this post was submitted on 20 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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In a win for the climate, urban speed limits are dropping | Slower traffic speeds protect pedestrians and cyclists, helping more people access climate-friendly transportation. (yaleclimateconnections.org)
submitted 1 year ago by [email protected] to c/[email protected]
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[–] [email protected] 3 points 1 year ago (2 children)

In urban areas, speed limits make very little difference to journey times because you spend so much of your journey either stationary at junctions or accelerating or decelerating out of and in to junctions. If you were to track how much time you spend actually doing ~30mph in a journey through a 30mph zone, you'd find it's very little of it!

[–] Mojojojo1993 2 points 1 year ago

Fair enough. Bit again. Get a bus then or tram train whatever.

I'more talking about out of the cities. Out of urban areas

[–] bigschnitz 2 points 1 year ago

In well designed urban areas, where lights are synchronized I would expect a change in speed limit without changes in traffic light logic to increase time spent waiting at lights.

This has a knock on effect in heavy traffic areas as a car in front stopping might take 10 seconds to take off when the signal changes, but each car behind them has the cumulative delay of each driver in front, so a 10 seconds delay for the first car would likely be closer to a full minute for the fifth car.

I'm not sure that this extra time spent idling would be enough to undo the reduction in emissions due to lowering speed limits (more likely for EVs I imagine), but if implemented sloppily (as has been the case every time I've ever seen a speed limit on a road reduced), it does add significant time to commutes during busy times and should actually be thought through properly, with other changes to optimize traffic because of it, fully considered.

A far more effective and cheaper way of reducing emissions is invest in reliable and affordable public transit options, or better yet safe cycle paths.