this post was submitted on 10 Jul 2025
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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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Submerged in about 40 meters (44 yards) of water off Scotland’s coast, a turbine has been spinning for more than six years....

The MeyGen tidal energy project off the coast of Scotland has four turbines producing 1.5 megawatts each, enough electricity collectively to power up to 7,000 homes annually.

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[–] Scott_of_the_Arctic@lemmy.world 14 points 2 days ago (8 children)

Not sure how feasible it is to roll this out large scale. There aren't that many stretches of water as lively as the pentland firth.

[–] Semi_Hemi_Demigod@lemmy.world 18 points 2 days ago (4 children)

This is true, but I think the big thing is that this lasted as long as it did. Material science is important, and if we want Io scale these up for more general use we need to make sure they can at least survive.

Thanks to the power of two, a larger diameter blade could capture a lot more energy, and might be put in places with lesser tidal bores.

[–] Scott_of_the_Arctic@lemmy.world 1 points 21 hours ago* (last edited 21 hours ago) (1 children)

The problem is not that there isn't enough tidal power. The problem is that the pentland firth is both fast enough and deep enough. Orkney alone probably has enough tidal power to serve all of Scotland's needs, but most of the tide races are no more than 5 meters deep. The meygen turbine has a 18 m diameter so it's hard to find places that can support it in a way that doesn't pose a danger for surface vessels but also has a current fast enough to generate a meaningful amount of electricity.

[–] Semi_Hemi_Demigod@lemmy.world 0 points 21 hours ago

If we’re going to get to 100m diameter tidal power systems in hundreds of meters of water we’ve got to start somewhere.

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