New Research

[knocker]

Ocean winds keep Antarctica cold, Australia dry

 

New Australian National University-led research has explained why Antarctica is not warming as much as other continents, and why southern Australia is recording more droughts.Read more at: http://phys.org/news/2014-05-ocean-antarctica-cold-australia.html#jCp

[knocker]

This pertains to the press release above

 

Evolution of the Southern Annular Mode during the past millennium

 

 

The Southern Annular Mode (SAM) is the primary pattern of climate variability in the Southern Hemisphere^{1, 2}, influencing latitudinal rainfall distribution and temperatures from the subtropics to Antarctica. The positive summer trend in the SAM over recent decades is widely attributed to stratospheric ozone depletion²; however, the brevity of observational records from Antarctica¹â€”one of the core zones that defines SAM variability—limits our understanding of long-term SAM behaviour. Here we reconstruct annual mean changes in the SAM since AD 1000 using, for the first time, proxy records that encompass the full mid-latitude to polar domain across the Drake Passage sector. We find that the SAM has undergone a progressive shift towards its positive phase since the fifteenth century, causing cooling of the main Antarctic continent at the same time that the Antarctic Peninsula has warmed. The positive trend in the SAM since ~AD 1940 is reproduced by multimodel climate simulations forced with rising greenhouse gas levels and later ozone depletion, and the long-term average SAM index is now at its highest level for at least the past 1,000 years. Reconstructed SAM trends before the twentieth century are more prominent than those in radiative-forcing climate experiments and may be associated with a teleconnected response to tropical Pacific climate. Our findings imply that predictions of further greenhouse-driven increases in the SAM over the coming century³ also need to account for the possibility of opposing effects from tropical Pacific climate changes.

 

http://www.nature.co...limate2235.html

Edited May 12, 2014 by knocker

[knocker]

Study: Dangerous storms peaking further north, south than in past

 

New analysis of cyclones shows migration away from tropics and toward the poles in recent decades.

 

http://newsoffice.mit.edu/2014/study-dangerous-storms-peaking-further-north-south-past-0514

Edited May 14, 2014 by knocker

[Gray-Wolf]

Someone posted on the Nino thread charts showing that strong Ninos were getting stronger but spaced further apart. I wonder if the expansion of the tropical belt has a role in this with Cyclones that would have produced WWB, and reinforced the formation of nino, now give weaker aid by being further from the equator?

 

97's Super was aided in its formation by a super typhoon around the equator I seem to recall?

[BornFromTheVoid]

Humans caused nearly 90 percent of sea level rise from warming of upper ocean, study says

 

WASHINGTON, DC – Human-generated emissions are largely responsible for warming the top layer of the ocean over the past four decades, causing water to expand and sea level to rise, according to a new study.

 

Climate models show that human activities, like burning fossil fuels, are responsible for 87 percent of the sea level rise since 1970 that’s been caused by swelling volume of the upper ocean. Natural forces, like solar radiation and volcanic activity, are responsible for the remainder of the increase in the upper ocean’s share of warming-induced, or thermosteric, sea level rise, according to a new study recently published in Geophysical Research Letters, a journal of the American Geophysical Union.

 

More here http://blogs.agu.org/geospace/2014/05/15/humans-caused-nearly-90-percent-sea-level-rise-warming-upper-ocean-study-says/

[knocker]

The influence of different El Niño types on global average temperature

 

Abstract

The El Niño–Southern Oscillation is known to influence surface temperatures worldwide. El Niño conditions are thought to lead to anomalously warm global average surface temperature, absent other forcings. Recent research has identified distinct possible types of El Niño events based on the location of peak sea surface temperature anomalies. Here we analyze the relationship between the type of El Niño event and the global surface average temperature anomaly, using three historical temperature data sets. Separating El Niño events into types reveals that the global average surface temperatures are anomalously warm during and after traditional eastern Pacific El Niño events, but not central Pacific or mixed events. Historical analysis indicated that slowdowns in the rate of global surface warming since the late 1800s may be related to decadal variability in the frequency of different types of El Niño events.

 

http://onlinelibrary.wiley.com/doi/10.1002/2014GL059520/abstract;jsessionid=BA1B3D2EF8E15C12F1476A6E6CCEDCC4.f03t01

[knocker]

Possible North Atlantic origin for changes in ENSO properties during the 1970s

 

Abstract

The most intense El Niño episodes in more than a century occurred after the 1970s climate shift. Previous studies show that the characteristics of the El Niño-Southern Oscillation (ENSO) phenomenon changed synchronously with the shift, but the associated causes are not fully understood. An analysis of the observed tropical Pacific sea surface temperature (SST) anomalies shows that their increase in the eastern part of the basin after the 1970s is not related to the canonical ENSO pattern, but to the tropical Pacific meridional mode (TPMM). We present observational evidence which supports the hypothesis that the change in the TPMM was triggered by the great salinity anomaly (GSA), which manifested in the North Atlantic during the late 1960s. The GSA induced a weak Labrador convection and a SST dipole south of Greenland. The associated atmospheric structure includes a North Pacific Oscillation sea level pressure dipole in the Pacific sector. This excites the TPMM which contributes to the intense El Niño events and to the enhanced ENSO’s asymmetry, observed after the shift. Our results imply that, if the GSA has not an anthropic origin, as was suggested, then the tropical Pacific climate shift has a natural origin. This is supported by the end of the North Atlantic regime in the 1990s and by the rebound of the tropical Pacific after 1998.

 

http://rd.springer.com/article/10.1007%2Fs00382-014-2173-x?utm_content=buffer59ddc&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

[knocker]

Can we trust climate models?

 

What are the predictions of climate models, should we believe them, and are they falsifiable? Probably the most iconic and influential result arising from climate models is the prediction that, dependent on the rate of increase of CO₂ emissions, global and annual mean temperature will rise by around 2–4°C over the 21st century. We argue that this result is indeed credible, as are the supplementary predictions that the land will on average warm by around 50% more than the oceans, high latitudes more than the tropics, and that the hydrological cycle will generally intensify. Beyond these and similar broad statements, however, we presently find little evidence of trustworthy predictions at fine spatial scale and annual to decadal timescale from climate models.

 

http://onlinelibrary.wiley.com/doi/10.1002/wcc.288/pdf

[knocker]

A new study has found that the Antarctic Ice Sheet began melting about 5,000 years earlier than previously thought coming out of the last ice age – and that shrinkage of the vast ice sheet accelerated during eight distinct episodes, causing rapid sea level rise.

 

http://www.reportingclimatescience.com/news-stories/article/antarctic-ice-sheet-was-unstable-at-end-of-last-ice-age.html

[knocker]

An adaptability limit to climate change due to heat stress

 

Abstract

Despite the uncertainty in future climate-change impacts, it is often assumed that humans would be able to adapt to any possible warming. Here we argue that heat stress imposes a robust upper limit to such adaptation. Peak heat stress, quantified by the wet-bulb temperature T_W, is surprisingly similar across diverse climates today. T_W never exceeds 31 °C. Any exceedence of 35 °C for extended periods should induce hyperthermia in humans and other mammals, as dissipation of metabolic heat becomes impossible. While this never happens now, it would begin to occur with global-mean warming of about 7 °C, calling the habitability of some regions into question. With 11–12 °C warming, such regions would spread to encompass the majority of the human population as currently distributed. Eventual warmings of 12 °C are possible from fossil fuel burning. One implication is that recent estimates of the costs of unmitigated climate change are too low unless the range of possible warming can somehow be narrowed. Heat stress also may help explain trends in the mammalian fossil record.

 

http://www.pnas.org/content/107/21/9552.long

[knocker]

Warming climates intensify greenhouse gas given out by oceans

 

Rising global temperatures could increase the amount of carbon dioxide naturally released by the world's oceans, fuelling further climate change, a study suggests.Read more at: http://phys.org/news/2014-06-climates-greenhouse-gas-oceans.html#jCp

[knocker]

How robust is the recent strengthening of the Tropical Pacific trade winds?

 

Abstract

The persistent strengthening of the trade winds over the Pacific Ocean over the past 20 years has recently been proposed as a driver for the increase of ocean heat uptake linked to the hiatus in surface global warming. Crucial aspects in this argument are the reliability of the wind signal, usually derived from atmospheric reanalyses, and the ability of models to represent it. This study addresses these two aspects by comparing various observations with reanalyses and model integrations from the ECMWF system. We show that the strengthening of trades over the Pacific is a robust feature in several observational data sets as well as in the reanalyses based on full and limited sets of observations. The wind trend is also reproduced in an atmospheric model integration forced by Sea Surface Temperature analysis, a result that opens the doors to further investigation on the nature of the changes.

 

http://onlinelibrary.wiley.com/doi/10.1002/2014GL060257/abstract?utm_content=buffer3d6c2&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

[keithlucky]

West Antarctic glacier being melted by magma not GW http://phys.org/news/2014-06-major-west-antarctic-glacier-geothermal.html#jCp

Edited June 10, 2014 by keithlucky

[jonboy]

West Antarctic glacier being melted by magma not GW http://phys.org/news/2014-06-major-west-antarctic-glacier-geothermal.html#jCp

 

Well GW can blow hot and cold when he wants!!!!!!

[knocker]

West Antarctic glacier being melted by magma not GW http://phys.org/news/2014-06-major-west-antarctic-glacier-geothermal.html#jCp

 

Firstly I have already posted a link to the full paper in the Antarctic thread.

 

Your comment "West Antarctic glacier being melted by magma not GW" is incorrect.

 

 

Thwaites Glacier, the large, rapidly changing outlet of the West Antarctic Ice Sheet, is not only being eroded by the ocean, it’s being melted from below by geothermal heat, researchers at the Institute for Geophysics at The University of Texas at Austin (UTIG) report in the current edition of the Proceedings of the National Academy of Sciences.

 

The geothermal heat is adding to this effect, not replacing it. so blowing hot and cold is fine.

 

As i noted in my earlier post AW and the illiterati also whipped themselves into a frenzy over this so HotWhopper nipped it in the bud. Or stopped the geothermal flow of hot air so to speak.

 

Geothermal flux, West Antarctica and deniers at WUWT

http://blog.hotwhopper.com/2014/06/geothermal-flux-west-antarctica-and.html

[knocker]

New permafrost is forming around shrinking Arctic lakes

 

Researchers from McGill and the U.S. Geological Survey, more used to measuring thawing permafrost than its expansion, have made a surprising discovery. There is new permafrost forming around Twelvemile Lake in the interior of Alaska. But they have also quickly concluded that, given the current rate of climate change, it won’t last beyond the end of this century.

 

http://www.mcgill.ca/newsroom/channels/news/new-permafrost-forming-around-shrinking-arctic-lakes-237010

[knocker]

How Earth avoided global warming, last time around

 

Geochemists have calculated a huge rise in atmospheric carbon dioxide was only avoided by the formation of a vast mountain range in the middle of the ancient supercontinent, Pangea. A new model explains some of the events in the 80 million years following the start of the Carboniferous period.

 

http://www.sciencedaily.com/releases/2014/06/140611143733.htm

Edited June 12, 2014 by knocker

[knocker]

Increased frequency of extreme Indian Ocean Dipole events due to greenhouse warming

 

The Indian Ocean dipole is a prominent mode of coupled ocean–atmosphere variability^{1, 2, 3, 4}, affecting the lives of millions of people in Indian Ocean rim countries^{5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}. In its positive phase, sea surface temperatures are lower than normal off the Sumatra–Java coast, but higher in the western tropical Indian Ocean. During the extreme positive-IOD (pIOD) events of 1961, 1994 and 1997, the eastern cooling strengthened and extended westward along the equatorial Indian Ocean through strong reversal of both the mean westerly winds and the associated eastward-flowing upper ocean currents^{1, 2}. This created anomalously dry conditions from the eastern to the central Indian Ocean along the Equator and atmospheric convergence farther west, leading to catastrophic floods in eastern tropical African countries^{13, 14} but devastating droughts in eastern Indian Ocean rim countries^{8, 9, 10, 16, 17}. Despite these serious consequences, the response of pIOD events to greenhouse warming is unknown. Here, using an ensemble of climate models forced by a scenario of high greenhouse gas emissions (Representative Concentration Pathway 8.5), we project that the frequency of extreme pIOD events will increase by almost a factor of three, from one event every 17.3 years over the twentieth century to one event every 6.3 years over the twenty-first century. We find that a mean state change—with weakening of both equatorial westerly winds and eastward oceanic currents in association with a faster warming in the western than the eastern equatorial Indian Ocean—facilitates more frequent occurrences of wind and oceanic current reversal. This leads to more frequent extreme pIOD events, suggesting an increasing frequency of extreme climate and weather events in regions affected by the pIOD.

 

http://www.nature.com/nature/journal/v510/n7504/full/nature13327.html

[knocker]

Arctic warming linked to fewer European and US cold weather extremes, new study shows

 

Climate change is unlikely to lead to more days of extreme cold, similar to those that gripped the USA in a deep freeze last winter, new research has shown. The Arctic amplification phenomenon refers to the faster rate of warming in the Arctic compared to places further south. It is this phenomenon that has been linked to a spike in the number of severe cold spells experienced in recent years over Europe and North America.

 

http://www.sciencedaily.com/releases/2014/06/140615143834.htm

[Gray-Wolf]

Interesting knocks, i mean the the way an average U.S, winter was greeted by some commentators and U.S. news outlets and not the fact that the Arctic is warming rapidly?

 

I mean they live there and have lived through much colder winters and yet half the country appeared convinced it was the beginning of "The dat after tomorrow" ?

[knocker]

Mid-latitude interhemispheric hydrologic seesaw over the past 550,000 years

 

An interhemispheric hydrologic seesaw—in which latitudinal migrations of the Intertropical Convergence Zone (ITCZ) produce simultaneous wetting (increased precipitation) in one hemisphere and drying in the other—has been discovered in some tropical and subtropical regions^{1, 2, 3}. For instance, Chinese and Brazilian subtropical speleothem (cave formations such as stalactites and stalagmites) records show opposite trends in time series of oxygen isotopes (a proxy for precipitation variability) at millennial to orbital timescales^{2, 3}, suggesting that hydrologic cycles were antiphased in the northerly versus southerly subtropics. This tropical to subtropical hydrologic phenomenon is likely to be an initial and important climatic response to orbital forcing³. The impacts of such an interhemispheric hydrologic seesaw on higher-latitude regions and the global climate system, however, are unknown. Here we show that the antiphasing seen in the tropical records is also present in both hemispheres of the mid-latitude western Pacific Ocean. Our results are based on a new 550,000-year record of the growth frequency of speleothems from the Korean peninsula, which we compare to Southern Hemisphere equivalents⁴. The Korean data are discontinuous and derived from 24 separate speleothems, but still allow the identification of periods of peak speleothem growth and, thus, precipitation. The clear hemispheric antiphasing indicates that the sphere of influence of the interhemispheric hydrologic seesaw over the past 550,000 years extended at least to the mid-latitudes, such as northeast Asia, and that orbital-timescale ITCZ shifts can have serious effects on temperate climate systems. Furthermore, our result implies that insolation-driven ITCZ dynamics may provoke water vapour and vegetation feedbacks in northern mid-latitude regions and could have regulated global climate conditions throughout the late Quaternary ice age cycles.

 

http://www.nature.com/nature/journal/v508/n7496/full/nature13076.html

 

Brief discussion

 

http://www.kigam.re.kr/Contents/mboard.asp?Action=view&strBoardID=B030&intPage=1&intCategory=0&strSearchCategory=|s_name|s_subject|&strSearchWord=&intSeq=16793

[knocker]

Regional weather extremes linked to atmospheric variations

 

Variations in high-altitude wind patterns expose particular parts of Europe, Asia and the US to different extreme weather conditions, a new study has shown. Changes to air flow patterns around the Northern Hemisphere are a major influence on prolonged bouts of unseasonal weather -- whether it be hot, cold, wet or dry.

 

http://www.sciencedaily.com/releases/2014/06/140622142230.htm

[knocker]

Average seasonal rainfall in India on a decline, reveals report by Stanford Woods Institute for the Environment

Read more at: http://indiatoday.intoday.in/story/average-seasonal-rainfall-monsoon-stanford-woods-institute/1/368395.html

 

One Quarter Of India Is Turning Into Desert

Edited June 26, 2014 by knocker

[knocker]

High CO2 levels cause warming in the tropics

http://www.sciencecodex.com/high_co2_levels_cause_warming_in_the_tropics-136583

[keithlucky]

New paper finds sea levels stable/fallen  in the last 2000yrs in the NE Atlantic http://www.sciencedirect.com/science/article/pii/S0277379114002261