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Cake day: July 10th, 2023

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  • https://www.ipcc.ch/report/ar6/syr/

    I’m looking at the Full Volume, and on page 71 you can see

    With about 2°C warming, climate-related changes in food availability and diet quality are estimated to increase nutrition-related diseases and the number of undernourished people, affecting tens (under low vulnerability and low warming) to hundreds of millions of people (under high vulnerability and high warming) … Climate change risks to cities, settlements and key infrastructure will rise sharply in the mid and long term with further global warming, especially in places already exposed to high temperatures, along coastlines, or with high vulnerabilities (high confidence).

    At global warming of 3°C, additional risks in many sectors and regions reach high or very high levels, implying widespread systemic impacts, irreversible change and many additional adaptation limits (see Section 3.2) (high confidence). For example, very high extinction risk for endemic species in biodiversity hotspots is projected to increase at least tenfold if warming rises from 1.5°C to 3°C (medium confidence). Projected increases in direct flood damages are higher by 1.4 to 2 times at 2°C and 2.5 to 3.9 times at 3°C

    Global warming of 4°C and above is projected to lead to far-reaching impacts on natural and human systems (high confidence). Beyond 4°C of warming, projected impacts on natural systems include local extinction of ~50% of tropical marine species (medium confidence) and biome shifts across 35% of global land area (medium confidence). At this level of warming, approximately 10% of the global land area is projected to face both increasing high and decreasing low extreme streamflow, affecting, without additional adaptation, over 2.1 billion people (medium confidence) and about 4 billion people are projected to experience water scarcity (medium confidence). At 4°C of warming, the global burned area is projected to increase by 50 to 70% and the fire frequency by ~30% compared to today

    However, if you really want to get into it, you can read the Climate Change 2022: Impacts, Adaptation and Vulnerability Full Report. It has a lot more details about the effects of climate change on all parts of the world, but it’s also a 3,000 page pdf.


  • ltxrtquq@lemmy.mltoMicroblog Memes@lemmy.worldI'm Greganent?
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    28 days ago

    “Driven” suggest more than half of total pregnancies,

    Less than 20% of a total is “significant”?

    The amount the percentage represents is irrelevant. A billion people could be involved, but if the total is 7 billion, it’s not going to be a significant part of the total trend.

    In the terms of your analogy, this is about 3 people out of 20 pedaling a (weirdly long) bike and steered by all of them (somehow). Would you say that group of 3 are driving? Or would you concede it’s the two groups of 6 that are mostly driving the bike?

    Your “words wholly” includes more than whatever you think it does.

    My point has always been about this study

    Has it? I think you’re far less clear and careful with your words than you think you are. You’ve been arguing from the start that less than half of something isn’t and can’t be significant. We aren’t even discussing the text in this study that you can read in the screenshot:

    More than half the drop of America’s total fertility rate is explained by women under the age of 19 now having next to no children.

    What you’re saying now about “the traditional driver of USA birth rates” isn’t reflected in your other comments.


  • ltxrtquq@lemmy.mltoMicroblog Memes@lemmy.worldI'm Greganent?
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    29 days ago

    Your numbers are all over the place and don’t really make sense for what you’re talking about. 3 plus two groups of 6 would only be 15 out of 20, so where did the other 5 people go?

    But more to the point, if those 3 stop pedaling, or pedal harder than everyone else combined, or apply the brakes, or tip the bike over, any number of other things they could absolutely change the speed/direction of the bike.











  • ltxrtquq@lemmy.mltoScience Memes@mander.xyzSquare!
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    2 months ago

    Given r=f(θ), we are generally not concerned with r′=f′(θ); that describes how fast r changes with respect to θ

    You’re using the derivative of a polar equation as the basis for what a tangent line is. But as the textbook explains, that doesn’t give you a tangent line or describe the slope at that point. I never bothered defining what “tangent” means, but since this seems so important to you why don’t you try coming up with a reasonable definition?


  • ltxrtquq@lemmy.mltoScience Memes@mander.xyzSquare!
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    2 months ago

    I think we fundamentally don’t agree on what “tangent” means. You can use

    x=f(θ)cosθ, y=f(θ)sinθ to compute dydx

    as taken from the textbook, giving you a tangent line in the terms used in polar coordinates. I think your line of reasoning would lead to r=1 in polar coordinates being a line, even though it’s a circle with radius 1.


  • ltxrtquq@lemmy.mltoScience Memes@mander.xyzSquare!
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    2 months ago

    Given r=f(θ), we are generally not concerned with r′=f′(θ); that describes how fast r changes with respect to θ

    I think this part from the textbook describes what you’re talking about

    Instead, we will use x=f(θ)cosθ, y=f(θ)sinθ to compute dydx.

    And this would give you the actual tangent line, or at least the slope of that line.


  • ltxrtquq@lemmy.mltoScience Memes@mander.xyzSquare!
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    2 months ago

    Polar Functions and dydx

    We are interested in the lines tangent a given graph, regardless of whether that graph is produced by rectangular, parametric, or polar equations. In each of these contexts, the slope of the tangent line is dydx. Given r=f(θ), we are generally not concerned with r′=f′(θ); that describes how fast r changes with respect to θ. Instead, we will use x=f(θ)cosθ, y=f(θ)sinθ to compute dydx.

    From the link above. I really don’t understand why you seem to think a tangent line in polar coordinates would be a circle.


  • ltxrtquq@lemmy.mltoScience Memes@mander.xyzSquare!
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    2 months ago

    A straight line in polar coordinates with the same tangent would be a circle.

    I’m not sure that’s true. In non-euclidean geometry it might be, but aren’t polar coordinates just an alternative way of expressing cartesian?

    Looking at a libre textbook, it seems to be showing that a tangent line in polar coordinates is still a straight line, not a circle.