New Research

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Ocean-atmospheric state dependence of the atmospheric response to Arctic sea ice loss

Quote

The Arctic is warming faster than the global average. This disproportionate warming – known as Arctic amplification – has caused significant local changes to the Arctic system and more uncertain remote changes across the Northern Hemisphere midlatitudes. Here, we use an atmospheric general circulation model (AGCM) to test the sensitivity of the atmospheric and surface response to Arctic sea ice loss to the phase of the Atlantic Multidecadal Oscillation (AMO), which varies on (multi-)decadal timescales. Four experiments are performed, combining low and high sea ice states with global sea surface temperature (SST) anomalies associated with opposite phases of the AMO. A trough-ridge-trough response to wintertime sea ice loss is seen in the Pacific-North America sector in the negative phase of the AMO. We propose that this is a consequence of an increased meridional temperature gradient in response to sea ice loss, just south of the climatological maximum, in the central midlatitude North Pacific. This causes a southward shift in the North Pacific storm track, which strengthens the Aleutian Low with circulation anomalies propagating into North America. While the climate response to sea ice loss is sensitive to AMO-related SST anomalies in the North Pacific, there is little sensitivity to larger magnitude SST anomalies in the North Atlantic. With background ocean-atmospheric states persisting for a number of years, there is the potential to improve predictions of the impacts of Arctic sea ice loss on decadal timescales.

http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0531.1  (open access)

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Effects of Arctic Sea Ice Decline on Weather and Climate: A Review

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The areal extent, concentration and thickness of sea ice in the Arctic Ocean and adjacent seas have strongly decreased during the recent decades, but cold, snow-rich winters have been common over mid-latitude land areas since 2005. A review is presented on studies addressing the local and remote effects of the sea ice decline on weather and climate. It is evident that the reduction in sea ice cover has increased the heat flux from the ocean to atmosphere in autumn and early winter. This has locally increased air temperature, moisture, and cloud cover and reduced the static stability in the lower troposphere. Several studies based on observations, atmospheric reanalyses, and model experiments suggest that the sea ice decline, together with increased snow cover in Eurasia, favours circulation patterns resembling the negative phase of the North Atlantic Oscillation and Arctic Oscillation. The suggested large-scale pressure patterns include a high over Eurasia, which favours cold winters in Europe and northeastern Eurasia. A high over the western and a low over the eastern North America have also been suggested, favouring advection of Arctic air masses to North America. Mid-latitude winter weather is, however, affected by several other factors, which generate a large inter-annual variability and often mask the effects of sea ice decline. In addition, the small sample of years with a large sea ice loss makes it difficult to distinguish the effects directly attributable to sea ice conditions. Several studies suggest that, with advancing global warming, cold winters in mid-latitude continents will no longer be common during the second half of the twenty-first century. Recent studies have also suggested causal links between the sea ice decline and summer precipitation in Europe, the Mediterranean, and East Asia.

http://link.springer.com/article/10.1007/s10712-014-9284-0

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Not new research but interesting all the same

This Lady Scientist Defined the Greenhouse Effect But Didn’t Get the Credit, Because Sexism

http://www.smithsonianmag.com/science-nature/lady-scientist-helped-revolutionize-climate-science-didnt-get-credit-180961291/

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We have been observing sea level with satellites for twenty four years now

 

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Well it's nearly new

Carbon dioxide – a medical view from 1866

https://agwobserver.wordpress.com/2016/12/22/carbon-dioxide-a-medical-view-from-1866/

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There was no pause

http://www.realclimate.org/index.php/archives/2017/01/there-was-no-pause/#ITEM-19932-2

[jvenge]

13 hours ago, knocker said:

There was no pause

http://www.realclimate.org/index.php/archives/2017/01/there-was-no-pause/#ITEM-19932-2

I thought links to blogs and such weren't allowed?

Anyway.

http://science.sciencemag.org/content/355/6322/276

Quote

Abstract

The last interglaciation (LIG, 129 to 116 thousand years ago) was the most recent time in Earth’s history when global mean sea level was substantially higher than it is at present. However, reconstructions of LIG global temperature remain uncertain, with estimates ranging from no significant difference to nearly 2°C warmer than present-day temperatures. Here we use a network of sea-surface temperature (SST) records to reconstruct spatiotemporal variability in regional and global SSTs during the LIG. Our results indicate that peak LIG global mean annual SSTs were 0.5 ± 0.3°C warmer than the climatological mean from 1870 to 1889 and indistinguishable from the 1995 to 2014 mean. LIG warming in the extratropical latitudes occurred in response to boreal insolation and the bipolar seesaw, whereas tropical SSTs were slightly cooler than the 1870 to 1889 mean in response to reduced mean annual insolation.

 

[knocker]

7 minutes ago, jvenge said:

I thought links to blogs and such weren't allowed?

 

 

The blog in question contains links to the relevant peer reviewed papers. And are you suggesting links to such as Isaac Helds's blog are not permissible? If that is the case this section might just as well close.

https://www.gfdl.noaa.gov/blog_held/

Edited January 23, 2017 by knocker

[jvenge]

5 minutes ago, knocker said:

The blog in question contains links to the relevant peer reviewed papers. And are you suggesting links to such as Isaac Helds's blog are not permissible? If that is the case this section might just as well close.

https://www.gfdl.noaa.gov/blog_held/

Sorry, I personally don't care about blogs and such, link to as many as people want :-) I just remember being told at some point that links to blogs weren't allowed. Are they allowed if they are a person's summary/opinion of various papers?

[knocker]

I can really only refer you to the guide lines which Paul introduced after this area became boringly nonsensical.

https://www.netweather.tv/forum/topic/83699-new-climate-change-science-based-discussions/#comment-3242239

Just to add the blogs probably referred to were along the lines of Climate Depot which no self respecting believer in science would touch with a barge pole irrespective of their climate change beliefs.

[jvenge]

1 minute ago, knocker said:

I can really only refer you to the guide lines which Paul introduced after this area became boringly nonsensical.

https://www.netweather.tv/forum/topic/83699-new-climate-change-science-based-discussions/#comment-3242239

Just to add the blogs probably referred to were along the lines of Climate Depot which no self respecting believer in science would touch with a barge pole irrespective of their climate change beliefs.

Open to interoperation, it seems :-) 

 

[Paul]

23 minutes ago, jvenge said:

Open to interoperation, it seems :-) 

 

Not really - the key phrase being 'non-scientific' blogs. I don't think you could accuse the GFDL site of being that...

[jvenge]

Just now, Paul said:

Not really - the key phrase being 'non-scientific' blogs. I don't think you could accuse the GFDL site of being that...

Well, I guess it depends who decides what a scientific blog is. Have a list of what are considered acceptable?

 

[Paul]

I think most people are prepared to accept that a scientific blog is produced by scientists, contains peer reviewed info within it and so on. What is not a scientific blog is one which takes all of the scientific research and basically claims, without any scientific reasoning that it's all wrong. I don't think we need to make a list of blogs, as we ought to be able to work on the assumption that those with an interest in the subject can get to the bottom of that themselves, plus frankly we don't have the time or resources to make a definitive list even if we wanted to. 

The onus is on you to make your best attempt to follow the forum guidelines.

[jvenge]

Just now, Paul said:

I think most people are prepared to accept that a scientific blog is produced by scientists, contains peer reviewed info within it and so on. What is not a scientific blog is one which takes all of the scientific research and basically claims, without any scientific reasoning that it's all wrong. I don't think we need to make a list of blogs, as we ought to be able to work on the assumption that those with an interest in the subject can get to the bottom of that themselves, plus frankly we don't have the time or resources to make a definitive list even if we wanted to. 

The onus is on you to make your best attempt to follow the forum guidelines.

Quite clear, thanks. Basically, no whining blogs, moaning about papers and data, without any scientific reasoning to do so.

[BornFromTheVoid]

1 hour ago, jvenge said:

Anyway.

http://science.sciencemag.org/content/355/6322/276

 

An interesting paper. Especially this:

The global mean annual values [SSTs] were ∼0.5°C warmer than they were 150 years ago and indistinguishable from the 1995–2014 mean. This is a sobering point, because sea levels during the last interglacial period were 6 to 9 m higher than they are now.

So the global mean temps were cooler than today but sea levels were 6-9m higher. That strongly suggests that we've passed the point that locks in collapse of either Greenland and/or large parts of the Antarctic ice sheet, yet we have even more warming to come.

[jvenge]

12 minutes ago, BornFromTheVoid said:

An interesting paper. Especially this:

The global mean annual values [SSTs] were ∼0.5°C warmer than they were 150 years ago and indistinguishable from the 1995–2014 mean. This is a sobering point, because sea levels during the last interglacial period were 6 to 9 m higher than they are now.

So the global mean temps were cooler than today but sea levels were 6-9m higher. That strongly suggests that we've passed the point that locks in collapse of either Greenland and/or large parts of the Antarctic ice sheet, yet we have even more warming to come.

I'm not sure if that's what it says. If SST were 0.5C warmer than they were 150 years ago, indistinguishable from the 1995-2014 mean, I'm not sure how you can say they were colder than today...

Quote

The last interglaciation (LIG, 129 to 116 thousand years ago) was the most recent time in Earth’s history when global mean sea level was substantially higher than it is at present. However, reconstructions of LIG global temperature remain uncertain, with estimates ranging from no significant difference to nearly 2°C warmer than present-day temperatures.

I take this to mean that if the earth warmed an ADDITIONAL 2 degrees, and considering that sea level rises were 6 to 9m higher then, that's how much we could look to see. I must admit, if that were to happen in a short period, it would be fairly devastating.

 

Edited January 23, 2017 by jvenge

[BornFromTheVoid]

25 minutes ago, jvenge said:

I'm not sure if that's what it says. If SST were 0.5C warmer than they were 150 years ago, indistinguishable from the 1995-2014 mean, I'm not sure how you can say they were colder than today...

 

Because in the last 2 years we've set numerous monthly records for global SSTs, and both 2015 and 2016 set annual records too. So we're now well above the 1994-2014 average.

Global SSTs for 2015 and 2016

The last interglaciation (LIG, 129 to 116 thousand years ago) was the most recent time in Earth’s history when global mean sea level was substantially higher than it is at present. However, reconstructions of LIG global temperature remain uncertain, with estimates ranging from no significant difference to nearly 2°C warmer than present-day temperatures.

That's referring to air temperatures, I think, not SSTs

Edited January 23, 2017 by BornFromTheVoid

[jvenge]

31 minutes ago, BornFromTheVoid said:

Because in the last 2 years we've set numerous monthly records for global SSTs, and both 2015 and 2016 set annual records too. So we're now well above the 1994-2014 average.

Global SSTs for 2015 and 2016

The last interglaciation (LIG, 129 to 116 thousand years ago) was the most recent time in Earth’s history when global mean sea level was substantially higher than it is at present. However, reconstructions of LIG global temperature remain uncertain, with estimates ranging from no significant difference to nearly 2°C warmer than present-day temperatures.

That's referring to air temperatures, I think, not SSTs

No idea, sadly, I can't manage to get the full paper, only extracts.

I don't think the 2015 and 2016 SST would make much of a difference to his overall conclusion and also need to take into account 2015 and 2016 being in the years of a Super El Nino, so I'd say UNLIKELY (anything is possible), to be observed again in 2017, although it already looks like another El Nino will develop in the summer, so who knows.