New study finds growth of Antarctic sea ice accelerated 53% since 2006

Opposite Behaviors? Arctic Sea Ice Shrinks, Antarctic Grows

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September 2012 witnessed two opposite records concerning sea ice. Two weeks after the Arctic Ocean's ice cap experienced an all-time summertime low for the satellite era (left), Antarctic sea ice reached a record winter maximum extent (right). But sea ice in the Arctic has melted at a much faster rate than it has expanded in the Southern Ocean, as can be seen in this image by comparing the 2012 sea ice levels with the yellow outline, which in the Arctic image represents average sea ice minimum extent from 1979 through 2010 and in the Antarctic image shows the median sea ice extent in September from 1979 to 2000. (Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio and NASA Earth Observatory/ Jesse Allen)

ScienceDaily (Oct. 23, 2012) — The steady and dramatic decline in the sea ice cover of the Arctic Ocean over the last three decades has become a focus of media and public attention. At the opposite end of Earth, however, something more complex is happening.

A new NASA study shows that from 1978 to 2010 the total extent of sea ice surrounding Antarctica in the Southern Ocean grew by roughly 6,600 square miles every year, an area larger than the state of Connecticut. And previous research by the same authors indicates that this rate of increase has recently accelerated, up from an average rate of almost 4,300 square miles per year from 1978 to 2006. [an increase of 53% between 1978-2010 vs. 1978-2006 rate]

"There's been an overall increase in the sea ice cover in the Antarctic, which is the opposite of what is happening in the Arctic," said lead author Claire Parkinson, a climate scientist with NASA's Goddard Space Flight Center, Greenbelt, Md. "However, this growth rate is not nearly as large as the decrease in the Arctic."

Earth's poles have very different geographies. The Arctic Ocean is surrounded by North America, Greenland and Eurasia. These large landmasses trap most of the sea ice, which builds up and retreats with each yearly freeze-and-melt cycle. But a large fraction of the older, thicker Arctic sea ice has disappeared over the last three decades. The shrinking summer ice cover has exposed dark ocean water that absorbs sunlight and warms up, leading to more ice loss.

On the opposite side of the planet, Antarctica is a continent circled by open waters that let sea ice expand during the winter but also offer less shelter during the melt season. Most of the Southern Ocean's frozen cover grows and retreats every year, leading to little perennial sea ice in Antarctica.

Using passive-microwave data from NASA's Nimbus 7 satellite and several Department of Defense meteorological satellites, Parkinson and colleague Don Cavalieri showed that sea ice changes were not uniform around Antarctica. Most of the growth from 1978 to 2010 occurred in the Ross Sea, which gained a little under 5,300 square miles of sea ice per year, with more modest increases in the Weddell Sea and Indian Ocean. At the same time, the region of the Bellingshausen and Amundsen Seas lost an average of about 3,200 square miles of ice every year.

Parkinson and Cavalieri said that the mixed pattern of ice growth and ice loss around the Southern Ocean could be due to changes in atmospheric circulation. Recent research points at the depleted ozone layer over Antarctica as a possible culprit. Ozone absorbs solar energy, so a lower concentration of this molecule can lead to a cooling of the stratosphere (the layer between six and 30 miles above Earth's surface) over Antarctica. At the same time, the temperate latitudes have been warming, and the differential in temperatures has strengthened the circumpolar winds flowing over the Ross Ice Shelf.

"Winds off the Ross Ice Shelf are getting stronger and stronger, and that causes the sea ice to be pushed off the coast, which generates areas of open water, polynyas," said Josefino Comiso, a senior scientist at NASA Goddard. "The larger the coastal polynya, the more ice it produces, because in polynyas the water is in direct contact with the very cold winter atmosphere and rapidly freezes." As the wind keeps blowing, the ice expands further to the north.

This year's winter Antarctic sea ice maximum extent, reached two weeks after the Arctic Ocean's ice cap experienced an all-time summertime low, was a record high for the satellite era of 7.49 million square miles, about 193,000 square miles more than its average maximum extent for the last three decades.

The Antarctic minimum extents, which are reached in the midst of the Antarctic summer, in February, have also slightly increased to 1.33 million square miles in 2012, or around 251,000 square miles more than the average minimum extent since 1979.

The numbers for the southernmost ocean, however, pale in comparison with the rates at which the Arctic has been losing sea ice -- the extent of the ice cover of the Arctic Ocean in September 2012 was 1.32 million square miles below the average September extent from 1979 to 2000. The lost ice area is euivalent to roughly two Alaskas.

Parkinson said that the fact that some areas of the Southern Ocean are cooling and producing more sea ice does not disprove a warming climate.

"Climate does not change uniformly: The Earth is very large and the expectation definitely would be that there would be different changes in different regions of the world," Parkinson said. "That's true even if overall the system is warming." Another recent NASA study showed that Antarctic sea ice slightly thinned from 2003 to 2008, but increases in the extent of the ice balanced the loss in thickness and led to an overall volume gain.
The new research, which used laser altimetry data from the Ice, Cloud, and land Elevation Satellite (ICESat), was the first to estimate sea ice thickness for the entire Southern Ocean from space.

Records of Antarctic sea ice thickness are much patchier than those of the Arctic, due to the logistical challenges of taking regular measurements in the fierce and frigid waters around Antarctica. The field data collection is mostly limited to research icebreakers that generally only travel there during spring and summer -- so the sole means to get large-scale thickness measurements is from space.

"We have a good handle of the extent of the Antarctic sea ice, but the thickness has been the missing piece to monitor the sea ice mass balance," said Thorsten Markus, one of the authors of the study and Project Scientist for ICESat-2, a satellite mission designed to replace the now defunct ICESat. ICESat-2 is scheduled to launch in 2016. "The extent can be greater, but if the sea ice gets thinner, the volume could stay the same."

New paper predicts decreased global tropical cyclones over the 21st century

A new paper published in Geophysical Research Letters models ocean temperatures, greenhouse gases, and aerosols from 1872 to 2099 and predicts "a clear decreasing trend of global tropical cyclone frequency throughout the 228 years of simulation." 

GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L19805, 5 PP., 2012
doi:10.1029/2012GL053360

Decreasing trend of tropical cyclone frequency in 228-year high-resolution AGCM simulations

Key Points

• Model simulations indicate a clear decreasing trend of TC [tropical cyclone] frequency
• The same model projects a decrease of TC [tropical cyclone] frequency in the future
• The decresing trend of TC is closely related to that of upward mass flux

Masato Sugi

Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan

Meteorological Research Institute, Tsukuba, Japan

Jun Yoshimura

Meteorological Research Institute, Tsukuba, Japan

We conducted 228-year long, three-member ensemble simulations using a high resolution (60 km grid size) global atmosphere model, MRI-AGCM3.2, with prescribed sea surface temperature and greenhouse gases and aerosols from 1872 to 2099. We found a clear decreasing trend of global tropical cyclone (TC) frequency throughout the 228 years of the simulation. We also found a significant multidecadal variation (MDV) in the long term variation of Northern Hemisphere and Southern Hemisphere TC count in addition to the decreasing trend. The decreasing trend and MDV in the long term variation of TC count correspond well to a similar decreasing trend and MDV of upward mass flux averaged over the TC genesis region and active TC season. It has been shown that the upward mass flux decreases primarily because the rate of increase of dry static stability, which is close to that of surface specific humidity, is much larger than the rate of increase of precipitation, which is nearly the same as that of atmospheric radiative cooling. Thus, it is suggested that the decreasing trend of TC count is mainly caused by the decreasing trend of upward mass flux associated with the increasing dry static stability.

New paper shows sea levels around Australia have declined over the past 7000 years

A new paper published in Quaternary Science Reviews is the "First synthesis of post-glacial sea level data around Australia in over 25 years," and shows that sea levels around Australia were from about 1 to 2.5 meters higher than the present 7000 years ago during the Holocene Thermal Maximum [which lasted 4000 years between 9000 to 5000 years ago]. The authors note that Australia is relatively stable tectonically and thus sea level data is not complicated by post-glacial isostatic and other adjustments, which would add considerable uncertainty to sea level reconstructions.   

According to the authors,

"Many of the issues, which challenged sea-level researchers in the latter part of the twentieth century, remain contentious today. Divergent opinions remain about: (1) exactly when sea level attained present levels following the most recent post-glacial marine transgression (PMT); (2) the elevation that sea-level reached during the Holocene sea-level highstand; (3) whether sea-level fell smoothly from a metre or more above its present level following the PMT; (4) whether sea level remained at these highstand levels for a considerable period before falling to its present position; or (5) whether it underwent a series of moderate oscillations during the Holocene highstand."

Fig. 7. Summary of the key sea-level data from Western Australia including barnacles, tubeworms (Baker et al., 2005), swash zone deposits ( [172] and [173]) and coral pavements (Collins et al., 2006).

Fig. 5. Summary of key sea-level data from New South Wales (compiled in Sloss et al., 2007). 

Fig. 4. Summary of sea-level data for the Queensland region (a). Indicators include barnacles ( [8] and [98]), beachrock (Hopley, 1980), foraminiferal transfer function (Woodroffe, 2009), mangroves (Larcombe et al., 1995), coral microatolls (Chappell et al., 1983) and oyster beds ( [8], [98] and [132]). Note the clear offset between the microatolls, barnacles and oysters compared with the beachrock and foraminifera data. The data fit within a tighter envelope when only the most reliable indicators are considered where the elevations can be directly measured to the modern counterparts (b; barnacles, microatolls and oyster beds).

Sea levels rose at a much faster rate from the peak of the last ice age around 20,000 years until about 8,000 years ago, and have been relatively stable over the past 8000 years.
Fig. 2. Summary of data showing the post-glacial sea-level rise for the Australasian region. The envelope is drawn to capture intertidal indicators and the zone between the terrestrial and marine directional indicators. Sites include New Zealand (NZ: e.g. Gibb, 1986), north-west shelf (NW shelf: e.g. [235], [236] and [116]), Huon Peninsula (Huon: e.g. [41],[65], [152] and [47]), Queensland (QLD: e.g. Larcombe et al., 1995), Sunda Shelf (Sunda: [88] and [89]), Western Australia (WA: e.g. [66], [178] and [179]), Northern Territory (NT: Woodroffe et al., 1987), South Australia (SA: Belperio et al., 2002) and New South Wales (NSW: Sloss et al., 2007). The following vertical errors have been assigned to the data: ±3 m for the intertidal (Inter.) indicators, +10, −1 for the marine indicators and +1, −10 for the terrestrial (Terr.) indicators. Note that meltwater pulse 1A (1A) is well represented in the Sunda Shelf data set.

Post-glacial sea-level changes around the Australian margin: a review

• Stephen E. Lewis^a, , , 
• Craig R. Sloss^b, 
• Colin V. Murray-Wallace^c, 
• Colin D. Woodroffe^c, 
• Scott G. Smithers^d

• ^a Catchment to Reef Research Group, TropWATER, James Cook University, Townsville, Queensland 4811, Australia
• ^b Earth, Environmental and Biological Sciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
• ^c School of Earth & Environmental Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia
• ^d School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia

• http://dx.doi.org/10.1016/j.quascirev.2012.09.006, How to Cite or Link Using DOI

• Permissions & Reprints

Abstract

It has been known since Rhodes Fairbridge’s first attempt to establish a global pattern of Holocene sea-level change by combining evidence from Western Australia and from sites in the northern hemisphere that the details of sea-level history since the Last Glacial Maximum vary considerably across the globe. The Australian region is relatively stable tectonically and is situated in the ‘far-field’ of former ice sheets. It therefore preserves important records of post-glacial sea levels that are less complicated by neotectonics or glacio-isostatic adjustments. Accordingly, the relative sea-level record of this region is dominantly one of glacio-eustatic (ice equivalent) sea-level changes. The broader Australasian region has provided critical information on the nature of post-glacial sea level, including the termination of the Last Glacial Maximum when sea level was approximately 125 m lower than present around 21,000–19,000 years BP, and insights into meltwater pulse 1A between 14,600 and 14,300 cal. yr BP. Although most parts of the Australian continent reveals a high degree of tectonic stability, research conducted since the 1970s has shown that the timing and elevation of a Holocene highstand varies systematically around its margin. This is attributed primarily to variations in the timing of the response of the ocean basins and shallow continental shelves to the increased ocean volumes following ice-melt, including a process known as ocean siphoning (i.e. glacio-hydro-isostatic adjustment processes).

Several seminal studies in the early 1980s produced important data sets from the Australasian region that have provided a solid foundation for more recent palaeo-sea-level research. This review revisits these key studies emphasising their continuing influence on Quaternary research and incorporates relatively recent investigations to interpret the nature of post-glacial sea-level change around Australia. These include a synthesis of research from the Northern Territory, Queensland, New South Wales, South Australia and Western Australia. A focus of these more recent studies has been the re-examination of: (1) the accuracy and reliability of different proxy sea-level indicators; (2) the rate and nature of post-glacial sea-level rise; (3) the evidence for timing, elevation, and duration of mid-Holocene highstands; and, (4) the notion of mid- to late Holocene sea-level oscillations, and their basis.

Based on this synthesis of previous research, it is clear that estimates of past sea-surface elevation are a function of eustatic factors as well as morphodynamics of individual sites, the wide variety of proxy sea-level indicators used, their wide geographical range, and their indicative meaning. Some progress has been made in understanding the variability of the accuracy of proxy indicators in relation to their contemporary sea level, the inter-comparison of the variety of dating techniques used and the nuances of calibration of radiocarbon ages to sidereal years. These issues need to be thoroughly understood before proxy sea-level indicators can be incorporated into credible reconstructions of relative sea-level change at individual locations. Many of the issues, which challenged sea-level researchers in the latter part of the twentieth century, remain contentious today. Divergent opinions remain about: (1) exactly when sea level attained present levels following the most recent post-glacial marine transgression (PMT); (2) the elevation that sea-level reached during the Holocene sea-level highstand; (3) whether sea-level fell smoothly from a metre or more above its present level following the PMT; (4) whether sea level remained at these highstand levels for a considerable period before falling to its present position; or (5) whether it underwent a series of moderate oscillations during the Holocene highstand.

Highlights

► First synthesis of post-glacial sea level data around Australia in over 25 years. ► Critical review of sea-level indicators used to reconstruct past sea-level change. ► Calibrated radiocarbon ages determine when sea level attained modern elevations. ► Examines the magnitude and length of the mid-Holocene highstand around Australia. ► Assesses the mechanisms responsible for mid–late Holocene sea-level changes

New paper suggests the Amazon has become wetter over past 100 years

A new paper suggests, contrary to claims of global warming alarmists that the Amazon will dry up, that the Amazon has become wetter over the past 100 years of slight global warming [0.7C]. The study finds an "intensification of the hydrological cycle" in the Amazon, which indicates an increase in precipitation. The authors note, "Climate models vary widely in their predictions for the Amazon, and we still do not know whether the Amazon will become wetter or dryer in a warmer world."

Tree rings go with the flow of the Amazon

by Staff WritersLeeds UK (SPX) Oct 05, 2012

Because of its vast size and location along the equator, the response of the hydrological cycle of the Amazon basin to climate change may significantly affect the magnitude and speed of climate change for the entire globe. It is therefore important to gain a better understanding of its hydrological cycle.

Tree rings go with the flow of the Amazon University of Leeds-led research has used tree rings from eight cedar trees in Bolivia to unlock a 100-year history of rainfall across the Amazon basin, which contains the world's largest river system.

The new study shows that the rings in lowland tropical cedar trees provide a natural archive of data closely related to historic rainfall.

Researchers measured the amounts of two different oxygen isotopes trapped in the wood's rings: oxygen-16 and the heavier oxygen-18. By looking at the varying amounts of the two isotopes, they could see how the pattern of rainfall changed year by year. This allowed them to see how much it rained over the Amazon basin over the past century.

The lead author of the study, Dr Roel Brienen from the School of Geography at the University of Leeds, said: "We already knew that some tropical tree species form annual rings and we also anticipated that the isotopic signature in these rings might record changes in the climate.

"What surprised us, however, is that just eight trees from one single site actually tell us how much it rained not just at that site but over the entire Amazon catchment. That is an area about 25 times the size of the UK. The isotope values recorded in tree rings were very closely related to annual variation in the river levels of the Amazon, and thus of the amount of rainfall that flows into the ocean."

The Amazon basin is among the richest natural ecosystems in the world, containing about one tenth of the planet's biodiversity and one fifth of the carbon stored in plant biomass. It is also among the wettest places in the world; about one fifth of the global land precipitation falls in the Amazon basin and drains into the Atlantic Ocean through the world's biggest river.

Because of its vast size and location along the equator, the response of the hydrological cycle of the Amazon basin to climate change may significantly affect the magnitude and speed of climate change for the entire globe. It is therefore important to gain a better understanding of its hydrological cycle.

Co-author Dr Manuel Gloor, also at the University of Leeds, said: "Climate models vary widely in their predictions for the Amazon, and we still do not know whether the Amazon will become wetter or dryer in a warmer world. We discovered a very powerful tool to look back into the past, which allows us to better understand the magnitude of natural variability of the system."

"In a similar way that annual layers in polar ice sheets have been used to study past temperatures, we are now able to use tree rings of this species as a natural archive for precipitation over the Amazon basin. If we find older trees with similar signal strength then this will greatly help us to advance our knowledge of the system."

Dr Brienen added: "The record is so sensitive that simply from the isotope values we can say which year we are looking at. For example, the extreme El Nino year of 1925-26 which caused very low river levels, clearly stands out in the record."

Although the century-long record provided by the trees is relatively short, some interesting trends are evident.

"The oxygen isotope series shows an increase over time, which may be due to an intensification of the hydrological cycle," said Dr Gloor. "That could also explain the observed long-term trend in river discharge. We need however to replicate this research at different places in the Amazon to really be able to say more."

The research is a collaboration between the University of Leeds, the Helmholtz Centre Potsdam (Germany), University of Utrecht and the Institut de Recherche pour le Developpement (IRD, Peru). The paper is published online in the journal Proceedings of National Academy of Sciences.

New paper finds significant, persistent influence of solar activity on regional cloud cover & climate

A new paper published in Environmental Research Letters finds that changes in solar activity have a significant and persistent effect upon cloud cover in some key climate-defining regions. As noted by the authors, "A consensus regarding the impact of solar variability on cloud cover is far from being reached. Moreover, the impact of cloud cover on climate is among the least understood of all climate components." Using data from 1984-2009, the authors studied variations in both solar UV [which can vary by over 20% within solar cycles] and cosmic rays [the Svensmark hypothesis], finding, "For some key geographical regions the response of clouds to [solar UV] and [cosmic ray modulation of clouds] is persistent over the entire time interval indicating a real link." The authors urge that "any analysis of solar effects on cloud cover (and, consequently, on climate) should be done at the regional level."

The full paper is available here

M Voiculescu and I Usoskin 2012 Environ. Res. Lett. 7 044004 doi:10.1088/1748-9326/7/4/044004

Persistent solar signatures in cloud cover: spatial and temporal analysis

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M Voiculescu¹ and I Usoskin²

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AbstractReferences

Letter

A consensus regarding the impact of solar variability on cloud cover is far from being reached. Moreover, the impact of cloud cover on climate is among the least understood of all climate components. This motivated us to analyze the persistence of solar signals in cloud cover for the time interval 1984–2009, covering two full solar cycles. A spatial and temporal investigation of the response of low, middle and high cloud data to cosmic ray induced ionization (CRII) and UV irradiance (UVI) is performed in terms of coherence analysis of the two signals. For some key geographical regions the response of clouds to UVI and CRII is persistent over the entire time interval indicating a real link. In other regions, however, the relation is not consistent, being intermittent or out of phase, suggesting that some correlations are spurious. The constant in phase or anti-phase relationship between clouds and solar proxies over some regions, especially for low clouds with UVI and CRII, middle clouds with UVI and high clouds with CRII, definitely requires more study. Our results show that solar signatures in cloud cover persist in some key climate-defining regions for the entire time period and supports the idea that, if existing, solar effects are not visible at the global level and any analysis of solar effects on cloud cover (and, consequently, on climate) should be done at the regional level.

New paper finds global warming is not a threat to humanity & GDP will be highest under the warmest scenario

A new paper published in Wiley Interdisciplinary Reviews: Climate Change "challenges claims that global warming outranks other threats facing humanity through the foreseeable future (assumed to be 2085–2100)." According to the author,

"World Health Organization and British government-sponsored global impact studies indicate that, relative to other factors, global warming's impact on key determinants of human and environmental well-being should be small through 2085 even under the warmest Intergovernmental Panel on Climate Change (IPCC) scenario. Specifically, over 20 other health risks currently contribute more to death and disease worldwide than global warming."

Furthermore,

"warming should reduce future global population at risk of water stress, and pressures on ecosystems and biodiversity (by increasing net biome productivity and decreasing habitat conversion)."

"For both developing and industrialized countries, net GDP per capita—albeit an imperfect surrogate for human well-being—should be (1) double the current US level by 2100 under the warmest scenario, and (2) lowest under the poorest IPCC scenario but highest under the warmest scenario through 2200. The warmest world, being wealthier, should also have greater capacity to address any problem, including warming. Therefore, other problems and, specifically, lowered economic development are greater threats to humanity than global warming."

Is climate change the number one threat to humanity?

1. Indur M. Goklany

Abstract:

This paper challenges claims that global warming outranks other threats facing humanity through the foreseeable future (assumed to be 2085–2100). World Health Organization and British government-sponsored global impact studies indicate that, relative to other factors, global warming's impact on key determinants of human and environmental well-being should be small through 2085 even under the warmest Intergovernmental Panel on Climate Change (IPCC) scenario. Specifically, over 20 other health risks currently contribute more to death and disease worldwide than global warming. Through 2085, only 13% of mortality from hunger, malaria, and extreme weather events (including coastal flooding from sea level rise) should be from warming. Moreover, warming should reduce future global population at risk of water stress, and pressures on ecosystems and biodiversity (by increasing net biome productivity and decreasing habitat conversion). That warming is not fundamental to human well-being is reinforced by lower bound estimates of net gross domestic product (GDP) per capita. This measure adjusts GDP downward to account for damages from warming due to market, health, and environmental impacts, and risk of catastrophe. For both developing and industrialized countries, net GDP per capita—albeit an imperfect surrogate for human well-being—should be (1) double the current US level by 2100 under the warmest scenario, and (2) lowest under the poorest IPCC scenario but highest under the warmest scenario through 2200. The warmest world, being wealthier, should also have greater capacity to address any problem, including warming. Therefore, other problems and, specifically, lowered economic development are greater threats to humanity than global warming. WIREs Clim Change 2012. doi: 10.1002/wcc.194

New paper finds climate change projections fail to consider the 'enormous thermal inertia of the ocean'

A paper published today in Climatic Change notes that even if the "small" possibility of catastrophic climate change from increased CO2 is true, due to "the enormous thermal inertia of the ocean, and the long timescales associated" "these considerations prevent the high temperatures [in the worst case scenario] from being reached for many centuries. A failure to include these factors risks distorting the resulting economic analyses." 

More on the enormous thermal inertia of the ocean and why CAGW will not occur

Why greenhouse gases cannot heat the oceans

Climate sensitivity: should the climate tail wag the policy dog?

from Climatic Change 

Abstract  

The small but stubbornly unyielding possibility of a very large long-term response of global temperature to increases in atmospheric carbon dioxide can be termed the fat tail of high climate sensitivity. Recent economic analyses suggest that the fat tail should dominate a rational policy strategy if the damages associated with such high temperatures are large enough. The conclusions of such analyses, however, depend on how economic growth, temperature changes, and climate damages unfold and interact over time. In this paper we focus on the role of two robust physical properties of the climate system: the enormous thermal inertia of the ocean, and the long timescales associated with high climate sensitivity. Economic models that include a climate component, and particularly those that focus on the tails of the probability distributions, should properly represent the physics of this slow response to high climate sensitivity, including the correlated uncertainty between present forcing and climate sensitivity, and the global energetics of the present climate state. If climate sensitivity in fact proves to be high, these considerations prevent the high temperatures in the fat tail from being reached for many centuries. A failure to include these factors risks distorting the resulting economic analyses. For example, we conclude that fat-tail considerations will not strongly influence economic analyses when these analyses follow the common—albeit controversial—practices of assigning large damages only to outcomes with very high temperature changes and of assuming a significant baseline level of economic growth.

New paper finds a natural 60-year oscillation in global mean sea level

A new paper published in Geophysical Research Letters "finds that there is a significant oscillation with a period around 60-years in the majority of the tide gauges examined during the 20th Century, and that it appears in every ocean basin." The authors note "The phase of the 60-year oscillation found in the tide gauge records is such that sea level in the North Atlantic, western North Pacific, Indian Ocean, and western South Pacific has been increasing since 1985–1990", meanwhile the figure below shows the eastern North Pacific and SW Pacific phase may have bottomed around the year 2000 and may be on an up phase currently. The authors note that "the possibility [of a 60-year natural cycle] should be considered when attempting to interpret the acceleration in the rate of global and regional mean sea level rise."

Climate has also long been known to have a natural ~ 60 year cycle, along with the Pacific Decadal Oscillation [PDO] and Atlantic Multidecadal Oscillation [AMO]. A very simple climate model consisting only of the "sunspot integral" + PDO + AMO predicts 96% of the variation in global temperature [R²= .96], whereas CO2 correlates poorly with global temperature [R² = .44]. 

Is there a 60-year oscillation in global mean sea level?

We examine long tide gauge records in every ocean basin to examine whether a quasi 60-year oscillation observed in global mean sea level (GMSL) reconstructions reflects a true global oscillation, or an artifact associated with a small number of gauges. We find that there is a significant oscillation with a period around 60-years in the majority of the tide gauges examined during the 20th Century, and that it appears in every ocean basin. Averaging of tide gauges over regions shows that the phase and amplitude of the fluctuations are similar in the North Atlantic, western North Pacific, and Indian Oceans, while the signal is shifted by 10 years in the western South Pacific. The only sampled region with no apparent 60-year fluctuation is the Central/Eastern North Pacific. The phase of the 60-year oscillation found in the tide gauge records is such that sea level in the North Atlantic, western North Pacific, Indian Ocean, and western South Pacific has been increasing since 1985–1990. Although the tide gauge data are still too limited, both in time and space, to determine conclusively that there is a 60-year oscillation in GMSL, the possibility should be considered when attempting to interpret the acceleration in the rate of global and regional mean sea level rise.

New paper finds CO2 rapidly increased during the last ice age

A paper published today in Geophysical Research Letters finds there was an "Abrupt change in atmospheric CO2 during the last ice age" which occurred "rapidly, over less than two centuries. This rise in CO2 was synchronous with, or slightly later than, a rapid increase of Antarctic temperature." The authors also report "carbon cycle modeling doesn't capture all of the processes for CO2 variations." Thus, rapid increases in atmospheric CO2 have been shown to occur naturally due to processes not captured by climate models. In addition, temperature rise during the last ice age was found to be synchronous or leading CO2 rise, implying that temperature controls atmospheric CO2, rather than CO2 controlling temperature. 

Related: 
Climate scientist Dr. Murry Salby explains why man-made CO2 does not control climate

More on the 1,500-year climate cycle noted below: Paper finds climate is 'highly sensitive to extremely weak' changes in solar activity

GEOPHYSICAL RESEARCH LETTERS, doi:10.1029/2012GL053018

Abrupt change in atmospheric CO2 during the last ice age

Key Points

• Half of CO2 increase during a 1500-year cold period occurred in < 200 yrs.
• Abrupt CO2 rise is synchronous, or slightly later than,a rapid Antarctic warming.
• Carbon-cycle-climate modeling doesn't capture all of the processes for CO2 variations.

Authors:

Jinho Ahn

Edward Brook

Andreas Schmittner

Karl J Kreutz

During the last glacial period atmospheric carbon dioxide and temperature in Antarctica varied in a similar fashion on millennial time scales, but previous work indicates that these changes were gradual. In a detailed analysis of one event we now find that approximately half of the CO2 increase that occurred during the 1500-year cold period between Dansgaard-Oeschger (DO) events 8 and 9 happened rapidly, over less than two centuries. This rise in CO2 was synchronous with, or slightly later than, a rapid increase of Antarctic temperature inferred from stable isotopes.

New paper finds clouds over the Pacific have a strong negative-feedback cooling effect

A new paper published in Geophysical Research Letters finds from satellite observations that "Clouds over the Pacific warm pool have a longwave cooling effect for increases in sea surface temperatures." Thus, clouds changes act as a negative feedback to sea surface warming. Climate models, however, erroneously assume clouds and water vapor act as positive feedbacks. The authors find a "strong" increase in outgoing longwave radiation [OLR] to space of 15.72 W/m2 for each 1C change in sea surface temperature. By way of comparison, the IPCC alleges a doubling of CO2 will decrease or "trap" OLR by 3.7 W/m2, a factor of 4 less. According to the authors, "This atmospheric cooling effect is found to be primarily associated with reduced areal coverage of clouds (a 14.4% decrease in cloud cover per 1C change in sea surface temperature).

GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L18802, 6 PP., 2012
doi:10.1029/2012GL052700

The observed variation in cloud-induced longwave radiation in response to sea surface temperature over the Pacific warm pool from MTSAT-1R imagery

Key Points

• Cloud's noise effect on SST hinders estimation of the radiative feedback
• Clear-sky SST helps meaningful estimation of the longwave response to SST change
• Clouds over the Pacific warm pool have longwave cooling effect for increased SST

Heeje Cho

Computational Science and Technology, Seoul National University, Seoul, South Korea

Chang-Hoi Ho

Computational Science and Technology, Seoul National University, Seoul, South Korea

School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea

Center for Climate/Environment Change Prediction Research, Ewha Womans University, Seoul, South Korea

Yong-Sang Choi

Center for Climate/Environment Change Prediction Research, Ewha Womans University, Seoul, South Korea

Department of Environmental Science and Engineering, Ewha Womans University, Seoul, South Korea

This study investigated variations in outgoing longwave radiation (OLR) in response to changes in sea surface temperature (SST) over the Pacific warm pool area (20°N–20°S, 130°E–170°W). OLR values were obtained from recent (January 2008–June 2010) geostationary window channel imagery at hourly resolution, which resolves processes associated with tropical convective clouds. We used linear regression analysis with the domain-averaged OLR and SST anomalies (i.e., ΔOLR, ΔSST; deviations from their 90-day moving averages). Results show that the regression slope appears to be significant only with SST least-affected by cloud radiative forcing, for which SST needs to be obtained as daily average over cloud-free regions (ΔSST_clear). The estimated value of ΔOLR/ΔSST_clear is 15.72 W m⁻² K⁻¹, indicating the presence of strong outgoing longwave radiation in response to surface warming. This atmospheric cooling effect is found to be primarily associated with reduced areal coverage of clouds (−14.4% K⁻¹).

Climate scientist Dr. Murry Salby explains why man-made CO2 does not control climate

In a highly recommended lecture, Dr. Murry Salby, professor and Climate Chair at Macquarie University, Australia, debunks the popular myth that man-made CO2 controls global temperature. Dr. Murry proves from observations the opposite is true: natural changes in global temperature instead control CO2 levels and that man-made emissions do not control either atmospheric CO2 or the climate. Dr. Salby also debunks the notion that changes in greenhouse gases control ocean temperatures, showing that the huge heat capacity of the ocean means that a tiny ocean cooling of < 0.0005C could cause all atmospheric warming of < 1C observed since pre-industrial times. Dr. Salby shows why nature, not man, is the cause of the increase in CO2 by demonstrating that only the integral of temperature changes explains the changes in atmospheric CO2, not a slow steady rise in man-made emissions.

Significant slides from the presentation are below:

Popular myths

A cooling of the ocean of < 0.0005C could alone account for a 1C rise in atmospheric temperature

A change in radiative forcing due to doubled CO2 is much smaller than the errors in Earth's energy budget assumptions

 

Change in surface temperature ["surface conditions"] causes changes in atmospheric CO2, not the opposite

Real world observations show atmospheric CO2 levels result from natural temperature changes not man-made emissions. CO2 does not cause changes in global temperature 

 

Dr. Judith Curry on a prior talk given by Dr. Salby

New paper finds glaciers in Glacier National Park retreated up to 6 times faster during the 1930's than the past 40 years

A new paper published in Quaternary Science Reviews finds that alpine glaciers in Glacier National Park, Montana retreated up to 6 times faster during the 1930's and 1940's than over the past 40 years.  The "Multi-proxy study of sediment cores retrieved from lakes below modern glaciers supports the first detailed Neoglacial chronology for Glacier National Park (GNP)" and shows "maximum reconstructed retreat rates [in] 1930" of about 125 meters per year, compared to near zero in ~1975 and about 20 meters/year at the end of the record in ~2005.  The authors report, "Results indicate that alpine glaciers in Glacier National Park advanced and retreated numerous times during the Holocene after the onset of Neoglaciation 6,500 years before the present" and "Retreat from the Little Ice Age maximum was the most dramatic episode of ice retreat in at least the last 1000 years."

Fig. 8. Relationship between climate, retreat of the Agassiz Glacier, and flux of carbonate in core UKL-1 from AD 1750 to the present. Dashed line shows CaCO₃ flux in mg/cm²/yr. Filled gray line illustrates the reconstructed retreat rate of the Agassiz Glacier from its LIA terminal moraine, calculated from dating of trees in the glacier forefield (Carrara and McGimsey, 1981). Carbonate flux began to rise at the onset of ice retreat, and reached a peak nearly synchronous with the maximum reconstructed retreat rates ca AD 1930. Filled black line presents a tree-ring compilation (BMS Douglas Fir) sensitive to summer drought collected in the vicinity of the Agassiz Glacier (Pederson et al., 2004). Black fill (note reversed scale) denotes wetter, cooler conditions that were responsible for advance of the Agassiz Glacier to its LIA maximum position. Retreat began with the switch to below-normal precipitation.

A lacustrine-based Neoglacial record for Glacier National Park, Montana, USA

• Jeffrey S. Munroe^a, , , 
• Thomas A. Crocker^a, 
• Alena M. Giesche^a, 
• Lukas E. Rahlson^a, 
• Logan T. Duran^a, 
• Matthew F. Bigl^a, 
• Benjamin J.C. Laabs^b

• ^a Geology Department, Middlebury College, 276 Bicentennial Way, Middlebury, VT 05753, USA
• ^b Department of Geological Sciences, SUNY Geneseo, Geneseo, NY 14454, USA

• http://dx.doi.org/10.1016/j.quascirev.2012.08.005,

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Abstract

Multi-proxy study of sediment cores retrieved from lakes below modern glaciers supports the first detailed Neoglacial chronology for Glacier National Park (GNP), Montana. Analysis focused on sedimentary properties sensitive to the extent and activity of upstream glacier ice, including: water, organic matter, carbonate, and biogenic silica content; bulk density; mass accumulation rate; phosphorus fractionation; magnetic susceptibility; L*a*b* color values; and grain size distribution. Results indicate that alpine glaciers in GNP advanced and retreated numerous times during the Holocene after the onset of Neoglaciation ca 6500 BP. The two oldest phases of glacier expansion were synchronous with the well-documented Garibaldi (5600–6900 BP) and Tiedemann-Peyto (1900–3700 BP) phases in western Canada. Younger phases correspond with the First Millennium Advance in western Canada, as well as glacier with advances in the Sierra Nevada. The culminating Little Ice Age (LIA) advance was the most recent and extensive of a series of advance/retreat cycles over the past millennium. Retreat from the LIA maximum was the most dramatic episode of ice retreat in at least the last 1000 years.

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Highlights

► A high-resolution, lacustrine-based Neoglacial record. ► Neoglaciation began 6500 BP. ► Intervals of expanded glaciers were broadly synchronous within the region. ► Retreat after the Little Ice Age was the most dramatic event of the last millennium.