Arguments
Recent Comments
Prev 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 Next
Comments 4001 to 4050:
-
Daniel Bailey at 02:25 AM on 13 May 2022Why and How to Electrify Everything
@David-acct, properly-equipped Mitsubishi Hyper Heat mini-split ductless systems can function to as low as -25 F. When such systems hit their base limit, they do shut down until temperatures rise above those minimal levels. In northern climates, the point is to pair these systems with backup systems that can take over in the event of really cold airmasses dropping out of the Arctic for those few times per year that they actually occur. No one is saying to use them as a standalone solution for all cases and climates.
- Just a guy who used to sell those systems for a time in Northern Michigan.
-
Eclectic at 21:09 PM on 12 May 2022Flying is worse for the climate than you think
Lawrie @3 , as far as jetfuels are concerned, their composition is described as predominantly hydrocarbon chains of C9 - C16 length (kerosene-like). "Biofuels" for jet engines have a similar composition ~ in part to allow usage in the already-existing modern jet engines (and in legacy jet engines too). It would be problematic to re-design / re-manufacture jet engines to use short-chain hydrocarbon fuels such as alcohols. And alcohols, although cheaper to produce, have lower energy density and would be proportionately heavier to carry : as well as requiring larger & therefore heavier tanks.
What exactly are biofuels, you ask? A loose definition would be :- any hydrocarbon molecule of one or more carbon atoms, derived from feedstock that has grown in recent years (say, less than 100 years) . . . as opposed to fossil fuels ~ where the feedstock comes from organisms that grew 100+ million years ago. An easy difference !
Why use the term "biofuels" ? A convenient term, since it is brief and people intuitively know what is meant by it.
-
Doug Bostrom at 17:47 PM on 12 May 2022Why and How to Electrify Everything
Point of clarification: heat pumps don't "stop working" at a certain temperature. Their efficiency becomes less, and at a certain point they'll not be able to keep up with load.
In combination w/backup heat sources, the net result in practice is that heat pumps still substantially reduce energy consumption even at very low air source temperature. That portion of gain which is not obtained via combustion (near or far) is "electrified."
Performance in lower source temperature is exhaustively covered here (w/state of the art off-the-shelf equipment as of 7 years ago):
Cold Climate Air Source Heat Pump (Minnesota Department of Commerce, Division of Energy Resources)
-
Lawrie at 14:05 PM on 12 May 2022Flying is worse for the climate than you think
walschuler talks of biofuels. Does anyone know what the chemical composition of "biofuels" is and how they compare with standard jet fuel for CO2 emissions? Strictly speaking are not fossil fuels also biofuels?
-
David-acct at 12:16 PM on 12 May 2022Why and How to Electrify Everything
Dana1981
your link to the heatpumps indicate they only work down to -10f & -13f
"Fujitsu cold climate heat pumps (AOU line) have a lot in common with Mitsubishi’s. But instead of delivering 100% of their capacity down to 5F, all but the smallest Fujitsu models offer 75-95% of their capacity. They’re rated to work down to -10F, just above Mitsubishi’s -13F."
That doesnt do much good when places like MN, MT, ND, SD regularly have 1-2 weeks at a time with -20f . Further
-
Eclectic at 07:39 AM on 12 May 2022Why and How to Electrify Everything
Doug @12 , thank you for that information.
I am not sure what is happening with the new vaunted pouch cell battery : but apparently Bolt advertises a very brisk 0-60 mph time . . . the sort of time which ( a few decades ago ) required a large sporty V8 engine.
-
Doug Bostrom at 02:35 AM on 12 May 2022Why and How to Electrify Everything
Eclectic, happy to answer.
Our vehicle is rarely discharged below 1/5th of remaining capacity, usually charged only to about 90% so that "one pedal driving" is fully available (another absolute boon thanks leaping from the 19th to 21st century). We rarely fast charge. As well, this car (Bolt) doesn't fast charge above 55kW, which for one who cares about battery longevity is indeed a good thing. W/regard to regenerative braking, I've seen return to battery hitting 70kW but it's not a problem as these events are very short and don't last long enough to expose imperfect cooling distribution in individual cells (due to engineering constraints on thermal management cells end up with a thermal gradient under prolonged high current in or out, which is not good due to pchem issues).
-
walschuler at 00:19 AM on 12 May 2022Flying is worse for the climate than you think
I think that biofuel, properly sourced, is the obvious and most scalable short term solution to the carbon footprint of aviation. Both United and KLM have demonstrated transatlantic flights on pure biofuel. The airlines should be first in line for properly raised biofuel and should be given deadlines for conversion, or airports or countries could incentivize the conversion by giving better terminal slots, reductuions in landing fees, or higher scores in route bids for use of biofuel. New high speed land connections are of course feasible but as a rule they are anything but short term projects. Biofuels for long distance oceanic shipping ought to be second in line.
-
dana1981 at 14:13 PM on 11 May 2022Why and How to Electrify Everything
Cold climate heat pumps: https://carbonswitch.com/best-cold-climate-heat-pump/
-
Eclectic at 10:01 AM on 11 May 2022Why and How to Electrify Everything
Indeed, Doug Bostrom @9 , it appears the commenter "Iain R" has not been keeping up with advances. In his post @3 , he claims that 'clean' electricity from renewables is an unworkable proposition, owing to the grid becoming "uncontrollable".
Iain R 's opinions are 10 years out of date. The evidence is in the South Australian example [mentioned @5 above] ~ where a big Tesla battery provides millisecond matching of load demand on the electricity grid, along with frequency control. All this is very desirable for electricity generators. And that ability, combined with grid market arbitraging, has made the S.A. Tesla big battery so profitable for the company owning it, that it has quickly paid off the battery's capital cost. And the company has even recently enlarged the battery by 50% .
It is a marvel how obsolete ideas can linger on.
(B) Slightly off-topic, Doug, but could you comment on how your car's (lithium?) battery battery is doing so well. Is this despite you "abusing" it with rapid recharges and lots of regenerative braking? . . . or are you babying it: with trickle charges, gentle accelerations, 20-80% charge cycles, and suchlike?
-
Doug Bostrom at 09:02 AM on 11 May 2022Flying is worse for the climate than you think
"Ghost Flights" can be thought of as a bright point of distinction as to whether governmental climate change mitigation policy is working at anything roughly approaching an effectively systemic level.
To Adam's thoughts on "fixing flying," I'd add: accept that flying costs more than we're paying. As with other of our activities, the cost of flying is artificially low because we're burning a messy fuel from the past that we didn't make and pushing the result onto people in the future, with no plan or intent to pay back. For our immediate benefit, we're stealing the future from other people.
Air travel at today's cost to us is theft.
When the dust settles, it's highly unlikely that a fully accounted air fare from point A to point B will be as strangely "cheap" as it is now, once theft is removed from the equation. A reformed thief accepts that muggings are no longer part of everyday living. Our habits and expectations will likely need to change.
-
Doug Bostrom at 08:42 AM on 11 May 2022Why and How to Electrify Everything
"Spinning mass" indeed used to be a challenging replacement problem to solve, for keeping voltage and AC frequency stable on the grid. That's now a fully solved technical problem, and in fact when one thinks through the fundamental physics of the matter, notional "solid state" grid stabilization is inherently more effective than KE in massive rotors in generators, "slow" ramping of PE from steam and combustion throttling, moderator rod insertion/removal and the like.
Similarly it used to be the case that heat pumps were largely ineffective in even fairly "mild" temperatures. No more.
It's no wonder we get stuck in the past, at least a little bit. Personally I'm having a hard time adjusting my own head to progress. I'd never have believed only 10 years ago that I'd own an automobile capable of traveling 300 miles on a fundamentally squishy and historically unreliable pot of electrochemistry, but here I am today, with a four year old EV having 50,000 miles on the clock and no sign of degradation in the chemistry mess powering it. And driving the thing makes me feel like I'm 16 again, for better or worse. It's far better than the Victorian-era tech I used have under the hood— in 2017 and 116 years after Vickie shuffled her mortal coil.
Things change and we must keep up!
-
michael sweet at 01:06 AM on 10 May 2022Why and How to Electrify Everything
Ianr @4,
You claim that "with regard to heat pumps there is much misunderstanding and confusion betwen Coefficient of Performance and efficiency" but then do not explain what the confusion is. You seem very confused about efficiency.
To make it simple, for gas furnaces " High efficiency furnaces offer 90% or more AFUE." (that means for 100 joules of energy in the gas only 95 joules of heat is delivered to the room.) source. By contrast, a heat pump can deliver 400 joules of heat for every 100 joules of electricity used. In very cold weather current heat pumps deliver 250 joules of heat for every 100 joules of electriicity. As shown in Norway, they can be used to heat any structure in any cold except perhaps in the Antarctic. In ten years heat pumps will be more efficient. Gas is so last century.
Heat pumps save a lot of money over their lifetime but are more expensive to install. Many people only look at the installation costs and not the lifetime costs so the government helps them to save money by giving iincentives to reduce installation costs.
Moderator Response:[BL] For everyone:
Please note that you are responding to a user with the handle Iain R, not IanR. There is another user in the system with the handle IanR, but he has not been active for a while and is probably not the same person. Please pay close attention to user names.
-
michael sweet at 00:57 AM on 10 May 2022Why and How to Electrify Everything
Ianr@3
Many peer reviewed articles have been written about an all renewable energy energy system. For example see Connelly et al 2016. Connnelly reverences at least 20 other all renewable energy plans. Many more have been pubished since.
I am not aware of any energy plans that include more than 5% of all energy coming from nuclear power. Please ciite a peer reviewed article that uses nuclear power. Williams et al 2021 was the last group that I am aware of that supported an important place for nuclear. their 2021 paper says that renewable energ yill be cheapest.
Abbott 2012 lists about 15 reasons why nuclear can never produce more than about 5% of all energy. Can you tell us how you plan to get enough uranium for your wild scheme since all known reserves of uranium would only power the world for about 5 years.
-
Eclectic at 22:02 PM on 8 May 2022Why and How to Electrify Everything
IanR , the other area I would like to get your opinion on, is the non-Wind / non-Solar type of low-carbon electricity generation.
Geothermal seems to be "stuck in a hole" (excuse pun) and not going anywhere fast. Nuclear fission seems almost dead in the water, owing to huge costs and huge development delays ( though maybe Small Modular Reactors could come to the rescue here . . . but are currently at the pie-in-the-sky stage . . . as well as having the NIMBY problem ). Fusion reactors of various sorts are still at the experimental stages, and are likely very many decades away from economic practicality. And hydro-based generation is probably close to its upper limit of expansion. And tidal-based generation suffers from its own economic problems.
There doesn't seem to be much else going, in the low-carbon line. One possibilty not yet discussed, is fuel-cell electricity generation, using bio-fuel such as ethanol or "electro-fuel" such as methanol. Plane jetfuels need medium-chain hydrocarbons, such as bio-diesel equivalents. But ships, automobiles (cars, trucks, heavy machinery) could do well on alcohols as fuel . . . provided that the researchers can come up with fuel-cells using cheap catalysts & robust internal membranes. ~This could well be 10 or 20 years away.
Fuel-cell electricity generation would clearly require a huge development of fuel sources . . . and (possibly?) might be very useful for vehicles and for electricity generation at locations of low population, and eventually be cheaper than storage batteries.
-
Eclectic at 21:28 PM on 8 May 2022Why and How to Electrify Everything
IanR @3 : you may be the very person I can ask for your good opinion.
I was recently watching the Youtuber "Potholer54" and his video "A Clean Energy Solution Embraced By Both Sides". He discussed the large expansion of Wind/Solar electricity generation in Australia ~ in particular their state of South Australia. On viewing the Australian "NEM" website -National Energy Market - (reporting real time generation figures) over a number of weeks, I saw that South Australia was mostly showing renewables as 40 - 95% of the state total (depending on time of day). The non-renewable portion was supplied by CCGasTurbine generators.
I was very impressed by the 90 or 95% achieved during the middle part of the day. Apparently the grid stabilization is achieved by a lithium battery (Tesla) of 150 MW power (but only 194 MWh capacity) for a population of 2 million. Two or three synchronous condensers have recently been added to the mix ~ but I don't know if they are absolutely necessary or just supply an emergency stabilization back-up for the big battery.
Obviously this arrangement is not do-able to such a high extent, in many countries. But it does seem to be working well.
-
Iain R at 17:13 PM on 8 May 2022Why and How to Electrify Everything
John S,
with regard to heat pumps there is much misunderstanding and confusion betwen Coefficient of Performance and efficiency, although linked they are not the same. Efficiency starts at the power station where the fuel is burned, loses in generation, transmission and distrbution are about 60%.
Air source heat pumps are not particularly efficient and they certainly are less effective than gas heating when it gets really cold. They do work, as long as the house is designed for them but retrofitting a house designed for gas or oil heating is expensive and not economical in my view.
If it were governments would not be mandating that gas boilers, after a certain date, will not be allowed for sale. (U.K. anyway) If they are better and cheaper that is what the general public will choose. No need for any laws.
-
Iain R at 17:04 PM on 8 May 2022Why and How to Electrify Everything
It is a fantasy that we can produce 'clean' electricity by renewables it simply will not work.
The reason is basic and due to the nature of renewable generation, technically known as asynchronous, i.e. it is uncontrollable and grids need to be controlled to fine limits with regard to input and demand, i.e. they must be in balance at all times.
Fossil fuelled generation is generally considered as back up for grids with large penetration of renewable generation, however it is much more than that, they provide the balancing of input and demand as they can modulate output mostly automatically. They are the backbone of any grid and remove that backbone the grid will not function.
THE only possible solution is nuclear, unpopular as it is in many countries, but it is Hobson's choice for a reliable and non CO2 emitting electrical system. It is not without problems as nuclear is unflexible generally so work will be required in that area, possibly with small modular recators.
Renewables are a dead end!
California claim 100% renewble generation at times but that is only possible by connection to neighbouring grids. It does not mean renewables are a solution.
-
michael sweet at 11:40 AM on 7 May 2022Why and How to Electrify Everything
John S.:
When I Goggled "how cold can heat pumps work" I found this quote
"In fact, heat pumps are now the best heating option just about everywhere on the planet. Below 0° Fahrenheit, heat pumps can still heat your home with more than twice the efficiency of gas heating or standard electric heating (such as electric furnaces and baseboard heaters). They’ve been tested and approved as far north as the Arctic Circle, and are popular options in very cold countries like Finland and Norway." my emphasis. source
Please provide a reference to support your wild claim that heat pumps are not efficient in cold weather. My source says they are still efficient but not as efficient as during normal weather. Where I live heat pumps have an "emergency heat" switch for even colder weather. I use it about 2 days every other year. (My heat pump is in Florida and is designed to cool better than heat). As heat pumps continue to be developed we can expect efficiencies to improve across the board.
Most plans I have seen try to use as much district heating as possible because large installations can utilize energy more efficiently. Heat pumps are recommended for people who are not able to obtain district heating.
-
John S at 10:21 AM on 7 May 2022Why and How to Electrify Everything
Don't electify where equivalent or better service can be provided in a way that uses less valuable electricity system capacity; e.g. building heating and cooling can can be accomplished directly via district energy systems from natural resources like the sun or deep water or waste heat or surplus power with just a little help from heat pumps and seasonal thermal enegy storage. BTW air source heat pumps are not efficient at the very low temperature which is exactly where a lot of the heating is needed in the northern US and Canada and the heating peak demand could be about three times the current electricity system winter available capacity (my estimate for Ontario).
-
One Planet Only Forever at 07:08 AM on 7 May 2022What you need to know about carbon dioxide removal
As a resident of Alberta, Canada, I can confirm that a major part of the problem is the regional popularity of leadership that makes up harmful misleading claims to excuse harmful pursuits of benefit.
The Alberta leadersip has repeatedly claimed that reducing the emissions from fossil fuel burning related to the oil sands production and export by carbon capture and use, like injection of CO2 to produce more oil, is what the IPCC reference to carbon capture is all about.
The article makes it clear that the IPCC CDR is not what the Alberta leadership claim it is. Reducing fossil fuel emissions is helpful. But ending those emissions is reqired along with CDR. And the means a future without fossil fuel being exported for burning, not a net zero production of fossil fuels for export. But few Alberta voters will learn about that. Or if they do encounter the correction they are likely to ignore or dislike the correction of understanding.
A root of the problem appears to be the potential popularity of resistance to learning to be less harmful, especially if learning to be less harmful would appear to result a loss of status or benefits.
It continues to amuse me that even the promoters of the need to develop a zero harmful carbon impact future avoid pointing out the obvious need for reduced energy demand to be a significant measure of progress and advancement.
-
Aeyles at 01:21 AM on 6 May 2022What you need to know about carbon dioxide removal
During a long and somewhat tedious (March) trip across the U.S. Midwest between West Virginia and Denver, via AMTRAC, our spot check survey group visually inventoried the farmland. Most fields were devoid of winter plant cover cropping which clearly indicates that Micorrhizal fungi, etc, is not presently at work on the land. Without getting into details, it is clear that Midwestern soils play a role in holding plants erect, but provide little else without the customary chemical fertilizers essential to plant feedcrop production. Since 85% of global crop tonnage is fed to animals, one must wonder at the consequences we are probably facing in the not too distant future.
-
Aeyles at 22:52 PM on 5 May 2022What you need to know about carbon dioxide removal
Biochar has to be "made" in an oxygen-less heating environment. The energy to make Biochar significantly undermines its utility as a soils-carbon sequesterer. Australian soil scientists, such as Christine Jones, points out that sequestering carbon in the soil is highly dependent upon the environmental conditions of humidity, soil temperature, application at the right time of solar angle and variety and density of soil microorganisms in the target plot. further, the sequestered carbon may "escape" its capture site due to atmospheric conditions at, or after, the Biochar is installed in the targeted soil plot.
-
Aeyles at 22:31 PM on 5 May 2022What you need to know about carbon dioxide removal
There are a number of obstacles unaccounted for in these "remedies". Two, right off hand, come to mind: Farmers and Ranchers are not required to participate in "improvements", new techniques are "voluntary". Phytoplankton are being wiped out from ocean acidification which proceeds regardless of the effort to employ them in CO2 reversal schemes.
-
Aeyles at 22:27 PM on 2 May 20222022 SkS Weekly Climate Change & Global Warming News Roundup #17
I'm curious as to whether the article by Donald Brown was a rough first draft rather than a finished product. It contains a large number of typos and improper compositions that would have concerned an eighth grade English teacher. ?? Is there another place to look for what may have been his actual published version?
-
BaerbelW at 00:39 AM on 2 May 2022FLOATER: A Tool-Kit for evaluating Claims
Melanie Trecek-King, the author of the "Thinking is Power" articles, talks about "Floater" in this Skeptical Enquirer Webinar, recorded on April 29, 2022: https://youtu.be/FxbNGbv1eWE
Enjoy!
-
michael sweet at 12:19 PM on 30 April 2022Is Nuclear Energy the Answer?
The headline from Bloomburg today was:
"France’s Nuclear Shutdown Hits 50% of Reactors, Squeezing Supply
Some 28 reactors in France are now offline for maintenance
That’s keeping power prices high amid Europe’s energy crunch" my emphasis.So much for "always on power". In the greatest emergency Europe has had in decades half the reactors in France are out of comission.
The new reactor at Flamanville is 16 years into a 5 year build (11 years overdue) with the current target date sometime in 2023. Who would want to go further with that record?
John: I suggest you come back when there is better news for nuclear power.
-
John ONeill at 00:05 AM on 30 April 2022Is Nuclear Energy the Answer?
'France has temporally closed 4 nuclear power stations because of cracks and corrosion found near welds. That is about 13% of France's nuclear power. There is also a natural gas (methane) shortage this winter in the EU. Electricity prices are expected to rise. If there is a cold spell there will be difficulty dealing with it. Hopefully it will be windy so wind can help out.' (Michael Sweet, 280)
Despite the unscheduled downtime, France is still getting about 60% of its power from nuclear, at about a third the carbon footprint of the UK, and a quarter that of Germany. At the moment, Germany's 64 GW of wind is running at 4% capacity, and its 39 GW of coal is running at 54 % capacity. The 4 GW of German nuclear closed on December 31st had no mechanical faults, and nor do the last 4 GW they plan to close at the end of this year. That's been running all day at 95% or more. The 1.8 GW closed in France in 2020 also had no problems, apart from being nuclear. The French Energy Ministry is now the 'Ministry of the Ecological Transition', and the minister, Barbara Pompili, is a former Green party member with a history of opposition to the industry. (Power data from 'electricitymap.org', which anyone interested in energy should have on speed dial.)
-
Bob Loblaw at 22:29 PM on 28 April 2022From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
Yes, that is a good page on Wien's Law. When I saw MA Rodger's comment, my first thought was "didn't I include that link in my previous comment?" - but I must have fogotten to add it. I was looking at it, at the time.
-
Wol at 20:14 PM on 28 April 2022Climate change will transform how we live, but these tech and policy experts see reason for optimism
One of the most persistent bits of misinformation I see from those who incline towards accepting the reality of climate change is the notion that we should slow down the use of fossil fuels, period.
The "period" meaning that we can use the same amount, just over a longer period and then all's well with the world.
The fact that CO2 in particular is so long lasting and cumulative doesn't register. Climate is an incredibly complex subject yet the basic facts are so simple: with "friends" like that who needs denialists?
-
MA Rodger at 19:55 PM on 28 April 2022From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
Wikkipedia have a Wein's Law page (aka Wein's Displacement Law) which may assist in the explanation.
-
Bob Loblaw at 07:53 AM on 28 April 2022From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
Just to make the text from comment 25 a little easier to understand, here is an updated version of the Planck curve graph from comment 20 - adding 193K as a third line.
In this figure, you can see how the peak emission shifts to shorter wavelengths at higher temperatures - 15 μm at 193K, 11.4 μm at 255K, and 10.1 μm at 288K. That's what Wiens Law tells us.
Notice that the 15 μm emissions are higher for 255K than for 193 K, and higher again for 188K - but the 15 μm wavelength is not at the peak for the latter two.
-
Bob Loblaw at 07:20 AM on 28 April 2022From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
Well, no. It's more complex than that.
If you look at the diagram in comment 23, there are two sets of actual measurements - one looking up from the surface, and one looking down at an altitude of 20km. Let's think about what each one is looking at in more detail - but we'll pick the 15 μm wavelength as a single example.
- From the surface, we are looking at radiation emitted by the sky - at all heights. Some of the 15 μm radiation might have been emitted from just a few cm above the surface - nearly all of that would have been transmitted through the air (and CO2) because the distance is so short. Some of it might have been emitted tens of metres above, and some of it might have been emitted hundreds of metres above. From higher altitude, the 15 μm radiation has a much smaller chance of reaching the surface, because it has a much higher chance of being absorbed in the longer atmospheric path. This is due to the Beer-Lambert Law that is the subject of the blog post - the longer the path, the less likely the radiation will be transmitted (figure 5).
- From 20 km looking down, it is more or less the opposite. IR radiation emitted at the surface is unlikely to get to 20 km without being absorbed. Radiation emitted at 19 km altitude is more likely to reach 20 km, and radiation from just a few metres lower is highly likely to reach 20 km.
I wrote the following over at another blog the other day, in response to someone else discussing the greenhouse effect.
For the upward flux for any wavelength at a selected height (chose 100m, 5km, 20 km - anything you like) you need to remember the following:
1) every single photon of that wavelength is the same - there is no way of knowing if that photon was emitted from the surface, 5m, 100m, or any specific height below the viewing point.
2) It might have travelled 2cm, 2m, or 15km.
3) You have no idea what the temperature was in the atmosphere at the height that photon originated.
4) The probability that an individual photon will be absorbed at the current height has nothing to do with its origins. It has to do with its chances of interacting with a molecule that will absorb it.
The entire vertical profile needs to be integrated as a set of coupled equations. Radiative transfer calculations such as MODTRAN break the atmosphere into layers. For each layer, there will be:
1) A flux arriving from below, of unknown origin. Some of that flux will be absorbed, and some transmitted to the next layer above.
2) A flux arriving from above, of unknown origin. Some of that flux will be absorbed, and some transmitted to the next layer below.
3) An emission of radiation, half of which will be added to the upward-directed flux (1), and half to the downward-directed flux (2).
4) The flux going out the top will be the sum of what arrived from below and was not absorbed, plus the amount emitted upward by the layer.
5) The flux going out the bottom will be the sum of what arrived from above and was not absorbed, plus the amount emitted downward by the layer.
6) Obviously, the amount moving upward out of this layer will be the same as the amount moving upward into the layer above. This is how all layers are coupled together into one system.
With all these coupled layers absorbing, transmitting, and emitting, determining the flux of radiation requires a model of some sort. In the quoted text above, I referred to MODTRAN, which is one such model that you can read about - and try - online.
http://climatemodels.uchicago.edu/modtran/
At the second link, the online model will let you choose a height, looking up or down, the temperature structure, etc. Lots to play with.
In short, a stream of 15 μm photons will be coming from a variety of distances away, at a variety of temperatures (and may have been emitted by something other than CO2). All we know about it is that they are 15 μm photons that all look the same to us.
Looking only at the emission at 15 μm, comment 20 shows the Planck curves for 288K and 255K. The (blackbody) values for each curve at 15 μm are 18.2 and 11.7 W/m2/μm.
If I do the calculation for 193K, the curve will be lower (and the peak further to the right), and the 15 μm emission drops to 3.4 W/m2/μm. The peak wavelength doesn't enter the calculation. The emissivity for CO2 will not be 1, but it will be more or less the same at the different temperatures, so you would expect a 193K cloud of CO2 to be emitting only 30% of the 15 μm photons you'd get from a CO2 cloud at 255K.
-
Likeitwarm at 04:17 AM on 28 April 2022From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
Bob Loblaw @23
Thanks for clearing up my confusion. I thought 15 μm was only emitted from an object that was at the peak temperature, in this case 193K.
So, that means CO2 would receive the maximum amount of 15 μm at 193K?
From your example, 11.4 is a reduction from 15 by 24%. Would that mean there is a 24% reduction of 15 μm emission going from 193K up to 255K?
( I just don't like winter)
-
Bob Loblaw at 11:58 AM on 27 April 2022From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
Hello, Likeitwarm.
Yes, you are misinterpreting Wiens' law. It does not link a single photon to a specific temperature - it tells you the wavelength of the peak emission of all radiation from a blackbody as a function of temperature. You can read more about it here.
If you look at figure 2 of the blog post (or the non-log version for two IR temperatures in comment #20), you can see that Planck's Law tells us that any blackbody emitter, regardless of temperature, emits at all wavelengths. From those graphs, we can derive two interesting features:
- The area under each curve tells us the total amount of energy at all wavelengths. Stefan-Boltzman did the caculus for us, and we end up with a result that says the total area is σT4.
- The peak of the curve happens when the slope of the Planck Curve is zero, and Wien did the calculus for us on that one to get λpeak = (2898/T)
If an object was at 193K, then the peak emission would be at 15 μm, but the body would still be emitting radiation at other wavelengths. At 255K, the peak emission would be at 11.4 μm, but the object would still be emitting at 15 μm, too - just not as much as at 11.4 μm.
All this is thinking in terms of blackbodies - perfect emitters. For gases, they do not tend to emit as blackbodies. You revise Planck's Law with a wavelength-specific emissivity. For a blackbody, the emissivity is always 1 for all wavelengths, leading to the curves in figure 2. In gases, the emissivity is rarely 1, and the emission curves are not nice smooth ones like figure 2. With many gases in the atmosphere emitting at many different wavelengths, you end up with curves that look like this. You can see that the measured spectral sort of follow the blackbody curves, with drops where atmospheric emissivity is less than 1.
(That figure is from this blog post.)
So, you have done the calculation correctly in Wien's Law, but misinterpreted it because it only applies to blackbody radiation, and it only tells us what the peak is. Once you factor in emissivity for a specific gas, we no longer have a blackbody, and the peak from a specific gas (e.g. CO2) is more a function of what wavelength has the highest emissivity. Even as the temperature of that gas changes, the wavelength with peak emissivity does not change, so knowing the peak emissiion can tell us what gas we are dealing with, but not its temperature. (At least, not without a lot of other information.)
Moderator Response:[BL] 2022-08-06 image link fixed
-
Likeitwarm at 09:35 AM on 27 April 2022From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
Excuse me! Bob Loblaw. Brain out of gear!
-
Likeitwarm at 06:40 AM on 27 April 2022From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
Boblaw @20, So it matters not what temperature the emitter was at, except that it governs the number of photons emitted. I was thinking of Wien's law that says the wavelength of the radiation is linked to the temperature of the emitter, so I was assuming that 15 μm radiation indicated 193K as the temperature of the emitter, meaning that radiation could only come from very cold places like the poles of the earth. Did I read Wien wrong?
-
Doug Bostrom at 04:34 AM on 24 April 2022Skeptical Science New Research for Week #16 2022
Thank you for pointing that out, One Planet. Corrected.
Joel, yes indeed. It's a good metric to have in hand, not least because latent heat liberation from water vapor is a major component of extreme weather of various kinds. The authors make a good point.
-
One Planet Only Forever at 02:04 AM on 24 April 2022Skeptical Science New Research for Week #16 2022
The second link under Other Notables (How do Right-Wing...) is not working for me.
-
Joel_Huberman at 23:43 PM on 22 April 2022Skeptical Science New Research for Week #16 2022
Thanks, Doug, for pointing to the importance of using latent heat measurements in science communications. I was previously unaware of this fascinating, important issue.
-
BaerbelW at 21:56 PM on 18 April 2022New resource: myth deconstructions as animated GIFs
A Myth Deconstruction as an animated GIF is now also available for "The difference between weather and climate".
-
One Planet Only Forever at 07:25 AM on 15 April 2022The latest IPCC report has a lot to say about carbon fee and dividend
Aeyles,
I suspect that the $200/tonne value was considered to be a level of pricing that would effectively produce a rapid rate of reduction of fossil fuel use (something arguably required by 2013 due to the pathetic lack of action by the most harmful portion of the global population by that date).
But sensible leaders understand the need for carbon pricing to start at a lower level with everyone being motivated to change by understanding that the price will be increasing annually (starting at $40 to $80/tonne and increasing significantly annually, potntially to levels higher than $200 as required to achieve the required ending of harmful emissions).
Tragically 30 years ago most sensible leadership candidates failed to win the power to do that then. So here we are now, with many people still easily tempted to vote agsinst more sensible leadership.
-
Aeyles at 05:25 AM on 15 April 2022The latest IPCC report has a lot to say about carbon fee and dividend
At a climate conference in Alexandria, VA in the spring of 2013, the consensus of the group, which included Joseph Romm, was that a ton of CO2 would have to carry a carbon fee of $200, or about 57 cents per gallon at the pump, in order to be meaningful. Anyone know what has changed, since then, to drop the fee to the amount stated above?
-
One Planet Only Forever at 13:20 PM on 14 April 2022New IPCC report: Only political will stands in way of meeting the Paris targets
I share Eclectic's interest in seeing rayates55 provide more detailed thoughts.
I am well aware of the harmful history of success of political and consumerism misleading marketing tempting people to believe harmful misunderstandings rather than critically investigate things and learn to be less harmful and more helpful to others.
SkS includes many helpful tools regarding misleading marketing targeting climate science. Those understandings relate to other harmful misleading marketing that tempts people to like to benefit from harmful activity and related harmful misunderstanding that excuses the harm done, or discredits and distracts from evidence of the harm done, by those who benefit from harm being done.
Distracting misleading efforts can include attempts to focus attention on the growing population rather than the highest harming portion of the population that has set harmful examples that many lower status people can be expected to aspire to develop towards.
Clearly, the policy development that is required must focus on identifying harmful pursuits of benefit and make those pursuits less desirable (more expensive or harder to do) regardless of the potential popularity and profitability of more harmful actions being permitted.
The lack of political will is understandable and is understandably unacceptable.
-
MA Rodger at 05:52 AM on 14 April 2022Medieval Warm Period was warmer
astrophile @270,
The link in the OP is to the paper Mann et al (2008) which in turn does provide links to Fig s6 but not very helpfully. Another on-line version of the paper here does give a link to the Supporting Information. Fig s6 resides within that Supporting Information where you will see the OP's Fig 4 is reproducing the paper's Fig s6f.
-
astrophile at 04:32 AM on 14 April 2022Medieval Warm Period was warmer
I followed the link for the Mann 2008 article given for Figure 4 but I don't see any figure in that article that references global temperatures. Is it the wrong link or is the figure created in some other way?
-
swampfoxh at 13:28 PM on 13 April 2022New IPCC report: Only political will stands in way of meeting the Paris targets
Some contributors have noted that the planet birthed another 80 million humans in 2021, now estimated to be a little more than another 80 million in 2022. 80 million is a large number when we account for the carbon footprint and resource consumption of these added persons. At the current annual rate of population growth, we will be seeing another billion humans by mid 2032 or 2034. I realize that this topic is toxic, but it seems that this problem will overshadow all other efforts to climb down from the loomimg disaster.
Another large problem, industrial animal agriculture, is not mentioned in the above bar graphs, yet the elimination of animal agriculture is effectively painless because we can grow enough plant food to feed the global population. Industrial animal agriculture, as a leading cause of the climate problem we face, offers an immediate target to drastically reduce emissions and to substantially reduce several other negative impacts that are hoped to be addressed in the above graphs. Why can we not see more about this problem in the literature?
Moderator Response:[BL] Off-topic deleted. For some odd reason, you seem to think that complaining about the lack of emphasis on industrial agriculture is on-topic for nearly any blog post. It is getting very tiresome.
-
Bob Loblaw at 11:11 AM on 13 April 2022Models are unreliable
MichaelSF:
The direct answer to your question would have to be "I don't know", because most of the "predictions" that you claim have been made by "climate models" bear very little resemblance to the predicitons from climate models in the scientific literature.
If you want us to believe that such "predictions" actually exist, you are going to have to provide scientific references where the "climate models" are described and the "predictions" made.
Once you actually provide some sort of detail, it may be possible to answer your question. Until then, you're just engaging in rhetoric (meaning #2)
-
Eclectic at 10:41 AM on 13 April 2022Models are unreliable
MichaeISF @1305 , you sound a bit confused.
Climate models (for estimating future climate changes) base their predictions on the observed (and projected) rise in CO2 levels.
The CO2 level has continued to rise (observed fact). The world is warming (observed fact). Consequently, sea level is rising (observed fact) ~ so some increased flooding of coasts is occurring, and will get worse as a matter of course. (Unless you think the higher sea level is due to more polar bears staying in the water.)
Have you any evidence that "cancels" the facts?
-
MichaelSF at 08:36 AM on 13 April 2022Models are unreliable
Regarding models, the explanation is good, especially about whether or not a model is good or not.
My observation: Are these the same models that for the last 40 years (Since I was in high school.) that predicted global warming before it predicted global cooling before blaming any and all weather on climate change driven by man's activity?
Are these the same models that for the last 40 years have predicted global coastal flooding, sinking island, the extinction of polar bear, penguins and increasing deserts and that man has only 8-12 years to survive?
I make these observations to prove that is seems there are NOT any good models, based on a proven, accurate track record, that can be called "good".Moderator Response:[PS] You appear to be engaging in strawman arguments - ie making claims about what science has said that are not true. You can find details of how well past predictions have done in "Lessons from Past Predictions" series. Broecker's 1975 model holding up pretty well. See here for the "Scientists predicted cooling" myth. If you dispute this, then please provide 1/ a link the scientific prediction you think was mistaken, and 2/ link to evidence that it is wrong.
