New Research

[knocker]

Arctic sea ice still too thick for regular shipping route through Northwest Passage

Despite climate change, sea ice in the Northwest Passage (NWP) remains too thick and treacherous for it to be a regular commercial Arctic shipping route for many decades, according to new research out of York University.

 

Prior to this research, there was little information about the thickness of sea ice in the NWP, which meanders through the Canadian Arctic Archipelago. Yet, next to ice coverage and type, sea ice thickness plays the most important role in assessing shipping hazards and predicting ice break-up.

"While everyone only looks at ice extent or area, because it is so easy to do with satellites, we study ice thickness, which is important to assess overall changes of ice volume, and helps to understand why and where the ice is most vulnerable to summer melt," says lead researcher York Professor Christian Haas, the Canada Research Chair for Arctic Sea Ice Geophysics.

Read more at: http://phys.org/news/2015-09-arctic-sea-ice-thick-regular.html#jCp

 

Paper (open Access)

 

http://onlinelibrary.wiley.com/doi/10.1002/2015GL065704/full

Edited September 29, 2015 by knocker

[knocker]

Kate Marvel â€@DrKateMarvel Sep 28

The text accompanying this graphic (by @eroston) is clear, succinct, & (judging by the emails I get) read by no one. http://www.bloomberg.com/graphics/2015-whats-warming-the-world/ â€¦

[knocker]

View historical sea ice data collected around Alaska from the mid-1800s through today: http://toolkit.climate.gov/tool/historical-sea-ice-atlas â€¦

[drgl]

Kate Marvel â€@DrKateMarvel Sep 28

The text accompanying this graphic (by @eroston) is clear, succinct, & (judging by the emails I get) read by no one. http://www.bloomberg.com/graphics/2015-whats-warming-the-world/ â€¦

Why does the first graphic have a date range of 1880-2014 yet all the subsequent graphics the range is 1880-2005? It seems daft that a link that is dated 2015 omits 10 years worth of data.

[knocker]

Why does the first graphic have a date range of 1880-2014 yet all the subsequent graphics the range is 1880-2005? It seems daft that a link that is dated 2015 omits 10 years worth of data.

 

Read the methodology.

[drgl]

 

Phase-5 calls for a suite of "historical" experiments. Research groups were asked to see how well they could reproduce what's known about the climate from 1850-2005. They were also asked to estimate how the various climate factors—or "forcings"—contribute to those temperatures. That's why this graphic stops in 2005, even though the GISS observed temperature data is up-to-date. The years 2005-2012 were not a part of the Phase-5 "historical" experiment.

Makes no sense to me, we know what the climate has done up until yesterday, that's historical. Also, why were the years 2005-2012 not part of the experiment? This forum is titled "new research" , what's new about this?

[Gray-Wolf]

Makes no sense to me, we know what the climate has done up until yesterday, that's historical. Also, why were the years 2005-2012 not part of the experiment? This forum is titled "new research" , what's new about this?

 

Drives me mad when i see 'new' in front of things I know to be 'old/superseded'!!!! The whole IPCC document has me frothing because of it!!! ( Rant Over!)

[knocker]

What exactly should we count as 'new' before we post? Any particular time limit? (personally I wouldn't class 2012 as that old) Keeping in mind that due to the construction of the climate area these days some interesting posts have to be placed here that are not strictly research as there is no other obvious thread. Unless I'm completely misreading the situation.

Edited October 1, 2015 by knocker

[Gray-Wolf]

Hi Knocks! In the context of in here it would be someone posting up 'evidence' for their 'cause' that is old or superseded by more recent evidence? The way some folk suddenly fell in love with TAR4 prior to TAR5 being released ( even though they had spent 4 years declaring TAR4 useless... or worse!).

 

I have no problem with studies that run long but do not reach 'today' as I appreciate the process of making the paper and then having it peer reviewed takes time.

[drgl]

What exactly should we count as 'new' before we post? Any particular time limit? (personally I wouldn't class 2012 as that old) Keeping in mind that due to the construction of the climate area these days some interesting posts have to be placed here that are not strictly research as there is no other obvious thread. Unless I'm completely misreading the situation.

Maybe a study that uses data that is not 10 years old! We can all appreciate it takes time etc but this seems to be a study about how models perform on historical data, If the model can't get the past tense correct up to say a year ago I can't see it having much hope of getting anything in the future remotely correct either. It also makes one wonder what has happened in those 10 years that they can't(?! or won't?!) model? In your example, 2012 is still 3 years ago, however the point here is 2005 is 10 years ago. When this

 

 

Research groups were asked to see how well they could reproduce what's known about the climate from 1850-2005. They were also asked to estimate how the various climate factors—or "forcings"—contribute to those temperatures

 

is 1850-2015 & the model gets it correct I'll be interested.

[knocker]

Isaac Held's Blog

 

How unusual is the recent evolution of the tropical Pacific

Edited October 3, 2015 by knocker

[knocker]

What does global mean temperature tell us about local climate?

 

 

The subject of climate feedbacks focuses attention on global mean surface air temperature (GMST) as the key metric of climate change. But what does knowledge of past and future GMST tell us about the climate of specific regions? In the context of the ongoing UNFCCC process, this is an important question for policy-makers as well as for scientists. The answer depends on many factors, including the mechanisms causing changes, the timescale of the changes, and the variables and regions of interest. This paper provides a review and analysis of the relationship between changes in GMST and changes in local climate, first in observational records and then in a range of climate model simulations, which are used to interpret the observations. The focus is on decadal timescales, which are of particular interest in relation to recent and near-future anthropogenic climate change. It is shown that GMST primarily provides information about forced responses, but that understanding and quantifying internal variability is essential to projecting climate and climate impacts on regional-to-local scales. The relationship between local forced responses and GMST is often linear but may be nonlinear, and can be greatly complicated by competition between different forcing factors. Climate projections are limited not only by uncertainties in the signal of climate change but also by uncertainties in the characteristics of real-world internal variability. Finally, it is shown that the relationship between GMST and local climate provides a simple approach to climate change detection, and a useful guide to attribution studies.

 

http://rsta.royalsocietypublishing.org/content/373/2054/20140426

 

Comment by Ed Hawkins

 

What have global temperatures ever done for us?

 

http://www.climate-lab-book.ac.uk/2015/what-have-global-temperatures-ever-done-for-us/

[knocker]

Further to the above

 

Comment on Clark (2015)

 

In Weather this month, a paper by Colin Clark discusses temperature data from two rural stations in Somerset (UK). These two stations show a cooling trend over the last two decades which Clark suggests is opposite to that expected. The associated editorial suggests that this is a controversial finding.

 

http://www.climate-lab-book.ac.uk/2015/comment-on-clark/?utm_source=rss&utm_medium=rss&utm_campaign=comment-on-clark

[knocker]

2015: Still No Let Up in Ocean Warming

[knocker]

Worth a read as is the link

 

Guest Post: Understanding climate feedbacks
Prof Eric Wolff, Royal Society research professor at the University of Cambridge explains what climate feedbacks are and why they're so important, in a guest post for Carbon Brief. He also summarises the latest science on feedbacks -- which can amplify or buffer warming caused by CO2 -- as presented in a Royal Society special journal issue on the subject.

[knocker]

Understanding the Past to Better Predict Climate Change

 

Researchers at the University of Missouri hope that gaining an understanding of major changes in the Earth’s climate in the distant past can improve climate modeling to better predict the future direction of climate change. Fourth-year geologic sciences doctoral student Page Quinton, whose area of expertise is paleoclimatology, has been studying carbon and oxygen isotopes in rocks from the Ordovician Period. The Ordovician Period lasted almost 42 million years, beginning 485 million years ago and ending 443 million years ago. Quinton says by examining the changes in the ratio of different carbon and oxygen isotopes in rocks from this period through the use of a mass spectrometer, she has seen evidence of relatively rapid changes in carbon cycling that could be related to a drawdown in atmospheric carbon dioxide, resulting in an ice age.

 

https://coas.missouri.edu/news/understanding-past-better-predict-climate-change

[knocker]

The highlighted area may be of interest in the cold Atlantic thread but as the paper is paywalled I wont bother posting it there.  

 

 

Separating Internal Variability from the Externally Forced Climate Response

 

Separating low-frequency internal variability of the climate system from the forced signal is essential to better understand anthropogenic climate change as well as internal climate variability. Here both synthetic time series and the historical simulations from phase 5 of CMIP (CMIP5) are used to examine several methods of performing this separation. Linear detrending, as is commonly used in studies of low-frequency climate variability, is found to introduce large biases in both amplitude and phase of the estimated internal variability. Using estimates of the forced signal obtained from ensembles of climate simulations can reduce these biases, particularly when the forced signal is scaled to match the historical time series of each ensemble member. These so-called scaling methods also provide estimates of model sensitivities to different types of external forcing. Applying the methods to observations of the Atlantic multidecadal oscillation leads to different estimates of the phase of this mode of variability in recent decades.

 

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0069.1

Edited October 14, 2015 by knocker

[Nouska]

The highlighted area may be of interest in the cold Atlantic thread but as the paper is paywalled I wont bother posting it there.  

 

 

Separating Internal Variability from the Externally Forced Climate Response

 

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0069.1

 

Here's the pre-publication version in full.

 

http://www.meteo.psu.edu/holocene/public_html/Mann/articles/articles/FrankcombeEtAlJClimate15.pdf

[knocker]

Abrupt changes in the southern extent of North Atlantic Deep Water during Dansgaard–Oeschger events

 

 

The glacial climate system transitioned rapidly between cold (stadial) and warm (interstadial) conditions in the Northern Hemisphere¹. This variability, referred to as Dansgaard–Oeschger variability², is widely believed to arise from perturbations of the Atlantic Meridional Overturning Circulation^{3, 4, 5}. Evidence for such changes during the longer Heinrich stadials has been identified, but direct evidence for overturning circulation changes during Dansgaard–Oeschger events has proven elusive⁶. Here we reconstruct bottom water [CO₃^2−] variability from B/Ca ratios of benthic foraminifera and indicators of sedimentary dissolution, and use these reconstructions to infer the flow of northern-sourced deep water to the deep central sub-Antarctic Atlantic Ocean. We find that nearly every Dansgaard–Oeschger interstadial is accompanied by a rapid incursion of North Atlantic Deep Water into the deep South Atlantic. Based on these results and transient climate model simulations⁷, we conclude that North Atlantic stadial–interstadial climate variability was associated with significant Atlantic overturning circulation changes that were rapidly transmitted across the Atlantic. However, by demonstrating the persistent role of Atlantic overturning circulation changes in past abrupt climate variability, our reconstructions of carbonate chemistry further indicate that the carbon cycle response to abrupt climate change was not a simple function of North Atlantic overturning.

 

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2558.html

 

Article

 

 

A new study finds that changing climate in the polar regions can affect conditions in the rest of the world far quicker than previously thought. - See more at: https://www.cam.ac.uk/research/news/new-insights-into-the-dynamics-of-past-climate-change#sthash.AShkGWP5.dpuf

[knocker]

A new paper by Dr Kate Marvel with blogpost:

 

Blog: http://marvelclimate.blogspot.com/2015/10/the-whole-sum-and-parts.html â€¦

 

Paper: http://iopscience.iop.org/article/10.1088/1748-9326/10/10/104010 â€¦

[knocker]

Oceanographers will hate this: The AMO and AMOC are only an atmospherically driven phenomenon

 

Quote

 

The Atlantic Multidecadal Oscillation without a role for ocean circulation

The Atlantic Multidecadal Oscillation (AMO) is a major mode of climate variability with important societal impacts. Most previous explanations identify the driver of the AMO as the ocean circulation, specifically the Atlantic Meridional Overturning Circulation (AMOC). Here we show that the main features of the observed AMO are reproduced in models where the ocean heat transport is prescribed and thus cannot be the driver. Allowing the ocean circulation to interact with the atmosphere does not significantly alter the characteristics of the AMO in the current generation of climate models. These results suggest that the AMO is the response to stochastic forcing from the mid-latitude atmospheric circulation, with thermal coupling playing a role in the tropics. In this view, the AMOC and other ocean circulation changes would be largely a response to, not a cause of, the AMO.

 

http://www.sciencema...0/6258/320.full

[knocker]

The Carbon Brief Interview: Dr Gavin Schmidt
Carbon Brief's in-depth interview with Nasa climate scientist Dr Gavin Schmidt covers topics including climate sensitivity, Arctic sea ice, the 'slowdown' in global warming, and his use of Twitter. Roz Pidcock,

[knocker]

It might be of interest but a recent paper by Hansen, et al, has been under critical review and will not now be published. It's a train wreck. I haven't been following it that closely but Stoat and Eli cover it pretty well. A bad example of mixing science with advocacy but at least the system has worked this time and sorted it.

 

Hansen et al.: RIP

Edited October 17, 2015 by knocker

[Cloudman]

It might be of interest but a recent paper by Hansen, et al, has been under critical review and will not now be published. It's a train wreck. I haven't been following it that closely but Stoat and Eli cover it pretty well. A bad example of mixing science with advocacy but at least the system has worked this time and sorted it.

 

Hansen et al.: RIP

I see this is in ACP, I publish there quite frequently. It is a high impact journal with good refereeing standards with open discussion. An excellent avenue for scientific discussion.

[knocker]

Frank Pattyn

 

Summary of results of a particular fruitful workshop: "On the Rocks: The Challenges of Predicting Sea Level Rise" https://eos.org/features/on-the-rocks-the-challenges-of-predicting-sea-level-rise#.ViZndg48jGQ.twitter â€¦