Occasional Thoughts on Climate Change

[LibertyBell]

1 hour ago, tacoman25 said:

And yet we've seen an overall decline in violent crime since the 1980/90s, despite warming temps.

it's just a relative comparison to other seasons.

I can agree with your statement because the 1990s saw the most extreme heat and longest heatwaves here.

By the way, when did you move to Colorado?

Did you move there to see more snow?

[bluewave]

9 hours ago, donsutherland1 said:

Phoenix has a five-year master plan for expanding trees/shade. The City is aware of the growing risks its people face from increasingly frequent and intense heat.

https://www.phoenix.gov/content/dam/phoenix/heatsite/documents/ShadePhoenixPlan_Nov13CouncilDraft_topost_EN.pdf

It’s difficult for many of us who are cold and snow enthusiasts to understand why so many people choose to move to a place like Phoenix with such intense heat. I would enjoy visiting that region during some of the cooler times of the year since the Desert Southwest is one of the most beautiful parts of the country. You wonder how much more heat and drought it would take to actually slow the influx of new people into the area. In the mean time I hope they do all they can to try and expand the trees and shade. 

[donsutherland1]

2 minutes ago, bluewave said:

It’s difficult for many of us who are cold and snow enthusiasts to understand why so many people choose to move to a place like Phoenix with such intense heat. I would enjoy visiting that region during some of the cooler times of the year since the Desert Southwest is one of the most beautiful parts of the country. You wonder how much more heat and drought it would take to actually slow the influx of new people into the area. In the mean time I hope they do all they can to try and expand the trees and shade. 

I have a cousin out there. She has indicated that the City has a lot to offer, including culture, history, and nature. However, she has increasingly complained about the rising heat. 

[A-L-E-K]

she's right

will be ruins in less than a decade once we enter the post the air-conditioning era

[donsutherland1]

Portland, OR appears to be headed for an extreme heat event (Clarke et al., 2014 methodology) for the fifth year in a row. The City has been experiencing a rise in 90° and 95° days in its warming climate. 90° days are increasing by 1.45 days per decade. 95° days are increasing by 0.72 days per decade. Moreover, in Portland's warming climate, the 30-year mean June-September high temperature reached 78.0° in 2014. The frequency of extreme heat events has increased markedly to about once every 2.2 years (2014-2024). Prior to 2014, extreme heat events occurred once every 7.3 years.

 

[donsutherland1]

25 minutes ago, A-L-E-K said:

she's right

will be ruins in less than a decade once we enter the post the air-conditioning era

On a serious note, there is genuine longer-term risk that the City could pass the point of sustainability, particularly if ongoing aridification depletes its access to water. 

[bluewave]

14 hours ago, donsutherland1 said:

I have a cousin out there. She has indicated that the City has a lot to offer, including culture, history, and nature. However, she has increasingly complained about the rising heat. 

Most people who moved out to Phoenix did it with the understanding that they would have to reduce outdoor activities as the later morning and afternoons approached.

But what they are finding now is that even the early mornings for extended stretches are becoming too warm to do even basic outdoor exercise like walking.

The record number of 90° minimums this decade in the urban center has probably forced many to do more indoor exercise like the treadmill during the times of peak heat. 20-40 days with 90° minimums has become the norm during the 2020s.

 

Time Series Summary for Phoenix Area, AZ (ThreadEx) - Jan through Dec Top 5 years with 90° minimums
Click column heading to sort ascending, click again to sort descending.

1	2024	39	0
2	2023	35	0
3	2020	28	0
4	2025	21	132
5	2013	15	0
-	2003	15	0

[tacoman25]

15 hours ago, LibertyBell said:

it's just a relative comparison to other seasons.

I can agree with your statement because the 1990s saw the most extreme heat and longest heatwaves here.

By the way, when did you move to Colorado?

Did you move there to see more snow?

I've lived in CO for nearly 20 years. Moving here had little to do with the weather, but I do enjoy the frequent snowfall.

[TheClimateChanger]

On 8/20/2025 at 1:58 PM, TheClimateChanger said:

Excellent post, Tip. The part I emboldened in is an excellent point.  One I have made numerous times. When you factor that into the equation, there is NO central US warming hole. It disappears. Current summers FEEL much hotter than summers of the past, including the Dust Bowl, which were the driest (least humid) on record. And while some may say "heat index" is subjective, it's really just a proxy for the wet bulb temperature reading. And that can, in fact, become deadly, even at relatively modest dry bulb temperatures with full (or near full) saturation.

Anyways, I often see certain people who deny (some people on here get offended with the term "denier" even though they have used that term profusely in the past, but I digress)... people who deny climate change often say highs are of more value, because lows are more affected by UHI. I would actually argue the exact opposite, and say high temperature readings are more impacted by siting/exposure characteristics and equipment, and low temperatures give us a better look at actual trends.

I ran this scenario through AI and it confirmed that warming hole theory is not considering latent heat effects (increased water vapor), only sensible heat (dry bulb). Total heat (enthalpy) has likely continued to increase. In fact, if you consider latent heat effects, then places in the southwest with extreme sensible heat increases may actually have less total heat increase (since latent heat has decreased in those areas, evidenced by declining dewpoints).

 

[LibertyBell]

7 hours ago, TheClimateChanger said:

I ran this scenario through AI and it confirmed that warming hole theory is not considering latent heat effects (increased water vapor), only sensible heat (dry bulb). Total heat (enthalpy) has likely continued to increase. In fact, if you consider latent heat effects, then places in the southwest with extreme sensible heat increases may actually have less total heat increase (since latent heat has decreased in those areas, evidenced by declining dewpoints).

 

But heat increase is measured by rising temperatures, not dew points.

[LibertyBell]

10 hours ago, donsutherland1 said:

Portland, OR appears to be headed for an extreme heat event (Clarke et al., 2014 methodology) for the fifth year in a row. The City has been experiencing a rise in 90° and 95° days in its warming climate. 90° days are increasing by 1.45 days per decade. 95° days are increasing by 0.72 days per decade. Moreover, in Portland's warming climate, the 30-year mean June-September high temperature reached 78.0° in 2014. The frequency of extreme heat events has increased markedly to about once every 2.2 years (2014-2024). Prior to 2014, extreme heat events occurred once every 7.3 years.

 

Those areas are warming much faster than we are (in the summer anyway.)

Is there a reason why summers are much hotter there than they are here, Don?

 

[LibertyBell]

23 hours ago, bluewave said:

It’s difficult for many of us who are cold and snow enthusiasts to understand why so many people choose to move to a place like Phoenix with such intense heat. I would enjoy visiting that region during some of the cooler times of the year since the Desert Southwest is one of the most beautiful parts of the country. You wonder how much more heat and drought it would take to actually slow the influx of new people into the area. In the mean time I hope they do all they can to try and expand the trees and shade. 

you can be a snow and cold enthusiast and also enjoy hot summers.

I don't understand why ANYONE likes rain in the summer, even farmers I have talked to on Long Island prefer hot and dry summers.

 

[gallopinggertie]

10 hours ago, donsutherland1 said:

Portland, OR appears to be headed for an extreme heat event (Clarke et al., 2014 methodology) for the fifth year in a row. The City has been experiencing a rise in 90° and 95° days in its warming climate. 90° days are increasing by 1.45 days per decade. 95° days are increasing by 0.72 days per decade. Moreover, in Portland's warming climate, the 30-year mean June-September high temperature reached 78.0° in 2014. The frequency of extreme heat events has increased markedly to about once every 2.2 years (2014-2024). Prior to 2014, extreme heat events occurred once every 7.3 years.

 

PDX just reached 100, for the first time this year and setting a daily record. If the next few days reach forecast highs, the majority of August record highs at PDX will have been set in the past ten years!

[donsutherland1]

59 minutes ago, LibertyBell said:

Those areas are warming much faster than we are (in the summer anyway.)

Is there a reason why summers are much hotter there than they are here, Don?

 

A combination of factors: marine heatwaves, drying hot seasons (June-September), and background anthropogenic warming.

[donsutherland1]

1 hour ago, gallopinggertie said:

PDX just reached 100, for the first time this year and setting a daily record. If the next few days reach forecast highs, the majority of August record highs at PDX will have been set in the past ten years!

Yes, that's correct. So far, at least seven sites in Oregon or Washington have reached 100 or above. Daily records have fallen at locations including Corvallis, Portland, and Vancouver (WA). Portland finished with a high of 102.

[gallopinggertie]

17 hours ago, donsutherland1 said:

Yes, that's correct. So far, at least seven sites in Oregon or Washington have reached 100 or above. Daily records have fallen at locations including Corvallis, Portland, and Vancouver (WA). Portland finished with a high of 102.

It’s looking like this might only be the beginning of this particular hot period - here’s the new ECMWF forecast for Seattle and Portland, showing a two-week stretch that would average 10-15 degrees above normal for the region. Pretty wild.

I’ve lived in western Washington and Oregon my whole life, and the summer climate has really changed over just the past couple decades. Like you posted about, heat waves used to last maybe two or three days - now they stretch on for a week, or longer. Here in Portland our climate averages have historically fallen in the Csb (warm-summer Mediterranean) range, but are on track to push into Csa territory (hot-summer Mediterranean) before too long, perhaps when the new 2000-2030-year averages become the new baseline. Seattle probably will follow a few decades later. 

[donsutherland1]

1 hour ago, gallopinggertie said:

It’s looking like this might only be the beginning of this particular hot period - here’s the new ECMWF forecast for Seattle and Portland, showing a two-week stretch that would average 10-15 degrees above normal for the region. Pretty wild.

I’ve lived in western Washington and Oregon my whole life, and the summer climate has really changed over just the past couple decades. Like you posted about, heat waves used to last maybe two or three days - now they stretch on for a week, or longer. Here in Portland our climate averages have historically fallen in the Csb (warm-summer Mediterranean) range, but are on track to push into Csa territory (hot-summer Mediterranean) before too long, perhaps when the new 2000-2030-year averages become the new baseline. Seattle probably will follow a few decades later. 

So far, the ECMWF is an outlier in terms of a return to extreme heat, but the period looks abnormally warm. We'll see what the 12z ECMWF shows.

I agree with you about the changes in climate classifications. The warming is ongoing and fairly dramatic. At least one episode of extreme heat has become a fairly regular occurrence. The number of hot days has increased markedly. 

[bluewave]

20 hours ago, LibertyBell said:

you can be a snow and cold enthusiast and also enjoy hot summers.

I don't understand why ANYONE likes rain in the summer, even farmers I have talked to on Long Island prefer hot and dry summers.

 

That’s why so many people are moving out to the Desert Southwest. Many people are OK with the extreme summer heat and drought. Then they can take weekend ski trips during the winter to get their fill of snow and cold.