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> Since we're talking about a deadly heat-wave, people will certainly ask what global warming has to do with this. Roughly speaking, global temperatures have in

> Since we're talking about a deadly heat-wave, people will certainly ask what global warming has to do with this. Roughly speaking, global temperatures have increased by about 1 degree Celsius over the past century. So a simple answer is that global warming is responsible for about 1 degree of the 10-degree heat anomaly. I don't think it's quite that simple; the average temperature has increased by 1°C, but that doesn't mean there can't be spikes, or even that some areas can actually become colder due to different weather patterns. The climate is a complex system with a lot of feedback loops.

scythe 5y ago
>I don't think it's quite that simple; the average temperature has increased by 1°C Yes, there are regional variations. But India sits right near the average. So this isn't a real problem for my analysis. See: https://commons.wikimedia.org/wiki/File:Map_global_warming_2010-2019.png https://commons.wikimedia.org/wiki/File:Map_global_warming_2...
- Beltalowda 5y ago
  But that only describes average temperature increases for a particular area? I'm not talking about regional variations, I mean that "an average increase of n°C" doesn't mean "it's now always n°C warmer than 100 years ago". If much of the year is only 0.5°C warmer and the occasional heat-wave several degrees warmer, then you can still end up with an average that's much lower than the top of the heat-wave spike. I believe in some areas winters are actually even cooler than before and summers warmer (don't know if that's also the case in India). Averages are a really poor way to understand most things.
  - scythe 5y ago
    >I mean that "an average increase of n°C" doesn't mean "it's now always n°C warmer than 100 years ago". If much of the year is only 0.5°C warmer and the occasional heat-wave several degrees warmer, then you can still end up with an average that's much lower than the top of the heat-wave spike. These ideas are statistically possible, but that doesn't mean that they're physically reasonable. A 1 C increase is proportionally an 0.3% increase in the actual temperature. You don't expect a whole lot of nonlinear effects by default. The effect I'm concerned with comes mostly from heat stored in the ocean, which is not that unstable. Now, if you want to talk about fires or hurricanes or something, sure, that's complicated. Most of the things that would cause increased variability do not apply. Moving snow lines don't matter because it's India (and not near the mountains). Wind isn't that important because temperature gradients are small at the equator. Cloud cover is very low in India in April and it isn't high right now (we're talking about a local atmospheric high, that's not cloudy). Changes in albedo, kinda-maybe, but it's the end of the dry season so things are already as brown as they get. Changes in evaporation/precipitation, again, it's the end of the dry season in India. You could make a case for shifts in the tropopause or whatever but that's why I said "probably" and not "definitely". Most of my post was about the fact that a +1 C contribution to a +10 C excess temperature is more important than it sounds at first. I don't feel like combing through Indian temperature records to prove a lazy ceteris paribus, but if we were in a bar I'd bet ten bucks that I'm within a factor of two.

scythe 5y ago

>I don't think it's quite that simple; the average temperature has increased by 1°C Yes, there are regional variations. But India sits right near the average. So this isn't a real problem for my analysis. See: https://commons.wikimedia.org/wiki/File:Map_global_warming_2010-2019.png https://commons.wikimedia.org/wiki/File:Map_global_warming_2...

Beltalowda 5y ago
But that only describes average temperature increases for a particular area? I'm not talking about regional variations, I mean that "an average increase of n°C" doesn't mean "it's now always n°C warmer than 100 years ago". If much of the year is only 0.5°C warmer and the occasional heat-wave several degrees warmer, then you can still end up with an average that's much lower than the top of the heat-wave spike. I believe in some areas winters are actually even cooler than before and summers warmer (don't know if that's also the case in India). Averages are a really poor way to understand most things.
- scythe 5y ago
  >I mean that "an average increase of n°C" doesn't mean "it's now always n°C warmer than 100 years ago". If much of the year is only 0.5°C warmer and the occasional heat-wave several degrees warmer, then you can still end up with an average that's much lower than the top of the heat-wave spike. These ideas are statistically possible, but that doesn't mean that they're physically reasonable. A 1 C increase is proportionally an 0.3% increase in the actual temperature. You don't expect a whole lot of nonlinear effects by default. The effect I'm concerned with comes mostly from heat stored in the ocean, which is not that unstable. Now, if you want to talk about fires or hurricanes or something, sure, that's complicated. Most of the things that would cause increased variability do not apply. Moving snow lines don't matter because it's India (and not near the mountains). Wind isn't that important because temperature gradients are small at the equator. Cloud cover is very low in India in April and it isn't high right now (we're talking about a local atmospheric high, that's not cloudy). Changes in albedo, kinda-maybe, but it's the end of the dry season so things are already as brown as they get. Changes in evaporation/precipitation, again, it's the end of the dry season in India. You could make a case for shifts in the tropopause or whatever but that's why I said "probably" and not "definitely". Most of my post was about the fact that a +1 C contribution to a +10 C excess temperature is more important than it sounds at first. I don't feel like combing through Indian temperature records to prove a lazy ceteris paribus, but if we were in a bar I'd bet ten bucks that I'm within a factor of two.