Back in 2005 NOAA set up a climate reference network (USCRN).
Here is a graph of the month temperature anomalies over the last 18+ years:
As you can see, there hasn’t been much of any trend.
DB2
3 Likes
That’s odd. Here’s a link to NOAA’s site that shows a chart of global average surface temperature from 1880 to 2020. It doesn’t look quite as benign as your chart. There certainly is a trend in this chart and the rate of change has doubled since 1981.
1 Like
Of course, not all parts of the globe warm equally. It seems we have been fortunate here in the US over the past 18+ years of the USCRN.
DB2
1 Like
I don’t think anyone has stated that all parts of the globe warm equally.
I thought the chart of month temperature anomalies (whatever that is) was shown to demonstrate that global climate change is a myth. Perhaps I misunderstood your point.
While Earth has had global climate change throughout its existence, the increase in the velocity of the change (decades vs centuries) is unparalleled and presents a clear and present danger, not to Earth, but to humans.
4 Likes
True. I was pointing out that the USCRN temps are for the US only, whereas the data you linked are global.
Not at all.
By the way, temperature anomalies show how much the temps were above or below compared to the average for the 30-year reference period.
DB2
USCRN readings are virtually identical to that of ClimDiv, which goes back much further in time. Combining both methods allows a look at US temperature anomalies over the last century (from 1923). Aside from unusually high temps in the 1930s a rising trend seems to be taking place.
This is particularly the case if one considers that in 2010 the Iceland volcano Eyjafjallajökull
erupted and 2013 had several major eruptions. Both periods are associated with low temperature anomalies. Without those events the trend in rising temps would be much more apparent.
Since about 2003, the US is consistently seeing high temp anomalies in the range of that observed in the early 1930s. Probably just a coincidence but the disastrous Dust Bowl occurred from 1930-1936. It looks like current US temperatures are at least as bad as occurred during one of the worst ecological disasters in US history. If the trend really is rising, the next decade could be difficult.
3 Likes
So it looks like the US had a hot decade in the '30s (no surprise there) was essentially flat until the increase in the '90s and has been on a plateau since then.
DB2
So, if, on average, one had a gradually increasing temperature, but the variation was about the same relative to that moving average, you would get a chart like the one you displayed …
1 Like
No. The 30-year reference period is changed every 10 years, and the relative monthly values of the data series don’t change – so an increase would still show as an increase. In other worlds, the slope doesn’t change.
DB2
Not to me. It looks like a rising trend from 1990 to the present (my red dotted line)
Another way to look at the same set of data is by comparing NOAA climate normal temperatures. Every 10 years, the NOAA takes a 30 year average temperature for the nation. The two most recent 30-year averages were 1981-2010 and 1991-2020. The earlier averages were subtracted from the most recent to show how temperature has changed throughout the country. Turns out temperature has increased everywhere except for the northern plain states.
Here is another illustration of how US temperatures have been rising since the 1980s. This increase can be seen using surface temperature or atmospheric temperature as measured by satellites.
The warming trend in the US seems pretty obvious to me and is not particularly controversial. The data are the data.
2 Likes
And yet, looking at the graph in the OP, it is clear there isn’t a significant trend in the US over the last 18 years. That said, it is warmer than it was three decades ago so the warming occurred in the '90s.
DB2
1 Like
That’s not how regression lines are interpreted. Some stuff have high variability that makes it difficult to see trends without a lot of data points. Climate is like that, which is why one has to look for trends over long time periods.
With respect to US temps, looking over a 30+ year period a rising trend is pretty obvious. Look at smaller time intervals during those 30 years and the variability hides the long-term trend. In short, the inability to detect a short-term trend does not mean there isn’t an underlying long term trend that is a better representation of reality.
To put it another way, which do you think is more likely to be accurately predictive, the rising temp trend based on 30 years of data or your “temp plateau” based on 18 years of data?
Do you have any reason to believe that US temperatures should not be rising over the long term in the face of increasing atmospheric CO2 levels?
1 Like
bt, we are in agreement about the rising trend. At the same time, I think we would also agree that the USCRN shows there hasn’t been a rising trend for almost two decades. That is one surprised me, and I suspect most people would also be surprised to know that. As spinning pointed out, it is sort of a step function.
Getting back to the long-term graph you posted, it is also a bit surprising that US temps showed no significant trend from WW2 until 1990, almost half a century.
DB2
I don’t see that as being informative. There is no expectation to see climate trends over such small time intervals. That is why the NOAA bases reference temps over 30 year periods when assessing climate change impacts.
I think you are making a big deal out of something that is inconclusive.
It probably took a decade or so for the global economy to fully recover from WWII. If you look at the upthread global chart, temperature increases became apparent by 1950 or so. The impact to US temps may lag the rest of world by a couple of decades. That wouldn’t be all that surprising. Regional differences in climate impacts are to be expected.
Based on personal experience (i.e. physically living in one area for almost 60 contiguous years), AND supported by weather reports going back even further, the Upper Midwest portion of the US is significantly warmer and now has longer growing seasons. Plants AND insects that could not previously survive here–due to extended cold weather–are now found and flourishing in this area. Thus, it is not theory, it is fact. Global warming has changed the area significantly and will continue to do so for the foreseeable future. The federal agriculture dept has agreed as well, as they have changed their plant grow zones to show growing zones here are reasonably safe to grow crops that historically were not able to be grown here.
True. We have been fortunate here in the United States.
DB2
Any thoughts on why one would expect that pattern? We know land warms more than the ocean, but why less in North America?
DB2
Not really. The US is large and has a heterogeneous ecosystem. Some parts will be more affected than others and so on average the nation may appear to be less affected than say equatorial nations that will be more quickly impacted by rising temps.
But we are already seeing the long-term aridification of the west coast, the southwest, and the midwest. That is a big chunk of US agriculture that will be under increased heat and drought pressure. The US south is already being invaded by tropical pests and disease vectors and increased flooding along the eastern seaboard is just becoming detectable.
My guess is that the US will in the not too distant future be at a climatic disadvantage to places like Canada, northern Europe, and Russia.
1 Like