3 ms·

So tell me how they actually measured global mean temp back in 1850?

chefkoch 3y ago
https://en.m.wikipedia.org/wiki/Instrumental_temperature_record https://en.m.wikipedia.org/wiki/Instrumental_temperature_rec...
barelyauser 3y ago
There are things called 'proxies'. The same way you can assess the crime rate of a certain area by the amount of littering by the side of the road.
- vdaea 3y ago
  >The same way you can assess the crime rate of a certain area by the amount of littering by the side of the road. You mean incorrectly? Also, if I had to guess, proxies that show global warming to be bad are widely publicised, whilst proxies that show global warming not to occur are ignored.
  - rscho 3y ago
    "I don't know if this sign about a cliff ahead was right, so I'm gonna keep going pedal to the metal. Just in case..."
  - Propelloni 3y ago
    > Also, if I had to guess, proxies that show global warming to be bad are widely publicised, whilst proxies that show global warming not to occur are ignored. You are mixing categories. One is about the observable universe, ie. "does global warming happen"? The other one is a value judgement, ie. "is global warming bad?"
  - saalweachter 3y ago
    I mean, if you want to go down that route, why assume that the expansion of mercury in a glass tube is a good proxy for atmospheric temperature? Sometimes it feels hotter or colder than the mercury would indicate, after all. QED, it is impossible to determine if the climate is changing.
tromp 3y ago
With help from sea sponges as recently discussed in https://news.ycombinator.com/item?id=39268387 https://news.ycombinator.com/item?id=39268387
- ChrisArchitect 3y ago
  More discussion on the sponges and ocean warming: https://news.ycombinator.com/item?id=39275272 https://news.ycombinator.com/item?id=39275272
kybernetyk 3y ago
[flagged]
defrost 3y ago
With instrumentation across the globe at naval timekeeping stations of the various European empires - much of which persisted for a hundred years and thus overlapped with later instruments and broader coverage which allowed for levelling and blending. It's essentially a "construct your baseline" problem faced in many domains, the Fifth and other IPCC reports: This IPCC Special Report on Global Warming of 1.5°C uses the reference period 1850–1900 to represent pre-industrial temperature. This is the earliest period with near-global observations and is the reference period used as an approximation of preindustrial temperatures in the IPCC Fifth Assessment Report. ~ IPCC FAQ: https://www.ipcc.ch/site/assets/uploads/sites/2/2018/12/SR15_FAQ_Low_Res.pdf and naturally there are many papers that consider alternate baselines, data quality, proxies, etc. eg: Estimating Changes in Global Temperature since the Preindustrial Period (2017) https://journals.ametsoc.org/view/journals/bams/98/9/bams-d-16-0007.1.xml https://journals.ametsoc.org/view/journals/bams/98/9/bams-d-... ^^ Discussed in brief: https://www.climate-lab-book.ac.uk/2017/defining-pre-industrial/ https://www.climate-lab-book.ac.uk/2017/defining-pre-industr...

https://en.m.wikipedia.org/wiki/Instrumental_temperature_record https://en.m.wikipedia.org/wiki/Instrumental_temperature_rec...

barelyauser 3y ago

There are things called 'proxies'. The same way you can assess the crime rate of a certain area by the amount of littering by the side of the road.

vdaea 3y ago
>The same way you can assess the crime rate of a certain area by the amount of littering by the side of the road. You mean incorrectly? Also, if I had to guess, proxies that show global warming to be bad are widely publicised, whilst proxies that show global warming not to occur are ignored.
- rscho 3y ago
  "I don't know if this sign about a cliff ahead was right, so I'm gonna keep going pedal to the metal. Just in case..."
- Propelloni 3y ago
  > Also, if I had to guess, proxies that show global warming to be bad are widely publicised, whilst proxies that show global warming not to occur are ignored. You are mixing categories. One is about the observable universe, ie. "does global warming happen"? The other one is a value judgement, ie. "is global warming bad?"
- saalweachter 3y ago
  I mean, if you want to go down that route, why assume that the expansion of mercury in a glass tube is a good proxy for atmospheric temperature? Sometimes it feels hotter or colder than the mercury would indicate, after all. QED, it is impossible to determine if the climate is changing.

tromp 3y ago

With help from sea sponges as recently discussed in https://news.ycombinator.com/item?id=39268387 https://news.ycombinator.com/item?id=39268387

ChrisArchitect 3y ago
More discussion on the sponges and ocean warming: https://news.ycombinator.com/item?id=39275272 https://news.ycombinator.com/item?id=39275272

kybernetyk 3y ago

[flagged]

defrost 3y ago

With instrumentation across the globe at naval timekeeping stations of the various European empires - much of which persisted for a hundred years and thus overlapped with later instruments and broader coverage which allowed for levelling and blending. It's essentially a "construct your baseline" problem faced in many domains, the Fifth and other IPCC reports: This IPCC Special Report on Global Warming of 1.5°C uses the reference period 1850–1900 to represent pre-industrial temperature. This is the earliest period with near-global observations and is the reference period used as an approximation of preindustrial temperatures in the IPCC Fifth Assessment Report. ~ IPCC FAQ: https://www.ipcc.ch/site/assets/uploads/sites/2/2018/12/SR15_FAQ_Low_Res.pdf and naturally there are many papers that consider alternate baselines, data quality, proxies, etc. eg: Estimating Changes in Global Temperature since the Preindustrial Period (2017) https://journals.ametsoc.org/view/journals/bams/98/9/bams-d-16-0007.1.xml https://journals.ametsoc.org/view/journals/bams/98/9/bams-d-... ^^ Discussed in brief: https://www.climate-lab-book.ac.uk/2017/defining-pre-industrial/ https://www.climate-lab-book.ac.uk/2017/defining-pre-industr...