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climate change

  • 18-06-2013 11:49am
    #1
    Registered Users, Registered Users 2 Posts: 69 ✭✭


    'climate change' has been occuring long before humans ever existed and long before humans ever produced a serious amount of greenhouse gases etc... what makes us so sure that its us thats causing the current climate change despite the fact that silmilar changes have occured throughout history without our help... is this another example of humans egocentric-ness??


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Comments

  • Registered Users, Registered Users 2 Posts: 28,789 ✭✭✭✭ScumLord


    'climate change' has been occuring long before humans ever existed and long before humans ever produced a serious amount of greenhouse gases etc... what makes us so sure that its us thats causing the current climate change despite the fact that silmilar changes have occured throughout history without our help... is this another example of humans egocentric-ness??
    The climate is always changing and because it's always changing we do have some idea of how it changes naturally without human intervention. So it's not just a guess by scientists.

    Humans have been having a big effect on the ecosystem for a long time. When the last ice age was drawing to a close humans in north America went on a killing rampage and wiped out many species using just stone tools, I believe it was the largest extinction event since the meteor that wiped out the dinosaurs. Animals that survived previous ice ages disappeared when humans were brought into the equation.

    This isn't unique to humans either, other animals have been introduced to ecosystems and changed that ecosystem.

    I think rather than us changing the ecosystem it's probably more a case of we're speeding up the change that would happen anyway. We are obviously having an effect.

    The real problem with climate change is that we're effectively changing the environment away from one that's ideal for humans, rather than breaking the climate.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,599 Mod ✭✭✭✭Capt'n Midnight


    We own the nitrogen cycle. Humans fix more nitrogen than any other species.
    We are responsible for most of the ozone hole.

    You can argue about the CO2 from us vs. nature, but if you take into account desertification and desertification and changing the vegetation in most arable and many grassland areas andthe draining of bogs and clearing land by burning it's clear we are involved in other ways besides industrial emissions.

    Even if you argue that the underlying cycle is natural we are the storm surge at high tide.

    Yes volcanoes could out do us, but volcanoes can create mass extinctions so not really saying much,


  • Registered Users, Registered Users 2 Posts: 28,789 ✭✭✭✭ScumLord


    Yes volcanoes could out do us, but volcanoes can create mass extinctions so not really saying much,
    The other thing about volcanoes is that destructive as they are, in the long run they enrich the area surrounding them, they create new land and they are a recurring natural process. Our effect is probably like a nonstop volcano.


  • Registered Users, Registered Users 2 Posts: 69 ✭✭matthew2008


    cheers i see what youse are saying, over-simplified we are simply adding to what is (could be) a natural occurence! iv no background in science as of now but am always sceptical when humans put us as a cause of somethig (positive or negative) as i said above iv always thought we (people) are incredibly egocentric


  • Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    iv no background in science as of now but am always sceptical when humans put us as a cause of somethig...
    Why? It must be obvious that humans can have a major ecological impact?


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  • Registered Users, Registered Users 2 Posts: 28,789 ✭✭✭✭ScumLord


    I'm more worried about the chemical imbalances we're making. Our overuse of nitrogen in farming is turning entire lakes into algae colonies coking out all other forms of life.

    I always think of climate change as a big red cape keeping us distracted from the much more harmful things we're doing.


  • Registered Users, Registered Users 2 Posts: 69 ✭✭matthew2008


    djpbarry wrote: »
    Why? It must be obvious that humans can have a major ecological impact?
    its obvious that humans can have an ecological impact, but not obvious how major this impact is/could be imo... espically when you hear about how serious some people say climate change is


  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    ScumLord wrote: »
    I always think of climate change as a big red cape keeping us distracted from the much more harmful things we're doing.

    It is easy to think this when living in Ireland. Here, the effects so far have been minimal enough when compared with other parts of the world and we are lucky that the projections are pretty mild for Ireland also (although there is uncertainty of course)

    Its much more noticeable in other areas such as the Mediterranean.

    You are right of course though that there are other very serious issues also which attract less attention.


  • Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    its obvious that humans can have an ecological impact, but not obvious how major this impact is/could be imo...
    This is the crux of the issue. Climate change isn't obvious, therefore it's not accepted as reality.

    For example, the effects Deepwater Horizon oil spill were plain to see, so it's much easier for people to accept that oil spills are bad. However, increasing atmospheric carbon dioxide concentration, rising global mean temperature and rising sea levels are much more subtle changes that people can't see or feel the effects of and are therefore far less willing to accept there is anything to be concerned about.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,599 Mod ✭✭✭✭Capt'n Midnight


    Climate change is hard to see here because we have a mild climate being downwind of a large ocean.
    But we've had a lot of record matching events in recent years. Next time you are on holidays in a hot dry climate ask one of the older residents their opinion about climate change.

    Places with real weather get our annual variation in hours
    https://en.wikipedia.org/wiki/Spearfish,_South_Dakota
    Spearfish holds the world record for the fastest temperature change. On January 22, 1943 at about 7:30 a.m. MST, the temperature in Spearfish was -20°C. The Chinook wind picked up speed rapidly, and two minutes later (7:32 a.m.) the temperature was +7°C . The 27°C rise in two minutes set a world record that still holds. By 9:00 a.m., the temperature had risen to 12°C. Suddenly, the chinook died down and the temperature tumbled back to -20°C. The 32°C drop took only 27 minutes


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  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    Climate change is hard to see here because we have a mild climate being downwind of a large ocean.
    But we've had a lot of record matching events in recent years. Next time you are on holidays in a hot dry climate ask one of the older residents their opinion about climate change.

    Places with real weather get our annual variation in hours
    https://en.wikipedia.org/wiki/Spearfish,_South_Dakota

    Have to disgree with you about getting real weather. Ask anyone who takes a boat out on the west coast. We also had a spectacular temperature rise on Christmas day 2010


  • Closed Accounts Posts: 328 ✭✭Justin1982


    'climate change' has been occuring long before humans ever existed and long before humans ever produced a serious amount of greenhouse gases etc... what makes us so sure that its us thats causing the current climate change despite the fact that silmilar changes have occured throughout history without our help... is this another example of humans egocentric-ness??

    Its simple enough really. An increase in Carbon Dioxide gas levels (as well as other green house gases) in the atmosphere causing the average temperature of the Earth to heat up. Thats a fact. Humans are releasing a ridiculous amount of Carbon Dioxide into the atmosphere. Thats a fact. Humans are warming up the atmosphere.

    The doubt creeps in when climate scientists try to calculate by how many degrees the Earth on average will heat up over the next few years, how quickly, what the effects of that temp increase will be and how different regions will be affected.
    But they have a good idea and their models/theories are getting better all the time.
    You can bet your house on the average temperature of the earth not rising by more than 3 degrees over the next century. But you probably wont win I'm afraid.
    Even if there was a 80% percent chance that scientists models were all wrong. Its really not worth the risk for humanity to take.


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    Justin1982 wrote: »
    Its simple enough really. An increase in Carbon Dioxide gas levels (as well as other green house gases) in the atmosphere causing the average temperature of the Earth to heat up. Thats a fact. Humans are releasing a ridiculous amount of Carbon Dioxide into the atmosphere.

    Thats a fact.

    Could you give a specific reason why Carbon Dioxide is any more a contributor to atmospheric warming than any other gas?

    Preferably a peer-reviewed paper that explains the mechanism?

    The doubt creeps in when climate scientists try to calculate by how many degrees the Earth on average will heat up over the next few years, how quickly, what the effects of that temp increase will be and how different regions will be affected.
    But they have a good idea and their models/theories are getting better all the time.
    You can bet your house on the average temperature of the earth not rising by more than 3 degrees over the next century. But you probably wont win I'm afraid.
    Even if there was a 80% percent chance that scientists models were all wrong. Its really not worth the risk for humanity to take.

    Justin, out of your own scientific curiosity, have you made any attempt to investigate this issue yourself?


  • Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    Lbeard wrote: »
    Could you give a specific reason why Carbon Dioxide is any more a contributor to atmospheric warming than any other gas?

    Preferably a peer-reviewed paper that explains the mechanism?
    I believe Svante Arrhenius was the first to propose the mechanism:

    http://www.bibnum.education.fr/files/Arrhenius-texte.pdf


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    djpbarry wrote: »
    I believe Svante Arrhenius was the first to propose the mechanism:

    http://www.bibnum.education.fr/files/Arrhenius-texte.pdf

    Svante was hand wavy. And it's not modern physics.

    What's the modern physics explanation?


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,599 Mod ✭✭✭✭Capt'n Midnight


    Lbeard wrote: »
    Could you give a specific reason why Carbon Dioxide is any more a contributor to atmospheric warming than any other gas?

    Preferably a peer-reviewed paper that explains the mechanism?
    First off water vapour is the main contributor because of the amount of it in the atmosphere and the way clouds can reflect light back into space.

    There is no question that we have changed the composition of the atmosphere. So following on from that the question is whether that change is good or bad.


    A very important thing to remember is that most of the changes to the atmosphere have happened recently. Yes it started with the industrial revolution but most of the increase in CO2 has been in the last 50 years or so and presumably will continue to accelerate.


    But it's complicated.
    Aircraft are one of the ways we change the balance of the upper atmosphere.

    http://www.eci.ox.ac.uk/research/energy/downloads/aviation-climatecare.pdf
    Look at the graph on page 8
    read the appendix on page 10
    The level of understanding of each of these effects varies. The influence of carbon dioxide is well
    understood, ozone and methane progressively less so, and contrails and cirrus clouds poorly
    understood. Therefore the more effects that are included, the better the scientific picture, but the greater
    the uncertainty in values adopted.

    It's complicated as the gases from aircraft have different effects in different parts of the atmosphere. For instance they reduce methane.

    The CO2 and Water Vapour emissions generally weigh more than the fully loaded aircraft on anything other than short hops.

    Lots of stuff about the effects on cloud cover when aircraft were grounded after 9/11





    There is no question that massive volcanic eruptions or asteroid impacts could change it more , but that's not stuff that happens every day.

    The worry is about tipping points where there are changes that can't be easily reversed.
    - fires in Indonesia , it's going to take a century of "green" palm oil to undo the CO2 released there
    - Amazon rainforest changing to scrubland with semi-annual fires , happening in the west
    - permafrost melting releasing methane
    - methane hydrates release




    There is a also a financial aspect that really isn't part of the science discussion without evidence, but it boils down the balancing of the best options slow down changes or compensate those most affected or other.


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    It's complicated as the gases from aircraft have different effects in different parts of the atmosphere. For instance they reduce methane.

    The CO2 and Water Vapour emissions generally weigh more than the fully loaded aircraft on anything other than short hops.

    And what difference does removing methane from the upper atmosphere have?

    Once you burn it, heat is released, its' temperature is conserved in the reaction. Now you've got hot CO2 and water. You've just gone an made the upper atmosphere hotter - I suppose you have taken some heat out turning the jet blades.

    But what difference does it make if CO2 and water are in the upper atmosphere than methane?

    There must be a precise mechanism that makes a difference. This is chemistry and physics, not biology where there a zillions of mechanisms we don't understand. The precise mechanism that differentiates CO2 from methane in global warming......What is it?


  • Closed Accounts Posts: 328 ✭✭Justin1982


    Lbeard wrote: »
    Could you give a specific reason why Carbon Dioxide is any more a contributor to atmospheric warming than any other gas?

    Preferably a peer-reviewed paper that explains the mechanism?

    Justin, out of your own scientific curiosity, have you made any attempt to investigate this issue yourself?

    Its down to the fact that specifically green house gases are good absorbers/emitters of infrared radiation but not of radiation in the wavelength range of visible light and most radiation from the sun. So radiation gets through the atmosphere efficiently. Its absorbed by suface of earth fairly efficiently (apart from the poles). Same radiation is then re-emitted largely from surface of earth as infra-red radiation which doesnt get efficiently emitted back through the atmosphere as its absorbed by green house gases and turned largely into thermal energy of the atmosphere, ie. radiation energy from sun is largely turned into greater velocity of the green house gases, then gets passed to all other gases in atmosphere as green house gases bump into other gas molecules.

    I'm not sure I need a peer reviewed paper. I can highlight a process you are probably very familiar with already :D
    Probably the most convincing way of demonstrating how efficient green house gases is to consider a warm day with no clouds. Lets say it gets up to 30 degrees celcius. If later that night there is no clouds (a large accumulated green house gas) then temperature of atmosphere drops dramatically (possibly to < 10 degrees). On the other hand if clouds do develop before night fall then the temperature on the ground can remain quiet high (probably in the twenties).

    I have taken enough of an interest to look into the science of global warming when I was in college. The thing that really clarified it for me though was a special documentary on Global Warming carried out by BBC a few years ago which had the aim of clarifying the issue for the public. They had scientists from both sides of the divide. They were all asked a series of questions and asked to take a position. All of them took the position that they were 100% sure of the science of global warming. They were 100% sure that humans were causing global warming. They differed on the exact effect of global warming, the extent of it, how different regions would be affected and the degree change in average world temperature. But as far as I remember it, the anti global warming camp at least agreed that the temperature of earth would rise by at least 1 degree celcius by end of century.

    No one is sure of the exact consequences and degree of temperature rise or over how long. Thats where the researchers are still working and disagreeing.

    But there is other problems associated with global warming. If temp rises by a high number then it causes temp of oceans to heat up and ice caps to melt completely. There is large amounts of green house gas locked up in frozen form on the oceans floor in various parts of the world which could be heated up to required temp to escape as gas and cause a negative feedback effect. Large amounts of green house gas being released, causing even more warming and even more release of currently frozen green house gases. The science of it is fairly well known at this stage and its known that this has happened in the past a long way back in the Earths past and caused a lot of the Oceans longest living species to die out.

    The good news is that even if huge amounts of green house gas was released into atmosphere, if we stopped releasing more green house gas via human means then the Earth would naturally reabsorb the green house gases via various sinks (as its done in the past). Might happen over a long enough period though and its definitely possible for the Earth's atmosphere to reach high enough temp that it would be catastrophic for the human species in most parts of the world. A lot of ifs and buts of course. But all possible.


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    Justin1982 wrote: »
    Its down to the fact that specifically green house gases are good absorbers/emitters of infrared radiation but not of radiation in the wavelength range of visible light and most radiation from the sun. So radiation gets through the atmosphere efficiently. Its absorbed by suface of earth fairly efficiently (apart from the poles).

    Okay, you're not thinking about this properly. Forget what anyone has said - clear your mind and build everything from the ground up again. Some rhetorical questions. When atoms and molecules absorb radiation what happens? Does it give the atoms/molecules momentum? Visible light is the higher energy end of the spectrum. When you look at the blue sky, and you know why it's blue, and even the sun appears yellow when it should be white. Is there something inefficient happening to this incoming radiation? If it's going somewhere, where is it going?

    Same radiation is then re-emitted largely from surface of earth as infra-red radiation which doesnt get efficiently emitted back through the atmosphere as its absorbed by green house gases and turned largely into thermal energy of the atmosphere, ie. radiation energy from sun is largely turned into greater velocity of the green house gases, then gets passed to all other gases in atmosphere as green house gases bump into other gas molecules.

    Are you dead certain about this? Have you looked at the spectrographs? Are they being interpreted correctly?

    Is the absorption being interpreted correctly as having a thermal effect? Could some of the spectrum even be cooling the CO2.

    What makes a greenhouse gas thermally any different from any other gas (water is a special case because of clouds). If the entire atmosphere was CO2, what colour would the sky be?
    Probably the most convincing way of demonstrating how efficient green house gases is to consider a warm day with no clouds. Lets say it gets up to 30 degrees celcius. If later that night there is no clouds (a large accumulated green house gas) then temperature of atmosphere drops dramatically (possibly to < 10 degrees). On the other hand if clouds do develop before night fall then the temperature on the ground can remain quiet high (probably in the twenties).

    You've got it a little wrong. Clouds are made of ice particles, they're not actually a gas. How they trap heat is when hot particles shoot up, they hit the snowflakes and come racing back down. The clouds also reflect IR back down.

    The Green house effect is often wrong headly misunderstood. (I know this because I had very wrong headed misunderstandings of it). You have to think about the thermodynamics. Temperature is a measure of particle momentum - photons and atoms. If there are no clouds a hot atom, traveling straight up, will keep going until it loses all it's kinetic energy to potential energy do to gravity, it will then fall, regaining it's kinetic energy. Photons are a little different - the earths gravity is not strong enough to stop them escaping. You know all this, but have you really thought about it?
    I have taken enough of an interest to look into the science of global warming when I was in college. The thing that really clarified it for me though was a special documentary on Global Warming carried out by BBC a few years ago which had the aim of clarifying the issue for the public. They had scientists from both sides of the divide. They were all asked a series of questions and asked to take a position. All of them took the position that they were 100% sure of the science of global warming. They were 100% sure that humans were causing global warming. They differed on the exact effect of global warming, the extent of it, how different regions would be affected and the degree change in average world temperature. But as far as I remember it, the anti global warming camp at least agreed that the temperature of earth would rise by at least 1 degree celcius by end of century.

    Television is not the best source for science.

    One thing you'll find interesting if you look into this yourself, is many of the people on both sides of the "debate", say and write stuff that contradicts basic science. The hand waving is awful. Some will say its cosmic rays - but of course they won't offer the numbers.
    No one is sure of the exact consequences and degree of temperature rise or over how long. Thats where the researchers are still working and disagreeing.

    Is it meaningful or meaningless - think about the other questions and then think about this one.
    A lot of ifs and buts of course. But all possible.

    Look into the bits you should be able to understand quite well. You're in for a surprise..

    You understand quantum mechanics, if a climate scientist waved their hands at you and told you there was some hidden unknown mechanism, how credulous would you be?


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,599 Mod ✭✭✭✭Capt'n Midnight


    Lbeard wrote: »
    Is the absorption being interpreted correctly as having a thermal effect? Could some of the spectrum even be cooling the CO2.
    What does this mean ?

    Check out Stefans Law , fourth power of absolute temperature and all that

    Lasers are rare, in nature you generally don't get amplification, and doubling the energy by combining photons is also very rare so no so many green lasers in nature.

    The Green house effect is often wrong headly misunderstood. (I know this because I had very wrong headed misunderstandings of it). You have to think about the thermodynamics. Temperature is a measure of particle momentum - photons and atoms. If there are no clouds a hot atom, traveling straight up, will keep going until it loses all it's kinetic energy to potential energy do to gravity, it will then fall, regaining it's kinetic energy. Photons are a little different - the earths gravity is not strong enough to stop them escaping. You know all this, but have you really thought about it?
    ???

    escape velocity is a tad higher than the thermal energy of an atom, the nearest you'll get is having an atom in the upper atmosphere where the solar wind might strip if off. And it's a process that takes billions of years even with Venus so close to the sun and Mars with lower gravity.


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  • Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    Lbeard wrote: »
    Svante was hand wavy. And it's not modern physics.
    Eh? Arrhenius’ equation is still widely used (and still remarkably accurate)?
    Lbeard wrote: »
    The precise mechanism that differentiates CO2 from methane in global warming......What is it?
    I’m not entirely sure what you mean – the mechanism is the same. Both carbon dioxide and methane absorb energy in the infra-red, which causes molecular vibrations.


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    What does this mean ?

    Check out Stefans Law , fourth power of absolute temperature and all that

    Yes, because atom momentum is proportional to the photon momentum from the same body.

    Lasers are rare, in nature you generally don't get amplification, and doubling the energy by combining photons is also very rare so no so many green lasers in nature.

    Lasers are rare but photons are not. You haven't really thought this through, have you.

    escape velocity is a tad higher than the thermal energy of an atom, the nearest you'll get is having an atom in the upper atmosphere where the solar wind might strip if off. And it's a process that takes billions of years even with Venus so close to the sun and Mars with lower gravity.

    The thermal energy of an atom is in its' momentum. If you through a ball in the air, it will slow down, losing it's kinetic energy to potential energy, it will eventually stop. This is what happens to water molecules, they lose their kinetic energy to a point they can condense into clouds.

    Atoms generally cannot get enough kinetic energy to escape into space, but for photons it's easy. We lose heat to outer space through photons.


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    djpbarry wrote: »
    Eh? Arrhenius’ equation is still widely used (and still remarkably accurate)?

    Remarkably accurate as in whoever uses the equation gets the same answers as anyone else who uses it.

    I’m not entirely sure what you mean – the mechanism is the same. Both carbon dioxide and methane absorb energy in the infra-red, which causes molecular vibrations.


    Your explanation, I'm not going to say is completely incorrect, and it's an explanation lots of people use. Unfortunately it's mangled. When a molecule absorbs radiation, its' electrons move to a higher energy level - it doesn't vibrate. Explaining heat in terms of atoms vibrating is misleading.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,599 Mod ✭✭✭✭Capt'n Midnight


    Molecules can store vibrational and rotational energy too.
    And apart from the Nobel gases the vast bulk of the atmosphere is comprised of molecules.

    http://en.wikipedia.org/wiki/Molecular_vibration


    Also any kinetic energy an atom/molecule has would be shared very quickly due to collisions. Mean free path , random walk and all that. (distance travelled after n collisions is only square root of n )


  • Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    Lbeard wrote: »
    Remarkably accurate as in whoever uses the equation gets the same answers as anyone else who uses it.
    No, remarkably accurate as in it predicts experimental observations extremely well.
    Lbeard wrote: »
    Your explanation, I'm not going to say is completely incorrect, and it's an explanation lots of people use. Unfortunately it's mangled. When a molecule absorbs radiation, its' electrons move to a higher energy level - it doesn't vibrate.
    It most certainly does. Absorbing energy can cause atoms in a molecule to move periodically relative to each other (vibrate).


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    Molecules can store vibrational and rotational energy too.
    And apart from the Nobel gases the vast bulk of the atmosphere is comprised of molecules.

    http://en.wikipedia.org/wiki/Molecular_vibration

    Yeah. I thought someone would say that. In terms of molecules absorbing radiation, to say their vibrating, as in there's a thermal effect is misleading or wrong.
    Also any kinetic energy an atom/molecule has would be shared very quickly due to collisions. Mean free path , random walk and all that.

    Yes. But the random walk can take a particle high in the atmosphere as well as low. And in terms of collisions, you can think of the net direction of momentum over the net movement of a particle. Water molecules in clouds are colder than at the ground, but they store a lot of energy in potential energy. The net energy of water molecules in clouds is greater than water molecules near the ground. Because of gravity, energy content and temperature are not proportional to each other.
    (distance travelled after n collisions is only square root of n )

    This gets a lot more tricky with an atmosphere. It's even complicated when considering neutrons thermalising in a solid of uranium or plutonium. It requires quite a bit of modelling to know what you're getting.


  • Registered Users, Registered Users 2 Posts: 28,789 ✭✭✭✭ScumLord


    The worry is about tipping points where there are changes that can't be easily reversed.
    - fires in Indonesia , it's going to take a century of "green" palm oil to undo the CO2 released there
    - Amazon rainforest changing to scrubland with semi-annual fires , happening in the west
    It's not the first time in human history we've deforested large parts of the world. Europe probably had a lot of forrest at one stage and we removed most of it over a fairly short period of time. Not as quick as today but is there any way we can find evidence of how that affected the world? I'm sure the same happened throughout the civilised world of the time.

    Maybe removing that forrest mass wasn't as much of a strain because there was so much other forest throughout the world?


  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    ScumLord wrote: »
    Maybe removing that forrest mass wasn't as much of a strain because there was so much other forest throughout the world?

    The human population was also much lower and the industrial revolution had yet to begin.


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    fits wrote: »
    The human population was also much lower and the industrial revolution had yet to begin.

    These kind of arguments derail the whole discussion. To claim humans have an influence on climate temperature, you need a precise mechanism.

    Otherwise it's like claiming we're being punished by some magic force for not eating organic yogurt, and cous cous.


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  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    Lbeard wrote: »
    These kind of arguments derail the whole discussion. To claim humans have an influence on climate temperature, you need a precise mechanism.

    Otherwise it's like claiming we're being punished by some magic force for not eating organic yogurt, and cous cous.

    There is a direct link between human population and the industrial revolution, and greenhouse gases in the atmosphere.

    Are you questioning the fact that the proportion of CO2 in the atmosphere is higher than it was pre the industrial revolution, or are you dismissing the greenhouse effect completely?


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    djpbarry wrote: »
    No, remarkably accurate as in it predicts experimental observations extremely well.

    This equation Co) makes assumptions about carbon dioxide. In 1897 a lot of science was not available to Svante.

    It most certainly does. Absorbing energy can cause atoms in a molecule to move periodically relative to each other (vibrate).

    And how would this have any effect on particle momentum? - which is temperature.


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    fits wrote: »
    There is a direct link between human population and the industrial revolution, and greenhouse gases in the atmosphere.

    If humans have been putting more CO2 in the atmosphere, what difference does it make?

    You need a precise answer. Eye swiveling and hand waving is not enough. We have sinned against mudda naycha, she will punish us!!
    Are you questioning the fact that the proportion of CO2 in the atmosphere is higher than it was pre the industrial revolution, or are you dismissing the greenhouse effect completely?

    Okay....I'm on the edge of losing my temper. Because of the weird and fluffy way the "theory" has wafted around the imaginations of the public, etc, people have become a little confused, and believe things like CO2 being a "Greenhouse gas" - as distinct from other gases.

    All gases in the atmosphere are green house gases. ALL OF THEM.

    In the minds or many, the whole greenhouse principle is all tangled up. There is no glass. Or the glass is in fact gravity. It does work a lot like a greenhouse. But the terms allows for lots of silly trips of the imagination.

    I really don't want to hear another mangled version of the "greenhouse effect".


  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    Lbeard wrote: »
    Eye swiveling and hand waving is not enough. We have sinned against mudda naycha, she will punish us!!



    Okay....I'm on the edge of losing my temper. Because of the weird and fluffy way the "theory"

    There is no weird and fluffy language in this thread except from you. Frankly there is no room for this sort of language in scientific discussion.
    I really don't want to hear another mangled version of the "greenhouse effect".
    OK since you are so clever, why don't you do the research and read the papers and tell us exactly what is wrong with years and years of research?


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    fits wrote: »
    There is no weird and fluffy language in this thread except from you. Frankly there is no room for this sort of language in scientific discussion.

    I think you have some fluffy ideas.

    It's okay to forgive a naive in thinking that Greenhouse gases are distinct from other gases. It's another thing for someone who should know better - which in the event they deserve a kick in the ass.
    OK since you are so clever, why don't you do the research and read the papers and tell us exactly what is wrong with years and years of research?

    This is a question I know the answer to.

    But what would be the point in trying to explain it to you? It would be like time travelling back to the 50s and telling the innocent country folk or Ireland that there is no God or holy Mary, and the priest is sexually abusing children.

    But for other people. Those who would know enough that they should know better, I've given enough hints.


  • Moderators, Society & Culture Moderators Posts: 12,853 Mod ✭✭✭✭riffmongous


    ScumLord wrote: »
    It's not the first time in human history we've deforested large parts of the world. Europe probably had a lot of forrest at one stage and we removed most of it over a fairly short period of time. Not as quick as today but is there any way we can find evidence of how that affected the world? I'm sure the same happened throughout the civilised world of the time.

    Maybe removing that forrest mass wasn't as much of a strain because there was so much other forest throughout the world?

    Aside on forestry* I was at a seminar here in vienna on historical hydrology in central europe a few weeks ago and they showed a graph of what they reconstructed the % forest cover to be for the last 1200 years and interestingly the lowest amount was just before the Black Death hit, where it was less than 10% cover, compared to the ~40% it has been at for the last few hundred years due to a mixture of poor austrian industrialisation and conservation.


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  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    Aside on forestry* I was at a seminar on historical hydrology a few weeks ago and they showed a graph of what they reconstructed the % forest cover to be for the last 1200 years and interestingly the lowest amount was just before the Black Death hit, where it was less than 10% cover, compared to the ~40% it has been at for the last few hundred years due to a mixture of poor austrian industrialisation and conservation.

    Are you speaking about forest cover in Europe, or globally?


  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    Lbeard wrote: »
    I think you have some fluffy ideas.

    I am not a physicist but I don't think accepting the views of the vast majority of scientific experts in the area counts as 'fluffy'.


    This is a question I know the answer to.

    Why don't you try us?
    But what would be the point in trying to explain it to you? It would be like time travelling back to the 50s and telling the innocent country folk or Ireland that there is no God or holy Mary, and the priest is sexually abusing children.
    This language is not necessary.

    Enough with the hinting. Why don't you tell us?


  • Moderators, Society & Culture Moderators Posts: 12,853 Mod ✭✭✭✭riffmongous


    fits wrote: »
    Are you speaking about forest cover in Europe, or globally?

    Oops, sorry I meant to say it was just for the Austrian region.


  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    Oops, sorry I meant to say it was just for Austria

    Its quite an important distinction :)


  • Moderators, Society & Culture Moderators Posts: 12,853 Mod ✭✭✭✭riffmongous


    fits wrote: »
    Its quite an important distinction :)

    Yeah I just left it out of the beginning and referenced that it was just Austria at the end of the post, edited the original post now :D But it was quite interesting for me as an Irish person to see for how long forest conservation has been a principle here in Austria.

    The effects of deforestation on climate seems pretty interesting when you think of it conceptually, as plants usually remove CO2 from the air and when areas are deforested with burning techniques (like in south asia at the moment) you are releasing CO2 but also when you remove large areas of forest you are changing the albedo and this can lead to more feedback effects, more convection at the tropics in the amazon region, more high altitude clouds which can then also have an important effect on the energy balance, really interesting imo :)


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  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    But it was quite interesting for me as an Irish person to see for how long forest conservation has been a principle here in Austria.

    OT but, I think forest management and conservation in different parts of Europe are really interesting also, and we could certainly learn a lot in Ireland from our European neighbours.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,599 Mod ✭✭✭✭Capt'n Midnight


    Lbeard wrote: »
    If humans have been putting more CO2 in the atmosphere, what difference does it make?

    You need a precise answer. Eye swiveling and hand waving is not enough. We have sinned against mudda naycha, she will punish us!!
    To be very blunt IMHO most of the hand waving has come from your direction. And you haven't provided anything like the precision you are demanding.

    At this point you are sounding like an creationist demanding to be shown yet another missing link.

    Science doesn't prove things. It's the other way around. Theories are proposed and evidence can weed out the weak ones.

    We have changed the composition of the atmosphere. We've been able to measure the effects on such things as the ozone hole.

    Also remember that we are in an era of accelerating greenhouse production which means if there is an effect it will get worse.


    And where are you dragging in mother nature from ??
    Positive feedback can be really nasty. Checkout snowball earth.

    Okay....I'm on the edge of losing my temper. Because of the weird and fluffy way the "theory" has wafted around the imaginations of the public, etc, people have become a little confused, and believe things like CO2 being a "Greenhouse gas" - as distinct from other gases.

    All gases in the atmosphere are green house gases. ALL OF THEM.

    In the minds or many, the whole greenhouse principle is all tangled up. There is no glass. Or the glass is in fact gravity. It does work a lot like a greenhouse. But the terms allows for lots of silly trips of the imagination.

    I really don't want to hear another mangled version of the "greenhouse effect".
    Strawman much ?

    One of the key aspects of science is communication. It's a truism that if you can't explain something to a seven year old then you don't really understand it yourself. And don't get me started on technobabble.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,599 Mod ✭✭✭✭Capt'n Midnight


    fits wrote: »
    OT but, I think forest management and conservation in different parts of Europe are really interesting also, and we could certainly learn a lot in Ireland from our European neighbours.
    We could also learn from the deforestation by ancient civilisations.

    Mayan's. The Roman provinces of North Africa. Large parts of Asia.


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    fits wrote: »
    I am not a physicist but I don't think accepting the views of the vast majority of scientific experts in the area counts as 'fluffy'.

    Enough with the hinting. Why don't you tell us?


    It's as simple as this, it's a misunderstanding of the physics. And there is a lot of fluffiness. There are people who know the physics who've just accepted claims without thinking about them. Svante Arrhenius made some incorrect assumptions based on not knowing the underlying mechanisms. People who've used his work to make claims seem oblivious to where he was wrong. And that's how we get to where we are now.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,599 Mod ✭✭✭✭Capt'n Midnight


    Lbeard wrote: »
    It's as simple as this, it's a misunderstanding of the physics. And there is a lot of fluffiness. There are people who know the physics who've just accepted claims without thinking about them. Svante Arrhenius made some incorrect assumptions based on not knowing the underlying mechanisms. People who've used his work to make claims seem oblivious to where he was wrong. And that's how we get to where we are now.
    Fluffy ?

    You are arguing about climate change based on work done in the 19th century as if there was no peer review on it since. In which case would you care to explain the 1970s worries about global cooling or otherwise at least accept that science means that theories get reviewed in light of the existing evidence.


  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    Lbeard wrote: »
    It's as simple as this

    And yet you cant explain where this misunderstanding is coming from can you?

    I think we've met before haven't we...


  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    We could also learn from the deforestation by ancient civilisations.

    Mayan's. The Roman provinces of North Africa. Large parts of Asia.

    Ireland was deforested by our ancestors also.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 93,599 Mod ✭✭✭✭Capt'n Midnight


    fits wrote: »
    Ireland was deforested by our ancestors also.
    Oh yeah our landscape is artificial. How long is since there were trees on the Ceide fields ?

    But the big one was when the trees were removed for the Royal Navy etc, about three centuries ago. Not so long ago we still had the lowest % of forest cover in Europe, probably still do.


    Clouds do provide some negative feedback. And being downwind of an ocean means if the weather over it gets warmer we'll have more clouds reflecting sunlight here.


  • Registered Users, Registered Users 2 Posts: 13,778 ✭✭✭✭fits


    Not so long ago we still had the lowest % of forest cover in Europe, probably still do.


    Its around 12% now, which is not an insignificant amount imo. Percentage forest cover of EU-27 area is 38%


  • Banned (with Prison Access) Posts: 311 ✭✭Lbeard


    Fluffy ?

    You are arguing about climate change based on work done in the 19th century as if there was no peer review on it since.

    No, no, no, no, no. It's Arrenhius' work is cited by those claiming man made CO2 is causing global warming. They even use his "forcings" equation.

    I'm saying Arhenius' work was wrong. There's nothing controversial in this statement. What should be controversial is anyone relying on his work.

    Anyway, that's enough. In this instance, I know what I'm taking about, and you don't. You're going on religious faith, and I'm not.


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