Originally posted by sylas
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My guess: people who are not knowledgeable or committed on the subject; but who see all the internet argument going on and don't know what to think.
Originally posted by Sylas
I suspect most people have some predispositions in sorting out subjects with which they are not familiar. By and large, most folks:
These presumptions can conflict with each other at times; the video is good in that it does not slip into personal attacks but goes straight to a focus on the substance, with information that is readily checked.
I'm going to summarize the points made.
I'm sure there will be people here who would like to argue one or more of these points. I'm not sure how much that achieves; though I do put my oar in on the topic from time to time. Honestly, the video is giving pretty solid information that is relatively easy to back up when you chase the specifics. There are a couple of points I'd rephrase a little; but nothing that would give any comfort to the sunglasses guy.
I don't think the video will work with people who are already (so-called) "climate skeptics"; but it's a pretty good summary of the basic science based reply to several commonly repeated misconceptions, useful for those who simply want to know what the scientific response is to the claims from sunglasses guy.
Cheers -- sylas
- Presume (in general) that a major field of academic study or science is not going to be riddled through and through with fraud or incompetence.
- Presume (in general) that confident assertions of fact used as the premise of an argument actually are true.
- Presume (in general) that most people talk about subjects in good faith.
These presumptions can conflict with each other at times; the video is good in that it does not slip into personal attacks but goes straight to a focus on the substance, with information that is readily checked.
I'm going to summarize the points made.
- The terms "global warming" and "climate change" are both correct, and have both been used for a long time. The planet as a whole is heating up, but not uniformly, and as a result climate is changing in many ways around the planet as patterns are shifting in response to the additional heat overall.
- Yes, the planet is warming.
- For the last fifty years and more; ever since the beginning of quantified study of global climate, science has indicated that atmospheric changes are likely to heat up the planet. This indication has indeed now been confirmed. In early days (about forty years ago) a minority of working scientists raised legitimate concerns about possible global cooling. That has always been a minority position, and it fairly quickly fell by the wayside as measurement and theory developed. (Really. The papers and research are all on record. The global cooling concerns of the 1970s -- though perfectly serious science at the time -- were always very much in the minority.)
- Yes, the planet is warming.
- Arctic sea ice is declining. There can be short periods (very short periods, like two or three years!) where there's a brief recovery, but the trend is a very strong downward spiral.
- In recent decades, when global warming has taken off strongly, the Sun has been getting very slightly dimmer, not brighter. The Sun is definitely not the cause of global warming.
- Humans are the cause of increasing CO2 levels. Natural exchange between atmosphere and ocean have larger magnitudes, but they cancel. (Or, to put it another way, not explicit in the video: carbon cycles around the atmosphere, the ocean and the biosphere, with very large seasonal exchanges of carbon moving between those stores of carbon. Humans are adding carbon into that overall cycle, and no other process even comes close in terms of magnitude of adding carbon to the overall cycle. The result is a very rapid increase in carbon in the ocean AND the atmosphere, in particular. The "Keeling curve" of measured CO2 in the atmosphere shows how this works:
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Every year huge amounts of carbon move in and out of the atmosphere in a regular cycle, so the curve looks like a wave, going up and down every year, rising by more than 5ppm in NH winter, and falling about the same amount in NH summer. Every year there's also an addition of new carbon, so the whole cycle keeps moving steadily upwards by about 1.5 to 2 ppm per year. This increase is roughly half of what humans are adding; the other half is getting flushed into the ocean. We also measure a steady change in the isotopes of carbon, showing that yes, the increase is from carbon coming from fossil fuels. - Volcanoes are not even close to human output for magnitude of CO2 change. They emit a fraction of a percent of what humans are emitting; claims to the contrary are just wrong.
- Water in the atmosphere is the largest contributor to the greenhouse effect. The only way to increase water in the atmosphere is to increase temperatures, because warm air holds more water. Water thus works to amplify any effect that heats or cools the atmosphere. It's a positive feedback on warming that is being driven mainly by increasing CO2 levels.
- Predictions of temperature change are actually quite a good match with what is being measured. (I'd quibble with how this is explained in the video, but the main point holds. Rates of warming really are pretty close to what is expected; and so too are the magnitudes of shorter term natural variability.)
- Climate can change for many reasons. (The video cites Milankovitch cycles; that's a major one over the last couple of million years.) At the moment, humans are the major cause of change at work.
- Ice ages and the end of ice ages are triggered by Milankovitch cycles. CO2 increase(conversely decrease) comes from the ocean in response to warming (conversely cooling) temperatures, and this amplifies the effect. So ice ages are not actually driven by CO2, but CO2 has a major effect in how much climate changes. (I'd have explained this a bit differently, myself. There's more involved than solubility. But as a starter the video is okay.)
- The consequences leading on from global warming are going to be mostly problems -- expensive ones. Minimizing the magnitude of change is the cost-effective choice.
I'm sure there will be people here who would like to argue one or more of these points. I'm not sure how much that achieves; though I do put my oar in on the topic from time to time. Honestly, the video is giving pretty solid information that is relatively easy to back up when you chase the specifics. There are a couple of points I'd rephrase a little; but nothing that would give any comfort to the sunglasses guy.
I don't think the video will work with people who are already (so-called) "climate skeptics"; but it's a pretty good summary of the basic science based reply to several commonly repeated misconceptions, useful for those who simply want to know what the scientific response is to the claims from sunglasses guy.
Cheers -- sylas
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