":
Comment today: I interviewed Anita Leinweber [author of the paper published in the Journal of Geophysical Research] for an article I wrote for The Catalina Marine Society. At the time of the study’s publication, no statistically significant linear trends had emerged in the upper 100 meters. But this past April (2014), Leinwebier saw a statistically significant trend in surface pH, calculated from additional data which extended to 2013. The pH values in the top meter had been decreasing by about 0.003 per year. (Calculations were not yet complete for other depths.) 
My article: California's Corrosive Ocean, http://www.catalinamarinesociety.org/files/MagVol5No1.pdf, p. 3
The article links to the data which supposedly shows a statistically significant "acidification" in surface pH, but plotting the data instead shows a very noisy dataset indicative of calibration problems with the pH meter, and a non-significant ~0.2 increase or alkalinization of pH:

Ocean 'alkalinization' in Santa Monica Bay
The data clearly does not support the claim of any statistically-significant decrease of pH or 'acidification'. However, it does illustrate that ocean pH routinely changes 0.5 pH units [50% change in H+ protons] or more over the course of a single day, much larger than the claimed "acidification" of 0.1 pH units from pH 8.2 to 8.1 over the past 150 years of industrialization. There is no reliable global ocean data demonstrating any change in pH due to the increase in atmospheric CO2; this claim is largely based upon very sparse data and models. If the oceans are warming, CO2 solubility decreases per Henry's Law, thus limiting the potential of "acidification" from an increase of CO2. 

The data also illustrates that pH meters require constant calibration and have surprisingly large measurement uncertainties. That's why there is an open $2 million dollar X-prize competition to develop an ocean pH meter to accurately, affordably, and efficiently measure ocean pH:

X-Prize $2 million pH sensor challenge
The Wendy Schmidt Ocean Health XPRIZE is a $2 million global competition that challenges teams of engineers, scientists and innovators from all over the world to create pH sensor technology that will affordably, accurately and efficiently measure ocean chemistry from its shallowest waters… to its deepest depthsLearn more about the competition.
There is no reliable evidence that global ocean pH is falling, and this Santa Monica Bay data certainly does not support the alarmist claims of "California's corrosive oceans."

Repost:

New paper finds no evidence of ocean 'acidification' in upper Santa Monica Bay

A new paper published in the Journal of Geophysical Research finds no evidence of ocean "acidification" in the upper 100 meters of the Santa Monica Bay from bi-weekly observations over the past six years. According to the authors, "No statistically significant linear trends emerge in the [biologically significant] upper 100 meters." 

Key points from prior posts on ocean "acidification":


A. Leinweber, N. Gruber

Abstract: We investigate the temporal variability and trends of pH and of the aragonite saturation state, Ωarag, in the southern California Current System on the basis of a 6 year timeseries from Santa Monica Bay, using bi-weekly observations of dissolved inorganic carbon and combined calculated and measured alkalinity. Median values of pH and Ωarag in the upper 20 m are comparable to observations from the subtropical gyres, but the temporal variability is at least a factor of 5 larger, primarily driven by short-term upwelling events and mesoscale processes. Ωarag and pH decrease rapidly with depth, such that the saturation horizon is reached already at 130 m, on average, but it occasionally shoals to as low as 30 m. No statistically significant linear trends emerge in the upper 100 m, but Ωarag and pH decrease, on average, at rates of -0.009 ± 0.006 yr-1 and -0.004 ± 0.003 yr-1 in the 100 to 250 m depth range. These are somewhat larger, but not statistically different from the expected trends based on the recent increase in atmospheric CO2. About half of the variability in the deseasonalized data can be explained by the El Niño Southern Oscillation (ENSO), with warm phases (El Niño) being associated with above normal pH and Ωarag. The observed variability and trend in Ωarag and pH is well captured by a multiple linear regression model on the basis of a small number of readily observable independent variables. This permits the estimation of these variables for related sites in the region.

Did Greenland & W Antarctic Ice Sheet Loss Suddenly Double?

No

Joe Romm and other alarmist news sources are gushing over a new paper published in the Cryosphere which they claim shows
World's Largest Ice Sheets Melting at Fastest Rates in Recorded History! 
Greenland And West Antarctic Ice Sheet Loss More Than Doubled In Last Five Years

But what does the paper actually show? The paper compares ice volume changes between three different satellite altimetry databases. As the authors note, one must be very careful about drawing conclusions in comparing databases from different measurement sources and which use different analysis methods. In this case, the CryoSat satellite database only covers a very short 2011-early 2014 time period of a little over 3 years and does not overlap the ICESat database from 2003-2009 or the IMBIE database from 2003-2008. Therefore, the CryoSat database cannot be directly calibrated against the other two databases and comparisons must be done with caution.

Table 4 shows the following volume changes in cubic kilometers/year of the Greenland + Antarctic ice sheets from the 3 datasets and time periods:

IMBIE:   2003-2008  -164
ICESat:   2003-2009  -207
CryoSat:  2011-2014  -503




and does show an increase in volume loss of 296 km^3yr-1 between the 2003-2009 ICESat database and the short 2011-2014 CryoSat database. Regardless of all the caveats of comparing these short, non-overlapping datasets, if we assume the numbers are true, what is the significance?

According to the IPCC, the Greenland + Antarctic ice sheets contain a total of 27.6 x 10^6 cubic km of ice, equivalent to 63.9 meters sea level rise. If this paper is correct, the combined ice sheets are losing 503/27600000 or 0.0018% of their mass per year, equivalent to 1.16 mm/yr sea level rise or 4.5 inches per century, hardly alarming, and almost exactly what the IPCC 2013 report claimed for the sea level rise contribution of 0.6 mm/yr from Greenland and 0.41 mm/yr from Antarctica, a total of 1.01 mm/yr.

A paper also published this week contradicts the claims of increased ice loss from the Antarctic Peninsula and finds the melt rate has instead decreased since 1993.
Further, if there was an actual doubling of ice loss from Greenland and Antarctica, that should have been found in a corresponding acceleration of sea level rise. No such acceleration has been found and Cazenave et al and Chen et al have instead found a recent deceleration of sea level rise, the opposite of what would be expected if the ice sheets had accelerated ice loss. In addition, worldwide glacier melt has decelerated since 1950, also the opposite of predictions of AGW theory. 

During an interglacial period sea levels normally rise and ice melts, and the system inertia lasts thousands of years until the onset of the next ice age. During the last interglacial, sea levels were up to 43 feet higher and Greenland was 8C warmer with a much smaller ice cap; there is no evidence this interglacial is any different. There’s no evidence of acceleration, therefore no evidence of anthropogenic influence on sea level rise for the past 20,000 years. 

Global temperatures have "paused" for the past ~18 years, another reason why Antarctic and Greenland ice loss could not have doubled within the past 5 years. The areas that show ice loss in the figure above are also located above volcanically active areas in Antarctica as well as volcanically active areas in Greenland, but not related to man-made CO2. 



The Cryosphere, 8, 1539-1559, 2014
www.the-cryosphere.net/8/1539/2014/
doi:10.5194/tc-8-1539-2014

Elevation and elevation change of Greenland and Antarctica derived from CryoSat-2


V. Helm, A. Humbert, and H. Miller
Glaciology Section, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany

Abstract. This study focuses on the present-day surface elevation of the Greenland and Antarctic ice sheets. Based on 3 years of CryoSat-2 data acquisition we derived new elevation models (DEMs) as well as elevation change maps and volume change estimates for both ice sheets. Here we present the new DEMs and their corresponding error maps. The accuracy of the derived DEMs for Greenland and Antarctica is similar to those of previous DEMs obtained by satellite-based laser and radar altimeters. Comparisons with ICESat data show that 80% of the CryoSat-2 DEMs have an uncertainty of less than 3 m ± 15 m. The surface elevation change rates between January 2011 and January 2014 are presented for both ice sheets. We compared our results to elevation change rates obtained from ICESat data covering the time period from 2003 to 2009. The comparison reveals that in West Antarctica the volume loss has increased by a factor of 3. It also shows an anomalous thickening in Dronning Maud Land, East Antarctica which represents a known large-scale accumulation event. This anomaly partly compensates for the observed increased volume loss of the Antarctic Peninsula and West Antarctica. For Greenland we find a volume loss increased by a factor of 2.5 compared to the ICESat period with large negative elevation changes concentrated at the west and southeast coasts. The combined volume change of Greenland and Antarctica for the observation period is estimated to be −503 ± 107 km3 yr−1. Greenland contributes nearly 75% to the total volume change with −375 ± 24 km3 yr−1.

Related: For an excellent background on the normal behavior of ice sheets including natural calving from the margins of outlet glaciers, see Glaciers: Science and Nonsense

Watch Now: New Documentary 'The Global Warming War'

Watch Now: New excellent documentary 'The Global Warming War' is available for viewing in entirety as as film festival preview. The documentary features many prominent skeptics including Dr. Tim Ball, Marc Morano, Dr. David Deming, Dr. J. Scott Armstrong, Steve Goreham, Dennis Avery, Dr. Vincent Gray, Myron Ebell, Joe D'Aleo, Dr. Mark Alliegro, Dr. John Theon, Dr. Henrik Svensmark, Lawrence Solomon, Dr. Marlo Lewis, John Coleman, Dr. James Wanliss, Dr. Bill Gray, Dr. Paul Driessen, and others and well worth watching. 

Trailer:




The full-length documentary film festival preview available here [password is 4festival]




New paper finds Chilean ocean temperatures were consistently warmer than present-day over most of past 12,000 years

A paper published today in Quaternary Research finds 6 more non-hockey-sticks in reconstructed sea surface temperatures [SSTs] over the past 12,000 years from 6 different latitudes along the southern coast of Chile. The reconstructed temperatures show most of the Holocene [past ~11,000 years] had consistently warmer sea surface temperatures than present-day temperatures. According to the authors, 
"The Holocene records show consistently warmer than present-day Sea Surface Temperatures except for [~ 600 years during the Little Ice Age]."
The paper joins hundreds of published non-hockey-stick temperature reconstructions worldwide demonstrating the Medieval, Roman, Egyptian, and Minoan Warm Periods, and Holocene Climate Optimum were all naturally warmer than present-day temperatures. 

Horizontal axis is thousands of years before the present. SST = Sea Surface Temperatures. Present-day SSTs indicated with arrows along the vertical axis
Add caption

LIA = Little Ice Age, MCA = Medieval Warm Period. Note top graph appears to be based upon one of Mann's bogus temperature reconstructions. Remaining graphs show SST reconstructions along southern coast of Chile. 

Here we provide three new Holocene (11–0 cal ka BP) alkenone-derived sea surface temperature (SST) records from the southernmost Chilean fjord region (50–53°S). SST estimates may be biased towards summer temperature in this region, as revealed by a large set of surface sediments. The Holocene records show consistently warmer than present-day Sea Surface Temperatures except for the past ~ 0.6 cal ka BP [Little Ice Age]. However, they do not exhibit an early Holocene temperature optimum as registered further north off Chile and in Antarctica. This may have resulted from a combination of factors including decreased inflow of warmer open marine waters due to lower sea-level stands, enhanced advection of colder and fresher inner fjord waters, and stronger westerly winds. During the mid-Holocene, pronounced short-term variations of up to 2.5°C and a cooling centered at ~ 5 cal ka BP, which coincides with the first Neoglacial glacier advance in the Southern Andes, are recorded. The latest Holocene is characterized by two pronounced cold events centered at ~ 0.6 and 0.25 cal ka BP, i.e., during the Little Ice Age. These cold events have lower amplitudes in the offshore records, suggesting an amplification of the SST signal in the inner fjords.

Thursday, August 21, 2014

New excuse for the "pause" in global warming #38: The "missing heat" is hiding in the deep Atlantic, not Pacific

Climate scientist author: “Every week there’s a new explanation of the hiatus”

Yes- so true, now up to 38 excuses for the 18 year "pause" in global warming by my count.

According to a new paper published today in Science, Trenberth's "missing heat" is really hiding in the deep Atlantic, not the deep Pacific as Trenberth claims. See Dr. Judith Curry's take on this today at her blog, and choice quotes:

"In the absence of a convincing explanation for warming since the mid 19th century, as well as the multi-decade hiatus periods, I find the [IPCC] extremely likely confidence level to be logically insupportable."

"JC message to Gavin Schmidt (as per our discussion on Dan Kahan’s blog): No I am not making things up re the 50-50 attribution argument. I regard it as a fundamental flaw in logic to infer high confidence in attribution since 1950, without understanding the warming in the early part of the 20th century and the mid century hiatus."
Regarding the anthropogenic aerosol forcing argument mentioned by Dr. Curry, that also appears to be blown out of the water by a paper published today in JGR-Atmospheres:

New paper finds changes in cloud cover caused global brightening & dimming, not man-made aerosols


Thus, very recently published papers point to a combination of natural ocean oscillations, natural changes in cloud cover, and changes in solar activity fully explaining the natural warming since the Little Ice Age, not man-made CO2 nor man-made aerosols.


Cause of global warming hiatus found deep in the Atlantic Ocean

Following rapid warming in the late 20th century, this century has so far seen surprisingly little increase in the average temperature at the Earth’s surface. At first this was a blip, then a trend, then a puzzle for the climate science community.

More than a dozen theories have now been proposed for the so-called global warming hiatus, ranging from air pollution to volcanoes to sunspots. New research from the University of Washington shows that the heat absent from the surface is plunging deep in the north and south Atlantic Ocean, and is part of a naturally occurring cycle. The study is published Aug. 22 in Science.

Subsurface warming in the ocean explains why global average air temperatures have flatlined since 1999, despite greenhouse gases trapping more solar heat at the Earth’s surface.

“Every week there’s a new explanation of the hiatus,” said corresponding author Ka-Kit Tung, a UW professor of applied mathematics and adjunct faculty member in atmospheric sciences. “Many of the earlier papers had necessarily focused on symptoms at the surface of the Earth, where we see many different and related phenomena. We looked at observations in the ocean to try to find the underlying cause.”

The results show that a slow-moving current in the Atlantic, which carries heat between the two poles, sped up earlier this century to draw heat down almost a mile (1,500 meters). Most of the previous studies focused on shorter-term variability or particles that could block incoming sunlight, but they could not explain the massive amount of heat missing for more than a decade.

“The finding is a surprise, since the current theories had pointed to the Pacific Ocean as the culprit for hiding heat,” Tung said. “But the data are quite convincing and they show otherwise.”
Tung and co-author Xianyao Chen of the Ocean University of China, who was a UW visiting professor last year, used recent observations of deep-sea temperatures from Argo floats that sample the water down to 6,500 feet (2,000 meters) depth. The data show an increase in heat sinking around 1999, when the rapid warming of the 20th century stopped.

“There are recurrent cycles that are salinity-driven that can store heat deep in the Atlantic and Southern oceans,” Tung said. “After 30 years of rapid warming in the warm phase, now it’s time for the cool phase.”

Rapid warming in the last three decades of the 20th century, they found, was roughly half due to global warming and half to the natural Atlantic Ocean cycle that kept more heat near the surface. When observations show the ocean cycle flipped, around the year 2000, the current began to draw heat deeper into the ocean, working to counteract human-driven warming.



(Top) Global average surface temperatures, where black dots are yearly averages. Two flat periods (hiatus) are separated by rapid warming from 1976-1999. (Middle) Observations of heat content, compared to the average, in the north Atlantic Ocean. (Bottom) Salinity of the seawater in the same part of the Atlantic. Higher salinity is seen to coincide with more ocean heat storage. 

The cycle starts when saltier, denser water at the surface northern part of the Atlantic, near Iceland, causes the water to sink. This changes the speed of the huge current in the Atlantic Ocean that circulates heat throughout the planet.

“When it’s heavy water on top of light water, it just plunges very fast and takes heat with it,” Tung said. Recent observations at the surface in the North Atlantic show record-high saltiness, Tung said, while at the same time, deeper water in the North Atlantic shows increasing amounts of heat.

The authors dug up historical data to show that the cooling in the three decades between 1945 to 1975 – which caused people to worry about the start of an Ice Age – was during a cooling phase. (It was thought to be caused by air pollution [debunked].) Earlier records in Central England show the 40- to 70-year cycle goes back centuries, and other records show it has existed for millennia.

Changes in Atlantic Ocean circulation historically meant roughly 30 warmer years followed by 30 cooler years. Now that it is happening on top of global warming, however, the trend looks more like a staircase.

The temperature oscillations have a natural switch. During the warm period, faster currents cause more tropical water to travel to the North Atlantic, warming both the surface and the deep water. At the surface this warming melts ice. This eventually makes the surface water there less dense and after a few decades puts the brakes on the circulation, setting off a 30-year cooling phase.

This explanation implies that the current slowdown in global warming could last for another decade, or longer, and then rapid warming will return [read Dr. Curry's opinion on this controversial statement]. But Tung emphasizes it’s hard to predict what will happen next.

A pool of freshwater from melting ice, now sitting in the Arctic Ocean, could overflow into the North Atlantic to upset the cycle.

“We are not talking about a normal situation because there are so many other things happening due to climate change,” Tung said.


Related: Bob Tisdale also debunks

New paper finds changes in cloud cover caused global brightening & dimming, not man-made aerosols

An important paper published today in the Journal of Geophysical Research Atmospheres finds that the well-known "global dimming" and "global brightening" of solar radiation at Earth's surface was primarily due to changes in cloud cover, not from anthropogenic aerosols from burning of fossil fuels as many climate alarmists including James Hansen have claimed. The observed trends of solar surface radiation dimming and brightening correspond well to the observed global temperature changes over the past 50 years. 

As noted by Dr. Roy Spencer,
"The most obvious way for warming to be caused naturally is for small, natural fluctuations in the circulation patterns of the atmosphere and ocean to result in a 1% or 2% decrease in global cloud cover. Clouds are the Earth’s sunshade, and if cloud cover changes for any reason, you have global warming — or global cooling."
Changes in cloud cover may occur due to solar amplification mechanisms such as via solar control of cosmic ray cloud nucleation and solar modulation of ocean and atmospheric oscillations, or may occur as a negative feedback to surface warming and increased evaporation. 


The rate of warming increased by a factor of 3.8 from 1992 to 2002 corresponding to the period of "global brightening," and was followed by global cooling and a "pause" or possible "dimming" of solar surface radiation.

The cause of solar dimming and brightening at the Earth's surface during the last half century: evidence from measurements of sunshine duration.

Gerald Stanhill et al


Analysis of the Angstrom-Prescott relationship between normalized values of global radiation and sunshine duration measured during the last 50 years made at five sites with a wide range of climate and aerosol emissions showed few significant differences in atmospheric transmissivity under clear or cloud covered skies between years when global dimming occurred and years when global brightening was measured. Nor in most cases were there any significant change in the parameters or in their relationships to annual rates of fossil fuel combustion in the surrounding 1° cells. It is concluded that at the sites studied changes in cloud cover rather than anthropogenic aerosols emissions played the major role in determining solar dimming and brightening during the last half century and that there are reasons to suppose that these findings may have wider relevance.



Related:

Clouds/aerosols control the climate, not man-made CO2

New paper finds sunshine "highly correlated" to temperature anomalies over past 50 years

New paper shows dimming of sunshine during the 1970's ice age scare, and brightening since the 1980's

New paper finds IPCC climate models unable to reproduce solar radiation at Earth's surface

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

New paper finds solar energy at Earth's surface greatly increased between 1973 and 1998

New paper finds large increase in sunshine since the 1980's; dwarfs alleged effect of CO2

New paper finds cloudiness in Spain has significantly decreased since 1960

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

Evidence solar radiation dominates climate change, not greenhouse gases

How climate models dismiss the role of the Sun in climate change [Part 4]

New paper finds melt rate of Antarctic Peninsula has decreased since 1993 & decrease in LW radiation from GHGs

According to Joe 'exploding head' Romm, the Antarctic Peninsula meltdown to China is now "non-linear, fastest in 1000 years!" However, a paper published today in The Cryosphere paints an entirely different picture.

The paper examines the surface energy budget on the two major Larsen & Wilkins ice shelves in the Antarctic Peninsula over the past 21 years from 1989-2010. According to the authors, "the automated weather station observations on the Larsen Ice Shelf did not show any significant temperature trend, and the reanalyses [of temperature data] showed warming trends only over the Wilkins Ice Shelf." However, the authors find a large upward biases in the reanalyzed data, stating, "Focusing on biases of seasonal means, our validation results include three interesting issues: (1) all three reanalyses had warm temperature biases in all seasons..."  Thus, it isn't clear how much, if any, of the warming of the Wilkins Ice Shelf is real vs. due to biases in the reanalyses, and meanwhile direct weather station observations of the Larsen Ice Shelf show no warming over the past 21 years.

Contrary to Romm's claim 4 months ago that the supposed Antarctic Peninsula meltdown is "non-linear, fastest in 1000 years," the authors instead find the fastest melt rates of the past 21 years were in 1992-1993 and have decreased since then:




The paper attributes the possible warming of the Wilkins Ice Shelf to natural changes in atmospheric pressure, wind, and cloud fraction, but not longwave radiation from the steady increase in greenhouse gases. Why? Because the authors paradoxically find that net longwave radiation from greenhouse gases has decreased over the past 21 years, rather than increased from the steady rise of greenhouse gases as predicted by AGW theory. 

This is shown in the following tables where LW = net longwave radiation from greenhouse gases at the surface of the Antarctic Peninsula, SW = net shortwave radiation from the Sun, Ann = Annual. There are statistically significant negative trends in net longwave radiation on both ice shelves, not positive as would be expected from the steady rise of well-mixed greenhouse gases. Another paper has also found a paradoxical decrease of longwave radiation from greenhouse gases over the past 14 years in the US Great Plains.


The authors also note that monthly mean temperatures only rose above the freezing point twice over the past 21 years, during the summers of 1989–1990 and 1994–1995. 
"Unfortunately the Larsen C AWS was out of commissionin summer 1992–1993, and thus could not be used for confirmingthe peaking of melt during that summer. During summers1989–1990 and 1994–1995, which are identifiable bythe high number of melt days on LCIS, the monthly meantemperature was above 0 C during one summer month accordingto the AWS. Monthly mean temperatures did not riseabove freezing point during any other period between 1989and 2010. According to the AWS data, summer 2002–2003,which experienced a large melt, was not distinctly warmerthan other summers."
Joe Romm

The Cryosphere, 8, 1519-1538, 2014
www.the-cryosphere.net/8/1519/2014/
doi:10.5194/tc-8-1519-2014



I. Välisuo1,2, T. Vihma1, and J. C. King3
1Finnish Meteorological Institute, Helsinki,Finland
2Departement of Physics, University of Helsinki, Helsinki, Finland
3British Antarctic Survey, Cambridge, UK

Abstract. Ice shelves in the Antarctic Peninsula have significantly disintegrated during recent decades. To better understand the atmospheric contribution in the process, we have analysed the inter-annual variations in radiative and turbulent surface fluxes and weather conditions over Larsen C Ice Shelf (LCIS) and Wilkins Ice Shelf (WIS) in the Antarctic Peninsula in 1989–2010. Three atmospheric reanalyses were applied: ERA-Interim by ECMWF, Climate Forecast System Reanalysis (CFSR) by NCEP, and JRA-25/JCDAS by the Japan Meteorological Agency. In addition, in situ observations from an automatic weather station (AWS) on LCIS were applied, mainly for validation of the reanalyses. The AWS observations on LCIS did not show any significant temperature trend, and the reanalyses showed warming trends only over WIS: ERA-Interim in winter (0.23 °C yr−1) and JRA-25/JCDAS in autumn (0.13 °C yr−1). In LCIS from December through August and in WIS from March through August, the variations of surface net flux were partly explained by the combined effects of atmospheric pressure, wind and cloud fraction. The explained variance was much higher in LCIS (up to 80%) than in WIS (26–27%). Summer melting on LCIS varied between 11 and 58 cm water equivalent (w.e.), which is comparable to previous results. The mean amount of melt days per summer on LCIS was 69. The high values of melting in summer 2001–2002 presented in previous studies on the basis of simple calculations were not supported by our study. Instead, our calculations based on ERA-Interim yielded strongest melting in summer 1992–1993 on both ice shelves. On WIS the summer melting ranged between 10 and 23 cm w.e., and the peak values coincided with the largest disintegrations of the ice shelf. The amount of melt on WIS may, however, be underestimated by ERA-Interim, as previously published satellite observations suggest that it suffers from a significant bias over WIS.


Related:

Tuesday, August 19, 2014

New paper finds groundwater extraction & 2004 earthquake are the primary causes of sea level rise in Thailand

A paper published today in Global and Planetary Change finds high rates of sea level rise along certain sections of the coast of Thailand are almost entirely due to "extreme land subsidence" [land sinking] rather than global warming. The authors find sea level rise increased significantly after the 2004 Sumatra Earthquake which greatly increased land subsidence in certain regions, and that rapid land subsidence is also due to groundwater extraction. 

Relative sea level change is primarily related to subsidence or post-glacial rebound [land height changes] rather than melting ice or steric sea level changes [thermal expansion from warming]. Global mean sea levels are rising at only about 1-1.6 mm/year, equivalent to 4-7 inches per century and without any evidence of acceleration. Without acceleration, there is no evidence of any human effect on global sea levels. 

The land at along the coast of Bangkok is sinking up to 20 times faster than the rate of global sea level rise

Sea level rise is primarily a local phenomenon primarily due to land height changes rather than global warming. 

Fast sea level rise in upper Gulf of Thailand due to land subsidence is explored
Sea level rise increased significantly after the 2004 Sumatra Earthquake
Seasonal sea level variations are driven by monsoonal winds
Annual and semi-annual sea level variations in Andaman Sea and Gulf of Thailand are very different

Abstract

The study addresses two important issues associated with sea level along the coasts of Thailand: first, the fast sea level rise and its spatial variation, and second, the monsoonal-driven seasonal variations in sea level. Tide gauge data that are more extensive than in past studies were obtained from several different local and global sources, and relative sea level rise (RSLR) rates were obtained from two different methods, linear regressions and non-linear Empirical Mode Decomposition/Hilbert-Huang Transform (EMD/HHT) analysis. The results show extremely large spatial variations in RSLR, with rates varying from ~ 1 mm y− 1 to ~ 20 mm y− 1; the maximum RSLR is found in the upper Gulf of Thailand (GOT) near Bangkok, where local land subsidence due to groundwater extraction dominates the trend. Furthermore, there are indications that RSLR rates increased significantly in all locations after the 2004 Sumatra-Andaman Earthquake and the Indian Ocean tsunami that followed, so that recent RSLR rates seem to have less spatial differences than in the past, but with high rates of ~ 20-30 mm y− 1 almost everywhere. The seasonal sea level cycle was found to be very different between stations in the GOT, which have minimum sea level in June-July, and stations in the Andaman Sea, which have minimum sea level in February. The seasonal sea-level variations in the GOT are driven mostly by large-scale wind-driven set-up/set-down processes associated with the seasonal monsoon and have amplitudes about ten times larger than either typical steric changes at those latitudes or astronomical annual tides.