4 ms·

Newtonian mechanics is the approximation of Einstein's work to the speeds and masses that are accessible on Earth, it is not wrong and usually still sufficient

by kaybe 8y ago

Newtonian mechanics is the approximation of Einstein's work to the speeds and masses that are accessible on Earth, it is not wrong and usually still sufficient unless you need insane precision or want to research large masses or speeds. Warmer air can hold more water vapor. This effect is of course included in the research.

southern_cross 8y ago
The whole thing with Mercury was readily visible and had been observed for a long time, but Newton and others never came up with an acceptable explanation for it while Einstein did. This didn't involve insane precision or high speeds or anything like that. (I guess the Sun counts as a pretty large mass, though.) And the basic rules of Newtonian gravity have been repeatedly questioned lately (beyond Einstein's revisions), but I don't know if any of that has stuck. > Warmer air can hold more water vapor. Yes indeed it can, and said water vapor (being a greenhouse gas) can induce more greenhouse gas effects. But this appears to be routinely glossed over, as if it's just a non-issue; not everyone agrees with that assessment, though. As to the warmer air thing, lots of people make statements to the effect that warmer air holding more water vapor will lead to much heavier rainfall and such. Which certainly MIGHT be true, but it doesn't HAVE to be true. Why? Because there's nothing that says that all of that additional water vapor has to fall out of the sky in one fell swoop; a lot of it may just stick around as higher humidity. Plus it is well-known that rain sometimes falls from the clouds only to evaporate again in the warmer, drier air underneath those clouds, so it never actually makes it to the ground, and generally warmer air may lead to more of that. You almost never hear these facts mentioned, though. Funny story: Some years back I was listening to a science podcast where a climatologist and an oceanographer were guests, and the subject of sea and air temperatures came up. The climatologist made a statement about "warming temperatures leads to more storms" and such, but the oceanographer corrected him, saying that while that used to be the thinking, further research had shown that if sea and air temperatures would changing more or less in tandem (both warming up together, in this case), then surprisingly the overall effect on storms actually appeared to be pretty inconsequential. And I thought the climatologist was going to blow a gasket over this; I mean, how DARE the oceanographer go "off message" like that!
- kaybe 8y ago
  > Yes indeed it can, and said water vapor (being a greenhouse gas) can induce more greenhouse gas effects. But this appears to be routinely glossed over, as if it's just a non-issue; not everyone agrees with that assessment, though. You mean as in the models don't include it? I'm very sure they do, I'd have to search for citation though. > As to the warmer air thing, lots of people make statements to the effect that warmer air holding more water vapor will lead to much heavier rainfall and such. Which certainly MIGHT be true, but it doesn't HAVE to be true. That's why we use models to try and figure out what the probable truth is. This part is hard though, and only 'medium confidence' is reached for any influence on the water cycle since 1960 at all. (https://ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_TS_FINAL.pdf https://ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_TS_FINA...) I wouldn't rely too much on those precipitations change forecasts yet either, but things will change if we keep going like this. > Funny story: .. Haha, I can imagine. The storm thing is complex and hard to predict too. Let me cite the IPCC report: 'Confidence remains low for long-term (centennial) changes in tropical cyclone activity, after accounting for past changes in observing capabilities. However, for the years since the 1970s, it is virtually certain that the frequency and intensity of storms in the North Atlantic have increased although the reasons for this increase are debated (see TFE.9). There is low confidence of large-scale trends in storminess over the last century and there is still insufficient evidence to determine whether robust trends exist in small-scale severe weather events such as hail or thunderstorms.' Table 11 here has details on the model runs: https://ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter11_FINAL.pdf https://ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter... Looks like your oceanographer was right. But I guess your point was the attitude, not the facts. There seems to be a general problem in communication since the beginning. Concluding, what's your general point? Do you think that CO2 is not a problem? Do you want to doubt the specific predictions? (The IPCC reports helps to differentiate between virtually certain and still doubtful points, they're not all the same.) Do you want to critize the attitude in communication? (I do think these issues need to be communicated and discussed better. Also, at this point it's really in the hands of politicians and society to work with this, not scientists.) Addendum: There is vivid discussion of the water issue here: https://www.skepticalscience.com/water-vapor-greenhouse-gas.htm https://www.skepticalscience.com/water-vapor-greenhouse-gas....

by kaybe 8y ago

southern_cross 8y ago

The whole thing with Mercury was readily visible and had been observed for a long time, but Newton and others never came up with an acceptable explanation for it while Einstein did. This didn't involve insane precision or high speeds or anything like that. (I guess the Sun counts as a pretty large mass, though.) And the basic rules of Newtonian gravity have been repeatedly questioned lately (beyond Einstein's revisions), but I don't know if any of that has stuck. > Warmer air can hold more water vapor. Yes indeed it can, and said water vapor (being a greenhouse gas) can induce more greenhouse gas effects. But this appears to be routinely glossed over, as if it's just a non-issue; not everyone agrees with that assessment, though. As to the warmer air thing, lots of people make statements to the effect that warmer air holding more water vapor will lead to much heavier rainfall and such. Which certainly MIGHT be true, but it doesn't HAVE to be true. Why? Because there's nothing that says that all of that additional water vapor has to fall out of the sky in one fell swoop; a lot of it may just stick around as higher humidity. Plus it is well-known that rain sometimes falls from the clouds only to evaporate again in the warmer, drier air underneath those clouds, so it never actually makes it to the ground, and generally warmer air may lead to more of that. You almost never hear these facts mentioned, though. Funny story: Some years back I was listening to a science podcast where a climatologist and an oceanographer were guests, and the subject of sea and air temperatures came up. The climatologist made a statement about "warming temperatures leads to more storms" and such, but the oceanographer corrected him, saying that while that used to be the thinking, further research had shown that if sea and air temperatures would changing more or less in tandem (both warming up together, in this case), then surprisingly the overall effect on storms actually appeared to be pretty inconsequential. And I thought the climatologist was going to blow a gasket over this; I mean, how DARE the oceanographer go "off message" like that!

kaybe 8y ago
> Yes indeed it can, and said water vapor (being a greenhouse gas) can induce more greenhouse gas effects. But this appears to be routinely glossed over, as if it's just a non-issue; not everyone agrees with that assessment, though. You mean as in the models don't include it? I'm very sure they do, I'd have to search for citation though. > As to the warmer air thing, lots of people make statements to the effect that warmer air holding more water vapor will lead to much heavier rainfall and such. Which certainly MIGHT be true, but it doesn't HAVE to be true. That's why we use models to try and figure out what the probable truth is. This part is hard though, and only 'medium confidence' is reached for any influence on the water cycle since 1960 at all. (https://ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_TS_FINAL.pdf https://ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_TS_FINA...) I wouldn't rely too much on those precipitations change forecasts yet either, but things will change if we keep going like this. > Funny story: .. Haha, I can imagine. The storm thing is complex and hard to predict too. Let me cite the IPCC report: 'Confidence remains low for long-term (centennial) changes in tropical cyclone activity, after accounting for past changes in observing capabilities. However, for the years since the 1970s, it is virtually certain that the frequency and intensity of storms in the North Atlantic have increased although the reasons for this increase are debated (see TFE.9). There is low confidence of large-scale trends in storminess over the last century and there is still insufficient evidence to determine whether robust trends exist in small-scale severe weather events such as hail or thunderstorms.' Table 11 here has details on the model runs: https://ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter11_FINAL.pdf https://ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter... Looks like your oceanographer was right. But I guess your point was the attitude, not the facts. There seems to be a general problem in communication since the beginning. Concluding, what's your general point? Do you think that CO2 is not a problem? Do you want to doubt the specific predictions? (The IPCC reports helps to differentiate between virtually certain and still doubtful points, they're not all the same.) Do you want to critize the attitude in communication? (I do think these issues need to be communicated and discussed better. Also, at this point it's really in the hands of politicians and society to work with this, not scientists.) Addendum: There is vivid discussion of the water issue here: https://www.skepticalscience.com/water-vapor-greenhouse-gas.htm https://www.skepticalscience.com/water-vapor-greenhouse-gas....