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  • Location: Newcastle Upon Tyne (Spital Tongues)
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  • Location: Newcastle Upon Tyne (Spital Tongues)

    So, this is a thread where we can ask questions to clear up some aspects of climate science, question the interpretation of a graph, validity of some statement you saw online, or more general questions, things like that. Where there is more uncertainty, a new thread might be created where a topic can be discussed or debated.
    Of course, the expertise for all areas of climate science are not present on this forum, but there are plenty of knowledgeable and educated members with climatology related qualifications who should be able to help with many questions or direct you towards good explanations from reputable sources elsewhere.

    For those that wish to answer questions, please stick to reputable sources and established science. Anyone attempting to espouse fringe theories or link to anti-science blogs will have their posts removed.

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    It's the basic laws of science (chemistry, optics, etc) that say CO2 causes warming, something that was recognised over 100 years ago and accept by even the most ardent climate science "sceptics" (wha

    So, as a first post, I thought I'd take a look at a graph that was posted in the IPCC thread a few times, first by @cheeky_monkey and then by @booferking. This graph is often posted by vario

    In a speech at the University of Oregon, James Hansen, NASA's chief atmospheric scientist, walks listeners thru the most recent geologic periods, and speaks to the commonly heard climate canard, "It's

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    Posted
  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)

    So, as a first post, I thought I'd take a look at a graph that was posted in the IPCC thread a few times, first by @cheeky_monkey and then by @booferking.

    Slide2.jpeg.9051af5006960f98ea0132d303ce

    This graph is often posted by various climate change denier groups (this version of it is also from a site that denies the basics of climate science). It shows past CO2 and temperature variations, stretching back nearly 600 million years. The CO2 appears to be from a 2001 paper by Berner and Kothavala, based on his model called GEOCARB. The uncertainty levels are massive back then, with CO2 at the 500 million year mark somewhere between 3,000ppm and 9,000ppm, but as the resolution is just 10 million years, there may have been much larger fluctuations too small for the model to capture too.
    It is generally posted to show that CO2 doesn't influence the climate, because how could CO2 have been that high in the past and yet the Earth didn't boil away!?

    There's a few reasons for this, but the most important we need to consider how different the Earth's climate was that far back. First off, we have the fact that the luminosity of the Sun has increased by several % since then. In the early life of the Earth, the Sun was so much less bright that really the Earth should have been completely frozen over. The fact that it wasn't is known as the "Faint Young Sun Paradox". As most evidence for atmospheric composition back then has been wiped out through the billions of years of geological processes, it's a tough problem. One of the proposed solutions to this paradox is that GhG concentrations were vastly higher than nowadays. Indeed, even back 500 million years ago, the Sun's brightness was reduced enough that we needed GhG levels much higher than today to simply to prevent glaciation. If CO2 levels had dropped below 3,000ppm during the Cambrian, the planet would have frozen over.

    Other, more minor aspects, include the levels of other GhGs, the positioning of the land masses and ocean currents which will influence the distribution and transport of global heat.

    Basically, 500 million years ago CO2 was likely well over 3,000ppm and so the graph is generally accurate. As the Sun's luminosity has increased the threshold level of atmospheric CO2 needed to keep glaciations away has decreased. But this doesn't change the fact that CO2 is an important GhG, in fact, it adds to the evidence that it is one. CO2 has been vital for keeping the Earth at a habitable temperature, despite significant changes in solar out over many hundreds of millions of years.

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  • Location: Sedgley Black country 731ft 222 metres
  • Location: Sedgley Black country 731ft 222 metres

    Thank you for this  that answers some questions   one question I have  and I admitt that this will probably be impossible to answer   but if we as an earth  became carbon neutral in 6 years ( figure I've used due to the protests)  how high would co levels rise?  Would they Platto  or would they still continue to rise  but at slower rate as what would be classed as the norm?  Also  is climate change innevitable?  In regard to  that the earth will get warmer  just that instead of 100 to 200 years  time  it will take longer   if this is true  then maybe it's time to star now in looking at tech to prevent this  ie  mirrors in front of the sun etc ? 

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    Posted
  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)
    1 hour ago, weirpig said:

    Thank you for this  that answers some questions   one question I have  and I admitt that this will probably be impossible to answer   but if we as an earth  became carbon neutral in 6 years ( figure I've used due to the protests)  how high would co levels rise?  Would they Platto  or would they still continue to rise  but at slower rate as what would be classed as the norm?  Also  is climate change innevitable?  In regard to  that the earth will get warmer  just that instead of 100 to 200 years  time  it will take longer   if this is true  then maybe it's time to star now in looking at tech to prevent this  ie  mirrors in front of the sun etc ? 

    I'll try address some of this tomorrow. But in future, try keep to one or 2 questions at a time!

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  • Location: Camborne
  • Location: Camborne
    11 hours ago, weirpig said:

    Thank you for this  that answers some questions   one question I have  and I admitt that this will probably be impossible to answer   but if we as an earth  became carbon neutral in 6 years ( figure I've used due to the protests)  how high would co levels rise?  Would they Platto  or would they still continue to rise  but at slower rate as what would be classed as the norm?  Also  is climate change innevitable?  In regard to  that the earth will get warmer  just that instead of 100 to 200 years  time  it will take longer   if this is true  then maybe it's time to star now in looking at tech to prevent this  ie  mirrors in front of the sun etc ? 

    To partly answer this

    Not all of the carbon released by fossil fuel burning has remained in the atmosphere.  Estimates based on careful historical inventories suggest that only about half of the total carbon released to date remains in the atmosphere as carbon dioxide. Most of the remainder has slowly infiltrated the ocean, with a smaller amount having been taken up by the terrestrial ecosystem (net of deforestation). In fact, it has been shown that the rate at which the ocean can take up the excess CO2 is limited by the mixing between the upper ocean and the deep ocean. This is a slow process, and if all fossil fuel burning were suddenly to cease, it would take in excess of 600 years for 80% of the excess CO2 to be taken out of the atmosphere. The remainder would stay in the atmosphere for millennia longer, owing to certain chemical processes (discussed briefly in Chapter eight) which limit the ability of the ocean to take up CO2. The slow net removal rate of CO2 allows fossil fuel emissions to accumulate in the atmosphere. Another consequence of the long lifetime of CO2 in the atmosphere is that the climatic effects of elevated CO2 will persist for centuries to millennia, even after any (much to be hoped-for) dramatic restriction of fossil fuel burning. Allowing for uptake by the ocean, there are enough fossil fuel reserves - primarily in the form of coal - to ultimately increase the atmospheric CO2 concentration to at least six times the pre-industrial value.  The number could go much higher if the ocean sink were to become less efficient, or if land ecosystems were to turn around and become a CO2 source rather than a sink.

    Source; Raymond Pierrehumbert, Principles of Planetary Climate"

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  • Location: Sedgley Black country 731ft 222 metres
  • Location: Sedgley Black country 731ft 222 metres
    49 minutes ago, knocker said:

    To partly answer this

    Not all of the carbon released by fossil fuel burning has remained in the atmosphere.  Estimates based on careful historical inventories suggest that only about half of the total carbon released to date remains in the atmosphere as carbon dioxide. Most of the remainder has slowly infiltrated the ocean, with a smaller amount having been taken up by the terrestrial ecosystem (net of deforestation). In fact, it has been shown that the rate at which the ocean can take up the excess CO2 is limited by the mixing between the upper ocean and the deep ocean. This is a slow process, and if all fossil fuel burning were suddenly to cease, it would take in excess of 600 years for 80% of the excess CO2 to be taken out of the atmosphere. The remainder would stay in the atmosphere for millennia longer, owing to certain chemical processes (discussed briefly in Chapter eight) which limit the ability of the ocean to take up CO2. The slow net removal rate of CO2 allows fossil fuel emissions to accumulate in the atmosphere. Another consequence of the long lifetime of CO2 in the atmosphere is that the climatic effects of elevated CO2 will persist for centuries to millennia, even after any (much to be hoped-for) dramatic restriction of fossil fuel burning. Allowing for uptake by the ocean, there are enough fossil fuel reserves - primarily in the form of coal - to ultimately increase the atmospheric CO2 concentration to at least six times the pre-industrial value.  The number could go much higher if the ocean sink were to become less efficient, or if land ecosystems were to turn around and become a CO2 source rather than a sink.

    Source; Raymond Pierrehumbert, Principles of Planetary Climate"

    Crikey  so in short  However high the co levels are in the atmosphere at the time  of either going carbon neutral  or at least reducing it   the levels will remain the same  if not maybe even rise  for years after.     That is one statistic i was unaware of   and i suppose highlights the fact  that the sooner we act the better it is for everyone.   that statistic also shows to me  that   keeping the temp rise below 1.5c  is going to be very difficult.     

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  • Location: Camborne
  • Location: Camborne

    I am afraid, due in no small measure to the misinformation campaign run by certain factions of the fossil fuel industry, that we are well into a damage limitation scenario

     

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    Posted
  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)

    With regards to the old Mars warming ideas, an interesting realclimate post on the topic here: 

    default.jpg
    WWW.REALCLIMATE.ORG

    Guest contribution by Steinn Sigurdsson. Recently, there have been some suggestions that global warming has...

     

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  • Location: Back in Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Location: Back in Edmonton Alberta(via Chelmsford, Exeter & Calgary)

    one Q? how accurate are climate models at reanalysis of the past...for example if you took all the observable data prior to say 1900 and we know what the increase of CO2 content of the atmosphere is for the 20th century and fed all that in using 1900 as a start, what would the models predict for the 20th century and how close would it be to the actual? im sure they have done this?

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  • Location: Coniston, Cumbria 90m ASL
  • Weather Preferences: wintry
  • Location: Coniston, Cumbria 90m ASL
    7 hours ago, knocker said:

    To partly answer this

    Not all of the carbon released by fossil fuel burning has remained in the atmosphere.  Estimates based on careful historical inventories suggest that only about half of the total carbon released to date remains in the atmosphere as carbon dioxide. Most of the remainder has slowly infiltrated the ocean, with a smaller amount having been taken up by the terrestrial ecosystem (net of deforestation). In fact, it has been shown that the rate at which the ocean can take up the excess CO2 is limited by the mixing between the upper ocean and the deep ocean. This is a slow process, and if all fossil fuel burning were suddenly to cease, it would take in excess of 600 years for 80% of the excess CO2 to be taken out of the atmosphere. The remainder would stay in the atmosphere for millennia longer, owing to certain chemical processes (discussed briefly in Chapter eight) which limit the ability of the ocean to take up CO2. The slow net removal rate of CO2 allows fossil fuel emissions to accumulate in the atmosphere. Another consequence of the long lifetime of CO2 in the atmosphere is that the climatic effects of elevated CO2 will persist for centuries to millennia, even after any (much to be hoped-for) dramatic restriction of fossil fuel burning. Allowing for uptake by the ocean, there are enough fossil fuel reserves - primarily in the form of coal - to ultimately increase the atmospheric CO2 concentration to at least six times the pre-industrial value.  The number could go much higher if the ocean sink were to become less efficient, or if land ecosystems were to turn around and become a CO2 source rather than a sink.

    Source; Raymond Pierrehumbert, Principles of Planetary Climate"

    Is this predicated on continuing global deforestation, stable tree (& plant) mass or increasing? i.e. if on average 1 tree stores 1000 kg of CO2 in it's life and we plant 1 million trees/year plus natural self seeding, would that slow down the CO2 levels to reduce that time lag with oceanic CO2 uptake?

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  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)
    1 hour ago, cheeky_monkey said:

    one Q? how accurate are climate models at reanalysis of the past...for example if you took all the observable data prior to say 1900 and we know what the increase of CO2 content of the atmosphere is for the 20th century and fed all that in using 1900 as a start, what would the models predict for the 20th century and how close would it be to the actual? im sure they have done this?

    It's one of the means of testing the accuracy of the models, so it's been done quite a lot. In the climate model evaluation chapters from most of the IPCC reports they show graphs of those very simulations.
    FIgure 9.8, about 28 pages down, is the one from the latest IPCC report: https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter09_FINAL.pdf
    And the first figure here, which is a bit more clear, from the previous report, about 12 pages down: https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter8-1.pdf

    You can see that they match global temperatures very well.One of the things to note is that while they capture cycles like El Nino variability well, the timing and length of Nino and Nina events differ from observations. So any one year might be a couple of tenths of a degree off observations, but the climate averages are near identical, and overall tends and patterns are pretty much bang on.

    Edited by BornFromTheVoid
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  • Location: Camborne
  • Location: Camborne
    2 hours ago, JeffC said:

    Is this predicated on continuing global deforestation, stable tree (& plant) mass or increasing? i.e. if on average 1 tree stores 1000 kg of CO2 in it's life and we plant 1 million trees/year plus natural self seeding, would that slow down the CO2 levels to reduce that time lag with oceanic CO2 uptake?

    I don't think he was predicating anything, merely giving an overall assessment at the time of writing hence "with a smaller amount having been taken up by the terrestrial ecosystem (net of deforestation)"

    Obviously deforestation has a role to play but taken as part of the photosynthesis cycle I suspect it shouldn't be overestimated, important though it is, Based on satellite chlorophyll observations,it has been estimated that photosynthesis fixes 100 gigatonnes of carbon each year,about half on land and half in the oceans. The fossil fuel emissions in a year are around  8% of this number. In other words world wide photosynthetic productivity would have to increase by 8% to take up the fossil fuel CO2 and 100% of that carbon would have to be buried as organic matter without being recycled by respiration. That, of course, would be an absurd situation, as virtually all of the photosynthetically fixed carbon is quickly respired back into the atmosphere, largely by bacteria who have had several billion years to become proficient at making use of organic carbon wherever they find it

    So my brief summation, strictly as a non expert, is that plating more trees rather than deforestation is quite obviously a better policy and may make a very small difference to the accumulation in the atmosphere, and for many reasons and should be adopted, But I suspect the horse has bolted

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  • Location: Back in Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Location: Back in Edmonton Alberta(via Chelmsford, Exeter & Calgary)
    3 hours ago, BornFromTheVoid said:

    It's one of the means of testing the accuracy of the models, so it's been done quite a lot. In the climate model evaluation chapters from most of the IPCC reports they show graphs of those very simulations.
    FIgure 9.8, about 28 pages down, is the one from the latest IPCC report: https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter09_FINAL.pdf
    And the first figure here, which is a bit more clear, from the previous report, about 12 pages down: https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter8-1.pdf

    You can see that they match global temperatures very well.One of the things to note is that while they capture cycles like El Nino variability well, the timing and length of Nino and Nina events differ from observations. So any one year might be a couple of tenths of a degree off observations, but the climate averages are near identical, and overall tends and patterns are pretty much bang on.

    how do they factor volcanic eruptions into the data..they are random events at random magnitudes? on the graph shown it shows the models matching actual falls in temps due to those eruptions..but there is know way of knowing when they will occur or their magnitude and thus what their short term impact on the climate might be?

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  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)
    14 minutes ago, cheeky_monkey said:

    how do they factor volcanic eruptions into the data..they are random events at random magnitudes? on the graph shown it shows the models matching actual falls in temps due to those eruptions..but there is know way of knowing when they will occur or their magnitude and thus what their short term impact on the climate might be?

    There is no way of predicting or properly simulating when an eruption will occur. So within the model, they add in the injection of material artificially into the atmosphere, on the same dates, location and with the same magnitude of known large eruptions, and then the physics of the model/s do the rest. They simulate the the distribution of aerosols around the globe, the decrease in energy reaching the surface and other effects. As far as I know, they don't get everything quite right, but in terms of global temperatures and patterns of temperature change, they do pretty well. That also means we can look at what kind of impact future eruptions might have.

    As it is, volcanic eruptions only produce short lived blips in global temperatures. But there are a another useful way to assess how well the model deals with atmospheric circulations and changes to its chemistry.

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  • Location: Back in Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Location: Back in Edmonton Alberta(via Chelmsford, Exeter & Calgary)
    2 hours ago, BornFromTheVoid said:

    There is no way of predicting or properly simulating when an eruption will occur. So within the model, they add in the injection of material artificially into the atmosphere, on the same dates, location and with the same magnitude of known large eruptions, and then the physics of the model/s do the rest. They simulate the the distribution of aerosols around the globe, the decrease in energy reaching the surface and other effects. As far as I know, they don't get everything quite right, but in terms of global temperatures and patterns of temperature change, they do pretty well. That also means we can look at what kind of impact future eruptions might have.

    As it is, volcanic eruptions only produce short lived blips in global temperatures. But there are a another useful way to assess how well the model deals with atmospheric circulations and changes to its chemistry.

    my only comment is they didnt pick up on the extent of the warming to just after 1940 and didnt pick out the cooling to 1970 ish at all..if you start at that 1940 warm period there seems to be only a +0.3c increase since then?

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  • Location: Coniston, Cumbria 90m ASL
  • Weather Preferences: wintry
  • Location: Coniston, Cumbria 90m ASL
    5 hours ago, knocker said:

    I don't think he was predicating anything, merely giving an overall assessment at the time of writing hence "with a smaller amount having been taken up by the terrestrial ecosystem (net of deforestation)"

    Obviously deforestation has a role to play but taken as part of the photosynthesis cycle I suspect it shouldn't be overestimated, important though it is, Based on satellite chlorophyll observations,it has been estimated that photosynthesis fixes 100 gigatonnes of carbon each year,about half on land and half in the oceans. The fossil fuel emissions in a year are around  8% of this number. In other words world wide photosynthetic productivity would have to increase by 8% to take up the fossil fuel CO2 and 100% of that carbon would have to be buried as organic matter without being recycled by respiration. That, of course, would be an absurd situation, as virtually all of the photosynthetically fixed carbon is quickly respired back into the atmosphere, largely by bacteria who have had several billion years to become proficient at making use of organic carbon wherever they find it

    So my brief summation, strictly as a non expert, is that plating more trees rather than deforestation is quite obviously a better policy and may make a very small difference to the accumulation in the atmosphere, and for many reasons and should be adopted, But I suspect the horse has bolted

    Glad I asked... I think ? 

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  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)
    9 hours ago, cheeky_monkey said:

    my only comment is they didnt pick up on the extent of the warming to just after 1940 and didnt pick out the cooling to 1970 ish at all..if you start at that 1940 warm period there seems to be only a +0.3c increase since then?

    I disagree. Both graphs show the global temperature measurements (in black) and the model runs. And they both show warming up to 1940 and the stabilisation/slight cooling to 1970. The first graph ends at about 2012, and the second at 2005. They both show around 0.5 or 0.6C warming since 1970, and both miss the 0.3C or so jump from the last 5 years.

    I've added both graphs below with a red line highlighting the parts you say are absent. Note that the scales, both horizontal and vertical in both are different, but that doesn't change the trends,

    mod1.thumb.JPG.8e2283b94e45ee400458dad2936d7b46.JPG  mod2.thumb.JPG.3ea4241e9d4335f15adf75e6aee9b002.JPG

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  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
    15 hours ago, 4wd said:
    41586_2018_411_Fig1_HTML.png
    WWW.NATURE.COM

    Satellite data for the period 1982–2016 reveal changes in land use and land cover at global and regional scales that reflect...

     

    A rather 'odd' post, 4WD -- for a Q&A thread: it neither asks nor answers any questions...??

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  • Location: Wonson, Throwleigh 845' ASL
  • Weather Preferences: winter
  • Location: Wonson, Throwleigh 845' ASL

    re; Volcanic eruptions, surely there have Historically been some huge eruptions producing millions of tonnes of sulphur - Co2 etc, these massive events have been recorded to drop the Earths temp on a Global scale, also have the  2 World War events been taken into account, the uptick in manufacturing on a global scale would also have effects on output levels, and then the 1000s of Nuclear tests also on a global scale ripping the atmosphere bandings to sheds and sending increased heat extremes into those areas.

    I believe there are many other factors yet to be considered  allowing these Co2 levels to increase.

    However, consider this, if the Earth cooled significantly it would have a worse effect on Humanity and everything that survives on her.

    Just my thoughts. 

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  • Location: Camborne
  • Location: Camborne
    1 hour ago, hooch5 said:

    re; Volcanic eruptions, surely there have Historically been some huge eruptions producing millions of tonnes of sulphur - Co2 etc, these massive events have been recorded to drop the Earths temp on a Global scale, also have the  2 World War events been taken into account, the uptick in manufacturing on a global scale would also have effects on output levels, and then the 1000s of Nuclear tests also on a global scale ripping the atmosphere bandings to sheds and sending increased heat extremes into those areas.

    I believe there are many other factors yet to be considered  allowing these Co2 levels to increase.

    However, consider this, if the Earth cooled significantly it would have a worse effect on Humanity and everything that survives on her.

    Just my thoughts. 

    Fine. Then you need to present these factors supported by credible scientific research which you can then post in the relevant thread, As far as I can seen you have merely posted an opinion here without any relevant questions, or indeed scientific support to justify them

    Edited by knocker
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  • Location: Near Newton Abbot or east Dartmoor, Devon
  • Location: Near Newton Abbot or east Dartmoor, Devon
    3 hours ago, hooch5 said:

    re; Volcanic eruptions, surely there have Historically been some huge eruptions producing millions of tonnes of sulphur - Co2 etc, these massive events have been recorded to drop the Earths temp on a Global scale, also have the  2 World War events been taken into account, the uptick in manufacturing on a global scale would also have effects on output levels, and then the 1000s of Nuclear tests also on a global scale ripping the atmosphere bandings to sheds and sending increased heat extremes into those areas.

    I believe there are many other factors yet to be considered  allowing these Co2 levels to increase.

    However, consider this, if the Earth cooled significantly it would have a worse effect on Humanity and everything that survives on her.

    Just my thoughts. 

    This is an interesting article that, I'm afraid, points out that volcanoes produce far less CO2 than human activity. Nor did the two world wars have much effect on the rise in CO2 and the nuclear tests likewise.

    What does have an effect is that every year human activity adds a few billions of tonnes of CO2 to the atmosphere. Each year, every year. Looking at the the carbon cycle what we produce each year is tiny compared to the total of CO2 in the carbon cycle but the point is that every year we add billions of tonnes of CO2 to the carbon cycle. Over the last century that has caused atmosphere CO2 to rise from 280ppm to 410ppm (a huge change to the whole atmosphere) and there really is no other explanation other than that we are responsible.

    Edited by Devonian
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  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)
    14 hours ago, hooch5 said:

    re; Volcanic eruptions, surely there have Historically been some huge eruptions producing millions of tonnes of sulphur - Co2 etc, these massive events have been recorded to drop the Earths temp on a Global scale, also have the  2 World War events been taken into account, the uptick in manufacturing on a global scale would also have effects on output levels, and then the 1000s of Nuclear tests also on a global scale ripping the atmosphere bandings to sheds and sending increased heat extremes into those areas.

    I believe there are many other factors yet to be considered  allowing these Co2 levels to increase.

    However, consider this, if the Earth cooled significantly it would have a worse effect on Humanity and everything that survives on her.

    Just my thoughts. 

    It's a matter of scale and residence time. The largest eruptions in the last 150 years have clearly affected the global climate. This has been both modelled and observed. The sulphur, and then subsequent sulphur dioxide don't last in the upper atmosphere all that long, which is why even major eruptions have little effect after a few years. The amount of CO2 released by eruptions is typically inconsequential too, with humans emitting at least 60 times the amount released by all volcanic activity each year
    But aside from that, there are no clear trends in volcanic activity or CO2 outgassing, so there's no reason t suspect that it contributes to the trend in CO2. Also, the carbon isotopes ratio is different for fossil fuel based carbon than atmospheric carbon, so we can measure the trends in this ratios over time and determine where the extra CO2 is coming from, and the answer is clear again - human activity.

    As for the energy, when you consider that in terms of the oceans alone, we have added the equivalent of 1.5 Hiroshima sized nukes worth of energy per second through global warming, the testing during WW2 doesn't seem significant at all. Currently. were adding 4 Hiroshima bombs worth of energy to the climate system per second.

    And cooling being a bad thing doesn't negate that warming is also bad.

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  • Location: Crymych, Pembrokeshire. 150m asl
  • Weather Preferences: Extremes of all kinds...
  • Location: Crymych, Pembrokeshire. 150m asl

    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!

    Edited by Sky Full
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