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IPCC climate crisis report delivers ‘final warning on 1.5C’

theguardian.com

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Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#381

Post by 8note »

PaulDavisThe1st wrote: post #185

Just in case it saves one person the effort to research this themselves ... for some reason I find the measurement of climate change in units of temperature a bit problematic (though entirely rational). It tends to suggest the old bugbear of "global warming", which of course gets translated by deniers (& skeptics) into "well it's colder here so that's wrong". I spent a while digging in to try to get some numbers on a…

When we do hit whatever +1.5C or +2C, Q will be 0. The amount of energy input to the earth system isn't changing - that's defined by the temperature of the sun, it's the output that is decreasing.

What your energy look describes is dT/dt, how quickly we will reach the new equilibrium.

At the new equilibrium, the temperature is likely still to be the best descriptor of the new normal - we describe most processes and states in terms of temperatures they happen at, because it's and intensive property rather than an extensive one. You don't have to temper this 300 TW number by the mass or surface area of the earth to get a sense of what's happening when you use temperature

What's the energy number at which a glacier will melt? What's the temperature?

∆T is one of the most important numbers in thermodynamics for good reason

Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#382

Post by 8note »

dkjaudyeqooe wrote: post #233
PaulDavisThe1st wrote: post #185

Just in case it saves one person the effort to research this themselves ... for some reason I find the measurement of climate change in units of temperature a bit problematic (though entirely rational). It tends to suggest the old bugbear of "global warming", which of course gets translated by deniers (& skeptics) into "well it's colder here so that's wrong". I spent a while digging in to try to get some numbers on a…

> anyone familiar with complex physical systems will understand that when you add energy to such a system, the effects are often hard to predict This is something that is very underappreciated. It's entirely possible that the climate becomes chaotic (in a mathematical sense) and there are sudden, drastic changes that cause economic and social devastation. It seems inevitable that people will be complacent until it's…

Here's an experiment for you: take a two bar pendulum and set it at the bottom with no motion.

Now turn up the temperature in your house until it starts moving. You can put it in the oven and crank up the heat if you want

Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#383

Post by defrost »

toxik wrote: post #379
guerrilla wrote: post #220

Earlier quoted context omitted.

Why would you be confused about this? Temperature of a function of energy. We're talking about a global average temperature. Energy is being captured and retained. That raises the global average temperature. The specifics don't matter. Predicting the weather on the other hand is very complicated because you're asking what specifically will happen in a specific place. The variables going into that are many and even if…

This is reductionist, the specifics of what goes on at the surface do matter, that is the whole point of the climate change debate. How much chemical energy can we dig up and how do the byproducts affect the radiative ability of the planet (ie green house gases).

> How much chemical energy can we dig up and how do the byproducts affect the radiative ability of the planet (ie green house gases).

These are known stable parameters, we have a long recorded history of resource use and the insulative properties of gases in a mixture are tabled.

It's also well known in numerical modelling and physics why a number of systems have easy to predict long term coarse behaviour while also having short term impossible to predict fine grained behaviour, this exactly addresses your question about how can climate (coarse long term) be predicted when weather (short term, fine grained) is difficult.

See the Dzhanibekov Effect and the work of both Smale and Lorentz for insight.

A rotating (about intermediate axis) wing nut has a determined long arc trajectory of its CoG (centre of gravity) .. but an unpredictable short term tumble about its CoG.

Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#384

Post by missedthecue »

kypro wrote: post #59

Assume we hit 1.5C and "nothing happens" does this help the cause? While I'm very concerned about how unchecked climate change could impact future crop yields I also worry that having a hard line like this probably won't help convince anyone, and could counter intuitively act as a "I told you so" for climate denialists when the world doesn't fall apart as soon as we hit 1.5C. A lot of the more convincing arguments I…

I've read studies which conclude that climate change improves crop yields because carbon is an input to photosynthesis -- often the bottleneck. In addition, global warming frees up more arable land. After all, there is far more landmass in the northern hemisphere than at or around the equator. The net result is that some land become intolerable in certain areas and a lot of land becomes newly arable in other areas.

Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#385

Post by Extasia785 »

hn_throwaway_99 wrote: post #231
Extasia785 wrote: post #43

Earlier quoted context omitted.

1.5 degrees is commonly talked about because almost every country on earth pledged to "pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels" [0] in the Paris agreement. We won't hit that anymore, but it makes sense for scientists to compare the taken measures with the original goal. Every degree matters and aiming for 1.5 and missing by 0.5 degrees is better than aiming for a "realist…

Thanks very much for your response, I think it makes the most sense - that is, 1.5 degrees isn't some "magic number", but every .1 degree makes things disproportionally worse , and we want to limit the damage as much as possible. In that case, I think still harping on the 1.5 degree number is a communications mistake. It is obviously impossible at this point (see the edit in my original comment), and so I think focus…

Well what you are criticizing is mainly a problem of the media. Look at the actual IPCC report [0], there multiple scenarios are outlined, with 1.5 degrees being the most optimistic one, which makes sense. I did not read through it yet, but from a quick glance they do describe the impact of different scenarios, while also presenting measures to reach those, just like you asked for. You sadly can not expect that kind of nuance from the media though, most articles (just like the linked The Guardian article) seem to focus exclusively on the 1.5 degrees scenario.

[0] https://report.ipcc.ch/ar6syr/pdf/IPCC_AR6_SYR_SPM.pdf

Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#386

Post by dexterlagan »

For a counterpoint, I thought wattsupwiththat's analysis was alright. But I'm not qualified enough to make a definitive judgment. Can somebody better informed tell me if this article is complete bull?

https://wattsupwiththat.com/2023/03/15/climate-crisis-what-c...

Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#387

Post by defrost »

missedthecue wrote: post #384
kypro wrote: post #59

Assume we hit 1.5C and "nothing happens" does this help the cause? While I'm very concerned about how unchecked climate change could impact future crop yields I also worry that having a hard line like this probably won't help convince anyone, and could counter intuitively act as a "I told you so" for climate denialists when the world doesn't fall apart as soon as we hit 1.5C. A lot of the more convincing arguments I…

I've read studies which conclude that climate change improves crop yields because carbon is an input to photosynthesis -- often the bottleneck. In addition, global warming frees up more arable land. After all, there is far more landmass in the northern hemisphere than at or around the equator. The net result is that some land become intolerable in certain areas and a lot of land becomes newly arable in other areas.

Many of those studies also conclude "more plant, less food", or:

    Temperature is not the only factor the models consider when simulating future crop yields. Higher levels of carbon dioxide in the atmosphere have a positive effect on photosynthesis and water retention, increasing crop yields, though often at a cost to nutrition.
and

    Increases in temperature and carbon dioxide (CO2) can increase some crop yields in some places. But to realize these benefits, nutrient levels, soil moisture, water availability, and other conditions must also be met.
https://climate.nasa.gov/news/3124/global-climate-change-imp...

https://theconversation.com/climate-change-is-affecting-crop...

https://climatechange.chicago.gov/climate-impacts/climate-im...

Here (W.Australia) we're busy trialing many wheat (and other) varieties for future use but its better to deal with AGW by reducing C02 (and methane and water vapor) in the atmosphere than by soft selling adaption.

Over threshold things are predicted to tip and get uncontrollably worse.

Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#388

Post by cambaceres »

c1sc0 wrote: post #374
rkuykendall-com wrote: post #363

Earlier quoted context omitted.

It seems inevitable that [conservatives] will be complacent until it's too late. Let's not white-wash the problem.

The problem looks pretty “white” to me already.

What does that mean?

Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#389

Post by Swinx43 »

mulmen wrote: post #287
saulpw wrote: post #257

Earlier quoted context omitted.

The US is basically the only country in the world that uses the Fahrenheit scale.

This is false. Fahrenheit is commonly used in Canada to this day. Awareness of the scale still exists in the UK as well. Any commonwealth country is likely to have awareness because metrication happened so late in those countries.

That is unfortunately not correct. I grew up in a commonwealth country, have travelled to many others, and now live in the UK. Not a single person I know in either country has even the faintest idea what Fahrenheit numbers mean for temperature. It is never used in any way in these countries.

Re: IPCC climate crisis report delivers ‘final warning on 1.5C’

#390

Post by mulmen »

Swinx43 wrote: post #389
mulmen wrote: post #287

Earlier quoted context omitted.

This is false. Fahrenheit is commonly used in Canada to this day. Awareness of the scale still exists in the UK as well. Any commonwealth country is likely to have awareness because metrication happened so late in those countries.

That is unfortunately not correct. I grew up in a commonwealth country, have travelled to many others, and now live in the UK. Not a single person I know in either country has even the faintest idea what Fahrenheit numbers mean for temperature. It is never used in any way in these countries.

It is used for cooking in Canada even today. Here’s a UK weather report from 1987 that uses both Celsius and Fahrenheit: https://youtu.be/NnxjZ-aFkjs. Celsius is the default but there are living people in the UK who recall using the Fahrenheit scale. This is much less common outside the commonwealth.
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