We noted elsewhere this week news items expressing surprise at the lack of loss of Arctic sea ice. And there’s more, because the underlying study, by Harry Stern of the University of Washington, was focused on September sea ice extent and went so far as to call it a regime shift. As in something has changed, but they’re not sure what. The only thing they can say for sure is it’s the opposite of what everyone predicted was going to happen. Settled science at its finest, folks. Have complete confidence in the models and ignore that silly old ice.
The study, titled “Regime Shift in Arctic Ocean Sea-Ice Extent” was published in Geophysical Research Letters and began:
“A regime shift is an abrupt, substantial, and persistent change in the state of a system. We show that a regime shift in the September Arctic sea-ice extent (SIE) occurred in 2007. Before 2007, September SIE was declining approximately linearly. In September 2007, SIE had its largest year-to-year drop in the entire 46-year satellite record (1979–2024). Since 2007, September SIE has fluctuated but exhibits no long-term trend.”
September is an important month for studying Arctic sea ice, especially if you’re trying to get rid of it, since it represents the annual minimum point in ice coverage. The melting goes on all summer, but after September the freeze begins again. So when scientists talk about declining Arctic sea ice they don’t mean the February coverage since it’s always 100 percent. They mean how far back the melt goes each year by September.
Stern presents a graph of particular importance given the tendency of both sides to allege cherry-picking on climate data generally and Arctic ice in particular because it presents both options. His graph shows the history of Arctic sea ice since 1979 two ways: on the left with a linear trend drawn through it and the other allowing for the “regime shift” in 2007:
The statistical model says that the right side of this chart fits the data better. It implies a trend downwards until 2007 then no trend after that year, rather than a steady trend downwards over the last four and a half decades.
So what changed in 2007? We are tempted to say that that’s the year after Al Gore’s movie An Inconvenient Truth came out with all its lurid predictions of climate disaster including the imminent disappearance of Arctic sea ice and the gods of Norse mythology decided to borrow from those in Greek mythology and make a bit of hubris-nemesis sport with Gore.
Stern offers a more materialistic explanation with, of all things, some humility about the limits of scientific understanding including his own:
“The fact that September Arctic SIE shows no trend during 2007–2024 may at first seem hard to explain. The Earth continues to warm, and the Arctic is warming faster than the global average (IPCC, 2021).”
He surveys the various ideas out there, all of which are variations on the “never mind that silly old ice” dogma of a continuing downward trend due to greenhouse gases superficially offset by increasing trends caused by natural cycles. Which, if true, means the disappearance of Arctic sea ice will resume soon.
If it doesn’t, someone somewhere will have a theory to explain that outcome too, one that preserves the essential notion that we humans are overheating the planet especially the poles even if some white stuff is obscuring the true picture.
Meanwhile, we at CDN are still not in a hurry to buy Arctic oceanfront real estate.
Do we really know that the Earth is warming right now? I know it's commonly accepted, but with NOAA putting their thumb on the temperature scale, do we have reliable independent evidence?
Since 2000 temperatures have increased marginally but as Nicolov et al have shown the temperature variation correlates highly with reduced albedo (cloud cover) using the NASA data from the CERES project. However as Nicolov points out if reduced cloud cover and therefore more solar irradiation reaching the surface can explain all 21st century warming there is no 'room' for warming from the radiative greenhouse effect.
No, we do not know the temperature of the earth, neither in historical terms not today. In practical terms to measure the earth’s temperature would require someone to randomly select thousands of lat/long points to adequately cover the variety of earth’s representative climate zones, then place like calibrated systems at each point (2/3 in the oceans) and take a temperature all at the same UTC time. No one has, or likely will ever, do this. Instead they have a non randomized method based on some of their readings and algorithms they developed to claim an earth’s temperature. One can either agree or disagree that this might be close enough, but no one knows because no one has taken a valid actual measurement to compare it to, and different people will have differing opinions of NOAA/NASA impartiality on the method and results.
Nothing to see here folx!Keep moving please!45 years is hardly enough time to postulate any trends,more ice or less ice.But yeah,it sounds like the alarmists are sweating a bit,getting fidgety and all that,cuz their models and doom and gloom predictions aren't quite panning out.
It is not a regime shift, it is a sinus wave form with a about a 90 year period.
I agree, do we really know what the temperature was before 1850? To within 100rd of a degree.
I suggest not. It was measured in very few places globally at that time. And modern climate "scientists" discredit 1930 temperature readings as needing to be "adjusted" .
Sure the proxy readings from Ice cores etc, will give you approximate temperature to say, lets be generous, 1C.
If the error on 1850 temperature is -1C then today's warming is rubbish.
OK, but what caused the reduced cloud cover?