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One Planet Only Forever at 05:00 AM on 27 January 2025Fact brief - Can CO2 be ignored because it’s just a trace gas?
Evan @6,
Your make a good point about the sensitivity of our amazing planet’s global climate conditions. It has prompted the following thoughts regarding attempts to ignore or dismiss CO2 impacts ...
The warming impact of increased levels of CO2 have been understood for more than 125 years. And the natural causes of glaciation and inter-glacial periods, like the Milankovitch cycles, have been reasonably understood for more than 80 years.
A challenging understanding, an inconvenient truth, is that human CO2 impacts causing global warming may be helpful in the future but are not helpful now. Those distant future actions could make the next natural glaciation event more ‘livable’.
The next glaciation is expected to naturally happen about 50,000 years from now. But studies, like the one reported in the Carbon Brief in 2016: Human emissions will delay next ice age by 50,000 years, indicate that the human caused increased CO2 levels have likely delayed the next glaciation by 50,000 years. That is nothing to be proud of. It was Too Much Too Soon.
It would be ‘great’ if lots of easy to access fossil fuels were still available for future humans to use to limit the negative impacts of future glaciations.
Fossil fuels are undeniably non-renewable. Future generations cannot benefit from burning them as much as current generations do. Rapidly ending fossil fuel use would leave more ‘limited resources’ for the benefit of future generations and reduce the climate change harm done to people today and to future generations. However, the ‘competitive marketplace’ fails to ‘naturally’ develop towards those understandably ‘great’ objectives. In fact, there is ample evidence that the marketplace developed, and continues to develop, misinformation efforts against the development of such ’helpful external influences on the marketplace’.
The undeniable marketplace efforts against learning to be less harmful and more helpful to Others clarifies what competitive free market activity can be expected to accomplish. The fundamental market function is managing the distribution and benefits from the use of scarce resources. It develops replacement alternatives as resources become scarcer. However, the marketplace will only seriously develop replacements that are less expensive than the increased cost of the activities that rely on scarcer resources (note political efforts to reduce the costs of fossil fuels).
More importantly, the market is unlikely to care to reduce harm or ensure that harm done is repaired. Limiting harm done, and avoiding the challenge of getting the beneficiaries of harm done to repair the damage done, requires external influence to make the more harmful ways less popular, more difficult, and more expensive.
Hopefully efforts to limit the success of misinformation, not just regarding climate science, will result in more helpful and less harmful political action. It is common sense that political actions need to be less likely to cycle in ways that are significantly negative for the future of humanity. However, limiting the sensitivity of political actions to harmful misunderstandings is likely less certain than improving the understanding of the sensitivity of the climate on this amazing planet to the impacts of human activity.
Scientific understanding is certain to be constantly improving the ability to develop sustainable improvements and limit harm done - The politics of popularity of beliefs is not certain to develop sustainable improvements or limit harm done.
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Evan at 00:40 AM on 26 January 2025Fact brief - Can CO2 be ignored because it’s just a trace gas?
One of the fundamental problems for understanding how a "trace" gas can have such a large impact is that most people don't understand how delicately balanced our ecosystem is. Consider that the orbits of Jupiter and Saturn, over 100,000-yr cycles (i.e., Milankovitch cycles), cause sealevel to go up and down 400 ft! That is a delicately-balanced system!
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Doug Bostrom at 05:21 AM on 25 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
There will be some complications and expense entailed in engineering and producing a remedy for the limitation Eric focuses on, but they're not showstoppers. We have everything in hand, technically speaking.
Related example: A few years ago I put together some PV-powered WiFi repeaters for a harbor up here in the NW. These use LiFePO4 batteries for overnight operation and these batteries cannot be charged successfully below about 0C, precluding reliable operation during winter. The problem was solved by equipping batteries with heater film, with a thermal snap switch in the battery housing attaching pre-controller power output from panels to the heaters and thereby diverting up to ~20W of PV output to warm batteries, until the snap switch disconnects after temperature rise. This has worked perfectly to maintain operations.
In the case of PV panels, a high-latitude/extreme conditions variant (as with DHW thermal collectors) could be equipped with inexpensive electronics (flea-power minimal microcontroller, monitoring optical and other inputs as required) and control warming of the panels when necesssary. The chief and only hard technical optimization problem to solve here is that of how to convert a bit of juice to heat where it's needed while keeping engineering trades low. This would likely entail a slight performance drop for ultimate panel power output, if an off-the-shelf technology was used for that (microgrid or resistive film coating) so as to minimize effects on mechanical packaging of the PV panels.
The magic of the market will address this, to the extent Eric's situation is a problem sufficient to provide motivaton. That magic is the only mystery in this scenario.
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MA Rodger at 00:02 AM on 25 January 2025Moving away from high-end emissions scenarios
To put some other numbers into this interchange.
Regarding rates of emissions:-
The Global Carbon Project give data for the various fossil fuel types going way back. Their budgets back to1959 also show numbers for Land Use Change emissions (as well as the ocean absorption and the land absorption).
The 1980 wobble in emissions resulted from the 1970s oil crisis driving efficiency measures but the high 1970s oil price led to over-production and what was called the "1980s oil glut" thus ending the wobble. I'm not so sure about talk in that link of a slow-down in economic growth also being a factor as use of gas and coal doesn't seem to have shown any signs of this oil-use wobble and continued apace (as this OurWorldInData graph shows).
Regarding atmospheric levels:-
The Land Use Change emissions are a significant part of global emissions and when added to FF emissions allow the calculation of the Atmospheric Fraction (Af) which is the annual ration (Atmospheric increase)/(Man-made emissions). This has remained pretty constant since the 1960s altough there is no underlying reason for it**.
The land-based absorption provides the lion's share of the wobbles in the Af with El Niño the primary wobble-driver.(**If an emissions-free world had a single emissions event, the annual absorption in Year 1 would be about 3% and through following non-emissions years the annual absorption would slowly decrease to zero over a millenium. How much atmospheric CO2 then remained would depend on the size of the emission - so roughly 25% remaining if the emission event was 600Gt(C), this the very rough size of our cumulative emissions to date.)
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Eclectic at 13:24 PM on 24 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
David-acct @14 ,
Yes, a perfectly good point. Costs must be viewed from several angles.
It is too broad to speak of electricity generation costs at simply peak demand times or at average annual GWh produced. "Minimum demands" must be considered, as well as back-up costs. And of course the longer term environmental and health costs.
Temporary reserves and redundancy costs also apply to gas/coal fuelled generation. LCOE has its official definition ~ but really should be looked at in the Big Picture. If only Life were simpler !
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David-acct at 10:21 AM on 24 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Nigelj
Thanks for the comment - you actually hit the nail on the head with the best observation with the core issue.Your comment " The capacity factor drops by about half. Could you not compensate by installing twice the number of panels? "
Yes you can compensate by installing twice the number of panels. That is exactly what has to be done to make a renewable system work.
The more important is the impact with utility solar.
First EIA website is a great source to cross check the data and provides a wealth of information.The combined decrease in electric generation from wind and solar during the winter months is approx 30%-40% lower during the winter months vs the spring and fall (even before taking into account the frequent 2-5 day wind doldrums that occur during the winter).
Electric demand during the winter is approximately 30%-40 higher than during the spring and fall. As heating is converted to electric, the demand from the spring/fall vs winter demand will continue to widen. As such, gross capacity of renewables for the winter needs to be approx 2x of the needed capacity during spring and fall to cover the winter demand.
Further the idled capacity during 6 or so months of the spring and fall due to the redundancy needed for the winter months wrecks havoc on the math used in the LCOE computations. Guess what happens to the LCOE computation when significant amounts of redundancy is needed to generate sufficient electricity during the winter.
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One Planet Only Forever at 09:28 AM on 24 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Evan,
To try to stay ‘close to topic’, but respond to your interest in the most beneficial ways to install home solar panels, I will start by saying that incorrect claims like the Myth that this Rebuttal addresses are attempts to unjustifiably discourage people from:
- supporting solar panel systems as part of the required correction of developed Grid generation systems
- considering the helpful installation of home solar systems.
A very important consideration is that the governing objective is to minimize CO2, or other lasting or significant global warming impacts, produced by electricity generation.
Grid electricity generation needs to be transitioned to be truly net-zero ghg. And grid, as well as home, solar panels can be part of that transition. Even a rapid correction of a grid system to responsibly limit the harm done can take many years. And ‘natural gas peaker plants’ are likely to be the last parts removed from regular operations (natural gas peaker plants may exist long-term as an ‘emergency-emergency back-up’ that is very rarely needed).
Based on that understanding, people can help more rapidly reduce the harm of electricity generation by installing home solar systems. And they should design home solar installation to maximize the total annual generated electricity, appreciating what affects the amount of electricity generated. They should not be discouraged by the reality that many factors affect the amount and timing of electricity generated. And they certainly should ignore misleading claims like “Solar panels don’t work in cold or cloudy climate.”, or when covered by snow.
Bob Loblaw, and others, have provided plenty of very helpful information, including information about how cold and cloud affect solar panel performance.
Moving a little further from the topic to add some more considerations for home solar installations...
Variation of pricing should guide the use of electricity. However, a focus on the ‘variation of grid pricing’ may result in choices that do not minimize the overall amount of CO2 emissions.
If CO2 per Grid-generated MW-hr does not vary with time of day then minimizing the ‘net demand for grid energy’ should minimize CO2 from grid energy production. That means maximizing the total annual home solar generation with unused home generated electricity stored for later use or delivered to the grid to reduce grid generation. Building home solar for maximum generation during ‘peak price times’ would likely reduce the total annual home generated electricity and result in more CO2 generation than building to maximize total annual generation.
However, if CO2 per MW-hr is significantly higher during peak price times, because of things like the use of natural gas peaker plants to meet peak demands, then designing the home system to reduce the ‘home grid demand’ during the peak ‘CO2 per MW-hr’ times may be more helpful. However, as the grid system is improved to reduce CO2 generation the home system built to maximize generation during those current peak CO2 times becomes less helpful than a home system designed to maximize total annual generation.
The story changes if home generated electricity cannot be delivered to the grid or will not be stored for later use. Minimizing the grid energy needed would still be the objective. But maximizing the home solar generation during times of peak home electricity use becomes a significant, but complex, consideration. This could lead to potential benefits from maximizing generation during peak use times. However, that would also lead to understanding the benefits of charging the EV during peak home solar generation times.
All of the above considered may result in the conclusion that the best thing to do is build the home solar system to maximize the annual total generation and then adjust the home electricity use to minimize CO2 emissions impact of grid energy needed.
Final points regarding panel orientation:
- Being able to manually adjust the angle from horizontal could allow seasonal adjustment that increases the total annual electricity generation.
- The extra cost of an automated tracking system that seeks the orientation that maximizes generation may be more beneficial than a system that tracks the sun. But automation does not always work as well in reality as it does in conceptual planning.
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Evan at 06:09 AM on 24 January 2025Moving away from high-end emissions scenarios
Nigelj@11
I also recall that during the 1990's the UK was making a large-scale shift from using coal to using natural gas in their "Dash for Gas". Also, France made a large-scale shift towards nuclear power in the 1980's and 1990's. Then Mt. Pinatubo blew in 1991, and from what I understand, the temporary cooling caused a drop in atmospheric CO2 concentrations due a variety of factors, such as increased uptake by cooler oceans. All of this was a temporary bump, and there were likely other factors that you pointed out, which together caused a temporary slowdown in the buildup of atmospheric CO2.
https://en.wikipedia.org/wiki/Dash_for_Gas
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nigelj at 05:41 AM on 24 January 2025Moving away from high-end emissions scenarios
Evan @10
Your explanation for the apparent acceleration in the acceleration of CO2 levels recently looks right. Looks like its not a real acceleration.
I was curious why there was a flattening in the growth rate of atmospheric CO2 growth around 1980 - 2000. This coincides with a slowing in the rate of CO2 emissions growth over the same period, and a global flattening off in oil production from 1980 - 2000 approx. ( See links below). I recall this was the time period when smaller cars became popular so presumably the net result from flattening oil production was a slower rate of emissions growth.
Im not sure why oil production slowed over that 1980 - 2000 period, but it followed the OPEC oil crisis of the late 1970s which caused a temporary drop in oil production, and one source talked about a decline in output from the big existing oil fields in Saudi Arabia. But after the 2000s global oil production was back to business as usual, presumably as the OPEC oil embargo had ended, and new oil field discoveries were made, and there was Americas oil fracking boom.
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michael sweet at 04:45 AM on 24 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Evan at 6,
Where I live in Florida most of the utility solar farms are on two dimensional tracking. They face East in the morning, horizontal at noon and West in the evening. I think that is standard for utility farms in the USA. I think they get more expensive evening power and more power the entire day. I have not seen two dimensional tracking for home use.
I get ads all the time for three dimensional tracking setups ground mount at home. They claim up to 40% more power than latitude mount. I have a big yard so more panels seem more cost effective than more expensive mounts. In a small yard they might work well.
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Bob Loblaw at 02:24 AM on 24 January 2025Moving away from high-end emissions scenarios
RickyO:
El Nino/La Nina cycles are well-known to cause variations in both temperatures and natural CO2 uptake/emission.
So, yes, this needs to be considered in looking at trends (especially short-term).
It is worth noting that El Nino/La Nina cycles and their effect on atmospheric CO2 cycles is a "feature" of one of the common contrarian arguments that the overall rise in CO2 is natural (ie., not due to burning fossil fuels). Unfortunately, it is a "feature" that the people making that argument do not realize. Their method of analysis mistakes those short-term cyclical effects for a long-term trend, and they mistakenly think that the long-term upward trend in temperature is caused by the CO2 trend (rather than the correct interpretation that the CO2 trend is causing the temperature trend).
You can read more about that myth on this SkS page.
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Bob Loblaw at 02:09 AM on 24 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Upstream, in comment 4, I talked about some of the aspects of solar panel installation and orientation. Words are nice, but pictures are often better, so I've graphed out some data to show some difference between clear/cloudy, winter/summer, and horizontal/tilted measurements of solar radiation.
The following graphs are a continental location, at about 50°N latitude.
All radiation graphs show five different measurements:
- The "Direct" measurement is "direct normal" - an instrument pointed directly at the sun, with a narrow field of view.
- "Diffuse" is the radiation on a horizontal surface of just the sky - direct sun blocked.
- "Global" is a full sky view (direct plus diffuse) on a horizontal surface.
- "Titled" is also direct plus diffuse, but at a 50° tilt to the south, so it sees some sky and some ground.
- "Reflected" is the same type of instrument as "Global", but upside-down so it sees all the solar radiation being reflected off the ground surface.
The first graph is a clear day at the beginning of January. Direct radiation peaks at over 900W/m2, and diffuse radiation is less than 100W/m2. Because the sun is low in the sky, the global reading is much less than the direct - peaking slightly over 300 W/m2. The tilted sensor, though, peaks at over 800 W/m2 - not only is it pointing much closer to the sun, but it also sees a lot of ground that is very bright. The reflected reading peaks at over 200W/m2 - the ground is snow covered, reflecting about 75% of the global signal, so much brighter than the deep blue sky of the diffuse signal.
Clearly, a tilted solar panel would produce much more power than a horizontal one. We can see why when we look at the solar elevation angle (how high about the plane of the panel the sun is located). This graph shows the elevation above a horizontal surface (global instrument) and tilted surface. The sun is barely 20° above the horizon of the horizontal sensor, but is over 60° above the tilted sensor's "horizon". Note that the daylight period is only about 8 hours - elevation>0° for the horizontal view. Even though the titled sensor has an elevation >0° for much longer, those "extra" hours mean nothing, as the view of the sun is blocked by the earth!
The next day, cloud moved in. Direct radiation is zero, except for a brief period in early afternoon when the clouds thinned enough to let a bit of direct sun through. The four other lines are, from highest to lowest, tilted, Global and Diffuse (virtually tied), and Reflected. With no direct sun, and a snow-covered surface that reflects most of the solar radiation, there isn't much difference between the horizontal and tilted readings.
Note that for the horizontal sensor (global) the cloudy day is not much lower than the clear day. It peaks around 250W/m2, compared to a little over 300W/m2 on the clear day.
What about summer? Here is a "mostly" clear day in early July. Direct beam peaks only slightly higher than in January, but global radiation is much higher because of the higher solar elevation. The titled sensor peaks a little higher than global - it's tilt is no longer much of an advantage over the global sensor, and the portion of ground it sees is now dark (reflecting only about 20% of the global). Diffuse is again <100W/m2.
Daylight is now more like 16 hours, though, so daily totals will be quite different from January. We also see something odd in the tilted sensor - it peaks higher than the global (horizontal) sensor, but in early morning and late afternoon, it sees less than the global sensor. In fact, at the extremes it looks like it is only seeing the diffuse radiation - no direct.
We can understand this by looking at the solar elevation again. Note that for the titled sensor, the sun "rises" much later and "sets" much earlier (elevation <0°) than for the global sensor. What is happening is that the sun rises in the NE and sets in the NW, so it is actually behind the tilted sensor, not in front of it.
And lastly, we'll look at a cloudy summer day, right on the summer solstice. We do see some direct sun getting through in the afternoon, but we can see the cloudy period that covers most of the day. We see a substantial reduction in global before noon local time (compared to the clear day). After 12pm, we see a higher value for global as the cloud thins and a bit of direct radiation makes it through the clouds. During the cloudy period, the tilted sensor is not much different than the global one - both are seeing the same diffuse radiation.
So, hopefully this helps illustrate some of the complexities related to solar panel installation and orientation. To refer back to the OP - no, cloudy skies does not mean "no solar energy". The OP is correct - the myth is busted.
This is only one location, and a few days of data. And this level of data is not readily available for most locations. But it does illustrate that installation may be dependent on local factors such as amount of cloud, type of cloud, timing during the day, etc.
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Evan at 22:32 PM on 23 January 2025Moving away from high-end emissions scenarios
RickyO@9,
The CO2 graphs at the link you provide provide a possible explanation to the apparent acceleration of atmospheric CO2 concentration suggested by my plot of the data. The NOAA graph of global increase by decade (see below) shows that in the 1990's, the rate of increase decreased a small amount from that in the 1980's. Further, the increase from the 1960's to the 1970's was about 0.5 ppm, almost the same as what it was from the 2000's to the 2010's. Therefore, perhaps it is the decrease in the 1990's that affects my plot and suggests an apparent increase in the rate thereafter. Although I've seen this NOAA data before, thanks for bringing it to our attention again.
Lan, X., Tans, P. and K.W. Thoning: Trends in globally-averaged CO2 determined from NOAA Global Monitoring Laboratory measurements. Version Monday, 06-Jan-2025 10:06:16 MST https://doi.org/10.15138/9N0H-ZH07
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RickyO at 17:46 PM on 23 January 2025Moving away from high-end emissions scenarios
Bob,
I tend to keep an eye on the Global Trend in CO2, rather than stories of emissions cuts:
gml.noaa.gov/ccgg/trends/gl_trend.html
The el nino boost in the trend is clear to see in 2016 and 2024. Doesn't seem to be fading as quickly in this time around, though. Worth watching?
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Evan at 06:47 AM on 23 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Thanks Bob for your comments. I always learn a lot from your posts, including the interesting rate structure. Where we live in Minnesota our current rates are 6.4 cents/kwh from 8 pm to 8 am (when we charge our car), 12 cents/kwh from 8 am to 4 pm, and 22 cents/kwh from 4 to 8 pm. The 35 cents I quoted was from a different pricing structure not appropriate for our time-of-day rates optimized for car charging.
Even though we live in the country, our roof is far from optimal. We also don't like the idea of ground-based solar. Not worth going into the details here of why.
So we are planning to hang panels off our deck. We designed our deck to hold 120 psf, because we want to use it as a large, raised-bed garden. The edge where we will hang the panels is supported by an I-Beam. Hence, we have plenty of strength to hang panels off the edge.
We are planning to have a few panels facing due east for morning generation, the bulk of the panels facing south, and a few panels facing west, or southwest, to catch the afternoon sun. The idea is to have some power from sunup to sundown, and the main power during the day.
I like the idea of hanging the panels off the deck, because the panels effectively extend the reach of the deck, providing lots of covered areas to park vehicles. And the panels will be readily accessible from the deck for snow removal and periodic cleaning.
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Bob Loblaw at 06:19 AM on 23 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Evan @ 6:
On a rooftop installation, you probably end up putting panels on more than one roof section, which would be oriented in different directions. That would even out the power production through the day. But if you have lots of roof surfaces to choose from (more than you want covered in panels), then choosing which ones to use gets challenging.
The time of day question is an interesting one. Where I live, the electricity rates are broken into peak, mid-peak, and off-peak hours, and the time periods are 7pm-7am, 7am-11am, 11am-5pm, and 5pm-7pm.
- If you're reading carefully, you'll notice that there are four time periods, but only three rate levels.
- 7pm-7am is always off-peak. Time to charge the electric car.
- 11am-5pm is mid-peak in winter, but peak in summer (A/C season here).
- 7am-11am and 5pm-7pm are peak in winter (go-to-work, return-from-work times), but they are mid-peak in summer.
- Current costs are $0.076 off-peak, $0.122 mid-peak, and $0.158 peak, so we're looking at differences of about a factor of 2.
...so I'd agree there are real possibilities to optimize the solar panel installation to get maximum cost savings. And hopefully the utility company has set rates so that peak rates are when the grid can most benefit from extra power. Maximizing local production during the hot part of the day in summer also means that there is less need for transmission infrastructure, as the power is produced where it is needed for A/C.
The common single-orientation leave-it-alone setup is pointing south, set at "latitude tilt". (Zero is flat. 45° works for 45° latitude. 60° is a lot of tilt, and starts to run into the fact that at 60° latitude the sun is well above the horizon for a lot of the day (and rises in the NE and sets in the NW, so something pointing due south is shaded part of the day!) In high latitudes, a flat panel works best.
Optimizing runs into more detailed calculations that simple rules-of-thumb don't do well at. I've done such calculations at a research site where we ran some instrumentation off solar-powered battery setups. It happened to be a research station where we collected the direct and diffuse radiation measurements needed to do the local optimization. (By coincidence, NW of where you are in Minnesota.)
Where I am now, we considered doing a rooftop solar installation, but in winter our south-facing roof area is partly shaded by the house next to us. Roof geometry is not good (and small yards make ground-based solar impractical).
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scaddenp at 06:19 AM on 23 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Yes, on a friends solar installation with thoroughly non-optimal roof, they just put up more panels. The panel cost is now so cheap, (inverters not so much), that just piling on panels makes sense.
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nigelj at 06:10 AM on 23 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
"The drop in electric genration from solar is well documented from numerous sources and as detailed in the monthly data from EIA, the Dec/January capacity factor for utility solar pv averages around 13.5% vs 30%-31% during June july and august.. "
The capacity factor drops by about half. Could you not compensate by installing twice the number of panels? This would increase costs, but for new homes it looks affordable. Costs in New Zealand for residential solar are as follows. "The Electricity Authority estimates the average set up for a 4.4kW installed system with around 10-11 panels to be around $12,000-$13,000". If you doubled the number of panels the cost is $24,000 - $26,000.
In New Zealand average home size is about 150M2, and cost around $4000 M2 to build so around $600,000 to build. Trim just 6M2 squared off the floor area, and you have paid for a solar power instillation capable of dealing with seasonal swings rather than relying on grid backup. I suppose its a question of what people value - the large homes we build now well beyond what is really needed, or a sustainable energy system that also ultimately saves them money.
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Evan at 05:22 AM on 23 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
I have a question for you Bob that is a little off topic, but which the readers may find interesting. It has to do with tradeoffs and generating power when it is most needed.
Specifically, wouldn't it be good to point some panels either West, or Southwest? The point being to maximize power generation in the late afternoon, when power companies are struggling to meet demand. In Minnesota, Time of Day electric rates are about 35 cents/kwh between 4-8 pm, whereas standard rates are 12 cents/kwh during the rest of the day, The 35 cents/kwh varies by the time of year and I'm sure other factors, but the point is that there are times when power is most valuable and most needed.
Do you agree that it makes sense to point some panels either West or Southwest to generate power during the heavy-use times, or do you think it still best to always point them due south and at the optimum lattitude-based angle? My assumption here is that a solar array is only generating a portion of the power needed, and that there is therefore continued reliance on some amount of grid power.
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Bob Loblaw at 02:55 AM on 23 January 2025Moving away from high-end emissions scenarios
Evan: the " Good Thing™" expression (capitalized, with the trademark symbol) is a measure of sarcasm, to ward off the usual "but it's all good for us" myth.
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Evan at 02:05 AM on 23 January 2025Moving away from high-end emissions scenarios
Bob@6
Thanks for your comments. I agree with your comments and those of Nigel as well.
Natural CO2 emissions are about 25 times higher than anthropogenic emissions. As you note, half of our tiny emissions are typically reabsorbed by land and oceans. Therefore, it would not take much of an increase in the natural emissions, nor much of a decrease in the natural absorption rate, to cause an increase in the rate of CO2 accumulation in the atmosphere.
This is why I encourage people to follow the evolution of the Keeling Curve, rather than following projected emissions budgets. The Keeling Curve includes the net effect of all emissions (natural + human) minus all sinks (natural + human) to give us an accurate reading of how we're doing. Whether or not it is a pretty picture, it is an accurate picture.
Did I miss something Bob? To what are you referrring with the trade marked "Good Thing"?
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Bob Loblaw at 01:35 AM on 23 January 2025Moving away from high-end emissions scenarios
Let's assume that the emissions data are not far off. From a simple mass balance perspective, there are several possible explanations for atmospheric CO2 concentrations not following the same trend.
- We know that only about half the emissions have historically stayed in the atmosphere; the other half being absorbed into the land and oceans.
- If that ratio is decreasing, so that the land and oceans can't keep up any more and are absorbing less, CO2 concentrations will accelerate even if emissions are constant.
- If the land and oceans are still absorbing the same ratio of human emissions, there must be some other source that is increasing.
- There is the potential of feedbacks that are leading to additional "natural" emissions - thawing permafrost, vegetation changes, forest fires, etc.
None of those seem like a Good Thing™.
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Bob Loblaw at 01:26 AM on 23 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Eric @ 3:
Your points about rooftop slope not being optimal for solar panels in some cases relates to some of the principles I mentioned in comment 4. Mounting panels at the same slope as the roof probably reduces installation costs, but may also reduce efficiency. And many houses do not have roofs that are pointed optimally south (or whatever direction is best in that location). In a ground installation, you have more options.
...but many people do not have ground space for large solar arrays, either. Even if you have space, there is the question of sky view factors: how much of the sky is unobstructed? The higher up you can place the panels, the fewer object will cause shade issues (trees, other building, etc.) Rooftop is better in crowded urban environments - but as you state, keeping them clean from debris gets harder. Even large amounts of accumulated dust can reduce panel efficiency if you live in a climate with little rain to wash the panels.
There are always trade-offs.
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Bob Loblaw at 01:10 AM on 23 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Comment 1 is a classic case of David-acct engaging in whataboutism, to distract from the rebuttal that points out that cold is not a problem, and solar panels do continue to generate power even with cloudy conditions (albeit at reduced rates).
As scaddenp points out in comment 2, David-acct is essentially going off-topic. David-acct is attempting to rebut something that isn't in the OP. David-acct acknowledges this in his comment, where he says "...key data for understanding the full context is missing..." David-acct wants to expand the context, to try to make a different point. This is a case of deflection - something politicians are good at when asked a question they don't want to answer.
David-acct's first link includes this graphic:
Wow. It turns out that you get more output from your solar panels where solar irradiance is higher. And solar irradiance is higher in clearer skies. Whodathunk.
Note that the graphic shows "direct normal solar irradiance". This is the strength of solar energy measured pointing an instrument with a narrow field of view (about the size of the sun) directly at the sun. The instrument used for this is the pyrheliometer. It does not include input from any of the rest of the sky (known as "diffuse radiation"). The sum of direct + diffuse gives total solar irradiance.
For any surface (the ground, a solar panel, the side of your house), you need to make a calculation to convert direct normal irradiance as measured pointing directly at the sun to an irradiance value at the orientation of the surface. The surface in question will only get the full "direct normal" value if that surface is pointing directly at the sun - e.g., the sun is directly overhead at that location for a horizontal surface (e.g. the ground), or the surface is tilted to point directly at the sun (a sun-tracking solar panel).
The graphic above does not indicate whether it's daily mean totals are corrected for a horizontal surface, or whether they represent the total available to a tracking system that always points at the sun. The use of the term "direct normal" implies the latter - "normal" is used in the geometric context of "at right angles to", and to stay at right angles to the sun's rays requires that you track the sun. If they mean the former, then they are sloppy in calling it "direct normal" - they should refer to it as "direct radiation on a horizontal surface".
And solar panels to use the non-direct radiation that comes in from the sky at angles other than the direct path to the sun. In a clear sky, this is the blue you see away from the sun, and is a small proportion of the total. In an overcast sky, diffuse radiation can be quite a bit higher than the diffuse radiation in a clear sky. And this is one of the points in the OP: just because it is cloudy does not mean that solar panels produce no power.
Another nuance in all this is that orientation of solar panels is important, to maximize the use of power available from the direct sun:
- In clear skies, a tracking system that points the panels directly at the sun (tracking both horizontally and vertically) gives maximum output.
- Under overcast conditions, you actually get the most output from a panel sitting horizontally. If it is tilted, part of what it sees is the ground, which is less bright than the overcast sky.
- For a fixed panel, you usually want to tilt it south (in the northern hemisphere) to get the best response from the high noon-time sun.
- but the best angle varies with the time of year. The sun is higher in the sky in summer.
- ...and in a specific location, you may also see seasonal differences in cloud cover, which alter the direct/diffuse rations and alter the "optimal" angle.
- ...and in some locations, there are time-of-day issues. In a location where cloud typically builds up through the day, so mornings are clear and afternoons are cloudy, you may be better off pointing your panels east rather than south.
So, there is lots to consider in siting solar panels. And all of the above is pretty well known to people studying the development of solar energy. (Granted - the details of direct versus diffuse radiation are often not measured at a lot of locations, but that does not mean that the principles are not known.)
...and lots more "context" than David-acct alludes to. I doubt he really understands how to interpret the sources he has linked to. But we're used to that now, based on his history here at SkS. At least this time he did not call it "raw data". But it is clear that - once again - he is simply trying to throw something at the wall in hope that it sticks, to discredit the statements in the OP. Once again, he's not doing a very good job.
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Eric (skeptic) at 21:17 PM on 22 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
The snow Sunday cut my main solar to essentially nothing probably through Friday. My rooftop panels charge a Generac lithium battery sitting next to my feet. I'm currently charging from AC since it was down to zero this morning. My laptop and two phone use about 20% of the battery per night. My Starlink is normally plugged into AC, but I can switch it to the Generac or my small portable generator when I need to. Those all run the fridge when needed (normally AC).
My rooftop solar (four 100W panels) are about 35 degrees pitch. They are not attached to the roof which is 25 degrees, but attached to pressure treated lumber straddling the peak. A separate panel now about 20 years old was putting out normal power yesterday and charges AGM batteries in the basement. It is mounted at a much steeper pitch, probably about 60 degrees.
The snow on Sunday was wet, followed by a hard freeze that has continued. The wet snow froze to the four panels and even if it slid down during the snowfall, a small amount at the bottom will basically kill power output. I know this because I have two panels on the ground mounted to a large resistor to constantly heat the bathroom on sunny days. They are fine now with a very steep winter angle with no snow at the bottom.
Which brings me to my point. Yesterday morning northern MD line voltage monitored by my friend dipped to 106V as many resistive heaters kicked on and as heat exchangers switched to defrost mode or turned off. There were probably also a higher load of old resistive heaters and space heaters running.
Point 1: maintainiing gas backup is essential.
Point 2: rooftop solar at roof pitch is not ideal for snow. It can work but can be out for days. Even my greater pitch has not helped and I cannot safely walk on the roof to clean off panels. Solar on the ground makes much more sense especially if panel pitch is adjusted for the season which help with both capture and snow sliding off. Utility solar makes the most sense.
Point 3: I see more people using ground mounted home solar instead of rooftop. There is still lots of rooftop solar and more being installed, and it can be ideal in summer for both pitch and matching peak AC demand. But winter still brings these occasional snow to cold challenges. I have no grid tie whatsoever and probably never will. But if I did it would be ground mounted and I would only do it with dynamic pricing and not the current net metering here in Virginia. Net metering is a subsidy from less well-off ratepayers to more well-off solar owners. Those solar owners are supplying valuable electricity at peak summer demand which is normally our highest here in Virginia and south.
But in winter in these unusual (and getting more unusual) situations those solar panels do nothing. They obviously don't detract from the grid, but those homes are currently getting cheap power from very expensive gas peaker plants paid with summer credits. If the credits were generated in similar peak situations then great, but there's no market mechanism to incentivize that in our simplistic net metering system.
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RickyO at 19:39 PM on 22 January 2025Moving away from high-end emissions scenarios
Thanks.
Taking into account all of the above, it's plausible that we're burning through the remaining carbon budget faster than the calculations (budget minus emissions) show.
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scaddenp at 15:05 PM on 22 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
Um, the myth doesnt say anything about winter. Just cold and cloudy, and the rebuttal acknowleges the impact of clouds. I was surprized to see that peak output from our panels didnt vary much from summer to winter - the increased efficiency cutting in - but the shorter days and increase in cloud certainly reduce daily output. A very very long way from "dont work" however.
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David-acct at 10:03 AM on 22 January 2025Sabin 33 #12 - Do solar panels work in cold or cloudy climates?
This is a classic case of the rebuttal omitting key information.
While the statements in the rebuttal are factually correct, key data for understanding the full context is missing ie there remains significant decline of overall electric generation from Solar during the winter months.The drop in electric genration from solar is well documented from numerous sources and as detailed in the monthly data from EIA, the Dec/January capacity factor for utility solar pv averages around 13.5% vs 30%-31% during June july and august.. Northern latitudes such as north of 45degrees north (minneapolis), the capacity factor during the winter months drops to around 7% -10%. Links to source data is provided below:
www.eia.gov/todayinenergy/detail.php?id=39832
www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_6_07_b
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One Planet Only Forever at 08:08 AM on 22 January 2025Fact brief - Can CO2 be ignored because it’s just a trace gas?
Noel Yrrep,
In addition to your well presented questioning of the questionable claims made-up by people who are resistant to learning how CO2 levels in the atmosphere significantly affect the global average surface temperature, the ‘hard of learning’ would struggle to explain:
How the surface is so much warmer than it would be without ‘trace amounts of ghg’ in the atmosphere. What evidence-based, independently verifiable, alternative understanding do they offer?
Some might claim that God made it this way, in a way that humans cannot ruin, therefore, it is not necessary for people to understand how it works. Others may claim that the activity in free market capitalism (the developed economy) will naturally be the best way to identify and solve any developed or developing problems if it is free from external observation and influences. Still Others may claim that popularity of a belief justifies it. And some may claim that everyone's personal opinion is as valid as any other opinion.
Those would be arguments based on orthodoxy (which means ‘the right opinion’).
Science is not a matter of opinion. Science, done scientifically, develops evidence-based improved understandings of what is going on.
So I would recommend that instead of “...those who don't accept the scientific orthodoxy behind the 'warming' role of CO2.”, you should say something like “...those who resist improving their awareness and understanding of the scientifically developed knowledge regarding the 'warming' role of CO2.”
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nigelj at 05:59 AM on 22 January 2025Moving away from high-end emissions scenarios
Evans graph shows atmospheric concentrations of CO2 continuing to increase and possibly even accelerating further , despite a reduction in the rate of emissions growth over the past ten years. According to Carbon brief: "Total global CO2 emissions have notably plateaued in the past decade (2015-24), growing at only 0.2% per year compared to the 1.9% rate of growth over the previous decade (2005-214) and the longer-term average growth rate of 1.7% between 1959 and 2014." This all seems perplexing.
I think there would be several possibilities why this is happening.
1). The possibility that reduction in the growth rate of emissions omits some sources of emissions as Ricky O points out such as burning wood pellets and the canadian wildfires. Also as the oceans warm and the permafrost melts, they release CO2 to the atmosphere. This process may be accelerating and thus negating the reduction in the growth rate of emissions, until emissions growth stops and emissions fall sufficiently.
2)The reduction in the growth rate of emissions is still within the margin of measuring error for growth in atmospheric concentrations so it hasnt shown up yet
3). There is no reduction in the growth rate of emissions because countries are not accurately reporting their emissions. However there are obvious ways of international agencies objectively assessing this such as data on the construction of renewable energy. I find it hard to believe that there is no reduction in emissions growth, although it is probably exaggerated to some extent.
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Evan at 23:59 PM on 21 January 2025Moving away from high-end emissions scenarios
RickyO, thanks for your comments.
I am well aware of what you are saying, and my question was meant to prompt this kind of thinking in the reader. As you well know, the Keeling curver represents the net difference between all sources and sinks, both natural and anthropogenic.
The subtle suggestion i was attempting to make with my comment is to encourage the reader to follow the evolution of the Keeling Curve, because in the end, it is atmospheric GHG concentrations that will govern future warming, and not our documented GHG emissions budgets. I know the two are related, but the Keeling Curve represents reality, whereas emissions budgets, both measured and projected, represent only part of what controls future warming.
I apologize for saying that I included 2025 data in my curve. I meant to say 2024 data.
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RickyO at 23:14 PM on 21 January 2025Moving away from high-end emissions scenarios
Evan,
Because declared CO2 emissions are not the same as CO2 released into the atmosphere.
For example:
and CO2 comes from other sources.
For example:
www.jpl.nasa.gov/news/new-nasa-study-tallies-carbon-emissions-from-massive-canadian-fires/
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Evan at 09:14 AM on 21 January 2025Moving away from high-end emissions scenarios
The article states,
"... growth in CO2 emissions slowed notably over the past decade ..."
When I plot atmospheric CO2 concentrations from 1970 to 2005 using 10-year moving averages, it shows an upward accelerating curve. When I plot the 10-year averages for 2010, 2015, and 2020 (which includes the data for 2025) the data points sit above the extrapolation of the 1970-2005 curve.
If "... growth in CO2 emissions slowed notably over the past decade ...", why is the Keeling curve currently accelerating upwards as fast or faster than it has since the 1970's?
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jimspy at 05:57 AM on 21 January 2025Nobody’s insurance rates are safe from climate change
Been ranting about the insurance element for a decade. I've often said that the most immediate danger from climate change is not hurricanes, floods, or wildfires, it's rising P&C carriers' premiums...then, cancellations....then abandonment of high-risk areas....and then, cancellation of REinsurance contracts by the Big Three: Munich Re, Swiss Re and GenRe. The first three have happened already. If the reinsurers bail, there will be defaults and bankruptcies in the P&C industry....and when that happens (not IF), well, Katy bar the door. An insurer bankruptcy will send our economy into freefall.
Meantime I've just heard that our esteemed President has just announced his intention to withdraw from the Paris climate accord. Have a pleasant apocolypse.
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Bob Loblaw at 00:57 AM on 21 January 2025At a glance - Is the CO2 effect saturated?
sychodefender:
Feel free to ask additional questions, and feel free to provide additional information on the parts you feel you do understand, as well as parts that seem to be more difficult. You can add links in your comments (the chain link icon on the Insert tab) to point to sources that you have used to inform yourself, or ones that raise questions you are not sure of.
The climate system is a complex system. There are simple models that help explain some of the simpler concepts - but they leave out the complex, subtle details, in order to make the simple aspects easier to see and understand. The complex models are as difficult to understand as complex weather data - many, many variables and relationships to follow.
The common problem in many contrarian papers that think they are disproving generally-accepted climate science is that they take models that are too simple and think that some odd feature in their simple model is the Ultimate Answer to Life, the Universe, and Everything (when in reality that odd feature is just something their model gets wrong).
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Bob Loblaw at 00:43 AM on 21 January 2025Fact brief - Can CO2 be ignored because it’s just a trace gas?
Yes, indeed, Evan (and Noel).
It is always interesting to see how the contrarians can both argue that "CO2 is a trace gas" and can't possibly imagine that it can have any effect - yet at the same time they argue that the CO2 effect is saturated, so adding more can't have any additional effect. And then turn around and do the "CO2 is plant food" dance.
If Elon Musk wanted to give me 0.04% of his net worth, I'm sure I could live a long and wealthy life on "trace money".
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Eclectic at 20:23 PM on 20 January 2025CO2 effect is saturated
MathWhizAsItIs @878 :-
Greetings again. Thanks for your link. Apart from your mathematics, there seem to be at least two faulty assumptions, indicating that your ideas are unphysical.
[page 3] "It must be noted that these photons are leaving the atmosphere without causing any warming." [UNQUOTE]. A bizarre concept indeed, when taken in full atmospheric context.
[page 4]. "First, we note that 10 meters seems to be ... the extinction altitude" [UNQUOTE]. Another bizarre unphysical concept.
Whiz , there may well be other serious faults in your presentation. Me, I stopped counting at two.
~ To slightly misquote Einstein's famous comment :-
"Two would be enough."
.
Sorry Moderators, but his nonsense is "up" here for many hours ~ and it is rather fun to reply to such science-denier absurdities.
Moderator Response:User MathWhiz has been banned. We don't do moderation 24/7, so it takes time.
After years of showing his inability to understand and properly use radiative transfer theory, there is no point in reading his current hallucinations. He has long since worn out his welcome here.
He is welcome to try to publish his results in a legitimate peer-reviewed journal. He is not welcome to keep spewing his garbage here.
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Evan at 10:04 AM on 19 January 2025Fact brief - Can CO2 be ignored because it’s just a trace gas?
Nicely stated Noel.
"Which is why "trace" amounts of CO2 supports the massive amount of plant life on land and in water."
Thanks for the reminder Bob of your very interesting and illustrative paper.
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Bob Loblaw at 08:39 AM on 19 January 2025Fact brief - Can CO2 be ignored because it’s just a trace gas?
Noel:
An illustration of why ppm is a bad set of units to look at the radiative effects of CO2 forms part of the discussion in this blog post I did a few years ago. (To toot my own horn.)
https://skepticalscience.com/from-email-bag-beer-lambert.html
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Noel Yrrep at 07:56 AM on 19 January 2025Fact brief - Can CO2 be ignored because it’s just a trace gas?
Carbon dioxide is a trace gas, but to put that in perspective, the amount of CO2 in the atmosphere is not physically insubstantial.
Focusing on parts per million to the exclusion of actual amounts is employing a mathematical sleight of hand. A sleight of hand that suits those who don't accept the scientific orthodoxy behind the 'warming' role of CO2.
- Each part per million of CO2 in the atmosphere represents approximately 2.13 gigatonnes of carbon, or 7.82 gigatonnes of CO2.
- 422 parts per million represents 3,300 gigatonnes of CO2.
- 422 parts per million represents 3,300,000,000,000 tonnes of CO2.
Which is why "trace" amounts of CO2 supports the massive amount of plant life on land and in water.
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Philippe Chantreau at 06:28 AM on 19 January 2025Is Nuclear Energy the Answer?
Michael,
I know I won't change your mind about nuclear as a large scale solution, but please give me the courtesy of keeping up the quality of argument expected from all participants here. I don't doubt that you have some notion of what kind of analysis is required before one can claim that some days are "representative" and I am sure that, if anyone on this forum was to make such claim on any subject, they would be asked to produce substantation.
There is an abundant literature about load following and and it disagrees with your contention that it is by nature uneconomical. Here is an example, that I have no doubt you could find just as easily as I could. It also contains information as to how the load following is achieved and it is not through shutting down the reaction. Virtually all reactors currently in use in France were designed for load following. Wikipedia has a page on load following, which is also very easy to find.
The reason EDf was partially privatized in 2004 was to satisfy a EU mandate. The following years saw underinvestment in infrastructure and maintenance. There was a number of problems with several reactors in 2021-22 but these have now been resolved and the parc is again exporting electricity all over Europe, so, once again, using the adverb "lately" is a little imprecise whren talking about the capacity decrease of 2021/22.
I won't dispute that nuclear electricity is more expensive than coal gas or oil, that is a fact. The carbon footprint, however, is much better. Perhaps there is a price to that, although that was not the reason why it was initially chosen as a solution.
I know very little about the US nculear reactor fleet and how it ise used, so I won't comment on that.
My contention is that France's programme has been largely successful and has produced yearly terawatts of carbon free electricity for decades. If not produced from that source, what would they have been using instead over the past 60 years? Oil, coal and gas, like England and Germany or even Denmark? Would that truly have been better?
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Charlie_Brown at 05:30 AM on 19 January 2025At a glance - Is the CO2 effect saturated?
sychodefender @18 and @22
The band saturation effect does have a diminishing logarithmic curve as explained by Bob Loblaw and as shown in Fig. 6a of Zhong & Haigh 2023. But the rate of modern global warming has not diminished to being negligible. Your descriptors of the effect: "distinct leveling off" and "surely can only have a very slow impact on warming" are misleading toward an incorrect conclusion.
I described the main problem with Kubicki, et al., above @16.
I described the main problem with Wijngaarden & Happer in “Is the CO2 effect saturated?” @716, page 29, Oct 5, 2024.
Moderator Response:[BL] A direct link to Charlie Brown's comment #716 is here. There are discussions of work by Wijngaarden and Happer earlier in the comment thread.
Sychodefender: note that the main article on the "Is the CO2 effect saturated" rebuttal has many, many comments. Some are useful; some are extremely misguided attempts to argue in favour of the myth. In some cases, a head vice is needed.
Addendum: comments from Charlie Brown fall in the "useful" class.
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sychodefender at 03:46 AM on 19 January 2025At a glance - Is the CO2 effect saturated?
Thanks Bob, I will try to take this all in, appreciate your very comprehensive replies.
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Jeff Cope at 20:39 PM on 18 January 2025Producing and transporting wind turbine components releases more carbon dioxide than burning fossil fuels
With 90% of wind turbine emissions from its transport, electrifying & renewablizing it would obviously make a tremendous difference practically & even a little help advocating for them. (Most people acting in good faith already know they're vastly better; others won't be convinced by facts, no matter how remarkable.)
I'm curious about whether there are any electric transport vehicles for wind turbine blades & other components, & what emissions are or will be compared to what I assume are now diesel. I think I'd know if any service operation vessels were low emission but I wonder how close they are?
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Bob Loblaw at 06:54 AM on 18 January 2025At a glance - Is the CO2 effect saturated?
Now for the question posed in #22, about the logarithmic effect of CO2.
There is more than one place in the CO2/climate system where we see logarithmic relationships.
The first place is in the fundamental aspect of the absorption of IR radiation by CO2 (or other greenhouse gases, such as methane). This is described mathematically by Beer's Law, which you can read about on Wikipedia, or by reading this post I made here at SkS about three years ago.
- In non-mathematical terms, the absorption of radiation by a given thickness of air occurs as a proportion of the radiation. If that thickness of air absorbs 10% of the radiation, it will absorb 100W/m2 out of 1000W/m2, but only 10W/m2 out of 100W/m2.
- So, if you start out with 1000W/m2, and absorb 100W/m2, you're left with 900 W/m2.
- But when that 900W/m2 passes through the next identical layer, only 90W/m2 is absorbed, and 810W/m2 is passed on.
- ...and in the next layer, 81W/m2 is absorbed, and 729 W/m2 is passed on.
- ...and so on.
- And this sequence is a logarithmic relationship.
- Although you never get to 0W/m2, after enough layers you do get to the point where it is essentially 0 for all practical purposes. At this point, you can say "with all those layers, absorption has reached a saturation point".
Those "skeptical" of the CO2 effect on climate focus on this "many layers already absorb all the IR" case and then argue "adding more CO2 will not absorb any more". They are wrong.
The catch is that this "saturation" idea only applies when you look at IR radiation that started in the beginning and passed through all those layers. There are two issues with this:
- Even if all the radiation is absorbed by many layers, adding CO2 will change how much was absorbed in layer 1, or layer 2, etc. Thus we are still changing where in the atmosphere the radiation is absorbed.
- This will alter the energy flows in the diagram I posted in the previous comment.
- This diagram shows how changing the absorption rate changes the amount absorbed in the earlier layers. (The diagram comes from this post, which I mentioned earlier.)
- The second issue related to what other commenters have said, that "skeptics" seem to ignore: that the atmosphere itself is emitting more IR radiation.
- Even though less and less of the original radiation entering layer 1 (closest to the surface, if we are thinking of our earth-atmosphere system) reaches the upper layers, constant emission of IR radiation locally (i.e., at that height) is replacing at least some of the IR radiation that was absorbed.
- The local emission depends on local temperature (the kinetic energy source)
- The local emission will be half upwards, and half-downwards, which means that it is now harder for that energy to reach a point where it can be lost to space (greenhouse effect discussion in previous comment).
There is another important place where a logarithmic relationship is seen. In Beer's Law, we talked about a layer containing something that absorbs IR radiation. What happens to the absorption ratio if we double the amount of CO2?
- We might think it doubles the amount of absorption, but this is only the case for low concentrations.
- At higher concentrations, the amount of absorption will not quite double
- ...and at yet higher concentrations, the absorption will not quite not quite double, etc.
- ...so we see a "law of diminishing returns".
- Eventually, at very high concentrations, there will be very little additional absorption. Again, we can call this "saturation".
- ...but current atmospheric CO2 concentrations are a loooong way from reaching this "saturation" point. We're a little over 400ppm now, and we'd need to get to concentrations several times higher before "saturation" is reached.
- From our starting point at 300ppm, we'll see 2-5C rise when we double to 600ppm, and then another 2-5C rise if we double again to 1200ppm, so we can see the logarithmic relationship.
- ...but a climate with 1200ppm of CO2 will not be a pleasant place compared to what we have now. The logarithmic decreasing effect will not save us from a very different world.
Whenever you see a "saturation" or "logarithmic" argument, you need to try to understand which version someone is claiming. The key error in all of them is that they are isolating one small part of a complex system and ignoring other parts that are affected by increasing CO2. Only by including the complex relationships among all the parts of the system can you determine the warming effects of CO2.
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Bob Loblaw at 06:08 AM on 18 January 2025At a glance - Is the CO2 effect saturated?
sychodefender:
Thanks for providing follow-up questions. It helps us determine just what it is you are trying to understand, and what information we can pass on to help. It is often difficult to know what a person already knows, and what level of explanation is needed.
First, for your question in #21 about where the energy comes from for re-emission of IR radiation.
- All objects (gas, liquid, solid) that have a temperature about 0 Kelvin (-273.15 Celsius) contain kinetic energy that will lead to emission of radiation. Colder object emits primarily at long wavelengths, while hot ones emit at shorter wavelengths. The sun emits primarily in the visible spectrum, while the earth-atmosphere system primary emits in the infrared range.
- Objects will not continually emit radiation unless they have another source of energy. If there was no energy input, the objects would eventually cool to 0K.
- The main source of energy input to the earth-atmosphere system is the sun.
- In a stable climate, the energy absorbed from the sun is exactly offset by the emission of IR radiation to space (averaged over the globe and over a suitable length of time).
- Most of the sun's energy is absorbed at the surface (land, ocean). The warm surface then sends energy back up by three main mechanisms:
- IR radiation
- Thermal transfer of energy from the surface to the air.
- Evaporating water at the surface, moving the water vapour up into the atmosphere, and then condensing the water vapour in the atmosphere. We call this "latent heat transfer" because it involved the latent heat of vaporization of water.
- So the gases (CO2 or others) that emit IR radiation at various points in the atmosphere get the required energy from the sun, after it gets moved around the earth-atmosphere system via the three mechanisms mentioned above.
A key aspect of this is that to understand how CO2 affects climate, a model has to look at all energy flows - not just radiation transfer. Adding CO2 alters the radiation part of the equation, but you can't just isolate the radiation terms. You need to watch that energy play out in the system as the thermal energy and latent heat terms respond.
- The really short version of the greenhouse effect is that the presence of the atmosphere makes it a lot harder for the solar energy absorbed at the surface to get emitted back to space as IR radiation. The surface ends up stabilizing at a much warmer temperature (about 33C warmer) than it would with no atmosphere at all.
- The really short version of adding more CO2 is that it makes it even harder, resulting in an even warmer surface.
Here is a diagram that shows those energy transfers (global averages) pictorially. Note that there are additional fluxes of energy within the atmosphere and back from the atmosphere to the surface. In a full climate model, you also need to consider how these vary globally, and over time (daily, seasonally, etc.)
I'll answer your other question in another comment.
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One Planet Only Forever at 05:38 AM on 18 January 2025Nobody’s insurance rates are safe from climate change
Eric (skeptic),
Goats were used in 2024.
County of LA Fire Department - Goat Grazing post (linked) opens with the following:
On Thursday, August 15, 2024, the County of Los Angeles Fire Department (LACoFD) was joined by several media outlets in a demonstration showcasing the use of 150 goats and sheep for effective vegetation management near Helispot 69 Bravo in Topanga.
Topanga is the region immediately west of Pacific Palisades.
Also, you state "But I have no weather risk here in rural Virginia." Do you have a scientific reference for your confidence that your region will remain 'weather risk free'? I notice that the regions of North Carolina hit by Helene were less less than 200 miles from the less populated parts of Virginia. With the tracks of hurricanes and their remnants changing due to climate change, hopefully you are correct about your region remaining impact free in the future.
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One Planet Only Forever at 05:09 AM on 18 January 2025Exploring the drivers of modern global warming
RickyO,
Saying that the 'rate of something has plateaued' means that the rate is constant. The rates had been increasing, meaning more change per year. Now the rates are no longer increasing. That is an improvement. But what is still required is the reduction of the rate to get down to 'zero' net annual impact - which would be when CO2 levels stop increasing.
And, since it is undeniable that 1.5 C warming will be exceeded, to be fair to future generations the current generations need to more rapidly develop to 'net-zero impact'. They need to also draw-down the over-shoot of CO2 and other ghgs levels (years of net-negative ghg impacts). Future generations will have enough trouble dealing with a 1.5 C increase.
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sychodefender at 22:59 PM on 17 January 2025At a glance - Is the CO2 effect saturated?
Just to be clear, are you saying that co2 does not have a diminishing logarithmic effect ?
The moderator kindly provided a link to a page showing a graph from Zhong and Haigh 2013, which plots a distinct levelling off as co2 levels rise, a logarithmic response that surely can only have a very slow impact on warming.
Apologies if I am traveling old ground but I'm trying to explain this to my children and they are inquisitive!
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sychodefender at 21:25 PM on 17 January 2025At a glance - Is the CO2 effect saturated?
Thanks for the rapid replies. I understand that co2 absorbs and constantly re-emits in all directions but I'm wondering how this additional kinetic energy comes into existence?
