Global heat stress intensification and its expanding footprint

[John Nissen]

Global heat stress intensification and its expanding footprint on the human population | Nature Climate Change https://share.google/k9833aideLymR2nr8 

[Paul Klinkman]

Dear Action Coalition,

The relationship between high humidity and human health is going to be complex.  At the top of the planet's temperature scale, high humidity saps human energy and sometimes it causes the demise of vulnerable people.  On the other hand, South Asians rejoice when the monsoon season starts in June.  The monsoon rains can drop surface temperature to perhaps 35 degrees Celsius, 90 degrees Fahrenheit.  The rains are cooling and the rainstorms water the farm fields.

I'm seeing a growing acceptance that precipitation causes the transport of latent heat from the earth's surface to the stratosphere.  Latent heat transported into the stratosphere is above the majority of the earth's atmosphere, and after water vapor condensation this transported heat radiates more quickly into space.  The Amazon Basin may be a sweaty environment but it's far cooler than the Sahara Desert in the daytime.

The absence of humidity puts stress on trees. Trees killed by drought and/or insects will feed megafires that burn down the living trees.  Trees in turn are our major source of humidity.  Bare ground is linked with megadroughts.  I suspect that we're going to continue to see a worldwide loss of forests from all causes, followed by more intense hot droughts.  

All of this indicates that we need to create more trees.  Trees not only cool individual neighborhoods in our cities, but together they cool our continents.  Unfortunately, a few tree seedlings won't in the short term replace the air humidification that a mature forest delivers.  Worst case, in some regions in the Horn of Africa not one green blade remained after their 2018-2022 megadrought, and probably no tree seeds remained to eventually repopulate the formerly tree covered land.

We can face these problems, one restored local community at a time.  That's the beauty of humidity restoration.

Yours in Hope,

Paul Klinkman

[John Nissen]

I looked up a reference just now [1], and found I could not access it, as I might have in the past.  Perhaps I missed it by a few hours!  Here is the notice I received:

The NSF Public Access Repository will be updated to support the latest award terms and conditions on June 26, 2026, between 7am-5pm. Users may notice changes to their records in PAR as embargo updates are applied.

Trump at work?

Anyway, my interest was in the claim that, not only are periods of extreme weather getting longer, but that this is accelerating.  The paper tries to relate the trend to global warming, but I think that the Arctic rapid warming effect on the jet stream, causing it to meander and stick more, is the real culprit.  The heat domes we are suffering here in Europe are due to a sticking jet stream.  There is very little wind to move the dome away.  Has anybody been monitoring the jet stream recently?

Cheers, John

[1] Martinez-Villalobos et al (Nature Geoscience, 2025)

Accelerating increase in the duration of heatwaves

https://par.nsf.gov/servlets/purl/10621726

[John Nissen]

Has anyone been monitoring the jet stream?  The heat dome we've just had in W Europe could be due to a sticking jet stream wave.  Have other parts of the NH also experienced a sticking jet stream?  

Cheers, John

[Paul Beckwith]

My recent video…

Jet Streams Connect European Heat Waves & Atlantic Ocean Cold Blob & North American Heat Waves: Chat

https://youtu.be/pIVhrjAoteA?si=5c36IlECymGs7vdm

On Wed, Jun 24, 2026 at 5:07 PM John Nissen <johnnis...@gmail.com> wrote:

Global heat stress intensification and its expanding footprint on the human population | Nature Climate Change https://share.google/k9833aideLymR2nr8 

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[Douglas Grandt]

John,

I take screenshots periodically here and the jet has changed little since mid-June 

These four show UK and EU from an extreme oblique angle June 15, 25 and 30, and I rotated the fourth directly over Europe to clearly show the jet allowing hot tropical air in to toast you to a crisp.

FYI, it correlates with New England’s mild, unusually cold the past couple weeks and current extreme heat climbing through this week across the U.S.

Doug

Sent from my iPhone (audio texting)

On Jul 1, 2026, at 4:10 AM, John Nissen <johnnis...@gmail.com> wrote:



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[DrPete Sudbury]

"The paper tries to relate the trend to global warming, but I think that the Arctic rapid warming effect on the jet stream, causing it to meander and stick more, is the real culprit."

... is a false antithesis, given it is global warming that causing the differential heating of poles vs equator, and theme the wandering jetstream.

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[John Nissen]

Hi Doug,

Thanks for those jet stream shots: very revealing. I expect forecasters follow jet stream movements very carefully; but the disruption of "normal" patterns make longer-term forecasting more and more difficult.  I think they now realise that there's been an acceleration in extreme weather.  The paper I quoted tried to explain this in terms of global warming alone, as Hansen did many years ago.  But the role of Arctic amplification is crucial..  When SAI is applied, it has to be ensured that the temperature gradient from pole to lower latitudes is not further reduced, exacerbating weather extremes.  I think that Doug MacMartin and Soumitra Das realise this.  It is the reason for promoting higher than mid latitude injection for SAI.

Cheers, John