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Tom Curtis at 19:01 PM on 18 April 2017Humans on the verge of causing Earth’s fastest climate change in 50m years
Digby Scorgie @6, nobody knows, and the time will depend on the rate of fossil fuel burning. Further, to a certain extent, increased energy resources and be used to counter much of the economic effect of AGW, particularly in highly industrialized areas. A sufficiently irrational person could greatly extend the time before it became impossible to maintain the technological civilization needed to burn fossil fuels by burning fossil fuels faster and faster. (This strategy requires calous disregard for those whose economic situation isn't so favoured.)
I do not think the OP argues for so high a benchmark on disruption, ie, that it will significantly impair our ability to burn fossil fuels. I think it is arguing that at some point the level of economic harm and natural disasters will catastrophic, potentially to the point of negative economic growth and declining population. Our civilization can survive declines in both of low percentage; and with it our ability to burn fossil fuels will also be preserved should we be mad enough.
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Humans on the verge of causing Earth’s fastest climate change in 50m years
Good article. It gives a lot of pertinent info about our situation in some fairly simple graphs. I was surprised to see the RCP4.5 and RCP6 lines so close together especially in the forcing graph (second one) so went back to the SKS post below. And fig 4 in this RCP guide shows that the numbers 4.5 and 6 actually refer to the forcing level (no doubt a lot of readers already knew this). So the gap between 4.5 and 6 seems too narrow when compared to the gap between 0 and 4.5, or am I interpreting this wrong. Perhaps of more interest is that fig 4 also gives temperature anomalies 2.4 degC for RCP4.5 and 3.0 degC for RCP6, and the CO2 eq figures are 650 and 850 ppm. These temperature figures, while bad, aren't as high as I expected, and give a glimmer of hope. James Hansen in Storms of My Grandchildren estimates a conversion of .75 when going from forcing to temp which gives 3.4 degC and 4.5 degC, which are more concerning.
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Tom Curtis at 18:48 PM on 18 April 2017Humans on the verge of causing Earth’s fastest climate change in 50m years
chriskoz @5, the figure is from the IEA's Resources and Reserves 2013. With regard to different estimates, this pyramid of US resources and reserves from the EIA is helpful:
Converting from short tons to tonnes (ie, metric tons) we have 232 Gigatonnes of estimated recoverable reserves, 1514 Gt of identified resources, and a total resource base of 3544 Gt of total resources. They further estimate that the US has 26% of the world's coal reserves, which would indicate a world recoverable reserves at 892 Gt of global recoverable reserves.
For comparison, IEA 2013 estimates 8,130 Gt as the total resource for hard coals and lignite in North America (ie, the US, Canada and Mexico). As that is more than double the US estimate, and the US has more coal than either Canada or Mexico, clearly the IEA 2013 estimate is larger - as will happen given that it is in part an estimate. If we assume all North American coal is in the US, and scale the IEA 2013 global estimate so that the North American estimate matches that by the EIA, then the global resource would be 7,500 Gt. Alternatively, if we scale the EIA US resource using the percentage of global share of the reserve, we get a total global resource of 13,630 Gt. Even on the low value, once you throw in tar sands, oil shale, deep sea oil and gas resources, arctic oil and gas resources, antarctic oil and coal (not incuded in any of the above) etc, a civilization determined to "burn, baby, burn" regardless of consequences could far exceed the RCP 8.0 scenario; and the Twink12 scenario is a reasonable scenario for such a strategy.
As to the large differences in estimates, that will be in part because they are estimates when we are talking about the total resource. More importantly, many estimates of amount of fossil fuels remaining in the ground restrict themselves to reserves, and/or reserves plus identified resources. I once did a spread sheet of all the publicly available estimates across coal, oil and gas. Only a few of the estimates included any oil sands, shale oil or unconventional gas (and they not all of it), and a range of criteria were used. Of 14 estimats across 9 sources, only 3 provided estimates that may have represented the Total Resource, with estimates of 3000 GtC (World Energy Council 2010, "possible"), 11,000 GtC (S&W 2011, "TRB") and 16,000 GtC (IEA 201, "estimated"). (Note, the values quoted are my estimate of the carbon content allowing for amounts not oxidized due to spills, etc, and for carbon content of the fuel, based on the original resource and/or reserve estimates. I do not think the WEC "possible" estimate is an estimate of the TRB, but rather an estimate of what part of that base could become economically accessible. The other estimates nearly match (S&W) or significantly exceed the Twink12 requirements - and all with limited examination of unconventional sources, and without allowing for LUC and cement emissions.
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Digby Scorgie at 17:43 PM on 18 April 2017Humans on the verge of causing Earth’s fastest climate change in 50m years
Is the following a fair summary?
On the one hand, we have a continuous increase in the burning of fossil fuels.
On the other hand, we have the increasingly damaging effects of climate change.
At some time in the future, climate effects will damage human civilization sufficiently to disrupt the burning of fossil fuels, resulting in a rapid decline in such burning.
If this summary is valid, the obvious question is: When?
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chriskoz at 17:11 PM on 18 April 2017Humans on the verge of causing Earth’s fastest climate change in 50m years
Tom@2,
Appology for my typo @1. I typed 5Pg and 10Pg (peta-grams == giga-ton), but I meant 5Eg and 10Eg (exa-gram) which is 1000 times more.
Where did you find your number "17,204 Gt of coal resources" and 728 Gt reserves? I searched various IEA publications but cannot find your numbers.
From the Wikipedia, the world's proven C reserves are 909,064 Mt. Such numbers obviously change as new discoveries are made and extraction methods (e.g. hydraulic fracking) improve.
The resources number can be very fluid and change depending on definition of "resources". The one from IPCC AR4, e.g. as shown among other C reservoirs in OA not OK series:
shows only 3700GtC of all fossil fuel resources.
Archer 2005, 2007 etc, that we both know very well, considers only a 5000PgC slug in their model. Accordingly, David teaches 5000PgC to be the most likely slug if all FF are burned (a version of your "world where Trump is President of the US"). That number is still nowhere near your number of 17Eg+ of coal only.
So I wonder where these large differences of various estimates of FF reservoir size do come from.
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Tom Curtis at 17:09 PM on 18 April 2017Humans on the verge of causing Earth’s fastest climate change in 50m years
green tortoise @3, even in a wink12 scenario, GMST will rise by about 10 C (the temperature at which wet bulb temperature emergencies become endemic in the tropics) only around 2200. By then, the vast majority of the fossil fuels have been burned, and if on that pathway, it would still take several decades to convert to renewable sources. Further, even then, a nation determined to "Put America First", or "Put Europe First" rather than putting the globe first, and which was determined to adapt to climate change by massively increased energy use powered by fossil fuels could still power on regardless.
Do I think it likely that governments will be persistently that stupid? No! But while a large number of influential think tanks, and several major governments continue to push "Burn, baby, burn", it is a scenario that ought to be included to show the real consequences of their policies. That is, in addition to scenarios that undershoot BAU (RCP 6) to guide those who want a sensible response to AGW, we need policies that overshoot it as a warning to those who do not (or those who do, but might be tempted by the massive PR campaign for fossil fuels being run by the likes of WUWT).
As an aside, I suspect you were tongue in cheek, but the quote was:
"You can fool all of the people some of the time, and some of the people all of the time, but you can't fool all of the people all of the time." (Quoted from memory.) The author was Abraham Lincoln, the first Republican President. To that, pro-fossil fuel lobby and the most recent Republican President has added the addendum, you can fool enough of the people enough of the time that you can sideline those who see through your nonsense.
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Tom Curtis at 16:51 PM on 18 April 2017Arctic icemelt is a natural cycle
jfrantz @64, the linked source is describing sea ice for both Antarctica and the Arctic. Antarctica has a fringe of sea ice that is preserved even in summer, though with minimal extent (about 4 million km squared). In winter it becomes very extensive, exceeding in extent the Arctic sea ice maximum, mostly because it can extent into open ocean. In terms of sea ice extent, the reduction in Arctic sea ice has been far greater, as shown in the graph in the section on Antarctic sea ice extent in the linked source. That graph, however, only extends to Dec, 2012. A more recent graph shows the Antarctic sea ice extent anomaly to have declined astonishingly over the last two years, reaching Arctic (and hence negative) levels by Dec 2016:
(Source)
The low extent anomaly has continued into 2017:
(Source)
With regard to sea ice volume, we are primarilly dependent on models, as there are insufficient depth measurements of the ice to provide a region wide, continuous time series.
A region wide model for Antarctic sea ice volume reported in 2014, and showed sea ice volume to 2010:
The trend of 28.7 km^3/yr compares to Arctic trends of -260 km^3/year in April, and -320 km^3/yr in September shown for the Arctic:
Obviously the recent massive retreat in Antarctic sea ice extent will also have been reflected in a retreat in Antarctic sea ice volume, but as we do not know to what extent it has been matched by a reduction in sea ice thickness, we do not know by how much.
Finally, if Al Gore did say that "arctic ice is floating and antarctic ice is on land", that is misleading (at least out of context). The peak Arctic sea ice volume was about 33,000 km^3 in April (the time of maximum volume). That is dwarfed by the 2,900,000 km^3 volume of the Greenland Ice Sheet. Looked at differently, 14,000,000 km^2 area of the Antarctic continent, while five times the minimum Antarctic sea ice extent is about 80% of the maximum Antarctic sea ice extent. Whether we look at either volume or extent, both polar regions are a story of land ice and sea ice. However, Antarctica is landice surrounded by sea, while the Arctic is sea ice surrounded by land. That makes a very large difference with regard to the rapidity of temperature responses, and the rapidity of albedo changes with warming or cooling, both being much faster in the Arctic. With regard to sea level rise, however, both poles are a land ice story.
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green tortoise at 15:25 PM on 18 April 2017Humans on the verge of causing Earth’s fastest climate change in 50m years
I also don't think that 12000 Ptg of fossil carbon could be liberated, mainly because, even incluiding the Trumps, Putins et al. pro-fossil fuel politicians and regimes, the human devastation would be so huge that humanity will be destroyed much before that happens.
As an example, most of the Middle East, that has some of the biggest (and cheapest) oil&gas resources would cross the 35°C (wet bulb temperature) boundary of human survival. Most people die of high fever above that temperature. Imagine hunded of millions of Arabs, Indians, Iranians and Africans storming Russia, China and Europe escaping the uninabitable landscapes behind.
Behind there would be disaster zones surely taken by extremist groups that would not certainly did a good maintenace to the legacy oil&gas facilities, just like has happened in the areas occupied by ISIS/ISIL/DAESH today, specially if bombed by the Putins and Trumps.
Given that human component, I don't think we can pass 6°C without destroying the fossil fuel infrastructure (either by climate disasters, political violence or global war).
This is a negative feedback, given some climate change, the planet become deadly for most people, and the following collapse prevents further fossil fuel burning. This is however the worst kind of negative feedback imaginable, because the biosphere is saved by killing us as if we were some kind of deadly virus or bacteria
There is catch, unfortuately: given the huge amount of carbon stored in shallow soil, permafrost and gas hydrates that could be destabilised by warming, maybe once the human emissions (and the human population) approach zero, those "natural" emissions triggered could push the planet to a state not seen since the Snowball Earth meltdown (i.e. Tmean= 50°C) in the Precambrian, killing everything that is not a microorganism.
If the Sun has warmed enough since the Snowball Earth meltdown, maybe even a moist greenhouse could be triggered, that will end only when the carbon is sequestered by the flash cap-carbonate reaction. If that is not enough to to compensate for the increasing water vapor greenhouse effect, the greenhouse state will last until Earth has lost most of its water to space, leaving a desert planet behind (I however doubt that Earth is vulnerable to runaway greenhouse like Venus).
I however have strong hope that nothing like that will happen, because "people can be all stupid sometimes, always there is some stupid people, but people cannot be all stupid alltimes" ( I don't remember who wrote that, any idea?).
After all, hope is what moved a lot of brave people against very adverse events in the past, and hope is badly needed to face this crisis.
By the way, I hope you have had a nice Easter.
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jfrantz at 13:59 PM on 18 April 2017Arctic icemelt is a natural cycle
Seroius and I think well founded question here.
In the source linked, http://nsidc.org/cryosphere/sotc/sea_ice.html they describe that antarctic ice has been increasing during this time period while arctic is decreasing. In terms of standard deviation from mean the arctic decrease has been twice as sharp, but:
1. In terms of volume of ice, are we net gaining or losing ice at the poles?
2. Since arctic ice is floating and antarctic ice is on land (pulling this from Inconvenient truth), should the antarctic ice be the main concern when it comes to rising sea levels? Or is that outweigh by the specific areas growing or shrinking (e.g. growing areas are sea ice, shrinking are land based)?
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Tom Curtis at 10:04 AM on 18 April 2017Humans on the verge of causing Earth’s fastest climate change in 50m years
chriskoz @1, while the IEA only estimated 728 Gt (=728 Pg) of coal reserves in 2010, they estimated 17,204 Gt of coal resources. The difference is that while reserves for reserves, they are recoverable given current mining technology, they are also economic to recover at current prices. Resources in excess of reserves are also recoverable given current technology, but are not economic to recover at current prices. The transition from resource to reserve can be quite rapid given changes in technology and/or increased demand. It follows that the Twink12K (ie, 12,000 GtC) is well within the limits of fossil fuel resources, and what is within the limit of fossil fuel reserves is a matter to be proven by future technological and economic developments.
That leaves aside emissions from LUC and cement manufacture.
It is unlikely that we would be able to burn that much fossil fuels before the effects of climate change made further burning of fossil fuels politically infeasible (if not necessarilly destroying the infrastructure, which is no more vulnerable than any other part of our civilizations infrastructure). In a world where Trump is President of the US, however, there are no guaranttees.
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chriskoz at 09:08 AM on 18 April 2017Humans on the verge of causing Earth’s fastest climate change in 50m years
The " Wink12K scenario" is based on this article, speculating the realease of 10Pg anthropogenic C, is the first such scenario I've seen. Apart from being unrealistic (only 5PgC of recoverable FF reserves have been estimated), I think homo sapiens would be technically unable to burn it before the transit climate change effects wiped off or seriously crippled the whole FF burning infrastructure. Then, it comes the increasing awareness that will put more pressure to curb the burning in the future, with possibly other/renewable energy sources replacing it. So, we can safely cross that Wink12K scenario as impossible.
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Tom Dayton at 05:14 AM on 18 April 2017Human CO2 is a tiny % of CO2 emissions
Pattio: The airborne fraction of CO2 has been fairly constant, despite the growth in the rate of anthropogenic CO2 emissions. Therefore the natural sinks are not static. That determination has been made by scientists who, therefore, do not in reality believe the sinks are static.
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Cedders at 04:46 AM on 18 April 2017CO2 effect is saturated
Hope this is the right place to point out that Figs 1 & 2 have disappeared from the 'Advanced' article, apparently after Altervista suspended their hosting. They're still available in the PDF and via the Wayback Machine.
Moderator Response:[DB] Updated. Thanks for the heads-up!
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Jagadees at 03:41 AM on 18 April 20172017 SkS Weekly Climate Change & Global Warming News Roundup #15
Please dont misunderstand what india is doing. we have a religion based fascist government in power. they are painting the color of religion everywhere, so all who get affected by that propaganda reacting with religious theme. Making just one river is sacred is a game for divide and rule and killing innocent people.
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Bob Loblaw at 02:34 AM on 18 April 2017Human CO2 is a tiny % of CO2 emissions
Pattio: as Michael says, please do provide a reference to support your claim that others hold the position that sinks are static.
The sources that I am familar with (e.g., the IPCC) pretty clearly recognize that about half of what is emitted to the atmosphere (by burning fossil fuels) is abosrbed by the oceans and biosphere (the "sinks"), which directly contradicts two of the claims you made in your opening paragraph:
- ...that others claim the sinks are static (unsupported because others feel that sinks have increased to absorb half of what is emitted)
- ...that your argument counters the claim that the sinks cannot process the increase in emissions (they can't, as evidenced by the fact that they can only process half, with the other half still residing in the atmosphere).
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MA Rodger at 02:26 AM on 18 April 2017Science of Climate Change online class starting next week on Coursera
curiousd @32.
I have tracked down this Schwarzchild Equation and, rather than the ones that explains the wobbles of the planet Mercury, it is a rather mundane equation that I didn't appreciate had a name and which is explained here. Frankly, I do not see how it could be used with the UoC MODTRAN model in a way that would lead to a misapprehension that emissivity=0.92. As Tom Curtis points out @37, the emissivity value is set out clearly in the output file which would be required reading for any "serious user."
Concerning the effect of using a single MODTRAN calculation as a global average, further rough calculations suggest to me that the impact of latitude and the annual & diurnal cycles do appear to provide enough additional flux above that single average figure to add 1% to 3% to the total. While these rough weighted calculations remain very sensitive to the assumed weightings, the outcome appears quite clear. Tom Curtis @35 adds weight to this finding. Add in the truncated frequency used in the UoC model analysis and the flux values are become very close to the Chen et al (2013) values.
Of course this does not mean there is no room for other approximations with significant effect on the result within the UoC model, or even errors. But if you wish to establish the potential of your "Correction Number Two" and your "Correction Number Three" you will need to present due reason. So far, that has not been done. And failing to explain your ideas, for instance the derevation of the "One km IR Radiance" values in the graph you presented up-thread (ie this graph), is not winning you any favours.
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John Hartz at 01:40 AM on 18 April 20172017 SkS Weekly Climate Change & Global Warming Digest #15
Joe; I posted the Abstract to the paper you had linked to in hopes that you would acturally read it. If you had, you would see that the researched forcused on a specific location — Bunaken Island (North Sulawesi), Indonesia — with unique sea level rise conditions and for a specific type of coral. For you to suggest that the results of this single study can be extrapolated worldwide is absurd.
The first of the two articles that I linked is not an advocacy article. You actually might learn something by carefully reading it.
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michael sweet at 01:34 AM on 18 April 2017Human CO2 is a tiny % of CO2 emissions
Pattio,
Can you provide a reference for your claim that someone says sinks are static? I am underthe impression that most of the sinks and sources of carbon respond to changes in the environment around them.
While you article is interesting, it is clear from the measured increase in CO2 in the atmosphere that natural sinks have not been able to absorb all the CO2 humans release. That may change in the future although it is not clear if the sinks will increase or decrease.
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JWRebel at 01:17 AM on 18 April 20172017 SkS Weekly Climate Change & Global Warming News Roundup #15
@Joe: I should have been more circumspect with my terminology, and avoided "personhood" which has been a more contentious term. Notwithstanding, corporations and other legal entities are considered "legal persons" by the law and are the subject of legal agency, and it is on the basis of this legal agency and the First Amendment rights that inhere in it, that the Supreme Court granted them the right to political contributions and action.
Common sense would dictate that a legal persoon has "personhood", but this is clearly not the case, as everybody recognizes that a "legal person" is no more than a legal artifice. Although universally recognized and employed, the concept of legal "persons" has been criticized in recent decades because it often enables the persons behind such social organizations "to get away with murder."
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Pattio at 00:47 AM on 18 April 2017Human CO2 is a tiny % of CO2 emissions
The following study published in Nature, April 5th 2017, shows a 31% ± 5% plant growth since the beginning of the industrial revolution. This would counter the claim that "sinks" are static and cannot process the comparatively tiny increase in carbon emissions due to human activity.
Large historical growth in global terrestrial gross primary production http://dx.doi.org/10.1038/nature22030
Large historical growth in global terrestrial gross primary production: "Growth in terrestrial gross primary production (GPP)—the amount of carbon dioxide that is ‘fixed’ into organic material through the photosynthesis of land plants—may provide a negative feedback for climate change1, 2. It remains uncertain, however, to what extent biogeochemical processes can suppress global GPP growth3. As a consequence, modelling estimates of terrestrial carbon storage, and of feedbacks between the carbon cycle and climate, remain poorly constrained4. Here we present a global, measurement-based estimate of GPP growth during the twentieth century that is based on long-term atmospheric carbonyl sulfide (COS) records, derived from ice-core, firn and ambient air samples5. We interpret these records using a model that simulates changes in COS concentration according to changes in its sources and sinks—including a large sink that is related to GPP. We find that the observation-based COS record is most consistent with simulations of climate and the carbon cycle that assume large GPP growth during the twentieth century (31% ± 5% growth; mean ± 95% confidence interval). Although this COS analysis does not directly constrain models of future GPP growth, it does provide a global-scale benchmark for historical carbon-cycle simulations."
Moderator Response:[DB] As others have noted, you will need to furnish a source citation for this claim:
"This would counter the claim that "sinks" are static"
Hotlinked DOI. An openly accessible copy is here.
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Tom Curtis at 00:28 AM on 18 April 2017Science of Climate Change online class starting next week on Coursera
curiousd @36:
"But as is, ModtranChicago gives in its output no information, either for the assumed emissivity or about the restricted underlying wave number range of 100 wn to 1500 wn.
That user will deduce an emissivity of 0.92, which I now know, but did not always know, is entirely too low."
Anybody using the UChicago version of Modtran will see in the user inteface a button labelled "Show raw model output". If they press that button, a new tab will open showing that output. Scrolling through it, they will see first the details about the atmospheric profile, absorber amounts etc, and will then come to a section labeled "RADIANCE(WATTS/CM2-STER-XXX)", which is then shown for wave numbers from 100 to 1500 cm^-1. At the bottom, the output shows the "INTEGRATED ABSORPTION FROM 100 TO 1500 CM-1". A little below that it informs us that "BOUNDARY EMISSIVITY = 0.980". In short, all the information you claim is not available, for which according to you, there is "no information" in its output, is all available just by pressing a button of mysterious function with the mystical label "raw model output" /sarc.
Beyond the false claim about what was not available in the Modtran output, there is nothing in your comment not dealt with by my comment to which you were responding.
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curiousd at 23:30 PM on 17 April 2017Science of Climate Change online class starting next week on Coursera
Hi Tom Curtis,
ModtranChicago is designed primarily for aid in teaching basic environmental science, and is an excellent tool for doing so as is.
It is, as far as I know, also the only source available to everyone for free of plots of outgoing OLR values as a function of altitude and GHG composition. Therefore, for someone such as I, who wishes to learn about at least the one dimensional version of atmospheric science on his own with no available guidance, the temptation will be to use the ModtranChicago output; there is no other choice.
But as is, ModtranChicago gives in its output no information, either for the assumed emissivity or about the restricted underlying wave number range of 100 wn to 1500 wn.
That user will deduce an emissivity of 0.92, which I now know, but did not always know, is entirely too low. See the post 31 above.
That user may then be applying the Schwarzchild Equation correctly and still will find very poor agreement with his "Standard" which is the output of ModtranChicago, for the region near 1 km. The user will then go back to the drawing board repeatedly to find his mistake.
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ubrew12 at 22:37 PM on 17 April 20172017 SkS Weekly Climate Change & Global Warming Digest #15
The NY Times is reporting that this year may bring another El Nino, which would be pretty devastating for the GBR.
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Tom Curtis at 20:24 PM on 17 April 2017Science of Climate Change online class starting next week on Coursera
curiousd @various, it was established in 1997 by Myhre and Stordal that using a single atmospheric profile in LBL and broadband radiative models will introduce inaccuracies to the calculation. That result was confirmed by Freckelton et al (1998). Myhre and Stordal state:
"The averaging in time and space reduce the radiative forcing in the clear sky case by up to 2%. This is due to the fact that blackbody emissions are proportional to T4 and that averaging reduce or remove spatial or temporal variations."
It follows that if you really want to test Modtran for bias, you would need to use (ideally) 2.5o x 2.5o cells based on weekly averages, and take the means. Failing to do so will introduce a bias, which based in Myhre and Stordal, is approximately equal to 50% of the bias you claim to have detected.
The University of Chicago version of Modtran does not permit that, restricting choices of atmospheric profiles to a Tropical zone, two Mid Latitude zones (summer and winter) and two Subarctic zones (summer and winter). Using default values for a clear sky, and with no GHG I found the difference between the OLWR at 70 km for each case, and for a areal and temporally weighted zonal means, and for the US standard atmosphere at default temperatures, and at a temperature adjusted to match OLWR to the average incoming radiation to have a mean bias of 5.35 +/- 3.69%. Tellingly, the least bias (2.33%) was found with the weighted means. The US standard atmosphere with surface temperature set to 254.5 K showed a bias of 4.19%. Given this, the case for any significant bias in the calculation of OLWR over the range of wave numbers covered by the model is unproven. Given the wide range of biases in different scenarios, it is not clear a single correction factor would work in any case.
Further, the idea that Modtran should be adjusted to determine a single OLWR value seems wrongheaded. Modtran is intended to predict observed IR spectrums given a knowledge of surface conditions, and trace gas and temperature profiles. Here is an example of such a prediction (strictly a retrodiction):
Clearly the University of Chicago version of Modtran is capable of reasonable but imperfect predictions of such observed spectrums. Given the limited ability to reproduce actual conditions (ie, site specific surface emissivity, specific temperature profiles, density profiles, etc) we do not expect anything else, in what is simply a teaching tool. Nor is any explicit bias obvious from the example above, with OLWR at specific wave numbers sometimes being over estimated and sometimes under estimated by the model. If you trully wanted to test Modtran 6 for bias (or for error margin), you would need to compare by wavenumber across a large, but representative range of such site specific profiles.
I have not been following the technical discussion above at any depth, but it seems to me that before you get to that discussion, you need to allow for the known constraints on any radiative transfer model, regadless of its accuracy line by line. Further, you would be better directing the technica discussion to the actual use of radiative transfer models rather than their use (and potential misuse) in testing zero dimensional first approximations of the greenhouse effect.
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curiousd at 17:59 PM on 17 April 2017Science of Climate Change online class starting next week on Coursera
Regarding:
"What you demonstrate here is that yor correction for emissivity ("Correction Number Three") is duplicating your correction resulting from the limited spectrum under analysis ("Correction Number One"). When you say "(a) You know nothing about the limited wavelengh range" you correct by adjusting the emissivity value ("Correction Number Three"). But we do know about the "the limited wavelengh range" and when we correct for it ("Correction Number One") the flux calculations match blackbody conditions for emissivity=0.98 as the UoC model says it uses."
The 0.92 emissivity result is a problem whether or not one obtains better values for the OLR at 250 K by correction one, or an improved clear sky OLR from correction two. It results in a result for the solution to the Schwarzchild Equation (S E) ,assuming no scattering (two stream approximation), that has entirely the wrong OLR for the 1km distance from ground if the emissivity is 0.98. To the point that instead of a 1 km OLR that is slightly less than the surface ORL, as is the case for 0.98 emissivity, at 0.92 the OLR is slightly greater at 1 km than the surface emissivity.
So consider the "serious user" of MILA who:
1. Assumes that 0.92 is the emissivity instead of 0.98 by doing the simple calculation above comparing the MILS emission from the ground and comparing to the Stefan - Boltzmann law.
2. Correctly numerically applies the SE expression for the outgoing stream in the two stream SE, perhaps applying the SE to only the difference between the 800 ppm and 400 ppm cases for CO2 to get the climate sensitivity. He /She is (unknowingly) using a drastically too low surface emissivity.
3. Since the upstream solution is I^(0) t* plus atmospheric contribution , if I^(0) is (0.92/0.98) factor too small relative to what one gets from MILA, since the atmospheric contribution term is independant of the surface, both the 400 ppm and 800 ppm contributions will be too small relative to what one obtains by just running MILA for 400 ppm and then 800 ppm and subtracting, where the dicrepancy is not much at,say, 20 km but really serious at 1 km.
4. The user will therefore conclude that his/her application of SE is incorrect even though it is not. The user is just (unknowingly) using the wrong emissivity.
Grant Petty states, on his page 215 that the I^(0) term is the "....only term whose value cannot be directly computed from knowledge of (symbol for wave length specific linear absorpion coefficient as function of z ) and (symbol for transmittance as function of z) alone (for given wavelength and viewing direction mu). " He then states:
"The expression we supply for I^(0) depends on what we assume about the nature of the surface. But regardless of those assumptions, there are two contributions that must be considered: (1) Emission by the surface itself, and (2) upward reflection of atmospheric radiation incident on the surface."
I am certain that MILA does not take reflection at the surface into account which is fine for an illustration for students, but then the value of the emissivity of the surface strongly influences both the OLR and the value of intensity 400 minus intensity 800 as function of altitude z.
So back to the serious user of MILA...He/She will think the emissivity is 0.92 instead of 0.98 and therefore get something that disagrees strongly with MILA at 1 km even though that serious user has been applying the SE correctly but whilst (unknowingly) using the wrong emissivity.
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MA Rodger at 16:52 PM on 17 April 2017Science of Climate Change online class starting next week on Coursera
Curiousd @29.
The 255k-239.7W/sqm is a standard blackbody calculation for emissivity=1 with the outward IR flux matching the absorbed solar radiation, thus the albedo remains from cloud & surface while GHG=0 because it is a blackbody. In terms of accurate measurement/assessment of the flux, today there is an energy imbalance due to AGW.
The UoC model gives 226.363W/sqm for 255K (and altitude =0) because emissivity=0.98 and the model only considers part of the spectrum, the value 226.363W/sqm being not greatly different from the 266.52W/sqm value calculated for the part-spectrum using SpectralCalc.com. (The difference is insignificant and could result from many understandable approximations.) Note the implications of this @31.
Putting #31 to one side and assuming your “corrections to Modtran for 0.98 emissivity” are not what is meant, but rather the +8W/sqm you argue for @7. (I miscalculated this as 9W/sqm @28) I set out @18 why I consider this +8W/sqm to be too high and that a +4W/sqm would be more appropriate. You present no reason for the +4W/sqm being incorrect.The impact of altitude on the flux magnitude has been considered up-thread but as my misinterprettion of your “Correction Number Two”. (Note that I did not indicate the sign +/- @14. In truth I had in mind a positive correction but it would actually be a negative correction.) The UoC model set with GHG inputs as zero does demonstrate a change in flux with altitude but it alters by less than the variation of area with altitude (the square of the effective radius). Thus with all GHGs reduced to zero in the UoC model, we should see a 2.2% reduction from surface to 70km. The actual reduction (varies with surface temperature) is roughly 0.5%. This is probably explained by the continued presence of minor GHGs in the UoC model which are not zeroed but remain unchanged with user input. If this is not the case & if there is no alternative explanation, if it does require correction, this would comprise a reduction of some 4W/sqm for 255K surface and a measured IR flux at 70km.
curiousd @31.
What you demonstrate here is that yor correction for emissivity ("Correction Number Three") is duplicating your correction resulting from the limited spectrum under analysis ("Correction Number One"). When you say "(a) You know nothing about the limited wavelengh range" you correct by adjusting the emissivity value ("Correction Number Three"). But we do know about the "the limited wavelengh range" and when we correct for it ("Correction Number One") the flux calculations match blackbody conditions for emissivity=0.98 as the UoC model says it uses.
curiousd @32.
I am pretty hazy about Schwarzschild but I would not expect there to be a significant gravitational effect (?! I am pretty hazy!) when calculating the radiation flux through a planet's atmosphere.
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Eclectic at 16:27 PM on 17 April 2017New study shows worrisome signs for Greenland ice
Haze @7
I am surprised that you feel "discussions at Skeptical Science are becoming increasingly constrained, and thus decreasingly informative, due to the current relative paucity of comments on most topics" (unquote)
My own impression (admittedly personal anecdotal) over the past 4 years of frequent observation of SkS, is that there is a good flow of informative discussion in the comments columns. If anything, I feel there is an even higher amount of such discussions than 3 or 4 years ago. On top of that, I must say (from reading many comments columns back to the previous decade) that I noticed fluctuations in activity in most of the lengthier columns — but that is only something to be expected, as new developments and new data come along from time to time. Perhaps, Haze, you are interested in a narrow range of climate topics : and that may have caused you to have a certain bias in your observations.
Possibly the most important factor in discussions is the absolute need (if any!) for any discussions in the comments column! A good many of the articles posted are so straightforward, that little discussion is required — save for the rebuttal of erroneous or peevish disputations that may appear in the comments column.Moderator Response:[DB] Thank you for your fine response, but as the comment you were responding to was moderated, it became necessary to also moderate your comment's response to the off-topic material.
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michael sweet at 11:41 AM on 17 April 2017Tuvalu sea level isn't rising
The link Rob P posted to the Tuvalu post explains a lot about local sea level rise.
A comment on the OP here: I visited Funafuti in December 1988. Only a very small portion of the atoll is 3 meters above sea level as mentioned in the OP. Most of the island is much lower. According to this Wikipedia article, the average height of Funafuti is less than 2 meters (no date given). This climate report shows knee deep water in the center of town. The island is so small that water from rain runs off immediately, the water would be at sea level. Even in 1988 there were large areas in the village that regularly flooded at high tide. A rise of even a few centimeters would have been immediately noticable. Since they are dependent on ground water for many uses flooding would ruin their water supply.
When you combine that with the fact that the El Nino cycle can raise sea level 20-30 cm (as described in the OP), and consider similar storm surge increases in sea level, it is no wonder that the people of Tuvalu are concerned.
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michael sweet at 10:18 AM on 17 April 20172017 SkS Weekly Climate Change & Global Warming Digest #15
Joe,
The sea level fall in Indonesia is unrelated to Global Warming. It is caused by the El Nino cycle. When El Nino appears the trade winds lessen. The water piles up on the Eastern Pacific near Peru. Sea levels in Indonesia fall. During La Nina the trade winds blow harder and sea levels in Indonesia rise (and fall in Peru). This animation clearly shows that sea level in 2016 fell in INdonesia while it rose in Peru.
According to AGW theory, the sea level for the entire globe will rise. Local effects are not relevant. In fact, global sea level did rise in 2015-2016 as this graph shows:
Deniers often confuse local sea level effects with global effects. Local effects are not contradictions to predicted global effects. I note that the article you cite claims that sea levels were at a 12 year low. It was not lower than that because sea level rise caused the base to get higher.
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Haze at 10:18 AM on 17 April 2017New study shows worrisome signs for Greenland ice
I agree that my comment does not relate directly to Greenland and as such is, strictly speaking, off topic. However I am not trying to create a haze but to generate discussion and perhaps through that gain a greater understanding of why Greenland and the Antarctic Penisular react differently to global warming. If this discussion is not relevant then no doubt the moderator will heed the exhortation of PluvIAL at 5 to remove my comment. I would note however that the dscussions at Skeptical Science are becoming increasingly constrained, and thus decreasingly informative, due to the current relative paucity of comments on most topics
Moderator Response:[DB] Continued off-topic snipped.
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chriskoz at 09:36 AM on 17 April 2017From the eMail Bag: A Deep Dive Into Polar Ice Cores
David@3,
Thanks for your pointers to the rellevant articles. Icidentally (or maybe not) Buizert 2015 is precisely about WDC (WAIS ice core), that I used as an example in my question, so I found it useful. Looks as they estimate Δ-age just on what you've said in the OP: firn densification modeling and ice-flow modeling. The age of ice is synchronized to the
layer-counted Greenland Ice Core Chronology (I did not know that counting of some ice core layers like this one in Greenland was possible like in dendrology). Another variable they used was a data set of δ15N-N2, which is a proxy for past firn column thickness. -
chriskoz at 09:10 AM on 17 April 2017Debunking Climate Myths from Politicians
broadbarrel,
Looks like readers and mods are ignoring your series of requests and I think rightly so.
Because you advocate to engage with current POTUS and his staff about climate science at the level this site represents. Such engagement is simply impossible. To engage with current POTUS about anything (not just climate science) is like descending to a mudpool to resttle with a pig. No one wants to engage in such a dirty fight. Certainly you want to raise the alarm in media when pig's ravagings are becoming dangerous/destructive (and that's how recent political articles on SkS do comment on some POTUS actions) but a sane person must just stop there. It would be more productive to engage in a clean, positive way. Following my analogy, even a pig can do noble things, e.g. help to plough a field in search for truffles. The equivalent of truffles for current POTUS would be money and fame and unlimitted dating of young girls. Again, that's the only level you could engage on, and this site should not be interested in such engagement.
If this post is frowned upon by mods because it goes way too derogatory on my POTUS (I'm US citizen voting in WA state). Even though First Amendment allows me to freely express my opinion hereabove, I still would be liable for defamation if I tried to e.g. say publicly similar thing about an MP in my country. I can't help it, because saying anything non derogatory on my POTUS would be hypocritical for me.
Moderator Response:[DB] Manpower is the sole limiting factor in keeping lists such as the Politicians List updated.
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curiousd at 08:34 AM on 17 April 2017Science of Climate Change online class starting next week on Coursera
Here is a general description of my knowledge of Atmospheric Physics and how I got where I am with such projects as trying to make sure I have applications of the Schwarzchild Equation correct. I was a condensed matter experimentalist with perhaps 75 publications in refereed journals. I also taugnt Freshman Physics of the Environment for many years. Upon retiring I decided to try and learn how to really calculate quantities such as the CO2 no feedback climate sensitiviy and therefore:
I bought large numbers of Atmospheric Physics books and tried to teach myself; my home institution has no one working there who knows the first thing about Atmospheric Physics, so this project has been attempted without human input or correction. Many hours a day were spent on this project and now three years have elapsed. My Rosetta Stone has been the text by Grant Hill, and I think now I have a decent general idea for a one dimensional version of these things.
But it is my opinion that even though Atmospheric Science is certainly correct, it is explained rather poorly to scientists not in the field and for one reason above all: There is a dearth of numerically worked examples for the most important things. Symbolic explanations alone are insufficient.
How could there be, for example, no worked numerical example for the solution to the Schwarzchild Equation for an atmosphere with 400 ppm CO2 to give the upward flux as a function of altitude? Regular Physics is not like this. The students start out learning F=Ma and then M = F/A. In a more advanced class the solutions to the one dimensional Schroedinger Eq. is worked out for any number of potential well problems. E&M is replete with boundary problems involving Gauss' Law.
I think that not having a worked example for the solution to Schwarzchild Equation, given the transmittance values one now has worked out for the user by SpectralCal, is like having no worked examples of the work energy theorem or momentum conservation.
My mistaken derivation of an emissivity of 0.92 for MILA was one of many stumbles that I have had to deal with. If there were merely a statement on the user output page of MILA that (1) an emissivity of 0.98 is assumed that would be agood thing. And if the statement were made that (2) the wavenumber band the computer uses is limited 100 wn to 1500 wn which can introduce errors so the user should be cautious would also be a good thing.
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curiousd at 07:53 AM on 17 April 2017Science of Climate Change online class starting next week on Coursera
Regarding "It is also unclear why this would indicate an Emissivity of 0.92."
Here is how you get the emissivity of 0.92.
(a) You know nothing about the limited wavelengh range.
(b) You wish to compare the OLR output of MILA with your efforts as someone who is trying to learn how to use the Schwarzchild Equation.
(c) You therefore determine what the MILA emissivity is (with no knowlege of the cut offs or of the actual 0.98 emissivity)
(d) You therefore go to the U.S. Standard atmosphere and learn that the upward OLR from Modtran looking down from zero altitude, is 360.472 W/m sqd.
(e) You use the Stefan Boltzmann law with emissivity one and T = 288.2 degrees K. You get 391.164 K.
(f) You divide 360.472 by 391.164. Your answer is 0.92
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nigelj at 06:43 AM on 17 April 20172017 SkS Weekly Climate Change & Global Warming Digest #15
Joe @5, you have a few reefs in Indonesia bleaching, due to a local fall in sea level. Most reefs globally, including the GBR, are bleaching due to global warming. You are not fully reading the articles you list, and you are missing the big picture. You did the same thing on the legal persons issue.
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joe - at 05:39 AM on 17 April 20172017 SkS Weekly Climate Change & Global Warming Digest #15
John A) As the article explains, and which you acknowlege, the bleaching and mortaility of the reefs is due to the falling sea level, an event unrelated to and contrary to AGW theory with rising sea levels
B) the Second two articles you cite/link are advocacy / opinion pieces.
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John Hartz at 04:30 AM on 17 April 20172017 SkS Weekly Climate Change & Global Warming Digest #15
Joe: Also see:
The big lie propagated by government and big business is that it is possible to turn things around for the reef without tackling global warming
Australia's politicians have betrayed the Great Barrier Reef and only the people can save it, Opinion by David Ritter, Guardian, Apr 9, 2017
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John Hartz at 04:23 AM on 17 April 20172017 SkS Weekly Climate Change & Global Warming Digest #15
Joe: The answer to your question can be found in:
Why dead coral reefs could mark the beginning of ‘dangerous’ climate change by Chelsea Harvey, Energy & Environment, Washington Post, Apr 12, 2016
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John Hartz at 03:55 AM on 17 April 20172017 SkS Weekly Climate Change & Global Warming News Roundup #15
Joe: On the other hand, Citizens United opened the floodgates for corporations to influence elections and the public policy decisions through the expenditure of unlimited amounts of money. The federal government of the US has effectively become a government of big business, by big business, and for big business.
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John Hartz at 03:47 AM on 17 April 20172017 SkS Weekly Climate Change & Global Warming Digest #15
Joe: Here's the Abstract of the paper you have provided a link to:
Abstract. The 2015–2016 El-Niño and related ocean warming has generated significant coral bleaching and mortality worldwide. In Indonesia, the first signs of bleaching were reported in April 2016. However, this El Niño has impacted Indonesian coral reefs since 2015 through a different process than temperature-induced bleaching. In September 2015, altimetry data show that sea level was at its lowest in the past 12 years, affecting corals living in the bathymetric range exposed to unusual emersion. In March 2016, Bunaken Island (North Sulawesi) displayed up to 85 % mortality on reef flats dominated by Porites, Heliopora and Goniastrea corals with differential mortality rates by coral genus. Almost all reef flats showed evidence of mortality, representing 30 % of Bunaken reefs. For reef flat communities which were living at a depth close to the pre-El Niño mean low sea level, the fall induced substantial mortality likely by higher daily aerial exposure, at least during low tide periods. Altimetry data were used to map sea level fall throughout Indonesia, suggesting that similar mortality could be widespread for shallow reef flat communities, which accounts for a vast percent of the total extent of coral reefs in Indonesia. The altimetry historical records also suggest that such an event was not unique in the past two decades, therefore rapid sea level fall could be more important in the dynamics and resilience of Indonesian reef flat communities than previously thought. The clear link between mortality and sea level fall also calls for a refinement of the hierarchy of El Niño impacts and their consequences on coral reefs.
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Tom Curtis at 03:22 AM on 17 April 2017New study shows worrisome signs for Greenland ice
PluviAL @5, still futher off topic, but the relocation of water from ice sheets near the poles to oceanic water near the equator will also change the duration of the Earth's day. The change in angular momentum involved will not be uniformly transferred to the interior, providing another trigger for earthquakes, and potentially vulcanism. Whether that mechanism, or the two you mention will raise either earthquake or volcanic frequency appreciably above background rates, however, is SFAIK, unknown.
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PluviAL at 02:50 AM on 17 April 2017New study shows worrisome signs for Greenland ice
Tom at 3: Thanks for that excellent summary of Antarctica dynamics, I enjoyed it and learned a lot. However, Haze is off topic and, frankly, seems to just be trying to create haze, not to provide a valid comment on Greenland's potential catastrophe. His comment should simply be removed, in my opinion.
I am of the, admittedly badly informed, opinion that Greenlanders will be fine, and benefit once they adapt. The rest of us would not be so lucky.
I fear the isostatic adjustment is much more serious than we realize; volcanism throughout the world may be its dichotomous side-effect, especially if at the same time East Antarctica rocks the continent as mass shifts from West to East. Volcanic and tectonic pressure points in other parts of the geode may slip catastrophically adding to CO2 loads, while reducing uptake, from temporary sudden cooling from vocanism.
The fear is a major motivation for me.
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joe - at 02:12 AM on 17 April 20172017 SkS Weekly Climate Change & Global Warming Digest #15
Ruins, Not Reefs: How Climate Change Is Fast-Forwarding Coral Science
Great Barrier Reef Bleached Staghorn Coral
A bleached coral near the Great Barrier Reef on March 16, 2017
The first article listed in the "stories of the week" discuss the coral bleaching. It should be noted that the GBR along with numerous reefs around indonesia are suffering coral bleaching due to a drop in sea level. Is it possible that other factors unrelated to AGW is causing the bleaching.
http://www.biogeosciences.net/14/817/2017/
Moderator Response:[Rob P] Coral die-offs from temporary falls in sea level are a natural phenomenon. The Samoans call it Taimasa - meaning foul-smelling (low) tides. This has to do with the shift in water mass in the Indo-Pacific region associated with ENSO. See the SkS post: What's happening to Tuvalu sea level?
As common sense would indicate, this only affects coral near the surface, especially those exposed at low tide. On the Great Barrier Reef, bleaching extends from the surface to 30-40 depths in some areas and it is from water that is too warm (coral bleaching being a breakdown of the symbiotic relationship between polyp and photosynthetic algae).
Lizard Island on the Great Barrier Reef saw catastrophic levels of bleaching in summer 2016, and yet look at the sea surface height variations for that area. The lowest monthly anomaly in recent times occurred in 2015 - well before bleaching was observed. Moreover, how do such small fluctuations cause bleaching in coral tens of metres deep?
So we can dismiss the sea level aspect as some silly climate change denier contrivance. The National Oceanic and Atmospheric Administration (NOAA) has a whole bunch of information on coral bleaching (Coral Reef Watch) if you're truly interested in understanding this. They even have a coral bleaching outlook, a climate model-based projection which utilizes sea surface temperature anomalies to forecast bleaching events.
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joe - at 23:20 PM on 16 April 20172017 SkS Weekly Climate Change & Global Warming News Roundup #15
In the USA, corporations of various legal feathers are routinely granted personhood. The Supreme Court ruled in 2010 (Citizens United versus Federal Election Commission) that as legal persons, corporations have the same first Amendment rights as natural persons,
JW - FYI the SC did not grant personhood or anything resembling personhood in CU.
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JWRebel at 23:03 PM on 16 April 20172017 SkS Weekly Climate Change & Global Warming News Roundup #15
@Joe: In the USA, corporations of various legal feathers are routinely granted personhood. The Supreme Court ruled in 2010 (Citizens United versus Federal Election Commission) that as legal persons, corporations have the same first Amendment rights as natural persons, and are therefore entitled to make political expenditures. Many see this as the final nail in American democracy, officially institutionalizing the rule of money.
Almost all large corporate persons have been found guilty of felonies multiple times, but when it comes to jail time, bankruptcy, and the other normal responsibilities of natural persons, it turns out that fictional legal persons have more rights but less responsibilities.
If we can enable faceless psychopathically inclined pools of capital to reap the rewards of actual personhood, without the concomitant obligations, there should be no reason why we cannot grant forests, wetlands, or rivers personhood.
[psychopathic is used here as a diagnostic, not a derogatory term: most corporations manifest all the diagnostic criteria for psychopathy] -
curiousd at 22:26 PM on 16 April 2017Science of Climate Change online class starting next week on Coursera
Correction: The equilibrium temp is close to 255 K in the above, not 239.7 K. I was confusing the temperature with the flux in this sentence. It has been a long night.
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curiousd at 22:20 PM on 16 April 2017Science of Climate Change online class starting next week on Coursera
Lets deal with correction number one first. Of course I set all GHG equal to zero. Basic texts on environmental physicssuch as the one by David Archer or the one by Wolfson, consider the case where the cloud albedo is kept, but the GHG effect is "turned off". The equilibrium temperature of such an earth, given an emissivity of one, is 239.7 degrees K. For Modtran Chicago, U.S. Standard atmosphere, and 255 degrees K, no GHG, the OLR is 225.07 W/msqd. If I add my corrections to Modtran for 0.98 emissivity I get not 225.07 W/meter sqd but 233 watts per meter sqd. There is no curvature of the Earth effect because if I look at the output from Modtran with zero GHG then the OLR is stays essentially constant but shows some small scatter all the way from altitude zero to altitude 70 km.
The tenberth reference is to show that the most modern satellite result is 239 watts/per meter squared at the assumed emissivity of 1.0.
If I pare my correction down to this statement are you good with this? -
william5331 at 18:48 PM on 16 April 2017New study shows worrisome signs for Greenland ice
It is unlikely that Greenland itself will suffer from sea level rise. In addition to the hydrostatic rebound, both instantaneous and long term, as the ice decreases, it's gravitational pull which pulls the surrounding water toward it like hitching up a skirt, will decrease. Incidentally, this release of the skirt of water will raise sea level even more in other locations than just due to the flow of Greenland glacial water into the ocean.
On a different topic there should be a dynamic process increasing the melt of the ice sheets where they are grounded below sea level. As the ever warming ocean water melts the ice front, the water in contact with the ice becomes less salty and hence lighter. This water should flow up under the ice ceiling, pulling in more warm ocean water along the sea bottom. The deeper the grounding line the greater this effect should be so the process should accelerate where the sea bottom is on a retrograde slope.
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Tom Curtis at 16:08 PM on 16 April 2017New study shows worrisome signs for Greenland ice
Haze @2:
1) The OP is about Greenland, not Antarctica, so discussion of the Antarctic Peninsula is technically of topic.
2) This is Figure 1 from the first paper you reference with regard to Antartic Peninsular temperatures (Oliva et al):
You will firstly note that 7 out of 10 temperature records are from the northern tip of the Peninsula, or islands lying still further north; and that consequently a simple mean of the temperature records does not show temperature trends over the peninsular as a whole due to spatial bias. Second, you will note that since 1998 temperature trends for the northern 7 stations and the 3 stations representing the bulk of areal extent of the peninsula have had opposite signs. That means (at best) of three regions of approximately equal area (northern, south west, and south east), we have one region warming, one cooling, and no data for the third. On that data, claims of cooling for the entire peninsular go far in excess of what is supported by the data. We can reasonably claim the pensinsula as a whole warmed from the 1950s to about 2000 as all records, and the records for the two regions with data showed that trend (and the trends in the cryosphere in the third supported it); but cannot make a claim to peninsula wide cooling since then if we are guided by the data.
3) Here is Figure 5 from Schmithusen et al:
You will note in particular that even with 4 x CO2, there is a positive change in regional forcing over the entire Arctic (though weakest over Greenland). You will further note that the regions of a negative change in the regional greenhouse effect are strictly limited to parts of East Antarctica, far from the sea. If you compare this with Fig 4 you will see that (approximately) Greenland forcing increases from a current mean value of about 5 W/m^2, as also does the West Antarctic Peninsula. East Antarctica, in constrast gets a stronger negative greenhouse effect relative to that which already exists there (on annual averages).
Further, despite the current negative regional forcing in central East Antarctica, temperatures there are still well above that which would be expected from insolation alone. That is because warm air comes in from the north. With ongoing warming in the north, the temperature gradient between maritime air above the circumpolar waters and that in the interior of Antarctica will increase, resulting in a stronger heat transfer between the two. Over the areas with an increase in radiative forcing (such as the Antarctic Peninsula), that will result in more warming than expected from regional changes in radiative forcing alone.
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broadbarrel at 14:22 PM on 16 April 2017Debunking Climate Myths from Politicians
Please be aware that President Donald Trump is an avid and blatant rejector of nearly all concerns for the ecology, enviroment, sustainable society and climate change.
Refer to url: http://www.climatecentral.org/news/trump-cabinet-climate-change-20920 Refer to url: https://www.ioes.ucla.edu/article/environmental-future-trump-administration/
Earch url has been archived at url: https://web.archive.org/ This is so recorded substantiation of their positions may not inadvertently "evaporate" and thereby become deniable.
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