38 Comments

A big scientific question that need answered in this issue is how much additional climate forcing occurs due to high-altitude emissions. The IPCC used to use a factor of 3x then stopped. The UK gov't has an estimate of 2x. Does anyone have any knowledge on this?

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The last time I looked at the data for commercial airliners they get around 80 passenger miles per gallon. That's like carrying four people in a mid-sized car. They are pretty fuel efficient.

Private jets, on the other hand, get between 5 - 20 passenger miles per gallon. Worse than most SUVs carrying a single person.

Private jets probably have a lower total carbon footprint, but their hypocrisy factor is huge. John Kerry call your office.

Remote work sounds like it would be a good solution, but that is not emissions free either. Data centers are very energy hungry. Still less travel sounds like a good idea for many reasons.

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Reality bites and beautifully reframes the issue. How to manage it not how remove the issue.

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Climate fanatics fail to recognize that humans are here--in greater numbers--despite the many climate ups-and-downs in recorded history. As for life on the planet--well, it's still here despite that nasty asteroid.

Get real.

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Why worry about rising CO2 emissions? We need to attend to the real issue that appears to be, somehow, forgotten in the relentless curse of 'net zero'. That is, "Is CO2 really a villain gas and is its bourgeoning presence in the atmosphere an existential threat to life on Earth?" Studies of the physics of greenhouse gases have confirmed that the temperature varies with the logarithm of the concentration of atmospheric CO2. The logarithmic dependence arises because CO2 gas absorbs infrared radiation at around 15 micrometers. The phenomenon of logarithmic dependence occurs because atmospheric CO2 gas soon becomes ‘saturated’ so that as more of the gas is added, the infrared radiation can no longer be absorbed as the wavelength is ’full’. This sensitivity to the doubling of CO2 gas in a feedback-free world is about 1 degree C as various empirical observations have shown. so, why concern ourselves with simply CO2 emissions when we know what the science says?

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Roger you are channeling Vaclav Smil on this one. Great essay.

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Most in-person conferences are farces and boondoggles. They can easily be replaced by Zoom meetings or phone calls.

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Finally - some common sense! Well done, Roger!

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"And based on history, I’m optimistic that we will."

I’d tend to agree with this statement , and it’s probably correct that we should give ourselves rough targets as to when we’d hope we can solve these and other problems. But what is insane is that these targets are set in stone, with legally enforceable sanctions, when there is no clear technology by which this can be achieved nor sufficient resources to execute a solution in the time period that will be enforced. Too often targets are set by technically ignorant politicians as a form of one-upmanship but, inevitably, science & technologists will get the blame

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Frankly, Net Zero makes no sense. Our current path leads to diminishing T's sometime before 2100. We will continue to reduce CO2 emissions thru increasing efficiency (e.g., chemical process intensification), and tech evolution (e.g., small modular nuclear reactors). Sea levels will continue to rise no matter what; for many cities subduction is a much greater problem (e.g., NOLA, SE FL, Norfolk).

When you add in the very real negative impacts of trying to get there (e.g., poorer quality of life in the developed world, and stamping on the necks of the poor in the developing world), I'm left questioning the ethical foundations of those who want to "achieve" it.

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May 30, 2023·edited May 30, 2023

Some flying really is gratuitous and unnecessary.

Having gotten tired of the security hassle of flying from San Francisco (where I live) to Vancouver, British Columbia (where I was born), I now drive. It takes two days (flying takes one), but it is a beautiful drive. It also has a lower carbon footprint.

Similarly, when I can avoid it, I drive to SoCal when I need to go there. This also has a lower carbon footprint and is enjoyable.

More recently, I've started to look into ways to use rail passenger travel in the Western United States and Canada.

We still fly to Europe about once every two years. (My husband's extended family live in Greece.) No guilt about that. I don't try to justify it. In fact, we love to fly long haul. Lufthansa, Norwegian, Aegean and British Airways are our favorite airlines.

We hope to visit Japan in the not too distant future.

As to professional conferences, one of the reasons I moved to Silicon Valley is because, for my field, many of the conferences are here in California.

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Air is already an elite form of travel especially if you move up from cattle class to business or first class.

This will make it more so and the thought of not having 2 weeks in the sun, twice a year, for the northern Europeans, because air is banned for them, will not be acceptable. Especially when the private jets of Gates et al are seen using the air miles of the general populace instead.

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May 30, 2023·edited May 30, 2023

"And based on history, I’m optimistic that we will."

I am curious on what history that is based. Most civilizations collapsed, for any number of complicated reasons. Historically, sophistication of culture and technology has not a strong track record of preventing collapse. In fact, in terms of longevity, hunter and gatherers have been more successful than, say, the Roman Empire.

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There is no good substitute for aircraft using jet fuel. For shorter trips, with the new high density batteries coming out, electric aircraft are doable, and much more energy efficient. But LRTs are better for short travel in any case. Especially if Musk can speed up tunnel construction and lower costs.

The REAL rationale for jet fuel substitution is to examine the carbon abatement cost of any of these methods. And then consider the value of that carbon dividend to Nuclear power substituting for Coal. The logic is overwhelming, use your carbon mitigation $ for Nuclear power expansion.

And in the Transportation sector, by far and away, logic dictates focusing on two things:

1) Almost all battery production should be going to replacing diesel trucks, diesel heavy equipment, mining equipment, rail locomotives, ferries, LRTs, buses and short distance shipping. Forget aircraft. Conserve heavy crude for jet fuel. Batteries will be in short supply for 50yrs or more so using them for wind/solar storage or light vehicles is just not wise.

2) Methanol replacing gasoline in vehicles. Methanol can be mass produced in vast quantities and synthesized carbon neutral from Nuclear hydrogen plus carbon from waste, biomass, seawater CO2 or flue gas (i.e. cement plant).

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