this post was submitted on 03 Mar 2024
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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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Energy efficiency of active travel (walking, cycling, ebike) compared to an electric car (slrpnk.net)
submitted 9 months ago* (last edited 9 months ago) by [email protected] to c/[email protected]
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[–] [email protected] 0 points 9 months ago* (last edited 9 months ago) (1 children)

Now do it at the same speed.

[–] Michal 4 points 9 months ago (1 children)

What sense would that make?

[–] [email protected] 2 points 9 months ago* (last edited 9 months ago) (1 children)

Kinetic energy is E=1/2mv^2 and because of aerodynamics and friction factors, energy efficiency (or, consumption) varies a lot at different speeds.

This graph has a nonlinear x scale because each vehicle’s entry is at a different speed, therefore the energy scale is nonsensical.

[–] Michal 3 points 9 months ago (1 children)

The end result will be useless because you won't cycle at car speeds and won't drive at walking speeds, so the energy per km wouldn't be realistic.

[–] [email protected] 2 points 9 months ago

Of course. But the way it is plotted now also gives a false sense of energy economy.

Maybe there’s another way to compare the data.

An energy-speed plot with multiple curves for the different vehicles comes to mind. Then simply stop plotting that curve when that vehicle is outside of its speed range.

I’m not contesting the notion that the plot is trying to convey; just that it’s not really the right format for visualizing this data.