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This is Chicago's temperature trend according to Berkeley Earth. My question is how did they get data for the 1700's when no station or settlement existed?
There is literally a link that says methodology. You could read it. They describe their methodology and include a link to the colonial archives.
Now I know we tend to be a bit American centric but the French had been exploring, trading and staying in the area at least short term (usual in the form of missions) since the 1600s. Explorers frequently took climactic data, at least temperature and weather observations, in their journals.
If it is true it's probably because the Ice Age is only now ending there. I personally suspect some of the data and earlier "cooler" temperatures. While a novel is no direct factual authority, novels about the Arctic such as Farley Mowat's Lost in the Barrens, written during the 1950's or early 1960's highlighted a warm spell in December that nearly ended tragically for the story's main characters. They were lured out of safe quarters to make a dash for the southland and of course winter's return overtook them.
That proves nothing directly except that the author was drawing from his own Arctic experiences.
Have you heard of the milankovitch cycles? They are the main global climate forcing (controlling) phenomena and are related to orbital variances such as tilt, procession and obliquity. Because we can observe all of those directly, we know which stage of the milankovitch cycle we are in, and we are well out of the ice age.
Your beliefs on the matter are irrelevant to the science.
As for historical data, we have ice cores, both long term and short term that are excellent proxies for temperature. Certainly better than novels.
As for the general premise of the entire thread, which appears to be that no observable warming of winters in one location means no global climate change that is ludicrous.
The marine and continental effect due to the high specific heat of water has such a large effect on areas located near large bodies of water that you would expect them to show less change than truly continental areas. Additionally, temperate areas are expected to show lower amounts of temperature change than polar regions and lower amount of precipitation changes than the tropics. So this is truly a case of picking the worst locale possible.
All of this looks highly suspect when trying to have a logical and fact based discussion of climate.
CO2 levels must of melted the mile thick ice covering Chicago 20,000 years ago
I promised myself not to contribute to this thread with some Ludacris comments. So have fun everyone.
Ice ages ended when orbital shifts occurred, but the theory is that greenhouse gases act as a positive feedback further warming the planet.
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changes in the CO2 and CH4 content have played a significant part in the glacial-interglacial climate changes by amplifying, together with the growth and decay of the Northern Hemisphere ice sheets, the relatively weak orbital forcing
Yes, if you scroll down it says one station within 1500 km; there's still some correlation in anamolies over that distance (a warmer than average year in Boston is likely to be a warmer than average year in Chicago — their method relies on correlation over distances).
The error range is huge for the 1700s because obviously the correlation isn't that strong. Still might be enough to estimate Chicago had a cold decade in the early 1800s.
Thanks for pointing that out. This is why I can't stand when climate scientists mix apples and oranges creating charts using proxy data and merging them with actual thermometer data And not necessarily will it be warm in Chicago if it's warm in Boston. That may or may not be the case, and even if it was, the anomaly may not be as great here as it was in Boston or vice versa. Just way too far a distance.
Thanks for pointing that out. This is why I can't stand when climate scientists mix apples and oranges creating charts using proxy data and merging them with actual thermometer data And not necessarily will it be warm in Chicago if it's warm in Boston. That may or may not be the case, and even if it was, the anomaly may not be as great here as it was in Boston or vice versa. Just way too far a distance.
No, it only uses thermometer data. The dataset accounts for the low correlation and uncertainty with huge ranges. The group that made Berkeley Earth aren't even climate scientists; they're physicists and statisticians. From what I read, their statistical method is considered good, but no one else has had climate histories based off temperature data 1000+ km away for obvious reasons.
No, it only uses thermometer data. The dataset accounts for the low correlation and uncertainty with huge ranges. The group that made Berkeley Earth aren't even climate scientists; they're physicists and statisticians.
But there is no thermometer data for Chicago. They are using historical data (proxy) from an a place that is over 1500km away to estimate my areas temperature, and create a plot of it.
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From what I read, their statistical method is considered good, but no one else has had climate histories based off temperature data 1000+ km away for obvious reasons.
NOAA still does this when making monthly global temperature plots. There are areas thousands of sqkm with no thermometers in Siberia, Africa, and Brazil yet, NOAA uses gridding to fill in those areas on temperature maps.
Example Oct 2015
Yet look at how much of the land surface is void of thermometers
Note how a huge swathe of South America has been labelled as “record warmest”. And what is this based on what? One station?
Did you know Eyjafjallajokull volcano eruption in 2010 negated every effort made in the previous 5 yrs to control CO2 emissions, in just 4 days!? That's just 1 volcano..
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And not necessarily will it be warm in Chicago if it's warm in Boston. That may or may not be the case, and even if it was, the anomaly may not be as great here as it was in Boston or vice versa. Just way too far a distance.
