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BornFromTheVoid

Climate Questions

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2 hours ago, Sky Full said:

This is a very useful thread for those of us who are worried by the conflicting opinions and data which jostle each other in the climate warming debate and confuse the unqualified onlooker.  There is plenty of atmospheric temperature based evidence to demonstrate that the global climate is warming but, in my opinion, still far too much reliance being placed on the ability of the human race to brake or even reverse the process.  The issue I wish to raise relates to the increasingly rapid retreat of the worlds glaciers and the drastic reduction in the size of the Arctic / Antarctic ice sheets.  There can be no argument about this because photographic evidence clearly shows glaciers retreating back up mountains in every range in the world.  The Antarctic ice sheet has been shown by satellite images to be breaking up for decades now and we all know that the North Pole could be ice free within 20 years.  Given that the ice bound regions of the world have for millennia reflected back into space a portion of the Suns energy and prevented the oceans in those areas from absorbing heat from the sun, my worry is this: as the ice gradually disappears is it not the case that the sun will have an increasingly warming effect on the globe which becomes self-accelerating (i.e. the more the ice melts, the warmer it gets, and the more the ice melts etc....).  Land and oceans left ice free will absorb far more energy and contribute to the overall warming far more than when covered with ice.  It seems too late to hope that we can replace the ice which has already melted so, even if we reduce our emissions today, is it also too late to stop the rest of the ice from melting now?  If this is true, could the world continue to heat up due to its less reflective nature even with zero emissions from mankind?  Is this process being taken into account by climate warming models?  Have there been any studies to show what the world would be like - habitable or not? - if it were to become largely ice-free (apart from sea level rises which would be devastating enough on their own)?

Sorry .... Far too many questions in one post!

 

Yes, Ice-albedo feedback is a well know, and long known, phenomena. You are right about the consequences of it.

Indeed, aiui, a good portion of the projected modeled warming is due to ice-albedo warming - though exactly how much I'm not sure.

As to 'too much reliance being placed on the ability of the human race to brake or even reverse the process.' well, (as bftv said in this post) 'This all feels a bit like a gambler. Someone that had a short period of success but now is almost broke, with his home, family, and career on the line. He starts asking around for solutions, but with the caveat that nobody suggests he stops gambling or reduce how much he gambles. Anyone that suggests those things he decries as naive and unrealistic, insinuates ulterior motives for suggesting them and uses whatever he can to try attack their character.'

 

 

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5 hours ago, Devonian said:

Yes, Ice-albedo feedback is a well know, and long known, phenomena. You are right about the consequences of it.

Indeed, aiui, a good portion of the projected modeled warming is due to ice-albedo warming - though exactly how much I'm not sure.

As to 'too much reliance being placed on the ability of the human race to brake or even reverse the process.' well, (as bftv said in this post) 'This all feels a bit like a gambler. Someone that had a short period of success but now is almost broke, with his home, family, and career on the line. He starts asking around for solutions, but with the caveat that nobody suggests he stops gambling or reduce how much he gambles. Anyone that suggests those things he decries as naive and unrealistic, insinuates ulterior motives for suggesting them and uses whatever he can to try attack their character.'

Thanks for the reply Devonian (a great Epoch, that).  I hope it didn't sound like I am against any effort being made to counter man-made climate change - I am in favour of any steps we can take to reduce the threat of global warming - but I am increasingly coming to the conclusion that there is little chance of successful action given the current human population of the planet and its projected growth rate in the future.

4 hours ago, knocker said:

And

The albedo effect and global warming

https://skepticalscience.com/earth-albedo-effect.htm

needless to say this is a very complex area and research is ongoing

Thanks for this link Knocker - it's clearly an extremely complex phenomenon and its effects seem to be difficult to accurately forecast with current levels of analysis and observation.  Returning to my question regarding the habitability of the Earth if all the ice were to melt, there was a reference to this which implied that the extra water vapour in the atmosphere would create more clouds which, although they are reflective are even more effective as a greenhouse gas and so would also further increase global temperatures.  As I understand this, in an extreme future, the Earth could conceivably become another Venus shrouded in insulating clouds with runaway surface temperatures rendering all life impossible......

Best we try and find a solution before this happens, then.

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19 hours ago, Sky Full said:

 

Thanks for this link Knocker - it's clearly an extremely complex phenomenon and its effects seem to be difficult to accurately forecast with current levels of analysis and observation.  Returning to my question regarding the habitability of the Earth if all the ice were to melt, there was a reference to this which implied that the extra water vapour in the atmosphere would create more clouds which, although they are reflective are even more effective as a greenhouse gas and so would also further increase global temperatures.  As I understand this, in an extreme future, the Earth could conceivably become another Venus shrouded in insulating clouds with runaway surface temperatures rendering all life impossible......

Best we try and find a solution before this happens, then.

First a brief summation from Raymond Pierrehumbert

The fact that Earth maintained habitable conditions while Venus succumbed to a runaway greenhouse and got too hot, and Mars lost its atmosphere and got too cold, raises the question of just how narrowly Earth escaped the fate of Mars and Venus. How much could Earth’s orbital distance be changed before it turned into Mars or Venus, and how would the answer to this question change if Earth were more massive (making it easier to hold onto atmosphere) or less massive (making it easier to lose atmosphere)? If Mars were as large as Earth, would it still be habitable today? What if Venus were as small as Mars? Perhaps if the orbits of Mars and Venus were exchanged, our Solar System would have three habitable planets, instead of just one.

The range of orbital distances for which a planet retains Earthlike habitability over billions of years is known as the habitable zone. Determining the habitable zone, and how it is affected by planetary size and composition as well as the properties of the parent star, is one of the central problems of planetary climate.

But to be more specific regarding your question then yes the earth’s habitability will end when the sun leaves the main sequence and expands into a red giant but that is about four billion years hence.

But a habitable crisis could occur before that. In particular, as the sun continues to brighten, at some point the brightness will outstrip the ability of the silicate weathering process to compensate by drawing down CO2. At that point the earth would succumb to a runaway greenhouse, become lethally hot, and lose all its water to space.

In short I don't think we need concern ourselves about a runaway greenhouse effect but we should most be very concerned about the way we knowingly slowly destroying our planet

Edited by knocker

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4 hours ago, knocker said:

But to be more specific regarding your question then yes the earth’s habitability will end when the sun leaves the main sequence and expands into a red giant but that is about four billion years hence.

But a habitable crisis could occur before that. In particular, as the sun continues to brighten, at some point the brightness will outstrip the ability of the silicate weathering process to compensate by drawing down CO2. At that point the earth would succumb to a runaway greenhouse, become lethally hot, and lose all its water to space.

In short I don't think we need concern ourselves about a runaway greenhouse effect but we should most be very concerned about the way we knowingly slowly destroying our planet

Thanks Knocker - that was a very interesting quotation and summary.  You are an absolute mine of information and of links to others with information or data, and we are lucky to have you!

To take this question a little further, if it is unlikely that human actions alone could cause a runaway greenhouse effect in the foreseeable or even the far distant future, it must be arguable that there continues to be a reasonable hope for humankind to live out its natural evolution on earth.   I have always believed that even moderate climate change might be capable of upsetting the delicate balance of nature, eventually bringing about the extinction of all complex animal life on the planet and that this would then remain the state of the world for many millions of years until different forms of life emerge and evolve to cope with the new conditions, much like the events of pre-history.   Perhaps climate change / global warming could be limited in its effects, serious though they may be, and life including humans may continue to exist after the worst happens, albeit in much reduced numbers and variety and even perhaps at the extreme edge of survival?  Not that this is should provide any excuse to continue consuming the worlds resources at the present rate, of course....

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Thank you SF but this area is much luckier in having the commitment and knowledge of BFTV over the years 🙂

Edited by knocker

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