New Research

[BornFromTheVoid]

AMO turning negative and gulf stream slowing down, another paper supporting the idea.

 

Ocean impact on decadal Atlantic climate variability revealed by sea-level observations

 

Decadal variability is a notable feature of the Atlantic Ocean and the climate of the regions it influences. Prominently, this is manifested in the Atlantic Multidecadal Oscillation (AMO) in sea surface temperatures. Positive (negative) phases of the AMO coincide with warmer (colder) North Atlantic sea surface temperatures. The AMO is linked with decadal climate fluctuations, such as Indian and Sahel rainfall, European summer precipitation, Atlantic hurricanes and variations in global temperatures. It is widely believed that ocean circulation drives the phase changes of the AMO by controlling ocean heat content. However, there are no direct observations of ocean circulation of sufficient length to support this, leading to questions about whether the AMO is controlled from another source. Here we provide observational evidence of the widely hypothesized link between ocean circulation and the AMO. We take a new approach, using sea level along the east coast of the United States to estimate ocean circulation on decadal timescales. We show that ocean circulation responds to the first mode of Atlantic atmospheric forcing, the North Atlantic Oscillation, through circulation changes between the subtropical and subpolar gyres—the intergyre region. These circulation changes affect the decadal evolution of North Atlantic heat content and, consequently, the phases of the AMO. The Atlantic overturning circulation is declining and the AMO is moving to a negative phase. This may offer a brief respite from the persistent rise of global temperatures, but in the coupled system we describe, there are compensating effects. In this case, the negative AMO is associated with a continued acceleration of sea-level rise along the northeast coast of the United States

 

Abstract page here

 

Review of the article here

[knocker]

Cheers BFTV you just beat me to it. I assume this was the other paper.

 

Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation

 

Possible changes in Atlantic meridional overturning circulation (AMOC) provide a key source of uncertainty regarding future climate change. Maps of temperature trends over the twentieth century show a conspicuous region of cooling in the northern Atlantic. Here we present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970. Since 1990 the AMOC seems to have partly recovered. This time evolution is consistently suggested by an AMOC index based on sea surface temperatures, by the hemispheric temperature difference, by coral-based proxies and by oceanic measurements. We discuss a possible contribution of the melting of the Greenland Ice Sheet to the slowdown. Using a multi-proxy temperature reconstruction for the AMOC index suggests that the AMOC weakness after 1975 is an unprecedented event in the past millennium (p > 0.99). Further melting of Greenland in the coming decades could contribute to further weakening of the AMOC.

 

http://www.nature.com/nclimate/journal/v5/n5/full/nclimate2554.html

 

Discussion by Stefan Rahmstorf

 

https://www.pik-potsdam.de/news/press-releases/atlantic-ocean-overturning-found-to-slow-down-already-today

Edited May 28, 2015 by knocker

[knocker]

Rutgers Climate Scientists Find More Evidence Linking Arctic Warming to Jet Stream Movement

 

Findings from a new Rutgers University climate change study support previous research that shows a link between the rapidly warming Arctic and an increase in extreme weather events.

 

Using self-organizing maps – statistical tools to help identify characteristic patterns in a data set – Rutgers climate scientists Jennifer Francis and Natasa Skific studied 48 years worth of daily atmospheric information to detect weather patterns that occur repeatedly. 

 

The patterns they found validated previous study findings that the polar jet stream has been meandering more north and south in the past two decades rather than traveling in a relatively straight path.  Scientists are studying the relation of changing jet stream patterns and Arctic warming to extreme weather conditions.

 

http://news.rutgers.edu/research-news/rutgers-climate-scientists-find-more-evidence-linking-arctic-warming-jet-stream-movement/20150601#.VXAaxFJH7PQ

 

The study

 

http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCIQFjAA&url=http%3A%2F%2Frsta.royalsocietypublishing.org%2Fcontent%2F373%2F2045%2F20140170.full-text.pdf&ei=GhtwVfzAG8riUbrwgYgH&usg=AFQjCNHYcHWG0kw1g--L6HPtgwH4Pgsaow&sig2=0ztDR12U-QJKrL2HxvY2LQ&bvm=bv.94911696,d.d24&cad=rja

 

[knocker]

Time for a famous Jim Reeves song methinks

 

Global warming slowdown never happened, federal study says

 

It is one of climate contrarians' most widely repeated arguments against mainstream climate science: Global warming slowed down — or even stopped — in 1998.

Even the United Nations Intergovernmental Panel on Climate Change (IPCC), which is the world's most credible mainstream climate-science authority, acknowledged in its 2013 report that warming slowed down during this period.

 

The IPCC said the temperature trend from 1998 to 2012 was about one-third to one-half of the warming trend during the period from 1951 to 2012.

 

However, a new study published Thursday in the journal Science by top climate researchers at the National Oceanic and Atmospheric Administration (NOAA) aims a kill shot at the hiatus once and for all. Led by Thomas R. Karl, who directs NOAA's National Centers for Environmental Information (NCEI) in Asheville, North Carolina, scientists say that the so-called pause in warming during that period was an artifact of improperly adjusted surface-temperature data.

 

http://mashable.com/2015/06/04/global-warming-hiatus-study/

Edited June 4, 2015 by knocker

[knocker]

A little more on the above

 

http://arstechnica.com/science/2015/06/updated-noaa-temperature-record-shows-little-global-warming-slowdown/

[knocker]

Sea level rise projections for northern Europe under RCP8.5

 

 

ABSTRACT: Sea level rise poses a significant threat to coastal communities, infrastructure, and ecosystems. Sea level rise is not uniform globally but is affected by a range of regional factors. In this study, we calculate regional projections of 21st century sea level rise in northern Europe, focusing on the British Isles, the Baltic Sea, and the North Sea. The input to the regional sea level projection is a probabilistic projection of the major components of the global sea level budget. Local sea level rise is partly compensated by vertical land movement from glacial isostatic adjustment. We explore the uncertainties beyond the likely range provided by the IPCC, including the risk and potential rate of marine ice sheet collapse. Our median 21st century relative sea level rise projection is 0.8 m near London and Hamburg, with a relative sea level drop of 0.1 m in the Bay of Bothnia (near Oulu, Finland). Considerable uncertainties remain in both the sea level budget and in the regional expression of sea level rise. The greatest uncertainties are associated with Antarctic ice loss, and uncertainties are skewed towards higher values, with the 95th percentile being characterized by an additional 0.9 m sea level rise above median projections.

 

Open access

 

http://www.int-res.com/abstracts/cr/v64/n1/p15-23/

[knocker]

Will rising temperatures mean more lives are saved than lost?

 

 

Higher temperatures and longer heatwaves will push more of us beyond our tolerance limits, leading to a rise in the number of deaths from heat-related illnesses, scientists say.

 

But you'll  sometimes see it argued in  parts of the  media that the number of lives saved each year as winters get warmer will outweigh these extra deaths caused by heat-exposure.

A new study strongly counters this view, however.

 

http://www.carbonbrief.org/blog/2015/06/carbon-brief-explainer-will-rising-temperatures-mean-more-lives-are-saved-than-lost-%281%29/?utm_source=Daily+Carbon+Briefing&utm_campaign=3cdbaefc1f-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-3cdbaefc1f-303447709

[knocker]

The Atlantic 'conveyor belt' and climate: 10 years of the RAPID project

 

A global project that's been instrumental in shaping scientists' understanding of how the oceans affect our climate celebrated its tenth birthday recently.

 

A new paper published in Science looks back at 10 years of the RAPID project, which has been keeping tabs on how heat moves around in the Atlantic Ocean since 2004.

 

Over its short lifetime, the project has thrown up a few surprises. Parts of the Atlantic circulation seem to have slowed down, though whether that's down to human activity remains to be seen.

 

Carbon Brief talks to one of RAPID's founding scientists, Prof Harry Bryden from the National Oceanography Centre in Southampton, about the project.

 

http://www.carbonbrief.org/blog/2015/06/the-atlantic-conveyor-belt-and-climate-10-years-of-the-rapid-project/?utm_source=Daily+Carbon+Briefing&utm_campaign=4673856fc6-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-4673856fc6-303447709

[knocker]

Attribution of climate extreme events

 

There is a tremendous desire to attribute causes to weather and climate events that is often challenging from a physical standpoint. Headlines attributing an event solely to either human-induced climate change or natural variability can be misleading when both are invariably in play. The conventional attribution framework struggles with dynamically driven extremes because of the small signal-to-noise ratios and often uncertain nature of the forced changes. Here, we suggest that a different framing is desirable, which asks why such extremes unfold the way they do. Specifically, we suggest that it is more useful to regard the extreme circulation regime or weather event as being largely unaffected by climate change, and question whether known changes in the climate system's thermodynamic state affected the impact of the particular event. Some examples briefly illustrated include 'snowmaggedon' in February 2010, superstorm Sandy in October 2012 and supertyphoon Haiyan in November 2013, and, in more detail, the Boulder floods of September 2013, all of which were influenced by high sea surface temperatures that had a discernible human component.

 

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2657.html

 

Jeff Masters

 

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=3025

Edited June 23, 2015 by knocker

[knocker]

Solar minimum could bring cold winters to Europe and US, but would not hold off climate change

 

Over the past few decades, our Sun has been relatively active, giving off high levels of the solar radiation that warms the Earth. However, in recent years this peak activity has tailed off, prompting scientists to wonder if the Sun is heading into a period of lower output.

A new study says even if the Sun's activity did drop off for a while, it wouldn't have much impact on rising global temperatures. But it could mean a higher chance of a chilly winter in Europe and the US, the researchers say.

 

http://www.carbonbrief.org/blog/2015/06/solar-minimum-could-bring-cold-winters-to-europe-and-us/?utm_source=Daily+Carbon+Briefing&utm_campaign=a1da6ab9d3-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-a1da6ab9d3-303447709

[jonboy]

I don't believe this has been highlighted anywhere which if it is the case I am surprised.

 

 

 

Accelerated modern human–induced species losses: Entering the sixth mass extinction

1. Gerardo Ceballos1,*, 
2. Paul R. Ehrlich2, 
3. Anthony D. Barnosky3, 
4. Andrés García4, 
5. Robert M. Pringle5 and 
6. Todd M. Palmer6

+ Author Affiliations

1. ↵*Corresponding author. E-mail: gceballo@ecologia.unam.mx

Science Advances  19 Jun 2015:
Vol. 1, no. 5, e1400253
DOI: 10.1126/sciadv.1400253

Abstract

The oft-repeated claim that Earth’s biota is entering a sixth “mass extinction†depends on clearly demonstrating that current extinction rates are far above the “background†rates prevailing between the five previous mass extinctions. Earlier estimates of extinction rates have been criticized for using assumptions that might overestimate the severity of the extinction crisis. We assess, using extremely conservative assumptions, whether human activities are causing a mass extinction. First, we use a recent estimate of a background rate of 2 mammal extinctions per 10,000 species per 100 years (that is, 2 E/MSY), which is twice as high as widely used previous estimates. We then compare this rate with the current rate of mammal and vertebrate extinctions. The latter is conservatively low because listing a species as extinct requires meeting stringent criteria. Even under our assumptions, which would tend to minimize evidence of an incipient mass extinction, the average rate of vertebrate species loss over the last century is up to 100 times higher than the background rate. Under the 2 E/MSY background rate, the number of species that have gone extinct in the last century would have taken, depending on the vertebrate taxon, between 800 and 10,000 years to disappear. These estimates reveal an exceptionally rapid loss of biodiversity over the last few centuries, indicating that a sixth mass extinction is already under way. Averting a dramatic decay of biodiversity and the subsequent loss of ecosystem services is still possible through intensified conservation efforts, but that window of opportunity is rapidly closing.

 

However to give balance here is a link to what Jim Steele director emeritus Sierra Nevada field Campus, San Francisco State University thinks of the paper.

http://wattsupwiththat.com/2015/06/25/apocalyptic-fear-mongering-sometimes-rush-limbaugh-is-right/

[knocker]

I'm not sure I would rely on Jim Steele giving balance on anything given his record.

 

Jim Steele, climate change and the sixth major extinction event

http://blog.hotwhopper.com/2013/08/jim-steele-climate-change-and-sixth.html

Edited June 25, 2015 by knocker

[jonboy]

I'm not sure I would rely on Jim Steele giving balance on anything given his record.

 

Jim Steele, climate change and the sixth major extinction event

http://blog.hotwhopper.com/2013/08/jim-steele-climate-change-and-sixth.html

 

Whoa quoting Hot Whopper as a reason not to read what the man has to say is a really really good excuse not!!!!

Edited June 25, 2015 by jonboy

[Methuselah]

Whoa quoting Hot Whopper as a reason not to read what the man has to say is a really really good excuse not!!!!

You could make similar, though somewhat more powerful, claim for WUWT, I think?

[jonboy]

You could make similar, though somewhat more powerful, claim for WUWT, I think?

 

At least I bother to read whatever I post before I do post rather than make comments that add zip all !!!!

[Methuselah]

At least I bother to read whatever I post before I do post rather than make comments that add zip all !!!!

I used to read WUWT and Iceagenow; but their view of how science is supposed to work is so opposed to me own, I gave up...

[keithlucky]

New paper says missing heat is not hiding in the Oceans http://www.ocean-sci-discuss.net/12/701/2015/osd-12-701-2015.pdf

[Methuselah]

New paper says missing heat is not hiding in the Oceans http://www.ocean-sci-discuss.net/12/701/2015/osd-12-701-2015.pdf

Mind you, in light of recent research into global temperature-rise, there might not even be any missing heat...http://mashable.com/...g-hiatus-study/

[knocker]

Decreasing intensity of open-ocean convection in the Greenland and Iceland seas

 

The air–sea transfer of heat and fresh water plays a critical role in the global climate system¹. This is particularly true for the Greenland and Iceland seas, where these fluxes drive ocean convection that contributes to Denmark Strait overflow water, the densest component of the lower limb of the Atlantic Meridional Overturning Circulation (AMOC; ref. 2). Here we show that the wintertime retreat of sea ice in the region, combined with different rates of warming for the atmosphere and sea surface of the Greenland and Iceland seas, has resulted in statistically significant reductions of approximately 20% in the magnitude of the winter air–sea heat fluxes since 1979. We also show that modes of climate variability other than the North Atlantic Oscillation (NAO; refs 3, 4, 5, 6, 7) are required to fully characterize the regional air–sea interaction. Mixed-layer model simulations imply that further decreases in atmospheric forcing will exceed a threshold for the Greenland Sea whereby convection will become depth limited, reducing the ventilation of mid-depth waters in the Nordic seas. In the Iceland Sea, further reductions have the potential to decrease the supply of the densest overflow waters to the AMOC (ref. 8).

 

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2688.html

 

Synopsis

 

Retreating sea ice linked to changes in ocean circulation, could affect European climate

 

http://www.sciencedaily.com/releases/2015/06/150629123428.htm

[knocker]

Contribution of changes in atmospheric circulation patterns to extreme temperature trends

 

Surface weather conditions are closely governed by the large-scale circulation of the Earth’s atmosphere. Recent increases in the occurrence of some extreme weather phenomena^{1, 2} have led to multiple mechanistic hypotheses linking changes in atmospheric circulation to increasing probability of extreme events^{3, 4, 5}. However, observed evidence of long-term change in atmospheric circulation remains inconclusive^{6, 7, 8}. Here we identify statistically significant trends in the occurrence of atmospheric circulation patterns, which partially explain observed trends in surface temperature extremes over seven mid-latitude regions of the Northern Hemisphere. Using self-organizing map cluster analysis^{9, 10, 11, 12}, we detect robust circulation pattern trends in a subset of these regions during both the satellite observation era (1979–2013) and the recent period of rapid Arctic sea-ice decline (1990–2013). Particularly substantial influences include the contribution of increasing trends in anticyclonic circulations to summer and autumn hot extremes over portions of Eurasia and North America, and the contribution of increasing trends in northerly flow to winter cold extremes over central Asia. Our results indicate that although a substantial portion of the observed change in extreme temperature occurrence has resulted from regional- and global-scale thermodynamic changes, the risk of extreme temperatures over some regions has also been altered by recent changes in the frequency, persistence and maximum duration of regional circulation patterns.

 

http://www.nature.com/nature/journal/v522/n7557/full/nature14550.html

 

Synopsis

http://phys.org/news/2015-06-weather-patterns-heatwaves.html

[knocker]

The importance of including variability in climate change projections used for adaptation

 

Our understanding of mankind’s influence on the climate is largely based on computer simulations^{1, 2}. Model output is typically averaged over several decades³ so that the anthropogenic climate change signal stands out from the largely unpredictable ‘noise’ of climate variability. Similar averaging periods (30-year) are used for regional climate projections^{4, 5, 6} to inform adaptation. According to two such projections, UKCIP02 (ref. 4) and UKCP09 (ref. 6), the UK will experience ‘hotter drier summers and warmer wetter winters’^{7, 8} in the future. This message is about a typical rather than any individual future season, and these projections should not be compared directly to observed weather as this neglects the sizeable contribution from year-to-year climate variability. Therefore, despite the apparent contradiction with the messages, it is a fallacy to suggest the recent cold UK winters like 2009/2010 disprove human-made climate change⁹. Nevertheless, such claims understandably cause public confusion and doubt¹⁰. Here we include year-to-year variability to provide projections for individual seasons. This approach has two advantages. First, it allows fair comparisons with recent weather events, for instance showing that recent cold winters are within projected ranges. Second, it allows the projections to be expressed in terms of the extreme hot, cold, wet or dry seasons that impact society, providing a better idea of adaptation needs.

 

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2705.html

 

Discussion

Chance of a very cold UK winter falls to less than 1% by 2100, new study suggests

 

http://www.carbonbrief.org/blog/2015/07/chance-of-a-uk-very-cold-winter-falls-to-less-than-1-by-2100/?utm_source=Daily+Carbon+Briefing&utm_campaign=a85c8bef87-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-a85c8bef87-303447709

[BornFromTheVoid]

Timing and climate forcing of volcanic eruptions for the past 2,500 years

 

Volcanic eruptions contribute to climate variability, but quantifying these contributions has been limited by inconsistencies in the timing of atmospheric volcanic aerosol loading determined from ice cores and subsequent cooling from climate proxies such as tree rings. Here we resolve these inconsistencies and show that large eruptions in the tropics and high latitudes were primary drivers of interannual-to-decadal temperature variability in the Northern Hemisphere during the past 2,500 years. Our results are based on new records of atmospheric aerosol loading developed from high-resolution, multi-parameter measurements from an array of Greenland and Antarctic ice cores as well as distinctive age markers to constrain chronologies. Overall, cooling was proportional to the magnitude of volcanic forcing and persisted for up to ten years after some of the largest eruptive episodes. Our revised timescale more firmly implicates volcanic eruptions as catalysts in the major sixth-century pandemics, famines, and socioeconomic disruptions in Eurasia and Mesoamerica while allowing multi-millennium quantification of climate response to volcanic forcing.

 

 

And an interesting review, with interviews, on phys.org http://phys.org/news/2015-07-large-volcanic-eruptions-responsible-cold.html

[knocker]

And a guest post from one of the authors

 

http://www.carbonbrief.org/blog/2015/07/how-volcanic-eruptions-changed-climate-and-human-history/?utm_source=Daily+Carbon+Briefing&utm_campaign=9b97f5706e-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-9b97f5706e-303447709

[BornFromTheVoid]

Increased record-breaking precipitation events under global warming

 

In the last decade record-breaking rainfall events have occurred in many places around the world causing severe impacts to human society and the environment including agricultural losses and floodings. There is now medium confidence that human-induced greenhouse gases have contributed to changes in heavy precipitation events at the global scale. Here, we present the first analysis of record-breaking daily rainfall events using observational data. We show that over the last three decades the number of record-breaking events has significantly increased in the global mean. Globally, this increase has led to 12 % more record-breaking rainfall events over 1981–2010 compared to those expected in stationary time series. The number of record-breaking rainfall events peaked in 2010 with an estimated 26 % chance that a new rainfall record is due to long-term climate change. This increase in record-breaking rainfall is explained by a statistical model which accounts for the warming of air and associated increasing water holding capacity only. Our results suggest that whilst the number of rainfall record-breaking events can be related to natural multi-decadal variability over the period from 1901 to 1980, observed record-breaking rainfall events significantly increased afterwards consistent with rising temperatures.

 

http://www.bloomberg.com/news/articles/2015-07-08/world-suffering-surge-in-extreme-rainfall-due-to-climate-change

[knocker]

High geothermal heat flux measured below the West Antarctic Ice Sheet

 

Abstract

The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m², significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m². The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region.

 

Open Access

http://advances.sciencemag.org/content/1/6/e1500093