8 ms·

The world has warmed 1.5 °C, according to 300-year-old sponges

77 points by tigerlily 3y ago

clarada 3y ago
[flagged]
- neom 3y ago
  That's some fun conflation right there! The ice age ended over 11,500 years ago... this sponge is 300 years ago. The study focuses on industrialization's impact on the climate.
  - lainga 3y ago
    https://en.wikipedia.org/wiki/Little_Ice_Age https://en.wikipedia.org/wiki/Little_Ice_Age
    - neom 3y ago
      My mistake. Nevertheless, still certainly a conflation of information.
      - verisimi 3y ago
        You conflated the information!
    - BytesAndGears 3y ago
      Not sure that really refutes the point, since the temperature was down by about 0.25 degrees during that little ice age, according to the graph at the top of your link. after that little blip down it absolutely shot up. Little Ice Age barely had an affect on that graph, relatively
  - mbostleman 3y ago
    Aside from the correlation of the sponges' state changes and industrialization being in the same general time period, is there a causal link in the study? This is the part I struggle with when I think of the massive temperature and sea level changes on a geologic time scale. The numbers that the current climate concern are dealing with (temp, sea level rise, etc.) are so tiny. How are the models controlled from the variables in the otherwise seemingly chaotic, wild swings in the lifetime of the planet? It's amazing to me that we can zoom in and make such high resolution determinations like that. I wish, as a laymen, someone could explain how we do it.
- photochemsyn 3y ago
  Given that every other warm interglacial period since the Pliocene ended in a slow slide into another ice age, a steady warming trend is indeed remarkable. There have been some 18 ~100,000 year ice age cycles since the Pliocene, and each glacial maximum ended about 3X as rapidly as it formed, so the world should be slowly cooling at present - but thanks to Homo ignis burning all the fuel, that trend has been reversed. If you like, you could argue that human industry has saved the planet from another ice age anytime soon, but the job is certainly done at this point so we should stop burning fossil fuels now and try to stabilize the atmosphere at a constant steady state composition.
alienicecream 3y ago
And yet we are doing better than ever, almost like we can adapt. Maybe the apocalyptic predictions are overblown.
makeworld 3y ago
So we have already surpassed 1.5C by this measure, and will pass 2C earlier than predicted. Does that mean the various events predicted to occur around 2C will also occur earlier? Or not, because this paper measures from an early date?
- spywaregorilla 3y ago
  Earlier date, different baseline. Doesn't really change anything.
  - onlyrealcuzzo 3y ago
    Why is warming 1.5C from a prior date not as bad as warming 1.5C from the more referenced date? We were in an ice age 300 years ago. The climate has changed a lot compared to an ice age. Is it really going to change even more in the next 0.5C?
    - coldbrewed 3y ago
      The impacts of climate change are nonlinear. For example 100 year storms become 10 year storms, weather anomalies like polar vortices become much more common, and in general climactic extremes become both more extreme and more common. More concerningly, tipping points are reached (in order to rebuild the polar ice caps we won't need to go back -1.5C, but -4C), and tipping point events cause cascades that lock in climate change. Worse yet, we're exiting the stable climactic conditions that civilization assumes is present. Assumptions regarding maximum temperatures, precipitation, ground water are baked into our reservoirs, power transmission lines, asphalt roads, train tracks, et cetera. Increased extreme weather compromises our ability to maintain society; look no further than the heat domes in the Pacific Northwest or the cold snaps in Texas to see how those assumptions compromise basic societal functions. 0.5C doesn't imply slightly worse weather, it means the additions of staggering amounts of heat to our land, water, and seas -- and the resulting amplifications of storms.
    - abdullahkhalids 3y ago
      The last ice age ended over 10,000 years ago [1]. Parent might have been referring to the Little Ice Age [2], which according to the IPCC was > ...a multi-centennial period of relatively low temperature beginning around the 15th century, with GMST averaging –0.03 [–0.30 to 0.06] °C between 1450 and 1850 relative to 1850–1900. GMST = global mean surface temperature Hardly, counts as valid given that we are talking about 1.5C/0.03 = 50x bigger change right now. [1] https://en.wikipedia.org/wiki/Ice_age https://en.wikipedia.org/wiki/Ice_age [2] https://en.wikipedia.org/wiki/Little_Ice_Age https://en.wikipedia.org/wiki/Little_Ice_Age
hnthrowaway0328 3y ago
Montreal is particularly warm but dry this winter -- actually in many days warmer than Shanghai, China. I hope we don't have a super cold March this year.
- SebFender 3y ago
  Dry? It's been raining like crazy this year...
zx8080 3y ago
[flagged]
- elashri 3y ago
  I know that the comment is sarcastic but just in case, this will have the opposite effect, yes nuclear bombs will produce a lot of heat but that is for short amount of time and fires it will produce will last for sometime. But on the long time scale (months to years) the particles will precipitate in the sky and trapped and will cover most of the planet by radiation clouds which will prevent most of the sun photons from reaching the earth. So goodbye for planets and it will be the worst winter in earth's lifetime. Then you say small? But how can we have small nuclear war? The effects of any nuclear exchange will be seen throughout the world (not in geopolitical sense).
  - StopTheTechies 3y ago
    I don't believe any of this is true—it certainly smells a lot like Cold War propaganda from the 50s. I don't believe we currently have anywhere near the nukes produced to have this happen even if we tried to perfectly cover the surface of the earth with nuclear explosions. To block out the sun we'd need something more like the volcanic winter of 536, continually erupting. Nuclear war is bad, but it's certainly not "end life on earth" bad, or even "end humanity" bad by itself, just "deeply fracture humanity and probably enter a new era of civilization" bad.
    - rainbowzootsuit 3y ago
      Aircraft contrails have a measurable effect on surface temperature so you might don't need as much as one might think. https://globalnews.ca/news/2934513/empty-skies-after-911-set-the-stage-for-an-unlikely-climate-change-experiment/ https://globalnews.ca/news/2934513/empty-skies-after-911-set... https://www.forbes.com/sites/arielcohen/2021/01/11/bill-gates-backed-climate-solution-gains-traction-but-concerns-linger/ https://www.forbes.com/sites/arielcohen/2021/01/11/bill-gate... I'm sure he won't be a Mr. Burns trying to sell more power when reducing the effect of solar panels.
  - 3y ago
kjqgqkejbfefn 3y ago
What about this hockey-stick shaped curve ? https://revistapesquisa.fapesp.br/wp-content/uploads/2019/07/012-017_Notas_277-info.jpg https://revistapesquisa.fapesp.br/wp-content/uploads/2019/07...
- wolpoli 3y ago
  That appears to show the position of the magnetic north pole over the years. Does the location of magnetic pole affect local weather conditions?
- smashed 3y ago
  https://climate.nasa.gov/explore/ask-nasa-climate/3104/flip-flop-why-variations-in-earths-magnetic-field-arent-causing-todays-climate-change/ https://climate.nasa.gov/explore/ask-nasa-climate/3104/flip-...
- mitthrowaway2 3y ago
  What about it?
  - kjqgqkejbfefn 3y ago
    See for yourself: The ‘Sterno-Etrussia’ Geomagnetic Excursion Around 2700 BP and Changes of Solar Activity, Cosmic Ray Intensity, and Climate https://www.cambridge.org/core/journals/radiocarbon/article/sternoetrussia-geomagnetic-excursion-around-2700-bp-and-changes-of-solar-activity-cosmic-ray-intensity-and-climate/3F6746E7AF6783FF74C40E77080A16BD https://www.cambridge.org/core/journals/radiocarbon/article/... >The Sterno-Etrussia excursion may have amplified the climate shift, which, in the first place, was the effect of a decline of solar activity. During excursions and inversions, the magnetic moment decreases, which leads to an increased intensity of cosmic rays penetrating the upper atmosphere. Global changes in the electromagnetic field of the earth result in sharp changes in the climate-determining factors in the atmosphere, such as temperatures, total pressure field, moisture circulation, intensity of air flows, and thunderstorm activity. In addition, significant changes in the ocean circulation patterns and temperature regimes of oceans will have taken place. Global climate change during the 13,500-b.p. Gothenburg geomagnetic excursion https://www.nature.com/articles/265430a0 https://www.nature.com/articles/265430a0 >ROBERTS and Olsen1 suggested that high latitude atmospheric ionisation has an important role in nucleating cirrus clouds. And Harrison and Prospero2 deduce that, if this is correct, severe drops of the Earth's magnetic field strength, such as are believed to accompany reversals, would lead to increased upper atmospheric cloudiness at all latitudes and correspondingly to major climatic events. There is likely to be warming at high latitudes but considerable cooling in the middle latitudes, in a way analogous to the aerosols3. Are there connections between the Earth's magnetic field and climate? https://www.sciencedirect.com/science/article/abs/pii/S0012821X06007667 https://www.sciencedirect.com/science/article/abs/pii/S00128... >Understanding climate change is an active topic of research. Much of the observed increase in global surface temperature over the past 150 years occurred prior to the 1940s and after the 1980s. The main causes invoked are solar variability, changes in atmospheric greenhouse gas content or sulfur due to natural or anthropogenic action, or internal variability of the coupled ocean–atmosphere system. Magnetism has seldom been invoked, and evidence for connections between climate and magnetic field variations have received little attention. We review evidence for correlations which could suggest such (causal or non-causal) connections at various time scales (recent secular variation ∼ 10–100 yr, historical and archeomagnetic change ∼ 100–5000 yr, and excursions and reversals ∼ 103–106 yr), and attempt to suggest mechanisms. Evidence for correlations, which invoke Milankovic forcing in the core, either directly or through changes in ice distribution and moments of inertia of the Earth, is still tenuous. Correlation between decadal changes in amplitude of geomagnetic variations of external origin, solar irradiance and global temperature is stronger. It suggests that solar irradiance could have been a major forcing function of climate until the mid-1980s, when “anomalous” warming becomes apparent. Book on the subject: The Hidden Link Between Earth’s Magnetic Field and Climate https://books.google.fr/books?hl=fr&lr=&id=MeXEDwAAQBAJ&oi=fnd&pg=PP1&dq=earth's+magnetic+field+and+climate&ots=Ucy2YWVlNt&sig=zOg5f6zn1ZXAfe4W38b7uIQrcxk&redir_esc=y#v=onepage&q=earth's%20magnetic%20field%20and%20climate&f=false https://books.google.fr/books?hl=fr&lr=&id=MeXEDwAAQBAJ&oi=f... The Role of Geomagnetic Field Intensity in Late Quaternary Evolution of Humans and Large Mammals https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018RG000629 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201... >It has long been speculated that biological evolution was influenced by ultraviolet radiation (UVR) reaching the Earth's surface, despite imprecise knowledge of the timing of both UVR flux and evolutionary events. The past strength of Earth's dipole field provides a proxy for UVR flux because of its role in maintaining stratospheric ozone. The timing of Quaternary evolutionary events has become better constrained by fossil finds, improved radiometric dating, use of dung fungi as proxies for herbivore populations, and improved ages for nodes in human phylogeny from human mitochondrial DNA and Y chromosomes. The demise of Neanderthals at ~41 ka can now be closely tied to the intensity minimum associated with the Laschamp magnetic excursion, and the survival of anatomically modern humans can be attributed to differences in the aryl hydrocarbon receptor that has a key role in the evolutionary response to UVR flux. Fossil occurrences and dung-fungal proxies in Australia indicate that episodes of Late Quaternary extinction of mammalian megafauna occurred close to the Laschamp and Blake magnetic excursions. Fossil and dung fungal evidence for the age of the Late Quaternary extinction in North America (and Europe) coincide with a prominent decline in geomagnetic field intensity at ~13 ka. Latest Permian and earliest Triassic geomagnetic polarity timescale: A polarity reversal marks the greatest mass extinction https://www.sciencedirect.com/science/article/abs/pii/S0921818124000158 https://www.sciencedirect.com/science/article/abs/pii/S09218...
jmward01 3y ago
Global warming is real, but I wish we paid more attention to biodiversity and set goals there instead of fixating on temperature. I understand why temperature is there. It is easy to measure and an easy number to campaign around, but biodiversity, to me, is the actual point and focusing on temperature, while a major factor, diminishes the many other issues attacking it.
- vlovich123 3y ago
  We’re already doing piss poor responding to a simple number that’s super easy to measure and evaluate predictions against. Do you think a harder to measure more argumentative measure would make global warming easier to tackle?
  - blagie 3y ago
    Yes.
  - jmward01 3y ago
    It is a really hard problem to survive. The only somewhat successful, so far, long term strategy I know of is the one we see in nature, diversity. Healthy ecosystems are always diverse. Diversity helps absorb shocks and exploit nitches that enable growth. But here is the kicker, diversity is helpful in every system to keep it alive, including the diversity of arguments we use in educating people. By focusing on just one argument we are making a mistake. I'm not saying we throw out temp targets and discussing them, but we need more valid discussions to increase the diversity of the discussion so that it survives and thrives.
- xnx 3y ago
  Agree. Climate change is just one of the ways (and a big one) that habitat is being destroyed. Ocean acidification, conversion of forests and fields to farmland, and fertilizer runoff are others.
  - orwin 3y ago
    Climate change and acidification have the same main causes.
fuckyah 3y ago
[dead]
donatj 3y ago
For the Americans layman like myself, that's a warming of 2.7 °F
blagie 3y ago
Meh, don't care. Seriously, we had ice ages. Temperatures go up and down. I can't bring myself to care about 86 instead of 83 degrees F in the summer and 23 instead of 20 in the winter. It's like moving a few hundred miles south. People get by fine. I mean, I'm worried about all the weird chemicals in my food. That seems kinda wacky. I'm worried about all the biodiversity disappearing. Extreme-weather-itis would be scary, if it's actually a thing. I'm worried about breathing more CO2, and especially about the same in water (ocean acidification). I'm worried about many of the other impacts on climate. "Climate change" was a step forward in terminology from "global warming," but we need about five more steps before it's something people care about. We also need to acknowledge how much we don't know. Most of our models from 20 years ago didn't play out, which was obvious if you read the papers instead of listening to Al Gore. Bad things happened, but not the ones we thought would happen. It's a chaotic system. It doesn't work predictably.
- MR4D 3y ago
  Agreed. Many more people will die of heart disease And cancer than from global warming. Too many chemicals in our environment and food chain.
- deleted 3y ago
  [deleted]
- defrost 3y ago
  > I can't bring myself to care about 86 instead of 83 degrees F in the summer and 23 instead of 20 in the winter. Respectfully, you've not understood the measure and the meaning of global average. For most of the past 200K years, most of human 'advanced' existance there's been little change in the global mean and all the seasons have changed as per written history and your recollection. Lifting the global mean introduces more energy to the climate cells about the globe, driving more extreme changes, intoducing greater storms, setting us up for even more change as water vapor and methane levels rise which themselves are greater insulators that trap more heat than CO2.
  - blagie 3y ago
    > driving more extreme changes, intoducing [sp] greater storms Respectfully, the mean temperature is the wrong measure for that. You want to look at measures like variance / std. div. -- the second moment and not the first. That's why I listed under "Extreme-weather-itis" under things I care about. > setting us up for even more change as water vapor and methane levels rise which themselves are greater insulators that trap more heat than CO2 Respectfully, you don't know that. The phrase should be "setting ourselves up for something possibly very bad." Extrapolation works worse than interpolation, and it's a chaotic system. Respectfully, the level of imprecision and propaganda here is a root cause of scepticism. People can understand why we don't want to play Russian Roulette, especially when most of the barrels are loaded, each with a different munition. That's more honest and likely leads to the outcome you want.
egberts1 3y ago
Incredible sample size for an incredible error rate.
tcfhgj 3y ago
why is an article from Nature flagged?

77 points by tigerlily 3y ago

clarada 3y ago

[flagged]

neom 3y ago
That's some fun conflation right there! The ice age ended over 11,500 years ago... this sponge is 300 years ago. The study focuses on industrialization's impact on the climate.
- lainga 3y ago
  https://en.wikipedia.org/wiki/Little_Ice_Age https://en.wikipedia.org/wiki/Little_Ice_Age
  - neom 3y ago
    My mistake. Nevertheless, still certainly a conflation of information.
    - verisimi 3y ago
      You conflated the information!
  - BytesAndGears 3y ago
    Not sure that really refutes the point, since the temperature was down by about 0.25 degrees during that little ice age, according to the graph at the top of your link. after that little blip down it absolutely shot up. Little Ice Age barely had an affect on that graph, relatively
- mbostleman 3y ago
  Aside from the correlation of the sponges' state changes and industrialization being in the same general time period, is there a causal link in the study? This is the part I struggle with when I think of the massive temperature and sea level changes on a geologic time scale. The numbers that the current climate concern are dealing with (temp, sea level rise, etc.) are so tiny. How are the models controlled from the variables in the otherwise seemingly chaotic, wild swings in the lifetime of the planet? It's amazing to me that we can zoom in and make such high resolution determinations like that. I wish, as a laymen, someone could explain how we do it.
photochemsyn 3y ago
Given that every other warm interglacial period since the Pliocene ended in a slow slide into another ice age, a steady warming trend is indeed remarkable. There have been some 18 ~100,000 year ice age cycles since the Pliocene, and each glacial maximum ended about 3X as rapidly as it formed, so the world should be slowly cooling at present - but thanks to Homo ignis burning all the fuel, that trend has been reversed. If you like, you could argue that human industry has saved the planet from another ice age anytime soon, but the job is certainly done at this point so we should stop burning fossil fuels now and try to stabilize the atmosphere at a constant steady state composition.

alienicecream 3y ago

And yet we are doing better than ever, almost like we can adapt. Maybe the apocalyptic predictions are overblown.

makeworld 3y ago

So we have already surpassed 1.5C by this measure, and will pass 2C earlier than predicted. Does that mean the various events predicted to occur around 2C will also occur earlier? Or not, because this paper measures from an early date?

spywaregorilla 3y ago
Earlier date, different baseline. Doesn't really change anything.
- onlyrealcuzzo 3y ago
  Why is warming 1.5C from a prior date not as bad as warming 1.5C from the more referenced date? We were in an ice age 300 years ago. The climate has changed a lot compared to an ice age. Is it really going to change even more in the next 0.5C?
  - coldbrewed 3y ago
    The impacts of climate change are nonlinear. For example 100 year storms become 10 year storms, weather anomalies like polar vortices become much more common, and in general climactic extremes become both more extreme and more common. More concerningly, tipping points are reached (in order to rebuild the polar ice caps we won't need to go back -1.5C, but -4C), and tipping point events cause cascades that lock in climate change. Worse yet, we're exiting the stable climactic conditions that civilization assumes is present. Assumptions regarding maximum temperatures, precipitation, ground water are baked into our reservoirs, power transmission lines, asphalt roads, train tracks, et cetera. Increased extreme weather compromises our ability to maintain society; look no further than the heat domes in the Pacific Northwest or the cold snaps in Texas to see how those assumptions compromise basic societal functions. 0.5C doesn't imply slightly worse weather, it means the additions of staggering amounts of heat to our land, water, and seas -- and the resulting amplifications of storms.
  - abdullahkhalids 3y ago
    The last ice age ended over 10,000 years ago [1]. Parent might have been referring to the Little Ice Age [2], which according to the IPCC was > ...a multi-centennial period of relatively low temperature beginning around the 15th century, with GMST averaging –0.03 [–0.30 to 0.06] °C between 1450 and 1850 relative to 1850–1900. GMST = global mean surface temperature Hardly, counts as valid given that we are talking about 1.5C/0.03 = 50x bigger change right now. [1] https://en.wikipedia.org/wiki/Ice_age https://en.wikipedia.org/wiki/Ice_age [2] https://en.wikipedia.org/wiki/Little_Ice_Age https://en.wikipedia.org/wiki/Little_Ice_Age

hnthrowaway0328 3y ago

Montreal is particularly warm but dry this winter -- actually in many days warmer than Shanghai, China. I hope we don't have a super cold March this year.

SebFender 3y ago
Dry? It's been raining like crazy this year...

zx8080 3y ago

[flagged]

elashri 3y ago
I know that the comment is sarcastic but just in case, this will have the opposite effect, yes nuclear bombs will produce a lot of heat but that is for short amount of time and fires it will produce will last for sometime. But on the long time scale (months to years) the particles will precipitate in the sky and trapped and will cover most of the planet by radiation clouds which will prevent most of the sun photons from reaching the earth. So goodbye for planets and it will be the worst winter in earth's lifetime. Then you say small? But how can we have small nuclear war? The effects of any nuclear exchange will be seen throughout the world (not in geopolitical sense).
- StopTheTechies 3y ago
  I don't believe any of this is true—it certainly smells a lot like Cold War propaganda from the 50s. I don't believe we currently have anywhere near the nukes produced to have this happen even if we tried to perfectly cover the surface of the earth with nuclear explosions. To block out the sun we'd need something more like the volcanic winter of 536, continually erupting. Nuclear war is bad, but it's certainly not "end life on earth" bad, or even "end humanity" bad by itself, just "deeply fracture humanity and probably enter a new era of civilization" bad.
  - rainbowzootsuit 3y ago
    Aircraft contrails have a measurable effect on surface temperature so you might don't need as much as one might think. https://globalnews.ca/news/2934513/empty-skies-after-911-set-the-stage-for-an-unlikely-climate-change-experiment/ https://globalnews.ca/news/2934513/empty-skies-after-911-set... https://www.forbes.com/sites/arielcohen/2021/01/11/bill-gates-backed-climate-solution-gains-traction-but-concerns-linger/ https://www.forbes.com/sites/arielcohen/2021/01/11/bill-gate... I'm sure he won't be a Mr. Burns trying to sell more power when reducing the effect of solar panels.
- 3y ago

kjqgqkejbfefn 3y ago

What about this hockey-stick shaped curve ? https://revistapesquisa.fapesp.br/wp-content/uploads/2019/07/012-017_Notas_277-info.jpg https://revistapesquisa.fapesp.br/wp-content/uploads/2019/07...

wolpoli 3y ago
That appears to show the position of the magnetic north pole over the years. Does the location of magnetic pole affect local weather conditions?
smashed 3y ago
https://climate.nasa.gov/explore/ask-nasa-climate/3104/flip-flop-why-variations-in-earths-magnetic-field-arent-causing-todays-climate-change/ https://climate.nasa.gov/explore/ask-nasa-climate/3104/flip-...
mitthrowaway2 3y ago
What about it?
- kjqgqkejbfefn 3y ago
  See for yourself: The ‘Sterno-Etrussia’ Geomagnetic Excursion Around 2700 BP and Changes of Solar Activity, Cosmic Ray Intensity, and Climate https://www.cambridge.org/core/journals/radiocarbon/article/sternoetrussia-geomagnetic-excursion-around-2700-bp-and-changes-of-solar-activity-cosmic-ray-intensity-and-climate/3F6746E7AF6783FF74C40E77080A16BD https://www.cambridge.org/core/journals/radiocarbon/article/... >The Sterno-Etrussia excursion may have amplified the climate shift, which, in the first place, was the effect of a decline of solar activity. During excursions and inversions, the magnetic moment decreases, which leads to an increased intensity of cosmic rays penetrating the upper atmosphere. Global changes in the electromagnetic field of the earth result in sharp changes in the climate-determining factors in the atmosphere, such as temperatures, total pressure field, moisture circulation, intensity of air flows, and thunderstorm activity. In addition, significant changes in the ocean circulation patterns and temperature regimes of oceans will have taken place. Global climate change during the 13,500-b.p. Gothenburg geomagnetic excursion https://www.nature.com/articles/265430a0 https://www.nature.com/articles/265430a0 >ROBERTS and Olsen1 suggested that high latitude atmospheric ionisation has an important role in nucleating cirrus clouds. And Harrison and Prospero2 deduce that, if this is correct, severe drops of the Earth's magnetic field strength, such as are believed to accompany reversals, would lead to increased upper atmospheric cloudiness at all latitudes and correspondingly to major climatic events. There is likely to be warming at high latitudes but considerable cooling in the middle latitudes, in a way analogous to the aerosols3. Are there connections between the Earth's magnetic field and climate? https://www.sciencedirect.com/science/article/abs/pii/S0012821X06007667 https://www.sciencedirect.com/science/article/abs/pii/S00128... >Understanding climate change is an active topic of research. Much of the observed increase in global surface temperature over the past 150 years occurred prior to the 1940s and after the 1980s. The main causes invoked are solar variability, changes in atmospheric greenhouse gas content or sulfur due to natural or anthropogenic action, or internal variability of the coupled ocean–atmosphere system. Magnetism has seldom been invoked, and evidence for connections between climate and magnetic field variations have received little attention. We review evidence for correlations which could suggest such (causal or non-causal) connections at various time scales (recent secular variation ∼ 10–100 yr, historical and archeomagnetic change ∼ 100–5000 yr, and excursions and reversals ∼ 103–106 yr), and attempt to suggest mechanisms. Evidence for correlations, which invoke Milankovic forcing in the core, either directly or through changes in ice distribution and moments of inertia of the Earth, is still tenuous. Correlation between decadal changes in amplitude of geomagnetic variations of external origin, solar irradiance and global temperature is stronger. It suggests that solar irradiance could have been a major forcing function of climate until the mid-1980s, when “anomalous” warming becomes apparent. Book on the subject: The Hidden Link Between Earth’s Magnetic Field and Climate https://books.google.fr/books?hl=fr&lr=&id=MeXEDwAAQBAJ&oi=fnd&pg=PP1&dq=earth's+magnetic+field+and+climate&ots=Ucy2YWVlNt&sig=zOg5f6zn1ZXAfe4W38b7uIQrcxk&redir_esc=y#v=onepage&q=earth's%20magnetic%20field%20and%20climate&f=false https://books.google.fr/books?hl=fr&lr=&id=MeXEDwAAQBAJ&oi=f... The Role of Geomagnetic Field Intensity in Late Quaternary Evolution of Humans and Large Mammals https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018RG000629 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201... >It has long been speculated that biological evolution was influenced by ultraviolet radiation (UVR) reaching the Earth's surface, despite imprecise knowledge of the timing of both UVR flux and evolutionary events. The past strength of Earth's dipole field provides a proxy for UVR flux because of its role in maintaining stratospheric ozone. The timing of Quaternary evolutionary events has become better constrained by fossil finds, improved radiometric dating, use of dung fungi as proxies for herbivore populations, and improved ages for nodes in human phylogeny from human mitochondrial DNA and Y chromosomes. The demise of Neanderthals at ~41 ka can now be closely tied to the intensity minimum associated with the Laschamp magnetic excursion, and the survival of anatomically modern humans can be attributed to differences in the aryl hydrocarbon receptor that has a key role in the evolutionary response to UVR flux. Fossil occurrences and dung-fungal proxies in Australia indicate that episodes of Late Quaternary extinction of mammalian megafauna occurred close to the Laschamp and Blake magnetic excursions. Fossil and dung fungal evidence for the age of the Late Quaternary extinction in North America (and Europe) coincide with a prominent decline in geomagnetic field intensity at ~13 ka. Latest Permian and earliest Triassic geomagnetic polarity timescale: A polarity reversal marks the greatest mass extinction https://www.sciencedirect.com/science/article/abs/pii/S0921818124000158 https://www.sciencedirect.com/science/article/abs/pii/S09218...

jmward01 3y ago

Global warming is real, but I wish we paid more attention to biodiversity and set goals there instead of fixating on temperature. I understand why temperature is there. It is easy to measure and an easy number to campaign around, but biodiversity, to me, is the actual point and focusing on temperature, while a major factor, diminishes the many other issues attacking it.

vlovich123 3y ago
We’re already doing piss poor responding to a simple number that’s super easy to measure and evaluate predictions against. Do you think a harder to measure more argumentative measure would make global warming easier to tackle?
- blagie 3y ago
  Yes.
- jmward01 3y ago
  It is a really hard problem to survive. The only somewhat successful, so far, long term strategy I know of is the one we see in nature, diversity. Healthy ecosystems are always diverse. Diversity helps absorb shocks and exploit nitches that enable growth. But here is the kicker, diversity is helpful in every system to keep it alive, including the diversity of arguments we use in educating people. By focusing on just one argument we are making a mistake. I'm not saying we throw out temp targets and discussing them, but we need more valid discussions to increase the diversity of the discussion so that it survives and thrives.
xnx 3y ago
Agree. Climate change is just one of the ways (and a big one) that habitat is being destroyed. Ocean acidification, conversion of forests and fields to farmland, and fertilizer runoff are others.
- orwin 3y ago
  Climate change and acidification have the same main causes.

fuckyah 3y ago

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donatj 3y ago

For the Americans layman like myself, that's a warming of 2.7 °F

blagie 3y ago

Meh, don't care. Seriously, we had ice ages. Temperatures go up and down. I can't bring myself to care about 86 instead of 83 degrees F in the summer and 23 instead of 20 in the winter. It's like moving a few hundred miles south. People get by fine. I mean, I'm worried about all the weird chemicals in my food. That seems kinda wacky. I'm worried about all the biodiversity disappearing. Extreme-weather-itis would be scary, if it's actually a thing. I'm worried about breathing more CO2, and especially about the same in water (ocean acidification). I'm worried about many of the other impacts on climate. "Climate change" was a step forward in terminology from "global warming," but we need about five more steps before it's something people care about. We also need to acknowledge how much we don't know. Most of our models from 20 years ago didn't play out, which was obvious if you read the papers instead of listening to Al Gore. Bad things happened, but not the ones we thought would happen. It's a chaotic system. It doesn't work predictably.

MR4D 3y ago
Agreed. Many more people will die of heart disease And cancer than from global warming. Too many chemicals in our environment and food chain.
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defrost 3y ago
> I can't bring myself to care about 86 instead of 83 degrees F in the summer and 23 instead of 20 in the winter. Respectfully, you've not understood the measure and the meaning of global average. For most of the past 200K years, most of human 'advanced' existance there's been little change in the global mean and all the seasons have changed as per written history and your recollection. Lifting the global mean introduces more energy to the climate cells about the globe, driving more extreme changes, intoducing greater storms, setting us up for even more change as water vapor and methane levels rise which themselves are greater insulators that trap more heat than CO2.
- blagie 3y ago
  > driving more extreme changes, intoducing [sp] greater storms Respectfully, the mean temperature is the wrong measure for that. You want to look at measures like variance / std. div. -- the second moment and not the first. That's why I listed under "Extreme-weather-itis" under things I care about. > setting us up for even more change as water vapor and methane levels rise which themselves are greater insulators that trap more heat than CO2 Respectfully, you don't know that. The phrase should be "setting ourselves up for something possibly very bad." Extrapolation works worse than interpolation, and it's a chaotic system. Respectfully, the level of imprecision and propaganda here is a root cause of scepticism. People can understand why we don't want to play Russian Roulette, especially when most of the barrels are loaded, each with a different munition. That's more honest and likely leads to the outcome you want.

egberts1 3y ago

Incredible sample size for an incredible error rate.

tcfhgj 3y ago

why is an article from Nature flagged?