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That shows lack of understanding in purpose and use of the tree rings and it is not relevant to the topic. What I read from your statements is just that you don

by acqq 8y ago

That shows lack of understanding in purpose and use of the tree rings and it is not relevant to the topic. What I read from your statements is just that you don't understand how the past climates are scientifically reconstructed, and want to express the doubt in the results of all the work of all the scientist that agree (which is effectively all of them, minus the ones directly or indirectly funded by fossil fuel companies or motivated by political relations, if you have other impression, it's distorted by the intentional activity of said companies and political groups). But we don't configure the current modeling systems at all using the "prehistoric" reconstructions, the models and the currently measured values are much more precise. The "prehistoric" reconstructions only give you something to compare the orders of magnitudes. And comparing that, the warming is unprecedented. Which is not surprising giving that the humanity managed to extract and burn more then the half of all readily available oil from the Earth's crust in just 100 years. That very oil in the crust is however a result of more than 4 billion of years of the Earth's existence. If you’re reading this in some country like US, given that the average US car weights around 2 tonnes, your existence alone is probably responsible for the CO2 mass equivalent to the weight of 7–10 cars every year, and to the volume of CO2 which corresponds to the volume of more than 3000 cars. And the CO2, even if it's invisible for us, is actually "black" for something important: it's blocking the part of the spectrum that would allow the Earth surface to cool off. That's how small concentrations of it, compared to some other stuff in the air, produce such a big effect. The physics is simple and undeniable, and it's known that there will be always more problems caused by the growth of CO2 in the atmosphere which increases the surface temperature of the Earth.

jessaustin 8y ago
...more then the half of all readily available oil from the Earth's crust in just 100 years. We've been hearing this Peak Oil crap for years. Maybe eventually it will be true...
marcus_holmes 8y ago
Past climates are scientifically reconstructed from data recovered from physical objects that were present during those climates. One of the main sources, if not the main source, for that data is tree rings from old wood. If this statement is untrue, in any way, then please correct me, because yes, I've misunderstood how past climates are scientifically reconstructed. But I'm going to need you to explain what data is used during their reconstruction (and not some hand-wavy "it's very difficult and not for non-climate-scientists to understand").
- acqq 8y ago
  Tree rings are absolutely used as a proxy to infer the past, the science is called dendrochronology, and the application of it is called https://en.wikipedia.org/wiki/Dendroclimatology https://en.wikipedia.org/wiki/Dendroclimatology The limitations of it are known, and you won't find that the results of it are used for false claims by the real scientists: https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter05_FINAL.pdf https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapt... What I'm posting above is the real report by the The Intergovernmental Panel on Climate Change. If you look in the context, tree rings are just one piece of the big and complex picture. See my other comment for an example how those who just try to confuse simply ignore (and don't even care for) geological facts when they try to push their agenda. The same happens with those who try to sell you the doubt and false claims about the state of climate research. The scientifically known uncertainties in using the tree rings as proxies aren't changing any facts about the reality of global warming. It's undeniable basic physics. CO2 makes the Earth surface warmer because it blocks the part of the spectrum that would otherwise allow it to cool off. The part of the spectrum of the Sun that warms the surface up is however not blocked by the CO2. So the Earth gets the same effect that you have when you cover yourself with a blanket. It's warmer under it. It's undeniable and we are observing the effects every day: https://tidesandcurrents.noaa.gov/publications/techrpt83_Global_and_Regional_SLR_Scenarios_for_the_US_final.pdf https://tidesandcurrents.noaa.gov/publications/techrpt83_Glo... If we don't do anything the expected sea rise on US shores is estimated up to 2.5 m higher (8 feet) in 2100. The non-red lines in the graphs are for the scenarios if the humanity actually stops pushing CO2 in the atmosphere very soon. We're already not following the "blue" strategies.
topmonk 8y ago
> And the CO2, even if it's invisible for us, is actually "black" for something important: it's blocking the part of the spectrum that would allow the Earth surface to cool off. That's how small concentrations of it, compared to some other stuff in the air, produce such a big effect. > The physics is simple and undeniable, and it's known that there will be always more problems caused by the growth of CO2 in the atmosphere which increases the surface temperature of the Earth. Take a look at this graph of co2 vs temperature over a geological timescale: http://www.biocab.org/Geological_Timescale_op_712x534.jpg http://www.biocab.org/Geological_Timescale_op_712x534.jpg (from http://www.biocab.org/carbon_dioxide_geological_timescale.html http://www.biocab.org/carbon_dioxide_geological_timescale.ht...) From this, there doesn't seem to be any relationship at all and the co2 has been much higher during much of the history of earth. At the very least, you can't say that the relationship is simple.
- acqq 8y ago
  Take a look at who constructed the graph you quoted: http://citizenschallenge.blogspot.com/2012/10/nasif-s-nahle-google-scholar-and.html http://citizenschallenge.blogspot.com/2012/10/nasif-s-nahle-... Not a scientist. Now... anybody who is really interested in the real geological history knows that even the continents "weren't there" where they are now, when we look long enough in the past. Not to mention that, for the old enough times, not even plants existed on the land! https://en.wikipedia.org/wiki/Geological_history_of_Earth https://en.wikipedia.org/wiki/Geological_history_of_Earth In that context: https://www.skepticalscience.com/co2-higher-in-past-intermediate.htm https://www.skepticalscience.com/co2-higher-in-past-intermed... "However, until recently, CO2 levels during the late Ordovician were thought to be much greater than 3000 ppm which was problematic as the Earth experienced glacial conditions at this time. The CO2 data covering the late Ordovician is sparse with one data point in the CO2 proxy record close to this period - it has a value of 5600 ppm. Given that solar output was around 4% lower than current levels, CO2 would need to fall to 3000 ppm to permit glacial conditions." "(Young 2009). Rock weathering removes CO2 from the atmosphere. The process also produces a particular isotope of strontium, washed down to the oceans via rivers. The ratio of strontium isotopes in sediment layers can be used to construct a proxy record of continental weathering activity. The strontium record shows that around the middle Ordovician, weatherability increased leading to an increased consumption of CO2. However, this was balanced by increased volcanic outgassing adding CO2 to the atmosphere. Around 446 million years ago, volcanic activity dropped while rock weathering remained high. This caused CO2 levels to fall below 3000 ppm, initiating cooling. It turns out falling CO2 levels was the cause of late Ordovician glaciation." "So we see that comparisons of present day climate to periods 500 million years ago need to take into account that the sun was less active than now. What about times closer to home? The last time CO2 was similar to current levels was around 3 million years ago, during the Pliocene. Back then, CO2 levels remained at around 365 to 410 ppm for thousands of years. Arctic temperatures were 11 to 16°C warmer (Csank 2011). Global temperatures over this period is estimated to be 3 to 4°C warmer than pre-industrial temperatures. Sea levels were around 25 metres higher than current sea level (Dwyer 2008)." You have to understand geology to be able to compare. If you don't, people with agenda will easily sell you worthless graphs. Worthless as in "CO2 was higher when there were no plants and animals on the land at all, just the naked rocks." Nice target you have.

by acqq 8y ago

jessaustin 8y ago

...more then the half of all readily available oil from the Earth's crust in just 100 years. We've been hearing this Peak Oil crap for years. Maybe eventually it will be true...

marcus_holmes 8y ago

Past climates are scientifically reconstructed from data recovered from physical objects that were present during those climates. One of the main sources, if not the main source, for that data is tree rings from old wood. If this statement is untrue, in any way, then please correct me, because yes, I've misunderstood how past climates are scientifically reconstructed. But I'm going to need you to explain what data is used during their reconstruction (and not some hand-wavy "it's very difficult and not for non-climate-scientists to understand").

acqq 8y ago
Tree rings are absolutely used as a proxy to infer the past, the science is called dendrochronology, and the application of it is called https://en.wikipedia.org/wiki/Dendroclimatology https://en.wikipedia.org/wiki/Dendroclimatology The limitations of it are known, and you won't find that the results of it are used for false claims by the real scientists: https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter05_FINAL.pdf https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapt... What I'm posting above is the real report by the The Intergovernmental Panel on Climate Change. If you look in the context, tree rings are just one piece of the big and complex picture. See my other comment for an example how those who just try to confuse simply ignore (and don't even care for) geological facts when they try to push their agenda. The same happens with those who try to sell you the doubt and false claims about the state of climate research. The scientifically known uncertainties in using the tree rings as proxies aren't changing any facts about the reality of global warming. It's undeniable basic physics. CO2 makes the Earth surface warmer because it blocks the part of the spectrum that would otherwise allow it to cool off. The part of the spectrum of the Sun that warms the surface up is however not blocked by the CO2. So the Earth gets the same effect that you have when you cover yourself with a blanket. It's warmer under it. It's undeniable and we are observing the effects every day: https://tidesandcurrents.noaa.gov/publications/techrpt83_Global_and_Regional_SLR_Scenarios_for_the_US_final.pdf https://tidesandcurrents.noaa.gov/publications/techrpt83_Glo... If we don't do anything the expected sea rise on US shores is estimated up to 2.5 m higher (8 feet) in 2100. The non-red lines in the graphs are for the scenarios if the humanity actually stops pushing CO2 in the atmosphere very soon. We're already not following the "blue" strategies.

topmonk 8y ago

> And the CO2, even if it's invisible for us, is actually "black" for something important: it's blocking the part of the spectrum that would allow the Earth surface to cool off. That's how small concentrations of it, compared to some other stuff in the air, produce such a big effect. > The physics is simple and undeniable, and it's known that there will be always more problems caused by the growth of CO2 in the atmosphere which increases the surface temperature of the Earth. Take a look at this graph of co2 vs temperature over a geological timescale: http://www.biocab.org/Geological_Timescale_op_712x534.jpg http://www.biocab.org/Geological_Timescale_op_712x534.jpg (from http://www.biocab.org/carbon_dioxide_geological_timescale.html http://www.biocab.org/carbon_dioxide_geological_timescale.ht...) From this, there doesn't seem to be any relationship at all and the co2 has been much higher during much of the history of earth. At the very least, you can't say that the relationship is simple.

acqq 8y ago
Take a look at who constructed the graph you quoted: http://citizenschallenge.blogspot.com/2012/10/nasif-s-nahle-google-scholar-and.html http://citizenschallenge.blogspot.com/2012/10/nasif-s-nahle-... Not a scientist. Now... anybody who is really interested in the real geological history knows that even the continents "weren't there" where they are now, when we look long enough in the past. Not to mention that, for the old enough times, not even plants existed on the land! https://en.wikipedia.org/wiki/Geological_history_of_Earth https://en.wikipedia.org/wiki/Geological_history_of_Earth In that context: https://www.skepticalscience.com/co2-higher-in-past-intermediate.htm https://www.skepticalscience.com/co2-higher-in-past-intermed... "However, until recently, CO2 levels during the late Ordovician were thought to be much greater than 3000 ppm which was problematic as the Earth experienced glacial conditions at this time. The CO2 data covering the late Ordovician is sparse with one data point in the CO2 proxy record close to this period - it has a value of 5600 ppm. Given that solar output was around 4% lower than current levels, CO2 would need to fall to 3000 ppm to permit glacial conditions." "(Young 2009). Rock weathering removes CO2 from the atmosphere. The process also produces a particular isotope of strontium, washed down to the oceans via rivers. The ratio of strontium isotopes in sediment layers can be used to construct a proxy record of continental weathering activity. The strontium record shows that around the middle Ordovician, weatherability increased leading to an increased consumption of CO2. However, this was balanced by increased volcanic outgassing adding CO2 to the atmosphere. Around 446 million years ago, volcanic activity dropped while rock weathering remained high. This caused CO2 levels to fall below 3000 ppm, initiating cooling. It turns out falling CO2 levels was the cause of late Ordovician glaciation." "So we see that comparisons of present day climate to periods 500 million years ago need to take into account that the sun was less active than now. What about times closer to home? The last time CO2 was similar to current levels was around 3 million years ago, during the Pliocene. Back then, CO2 levels remained at around 365 to 410 ppm for thousands of years. Arctic temperatures were 11 to 16°C warmer (Csank 2011). Global temperatures over this period is estimated to be 3 to 4°C warmer than pre-industrial temperatures. Sea levels were around 25 metres higher than current sea level (Dwyer 2008)." You have to understand geology to be able to compare. If you don't, people with agenda will easily sell you worthless graphs. Worthless as in "CO2 was higher when there were no plants and animals on the land at all, just the naked rocks." Nice target you have.