this post was submitted on 11 Dec 2023
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Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.

As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades: Graph of temperature as observed with significant warming, and simulated without added greenhouse gases and other anthropogentic changes, which shows no significant warming

How much each change to the atmosphere has warmed the world: IPCC AR6 Figure 2 - Thee bar charts: first chart: how much each gas has warmed the world. About 1C of total warming. Second chart: about 1.5C of total warming from well-mixed greenhouse gases, offset by 0.4C of cooling from aerosols and negligible influence from changes to solar output, volcanoes, and internal variability. Third chart: about 1.25C of warming from CO2, 0.5C from methane, and a bunch more in small quantities from other gases. About 0.5C of cooling with large error bars from SO2.

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‘Megayachts’ are environmentally indefensible. The world must ban them. (www.theguardian.com)
submitted 11 months ago by [email protected] to c/[email protected]
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“The rich gazed at their superyachts, and decided they were not enough. The new breed of megayachts, which are at least 70 metres (230ft) in length, may be the most expensive moveable assets ever created.”

“First and foremost, owning a megayacht is the most polluting activity a single person can possibly engage in. Abramovich’s yachts emit more than 22,000 tonnes of carbon every year, which is more than some small countries. Even flying long-haul every day of the year, or air-conditioning a sprawling palace, would not get close to those emissions levels.

The bulk of these emissions happen whether or not a yacht actually travels anywhere. Simply owning one – or indeed building one – is an act of enormous climate vandalism.”

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[–] [email protected] 14 points 11 months ago

And when they're moving, they're highly inefficient as well. With a displacement ship hull designed to part the water their top speed is limited by their own length. A ship cannot overtake its own bow wake and with a length of let's say 70 meters you end up at a top speed of about 20 knots. Which isn't slow, but also not that much faster than cargo or passenger transport (maybe going 10 to 15 knots).

While a cargo ship is mostly longer and could theoretically sail faster, it is designed to be economical. It gets an engine that is most efficient at a certain speed, for example 12 knots at ahead standard, the propeller is cut for efficiency etc.

A yacht is designed to be comfortable and fast. It gets powerful engines that combust however much they need to combust. The propeller may be designed to produce less noise or vibration instead of being most fuel efficient.