Greenhouse gas discussion (tread carefully, be respectful)

Off-Topic (In the weeds/General Discussion)
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I was putting together a basic description of climate science based on electronics (to be more appropriate to readers here), and wanted to confirm some facts with my brother. He said I could quote him under the understanding that he was only an author on the IPCC report, and does not speak for the IPCC.

Me: Is there any plausible climate model that does not rely on some form of greenhouse effect for temperature regulation? As I understand it, the only scientific debate left is as to the actual sensitivity?

Brother: Nope. And the sensitivity itself isn’t really up for debate, at least in terms of basic physics. Arrhenius wasn’t far out with his first estimate back in 1897, if I remember right. Recent models “run hot” (return higher than expected transient climate sensitivity) because of emergent feedbacks from tropical convection/clouds (as model resolution improves, more and more processes can be empirically modelled, instead of parametrised). There’s no consensus on whether this is an error of modelling or a process that’s been overlooked (undiscovered). Still, assessments tend to filler out the “too-hot” models, just to be on the safe side. As for skeptics, the 6th assessment report went through the rounds of open/public review, received hundreds of thousands of comments/criticisms (across the three working groups, each of which had to be addressed in writing, with adjustments to the text to match. Essentially, it’s the single most robust scientific document in the history of humanity. It concluded that anthropogenic warming is incontrovertible. If some idiot thinks they can do better, they should publish their paper and sit back, waiting for the Nobel committee to call.

TL;DR There is no published evidence that challenges our understanding of the existence or cause of climate change in any serious way. But there is a mountain of evidence in support. If folks want to ignore the mountain, there’s little point in trying to convince them of anything.

What struck me most is “Essentially, it’s the single most robust scientific document in the history of humanity”. After a multi-year public review process, every comment received - be it from quacks or genuine scientists - was evaluated, tested and addressed in that report.

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We had a low low-slung thing fanatic in our complex years ago, also the same thing opens the damn throttle. One day as he gets onto the road outside the complex, the throttle really wide open … the thing sputters and stops. Bliss.

We actually stood outside smiling when he was pushing that thing back home.

It never happened again.

Back to the core thread …

We are in deep shiite … unless the world steps up (and it won’t) and think about what we are doing, and how. Mitigate our waste, be it plastic, methane, Co2 … everything.

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Part 1 or 2

Since this forum is mostly populated by people with a basic understanding of electrical systems, I thought I would have a go at explaining the basics of climate science in terms of one of the simplest electronic circuits - the class A amplifier. This is the first real electronic circuit anybody will be exposed to in an electronics course, and it demonstrates some of the key principals in climate science.

Let us start off with the most basic design possible:

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Now this is a truly horrible design. The transistor’s transfer characteristic is exponential, so the output will be horribly non-linear, have no negative range, and a big dead band around 0.

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But if we look at the right hand side of the curve, the exponential function there looks almost flat. So, let’s make our amplifier better by biasing the base-emitter voltage to around 0.7V, where it starts looking flat:

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We carefully adjust our bias resistors so that the output voltage is around half supply, apply an input, and hey-presto, it works perfectly.

For a few seconds, and then the output voltage starts getting lower and lower until it saturates near ground. In desperation, we tweak the resistors a little, and it works a little while longer before saturating again.

How did that happen? With the transistor working, it starts heating up a little bit. As the transistor warms up the collector current increases, the voltage drop across the output resistor increases, and the output voltage decreases.

To fix that, we add an emitter resistor:

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Now things get interesting - as more current flows through the transistor, more current flows through the emitter resistor, and the voltage drop over the resistor increases. This decreases the base-emitter voltage, which decreases the current…

We now have a self stabilising system, where any unwanted change automatically induces a compensating change to correct it.

But it is not a perfect correction. If we design the voltage across the emitter resistor to be around 0.7V, then Vout will change about 5% over typical device and temperature ranges. If we make the voltage around 3V then that typically goes down to about 0.1%.

This is one of the simplest feedback control systems you will find, and that undesired output change is termed the control error.

If you play around with feedback systems enough, you will also soon find another issue - oscillation. Whether it is the feedback howl of a PA system, or destructive power supply feedback on a power circuit, oscillation is the big problem with most feedback systems - particularly when there is an energy storage component (like a capacitor or inductor), which can add lag to the system.

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Part 2 of 2

How does this apply to climate systems?

The Earth is a closed system (mostly - there is some slow loss of gas to space).

If some energy from the sun reaches the planet, exactly the same amount of energy must leave, or the total energy (temperature) will increase.

If a gas is released into the atmosphere at some rate, it must be removed from the atmosphere at exactly the same rate, or it will continue to build up until it displaces all other gasses.

But the current temperatures and CO2 levels have been fairly stable for 1000s of years. How is it possible that such tight tolerances are maintained?

The answer is in feedback systems. More heat = more water evaporation = more clouds = more sunlight reflected away from Earth = less energy reaching and heating the surface. More CO2 = more plant growth = more CO2 consumption.

These are two of the simplest feedback mechanisms at play, but there are many, and they are all interrelated.

But just like with our basic class A amplifier, we have a control error - how much undesirable output is produced for a given input. The question is not if there will be an undesired change - but how big that change will be.

The basic physics of climate science is well understood. While there is some ‘debate’ on social media about whether or not the greenhouse effect exists (for example), there is no academic debate on this. It is basic physics, experimentally tested and verified.

Where the actual academic debate comes in is about what feedback effects might exist, what there strength is, and what the control error is.

There are still some academics with plausible theories which show that the control error may be negligible - but those all require some rather extreme, and so far unproven feedback loops. With currently known and characterised feedback systems, things do not look that cheerful.

In the end, as with any control system, there must be control error. And it is that control error which may destroy human society. Note, I say human society, not the world. The Earth will keep on ticking, the feedback loops will slowly drag everything back to normal, but for humans, any sustained period of lost agricultural output will spell wide-spread famine and war, even with relatively small temperature errors.

There have been super-large volcanic eruptions in the past, and these have often been extinction level events, with large scale die-off of large and energy hungry animals. There have been smaller, but still extremely large eruptions in recent history that have caused wide spread famine. But in each case, the global climate feedback systems have worked to bring everything back into balance. Sometimes it took decades, sometimes millennia. With a global population now topping 7 billion, out tolerance for food supply interruptions is slim to none. Even a small deviation in global climate can spark off a catastrophic loss of human life.

And as with other feedback systems, control error is not the only issue (although it is the biggest one we face at the moment). There are massive delay loops in our climate system, with ocean currents recirculating energy over decade (or millennia with the deep ocean currents). The provide significant control lag with the potential for instability and oscillation.

Push the system past some (as yet unknown) threshold, and we will soon end up with alternating periods of thousands of years of ice ages followed by thousands of years of extreme temperatures (which have also happened in the past).

We know for a fact that increased atmospheric CO2 must result in increased surface temperatures. We know for a fact that humans have been contributing substantially to global CO2 production, while at the same time reducing CO2 sinks. We know with near certainty that the final control error for this CO2 imbalance is likely to exceed 1.5C. We have confidence that with careful management and international cooperation, human society can survive that temperature change (but only just).

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Your explanation also reminds me in many ways of those same challenges in PID controllers. For the benefit of our readers, that’s a system where you also have a certain error you want to eliminate, and then you have processes that act directly proportional to it (the P component), but you also have processes that act proportional to the rate of change (the D component), and you have components that tend to wind up (remember how large the error was, the I component). Winding up the I component too much causes oscillation for several cycles afterwards.

Because the CO2 in the atmosphere has such a long life (up to 100 years) in the system, it feels very much like such a wind-up-able component. Conversely, plant growth is more of a D-component. The more CO2, the faster the RATE of growth. The water vapour is probably more of a P-component, it acts more directly.

I really do appreciate breaking it down like this, and getting to the heart of the matter, which is:

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Correct. Since the Earth is a closed system, all errors must integrate. So it is indeed a full PID control system (with a great many P, I and D terms).

History also shows us that it is indeed underdamped, showing oscillatory responses to various inputs.

Globally, we have failed to meet CO2 reduction requirements, and there is no realistic plan to do so. So we will be leaving a real shitshow for our children and grandchildren - but hopefully still a survivable one, if we can achieve the 1.5C cap.

Methane is an easy one to tackle, but expensive. Obama had finally brought in legislation that would force oil companies to capture methane instead of venting or flaring it off. But that was unfortunately repealed by his successor (no names will be mentioned). The current incumbent has re-introduced much more moderate restrictions (we can all guess where his funding comes from).

Fortunately, methane does not accumulate to the extent CO2 does, so it can be addressed more slowly, without any real impact on climate goals.

It is CO2 with the long term atmospheric build up, and very slow feedback loop to counter it, which is the big and immediate problem.

This is perhaps the only positive thing to come out of the Ukraine mess. While it may result in a temporary increase in wood burning for heat (and even this is actually renewable and neutral if done sustainably), it has also force all of Europe to accelerate their green energy programs. EV sales are skyrocketing and they have finally confirmed a near complete ban on ICE vehicles from 2035. Trains are again becoming more popular than aircraft for long distance travel and freight. All very positive for CO2 output.

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IEA: Mineral supplies for electric cars ‘must increase 30-fold’ to meet climate goals - Carbon Brief … and probably won’t

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That may well be one of the things which by 2028 (the review date the EU built into their plan), could cause the amendment of the deadline by another decade or so.

The other half of that argument is that if we assume the axiomatic truth of the proposition (that carbon is a problem), a lack of resources doesn’t really absolve us from the responsibility to do something. If you have to stop burning fossil fuels before you can go fully electric… well then you’re not going to drive for a few years! And of course that loss of freedom and autonomy is practically anathema to a Westerner.

Of course one obvious other solution is more trains and electric buses. Maybe we’ll do more of that.

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My gut tells me that this Global Warming is not going to be curbed in time due to politics and profits, i.e. top down.

Flipside. The world gets to understand what is going on and it changes from on ground level, i.e. bottom up.

The problem is that economics drives it all coupled with not everyone/country being on the same page/chapter, not even the same book even on a good day. So trying to get consensus and actions on a global scale needed to be taken ito Global Warming, is a mammoth, if not impossible, task to try and get going.

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Remember the hole in the Ozone crisis?
Was that all fixed successfully??

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It actually was fixed, believe it or not! Well, almost. The world cut their ozone depleting gas activities by 99%, and the Ozone layer will be back to its pre-80s levels by the middle of this century.

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Well, in time for what? As I understand it, the consequences gets progressively worse the longer you wait. While drastic weather changes is bad enough, and can cause widespread famine and death, it’s several orders less severe than a ice age that kills everyone except a small band of survivors in Iceland (I’m sure there are a few movies about that).

Something else I’m thinking about. When you discuss these things on social media, you will often meet someone who reckons it is all a scam, a way for some boogeyman (Gates and Soros are usually the goto people) to impose a world order, one that goes along with a drastic forced reduction in population.

The dark humour in that argument is that, if the climate alarmists are right, the reduction is coming anyway. You’ll just be blaming someone else for it when it does come.

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Hey, that’s great news!
So leave this crisis to these guys and it’ll get sorted…
No need to panic!

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This came up on me social media feed. The last block reads: The elite wants you to believe this is water!

conspiracy
conspiracy502×640 30.9 KB

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Sjoe … how on this earth is climate change going to be handled collectively … “this is water”.

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It was reported in the NYT, but only for paid subscribers.

This can work … WHEN the politics are sorted out.

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Iraq sure, but Libya and Syria? Sounds like he doesn’t consider the alternative outcome with no intervention.

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This is an interesting article:

https://arstechnica.com/science/2022/05/why-our-continued-use-of-fossil-fuels-is-creating-a-financial-time-bomb/

One of the takeaways is just how important things like carbon taxes actually are. Even if they are badly implemented, or the proceeds don’t actually go to green projects like they should. The important bit is to gradually ramp up the cost on polluting businesses, so that those companies are forced to gradually diversify or die.

Right now, there are probably half dozen promising battery technologies in development. If any one of these comes off and provides an indutrialisable battery with around double the current energy density, at about half the cost, it would actually destroy the global economy.

Oil companies would lose all their value and investments. Income would plummet. Workers laid off en-mass. And this is a huge segment of the global economy.

Even if you don’t consider the CO2 output or other environmental issues, this entire industry in on a knife edge of economic sustainability, and is only one invention from collapse.

So it is actually imperative that the pressure be increased slowly on these companies to reduce new investment. And to gradually reduce employment so that people can slowly migrate to new industries, in a controlled way.

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The investors can assess for themselves what the value of a company is, incorporating the risks facing the company, and invest accordingly. If you are investing a few billion, you will do your homework.

The free market has strong mechanisms for pricing known and unknown risks into share prices or bond yields. Saying the government should tax, and even do it corruptly, because it will force price discovery, is ignorant of the mechanisms that exist naturally, and it assumes that the government somehow knows the correct price and should force the market in that direction.

A much more effective role the government could play is to assess areas likely to be affected by weather events, such as hurricane and flood risks, and not zone those areas for building. This would reduce financial losses substantially from weather events, rising sea levels, etc. and the cost would not be borne through a tax.