China never going green

[ding]

America is one of the nations that is LARGELY responsible for the warming we've seen now.

Scientists come to opposite conclusions about the causes of recent climate change depending on which datasets they consider.

For instance, the panels on the left lead to the conclusion that global temperature changes since the mid-19th century have been mostly due to human-caused emissions, especially carbon dioxide (CO2), i.e., the conclusion reached by the UN IPCC reports. In contrast, the panels on the right lead to the exact opposite conclusion, i.e., that the global temperature changes since the mid-19th century have been mostly due to natural cycles, chiefly long-term changes in the energy emitted by the Sun.

Both sets of panels are based on published scientific data, but each uses different datasets and assumptions. On the left, it is assumed that the available temperature records are unaffected by the urban heat island problem, and so all stations are used, whether urban or rural. On the right, only rural stations are used. Meanwhile, on the left, solar output is modeled using the low variability dataset that has been chosen for the IPCC’s upcoming (in 2021/2022) 6th Assessment Reports. This implies zero contribution from natural factors to the long-term warming. On the right, solar output is modeled using a high variability dataset used by the team in charge of NASA’s ACRIM sun-monitoring satellites. This implies that most, if not all, of the long-term temperature changes are due to natural factors.

Here is the link to the full paper.
ShieldSquare Captcha

 

[daveman]

New Study: Hadley Center and CRU Apparently Cherry‐picked Russia’s Climate Data​

Climategate: CRU Was But the Tip of the Iceberg​

Perhaps the key point discovered by Smith was that by 1990, NOAA had deleted from its datasets all but 1,500 of the 6,000 thermometers in service around the globe.

Now, 75% represents quite a drop in sampling population, particularly considering that these stations provide the readings used to compile both the Global Historical Climatology Network (GHCN) and United States Historical Climatology Network (USHCN) datasets. These are the same datasets, incidentally, which serve as primary sources of temperature data not only for climate researchers and universities worldwide, but also for the many international agencies using the data to create analytical temperature anomaly maps and charts.

Yet as disturbing as the number of dropped stations was, it is the nature of NOAA’s “selection bias” that Smith found infinitely more troubling.

It seems that stations placed in historically cooler, rural areas of higher latitude and elevation were scrapped from the data series in favor of more urban locales at lower latitudes and elevations. Consequently, post-1990 readings have been biased to the warm side not only by selective geographic location, but also by the anthropogenic heating influence of a phenomenon known as the Urban Heat Island Effect (UHI).

For example, Canada’s reporting stations dropped from 496 in 1989 to 44 in 1991, with the percentage of stations at lower elevations tripling while the numbers of those at higher elevations dropped to one. That’s right: As Smith wrote in his blog, they left “one thermometer for everything north of LAT 65.” And that one resides in a place called Eureka, which has been described as “The Garden Spot of the Arctic” due to its unusually moderate summers.

Smith also discovered that in California, only four stations remain – one in San Francisco and three in Southern L.A. near the beach – and he rightly observed that

It is certainly impossible to compare it with the past record that had thermometers in the snowy mountains. So we can have no idea if California is warming or cooling by looking at the USHCN data set or the GHCN data set.

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It's easy to win if you stack the deck.