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Comment by beachy | Hacker News Reader

There's a lot to hate about Covid-19 but the planet must be breathing a sigh of relief at the reduction in planes and cruise ships pumping carbon into the air.

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Airlines = 2% of global carbon emissions

Cruise ships = 0.2% of global emissions.

Stopping both will have a negligible effect on global carbon, probably near 0 since more people will drive as a result.

* https://www.atag.org/facts-figures.html

* https://www.tourismdashboard.org/explore-the-data/cruise-shi...

Cruise ships are massive emitters of sulphur dioxide.

> The results [of the study] show that the luxury cruise brands owned by Carnival Corporation & PLC emitted in 2017 in European seas alone 10 times more disease-causing sulphur dioxide than all of Europe’s 260+ million passenger vehicles. Spain, Italy, Greece, France and Norway are the most exposed countries to cruise ship air pollution in Europe.

https://www.transportenvironment.org/publications/one-corpor...

Doesn’t sulfur dioxide having a cooling effect on the climate?

I'm not versed on the subject but a quick google search seems to indicate it's a very obvious net negative for the environment. It's not just about temperature...

This doesn't make a lot of sense since passenger vehicles use low sulfur diesel while cruise ships don't

> Ultra-low-sulfur diesel (ULSD) is a standard for defining diesel fuel with substantially lowered sulfur contents. As of 2016, almost all of the petroleum-based diesel fuel available in the UK, mainland Europe, and North America is of a ULSD type.

Wow! 2% of emissions? That's a lot. If you shut off airlines it's the same as a single year's growth in emissions.

> If you shut off airlines

Well the thing is that you don't.

Even if the airline industry is decimated, you would only see a fraction of that potential value go down.

In essence you're talking a fraction of 2% of all emissions.

That doesn't even register as noise in the overall trend.

It won’t totally fix the problem. Might as well not do it then.

If you want to address a problem, you don't waste your time focusing on inconsequent approaches.

And more importantly, you are doing absolutely nothing to fix the problem. You're passively watching while a temporary crisis affected an industry that has a potential contribution to the problem that is at best around 2%.

Sure, but I've heard that argument so often about so many different industries. The effect of changing any individual industry will be small -- so the solution is to change many of them rather than none of them.

Air travel is the most direct wallet-to-well way to spend one's money. Money spent on other things will spin up a lot of economic activity and will ultimately reach a fossil fuel extraction beneficiary anyways. Could it be that all the spinning-up on the less direct route would ultimately lead to faster fuel extraction/burning in total? It would surely allow more people to participate in the benefits stemming the economic activity caused by the more indirect wallet-to-well route (a social benefit of not flying), but I have repeatedly failed to wrap my head around the relative speed of fuel extraction/disposal of more direct burning vs more indirect burning.

> Stopping both will have a negligible effect on global carbon, probably near 0 since more people will drive as a result.

That seems to assume that people are still doing the same amount of travel, just not by air; but I don't think that's true.

I feel like most people travel because it's cheap. In Europe, and with a bit of preparation, you can get round trips between any 2 major cities for less than 100 euros, sometimes much less. Berlin<>Mallorca is often under 25 euros (round trip)

You can make it seem like there's no effect if people simply ride airplanes then disappear.

There's a whole economy before, during, and after. People taking trips on airplanes are often riding taxis and pumping CO2 into the air, buying up loads of goods during their trip that needs to be processed and manufactured (clothes, knick knacks, excess food), and so on. Countries and regions with economies dependent on tourism are taking huge hits to their GDP. That'll likely be reflected in lower emissions.

> riding taxis and pumping CO2 into the air, buying up loads of goods during their trip that needs to be processed and manufactured (clothes, knick knacks, excess food), and so on.

People would do exactly this locally as a substitute for travel. It might be a boon for a local economy, but doesn't help with carbon and other types of emissions.

Travel is a time of excess. There’s a lot of cost beyond just the airplane tickets. Those costs come from somewhere.

I see that type of message all the time and it's infuriating... It' not only about carbon, planes and ships are releasing way more nasty shit and frankly I doubt this is news to you. "where" the pollution happens is also a major issue. A 50cc scooter doesn't pollute much but if you have it running in your bedroom it quickly becomes an issue, same thing for higher atmosphere and oceans.

It's time to stop hiding behind meaningless numbers and face what's really happening.

> probably near 0 since more people will drive as a result.

Good luck driving from NY to Paris, or from Berlin to Barcelona for the weekend. People lived just fine when they didn't go to the other side of the world every few months.

https://en.wikipedia.org/wiki/Environmental_impact_of_aviati...

https://www.newscientist.com/article/2207886-it-turns-out-pl...

https://www.smartgreenpost.com/2019/06/06/smog-in-europe-cru...

https://www.transportenvironment.org/press/luxury-cruise-gia...

Cruise ships are one of the most climate friendly ways to vacation, given how many people fit on them.

(Vacations aren't climate friendly in general, but when you spread the emissions equally per passenger, it's remarkably efficient)

I don’t think many people will be driving from say NYC to London.

The LA Times had this story:

https://www.latimes.com/science/sciencenow/la-sci-sn-co2-sea...

In it they say:

> For every metric ton of carbon dioxide released into the air, three square meters of Arctic sea ice disappear.

[...]

> To put that in further perspective, Notz said, it means that driving about 2,500 miles in the average American car results in another three square meters of melted ice. A round-trip plane ride from New York to London costs another three square meters or so of Arctic sea ice.

If a single trip between the US and UK can melt that much ice per passenger, the airlines must be spewing a tremendous amount of CO2 into the air. I would think short flights would be even worse. I have a really hard time believing the airlines trade group's 2% figure.

> must be spewing a tremendous amount of CO2.

So you’d rather go with your gut and an incredibly vague (square feet of ice / passenger) metric than a straightforward %?

And what does square feet of ice even mean? Last I checked that’s meaningless and a volume of ice should be measured.

That article had a link to the study.

> Because climate-model simulations of the sea-ice loss differ substantially, we used a robust linear relationship between monthly-mean September sea-ice area and cumulative carbon dioxide (CO2) emissions to infer the future evolution of Arctic summer sea ice directly from the observational record.

Parent was probably thinking of the whole shipping industry which is responsible for ~3% of global emissions.

That’s an airline interest groups website so the figures are the rosiest you can find — not to say they’re egregiously wrong but they’re framed very positively.

Air travel doesn’t exist in isolation, less air travel _because_ less people are travelling means you would expect to see a reduction in car use too.

The figure agrees with the EESI, which claims 2.4% globally and 3% domestically: https://www.eesi.org/papers/view/fact-sheet-the-growth-in-gr...

I can't find any evidence that EESI has an industry bias.

I wonder how much of this is offset by the increase in shipping volume due to the increase in ecommerce volume.

Shipping by sea per item mile relative to alternative transportation methods is actually extremely efficient in emissions terms. Secondly, ecommerce might be up but overall consumption is down.

For ecommerce, "shipping" is certainly referring to shipping the item to the customer, ie. USPS/UPS/FedEx/Amazon trucks driving around.

Definitely been an increase in that.

It would still be a net loss in emissions compared to reality but less than a naive "there goes all of that fungible shipping demand forever" model as huge container ships are more efficient in emissions even though bunker oil tends to be dirtier than jet fuel. Plus overall goods consumption is certainly down with COVID.

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