Occasional Thoughts on Climate Change

[gallopinggertie]

Hong Kong recently broke its all-time high, during Typhoon Dolphin. Here is an excerpt from an environmental newsletter I receive, describing the day:

“

Dear Reader,

On Sunday, August 9th, the Hong Kong Observatory recorded a temperature of 36.9 C (98.4 F), the highest since records began in 1884.

I’ve often told my friends stateside to imagine Hong Kong’s normal summer climate as “Houston on steroids.” This past Sunday was something else: I was breaking into a sweat just standing in the shade waiting for the bus. There was no breeze, and you could feel the heat radiating into your body, as if you stepped into a sauna. In fact, the “feels like” temperature reached 46 C (114.8 F) — hotter than Houston, Miami, or Phoenix.”

[chubbs]

21 hours ago, GaWx said:

 Per the following reliable and objective source, year 2026 as of week 32 has had the lowest area burnt in North America since 2012 by a good margin vs other years as of the same week (by a third). Also, globally it has been by a large margin the lowest for this point in the year since 2012 as I’ve been posting despite being near the warmest globally along with 2025 being 2nd lowest. My point in posting about 2026 for N.A. and 2026/5 globally is not to say CC is causing a decrease in wildfire activity because I’m not saying that. Instead, my point in posting this is to show that that there isn’t a proven simple relationship between CC and wildfire related activity and that different kinds of wildfire related data from various sources from various periods can be presented in various ways:
 

I don't think area burned is telling you much about CC; because, other human factors are driving the long-term trends. Per Our World in Data, the vast majority of wildfires occur in grassland and savanna in the sub-tropics and tropics, roughly 50% in Africa. Forest burning is a small portion of area burned in all regions. Our World in Data cites  a Science paper that attributes the long-term decrease in area burned to the spread and intensification of agriculture. In Europe and North America, reduction in cropland burned is another important long-term trend.

Have to look at other stats to see the effect of climate change. The blog I linked makes the point that the intensity of the largest fires is increasing due to climate change. Big, intense fires are the most problematic but aren't well captured by the area burned stats. Here's a recent paper that finds that a small number of extreme fires are having an out-sized impact on the forest ecosystem in western and boreal North America.

https://www.science.org/doi/full/10.1126/sciadv.aeg5802

[chubbs]

This study provides an estimate of transient climate response (TCR) using CERES net radiation estimates and updates temperature-based estimates through 2025. The new TCR estimates for temperature are a little higher than previous studies (orange bars) and the CERES TCR estimates (red bars) are higher still, inline with TCR estimated with the warmer CMIP6 models. 

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2026EF008356

[Typhoon Tip]

2 hours ago, chubbs said:

This study provides an estimate of transient climate response (TCR) using CERES net radiation estimates and updates temperature-based estimates through 2025. The new TCR estimates for temperature are a little higher than previous studies (orange bars) and the CERES TCR estimates (red bars) are higher still, inline with TCR estimated with the warmer CMIP6 models. 

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2026EF008356

Intuitively it has to be higher.  Not intending to condescend but it occurs upon looking at this, the background state is accelerating two-fold:  once over for the fact that CC has not been linear over the last 2 to 3 decades, but now especially with the 2nd reason in the onsetting supposed record warm ENSO. ENSOs are correlated with warm global 'spikes' in temperature means.  Superimposing these two expectations over one another lends to 'adjusting' an increase in any derivatives that describe that system - a transience certainly being one of those... 

[GaWx]

 Joe Bastardi brings something up that I think merits further study. The contrast in temps between the tropics and Arctic has dropped significantly since 1999 because the Arctic has warmed ~2C while the tropics have warmed significantly less. GW has been most concentrated in the Arctic.

“A reduced equator-to-pole temperature gradient lowers zonal available potential energy (ZAPE) and surface baroclinicity. Baroclinic instability is the primary energy source for extratropical cyclones (the large-scale mid-latitude storms that form along the jet stream and frontal zones). With less available energy to draw from:

• Models (including coordinated experiments focused on Arctic sea-ice loss and amplification) generally show fewer individual cyclones each season across the northern mid-latitudes and Arctic.
• The remaining storms tend to be, on average, somewhat weaker, slower-moving, and longer-lived.”

Individual events can still be intense or produce more extreme rainfall because of thermodynamic changes.

Because of the distortion of warming, it leads to some things opposite of what is portrayed in the general sense.

Your point is that this differential warming can produce effects that run counter to the simple ‘warmer world = more of everything extreme’ narrative, especially for baroclinic storm frequency and intensity. The thought experiment cleanly highlights how the pattern of warming, not just global-mean temperature, controls the dynamical response.”

 

[Typhoon Tip]

2 hours ago, GaWx said:

 Joe Bastardi brings something up that I think merits further study. The contrast in temps between the tropics and Arctic has dropped significantly since 1999 because the Arctic has warmed ~2C while the tropics have warmed significantly less. GW has been most concentrated in the Arctic.

“A reduced equator-to-pole temperature gradient lowers zonal available potential energy (ZAPE) and surface baroclinicity. Baroclinic instability is the primary energy source for extratropical cyclones (the large-scale mid-latitude storms that form along the jet stream and frontal zones). With less available energy to draw from:

• Models (including coordinated experiments focused on Arctic sea-ice loss and amplification) generally show fewer individual cyclones each season across the northern mid-latitudes and Arctic.
• The remaining storms tend to be, on average, somewhat weaker, slower-moving, and longer-lived.”

Individual events can still be intense or produce more extreme rainfall because of thermodynamic changes.

Because of the distortion of warming, it leads to some things opposite of what is portrayed in the general sense.

Your point is that this differential warming can produce effects that run counter to the simple ‘warmer world = more of everything extreme’ narrative, especially for baroclinic storm frequency and intensity. The thought experiment cleanly highlights how the pattern of warming, not just global-mean temperature, controls the dynamical response.”

 

The tropics have expanded more to accommodate heating - this is balancing the wholesale integrated PV=nrT ideal gas state.   Increasing the temp --> increases either P, V or both, on the left side of the equation.

That expansion is the Hadley Cell ...

But this is not linear.  Generally, gases expand more significantly the higher temperature.  Thus, the colder Arctic domain can increase more temperature, before it begins to expand ...

The atmosphere is free to expand in the horizontal and upward direction.  It's obviously not expanding through the ground...  The disproportionate expansion at higher temperatures thus causes the HC expansion, and the temperature only shows a more modest rise - it's a trade off. More volume as thermal energy is increasing, the register of the actual kinetic temperature is slowed.  If the tropics were in a closed container, it'd have risen more than what is being measured.