How does AGW mostly show up?

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Expand view Topic review: How does AGW mostly show up?

Re: How does AGW mostly show up?

Post by Bongalong » 23 Jul 2018, 14:38

HBS Guy wrote:Who knows?

Not you!!

Re: How does AGW mostly show up?

Post by HBS Guy » 23 Jul 2018, 14:16

Who knows?

Re: How does AGW mostly show up?

Post by Bongalong » 23 Jul 2018, 13:47

HBS Guy wrote:Too deep for me, DRAH.

You're possibly too superficial then :OMG

Re: How does AGW mostly show up?

Post by HBS Guy » 21 Jul 2018, 18:17

Too deep for me, DRAH.

Re: How does AGW mostly show up?

Post by Bongalong » 21 Jul 2018, 17:06

HBS Guy wrote:Just reporting the science.

No, sins of omission are sins of omission!

Re: How does AGW mostly show up?

Post by HBS Guy » 19 Jul 2018, 19:39

Just reporting the science.

Re: How does AGW mostly show up?

Post by Bongalong » 19 Jul 2018, 19:14

HBS bruther: you are arguing about totally- (...and do I mean totally, not like a little bit...)- different kettles of statistical fish mate.... :OMG

Don't be surprised when some pedantic person comes along and goes: "...you're not quite right mate sleeping on them curious looking set of stairs in such a curiuos-to-match fashion are you bros?"


:bgrin :bgrin

Re: How does AGW mostly show up?

Post by HBS Guy » 19 Jul 2018, 11:06

Following up on the Antarctic adding net meltwater to the oceans:

Lasers from space show thinning of Greenland and Antarctic ice sheets

The most comprehensive picture of the rapidly thinning glaciers along the coastline of both the Antarctic and Greenland ice sheets has been created using satellite lasers. The findings are an important step forward in the quest to make more accurate predictions for future sea level rise.

Reporting this week in the journal Nature researchers from British Antarctic Survey and the University of Bristol describe how analysis of millions of NASA satellite measurements* from both of these vast ice sheets shows that the most profound ice loss is a result of glaciers speeding up where they flow into the sea.

The authors conclude that this ‘dynamic thinning’ of glaciers now reaches all latitudes in Greenland, has intensified on key Antarctic coastlines, is penetrating far into the ice sheets’ interior and is spreading as ice shelves thin by ocean-driven melt. Ice shelf collapse has triggered particularly strong thinning that has endured for decades.

Lead author Dr Hamish Pritchard from British Antarctic Survey (BAS) says,

“We were surprised to see such a strong pattern of thinning glaciers across such large areas of coastline — it’s widespread and in some cases thinning extends hundreds of kilometres inland. We think that warm ocean currents reaching the coast and melting the glacier front is the most likely cause of faster glacier flow. This kind of ice loss is so poorly understood that it remains the most unpredictable part of future sea level rise.”


https://www.bas.ac.uk/media-post/lasers-from-space-show-thinning-of-greenland-and-antarctic-ice-sheets/

BAS—British Antarctic Survey.

Abstract of Nature article:
Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets
Hamish D. Pritchard, Robert J. Arthern, David G. Vaughan & Laura A. Edwards
Nature volume 461, pages 971–975 (15 October 2009) |

Abstract
Many glaciers along the margins of the Greenland and Antarctic ice sheets are accelerating and, for this reason, contribute increasingly to global sea-level rise1,2,3,4,5,6,7. Globally, ice losses contribute ∼1.8 mm yr-1 (ref. 8), but this could increase if the retreat of ice shelves and tidewater glaciers further enhances the loss of grounded ice9 or initiates the large-scale collapse of vulnerable parts of the ice sheets10. Ice loss as a result of accelerated flow, known as dynamic thinning, is so poorly understood that its potential contribution to sea level over the twenty-first century remains unpredictable11. Thinning on the ice-sheet scale has been monitored by using repeat satellite altimetry observations to track small changes in surface elevation, but previous sensors could not resolve most fast-flowing coastal glaciers12. Here we report the use of high-resolution ICESat (Ice, Cloud and land Elevation Satellite) laser altimetry to map change along the entire grounded margins of the Greenland and Antarctic ice sheets. To isolate the dynamic signal, we compare rates of elevation change from both fast-flowing and slow-flowing ice with those expected from surface mass-balance fluctuations. We find that dynamic thinning of glaciers now reaches all latitudes in Greenland, has intensified on key Antarctic grounding lines, has endured for decades after ice-shelf collapse, penetrates far into the interior of each ice sheet and is spreading as ice shelves thin by ocean-driven melt. In Greenland, glaciers flowing faster than 100 m yr-1 thinned at an average rate of 0.84 m yr-1, and in the Amundsen Sea embayment of Antarctica, thinning exceeded 9.0 m yr-1 for some glaciers. Our results show that the most profound changes in the ice sheets currently result from glacier dynamics at ocean margins.


https://www.nature.com/articles/nature08471

Re: How does AGW mostly show up?

Post by Bongalong » 17 Jul 2018, 14:32

HBS Guy wrote:Not to the extent it is in Antarctica.

Well, of course not.

There is in fact no sea ice at the south pole: totally different kettles of fish my friend!

Re: How does AGW mostly show up?

Post by HBS Guy » 17 Jul 2018, 13:54

Not to the extent it is in Antarctica.

Re: How does AGW mostly show up?

Post by Bongalong » 17 Jul 2018, 12:50

HBS Guy wrote:Some Antarctic sea ice used to be Antarctic land ice. Doesn’t happen in the Arctic Ocean.

Are you honestly trying to say none of the sea ice in the Arctic ocean is from glaciers?

:bgrin

Re: How does AGW mostly show up?

Post by HBS Guy » 16 Jul 2018, 14:36

Some Antarctic sea ice used to be Antarctic land ice. Doesn’t happen in the Arctic Ocean.

Re: How does AGW mostly show up?

Post by Bongalong » 16 Jul 2018, 14:25

It mainly shows up in the Arctic: loss of multi year sea ice.

Whislt there is multi-year sea ice in the Antarctic to the best of my knowledge they don't even bother measuring it.

To me.... that is how AGW mostly shows up: that is, in the comparison, .... and stark contrast, between Northern and Southern Hemisphere!

The rest is trying to figure out why.....

How does AGW mostly show up?

Post by HBS Guy » 16 Jul 2018, 13:28

We are getting more heat records than cold records, but the main sign of the increase in surface air temperatures is high night time minimum temperatures:

In recent decades there have been much greater increases in night minimum temperatures than in day maximum temperatures, so that over 1950–1993 the diurnal temperature range has decreased by 0.08°C per decade.


https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/1999RG900002

This should be of concern. That “plant food” that deniers call CO2 and nitrogen are taken up less by plants when night time minimum temperatures get too high. Also, like all fertilisers, you can have too much of it and with CO2 that means less CO2 and nitrogen uptake decreases—the stomata on the underside of leaves open less to reduce transpiration of water.

Full Abstract:

Surface air temperature and its changes over the past 150 years
P. D. Jones M. New D. E. Parker S. Martin I. G. Rigor
First published: 01 May 1999 https://doi.org/10.1029/1999RG900002 Cited by: 695

Abstract

We review the surface air temperature record of the past 150 years, considering the homogeneity of the basic data and the standard errors of estimation of the average hemispheric and global estimates. We present global fields of surface temperature change over the two 20‐year periods of greatest warming this century, 1925–1944 and 1978–1997. Over these periods, global temperatures rose by 0.37° and 0.32°C, respectively. The twentieth‐century warming has been accompanied by a decrease in those areas of the world affected by exceptionally cool temperatures and to a lesser extent by increases in areas affected by exceptionally warm temperatures. In recent decades there have been much greater increases in night minimum temperatures than in day maximum temperatures, so that over 1950–1993 the diurnal temperature range has decreased by 0.08°C per decade. We discuss the recent divergence of surface and satellite temperature measurements of the lower troposphere and consider the last 150 years in the context of the last millennium. We then provide a globally complete absolute surface air temperature climatology on a 1° × 1° grid. This is primarily based on data for 1961–1990. Extensive interpolation had to be undertaken over both polar regions and in a few other regions where basic data are scarce, but we believe the climatology is the most consistent and reliable of absolute surface air temperature conditions over the world. The climatology indicates that the annual average surface temperature of the world is 14.0°C (14.6°C in the Northern Hemisphere (NH) and 13.4°C for the Southern Hemisphere). The annual cycle of global mean temperatures follows that of the land‐dominated NH, with a maximum in July of 15.9°C and a minimum in January of 12.2°C.



Not a new paper but subsequent investigations have confirmed the result and conclusions. Plants will have less food values as night time minimum temperatures and CO2 concentrations keep rising!

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