Occasional Thoughts on Climate Change

[bluewave]

 

 

[donsutherland1]

12 minutes ago, bluewave said:

 

 

The official announcement from Météo-France:

Translation:

June 24, 2026

France has just experienced its hottest day ever recorded.

Across the country, the average temperature over 24 hours reached 30°C, exceeding the 29.9°C measured... the day before, which was already the hottest day ever recorded since measurements began in 1947.

 

[bluewave]

40 minutes ago, donsutherland1 said:

The official announcement from Météo-France:

Translation:

June 24, 2026

France has just experienced its hottest day ever recorded.

Across the country, the average temperature over 24 hours reached 30°C, exceeding the 29.9°C measured... the day before, which was already the hottest day ever recorded since measurements began in 1947.

 

Another extreme heatwave matching the findings of this recent paper. 
 

Conclusion

Actionable climate assessment for effective climate adaptation and mitigation requires skillful and reliable projections of extreme weather risks under different emission scenarios on a regional to local level. This holds particularly true for the representation of recently observed extremes of large magnitude that might be rare under current climatic conditions but will become more likely under continued GHG emissions (1, 56, 64). Skillful projections of trends in such “extreme-extremes” (unprecedented or record-shattering extremes) must build on a thorough physical understanding of why they are emerging and the nonlinear behavior responsible so that model simulations can be benchmarked and potential biases can be accounted for.

In large and densely populated areas such as western Europe and China and other areas that feature important biomes for the world climate such as the Amazon, and polar regions around Greenland and Canada, some of which have been discussed in the context of climate tipping points (65, 66), the multimodel mean of climate simulations of the past decades does not show the enhanced warming of the temperature distributions’ upper tails observed in these regions (Fig. 1 and SI Appendix, Fig. S5). Note that for the Amazon, the strongest trends have emerged over the past 23 y and are found for ERA5 only (SI Appendix, Fig. S4).

Often, the multimodel mean is used and prioritized in many assessments of climate risks, while upper percentiles are treated as implausible scenarios and are at times rejected as outliers. For instance, the 1.5 °C warming target established by the Paris Agreement was set largely based on avoiding “dangerous climate change,” in part associated with critical tipping elements and/or thresholds in the Earth system (65, 67). However, if impacts of global warming, such as amplified extreme heat, proceed faster than expected based on the multimodel mean projections used to support such a warming target, its utility may deserve reconsideration. We find that in numerous regions (Figs. 2 and 3), trends in the tail-widening of extreme heat distribution over the past 65 y exceed the 95th percentile of the model spread and, in some cases, even exceed the spread entirely. Trends shown in ERA5 reanalysis are outside of the modeled range for southern South America, the Arabian Peninsula, and Arctic Canada (Fig. 3 D, E, and H), irrespective of any model configuration investigated here, while the observed uncertainty intervals determined by bootstrapping overlap with the model spread. These findings hold for model simulations at higher resolution, or forced with historical SSTs, as well as with greatly expanded ensemble sizes (SI Appendix, Figs. S5, S8, and S9).

Newer modeling initiatives such as super-high-resolution frameworks suggested, e.g., in the Earth Virtualization Engine (EVE) (68) promise convection permitting resolution and may offer possibilities in improving the depiction of important mechanisms. However, no substantial improvement for the higher resolved subset of the investigated models was found. Super-high-resolution, convection-resolving models may better represent processes that link SSTs with Rossby waves and associated extremes (45), regional blocking, and realistic surface response of heat events to such atmospheric patterns (50, 51). However, limitations due to data storage and computing costs might be significant constraints for the study of extreme events with high-resolution modeling frameworks, as the long time series lengths and large ensemble sizes needed for adequate statistics and trend attribution may be too resource intensive and not readily available. Newer generation models have also shown an improved skill in modeling blocking events which is more pronounced in high-resolution models (47, 69). Given the importance of nonlinear feedbacks involving hydroclimatic processes, a proper representation of the seasonal relationships of the flow of energy and water in the soil–vegetation–atmosphere continuum needs to be assured (7). Reasonable forecasts of past extreme heatwaves suggest that models can in principle produce such extreme-extremes when directly forced with the correct boundary conditions (11, 70). Ensemble boosting techniques can be used to create large ensembles of extraordinary extremes at reduced computational cost (71, 72). In an evolutionary manner, these algorithms preserve those that follow an extreme trajectory while filtering out others. This allows a sampling around a specific event characteristic. A large ensemble of highly anomalous events, which would be featured only at an extremely low rate in large ensembles (20), allows for an in-depth and statistically robust analysis of the governing physics of extreme-extremes in models.

However, disentangling the relative importance of externally forced and internal variability in the observed trends may be key to attributing the sources of model–observation discrepancies. Coordinated single forcing large ensemble experiments such as the new Large Ensemble Single Forcing Model Intercomparison Project (LESFMIP) (73) might help in improving our understanding in the relative role of various external or internal drivers in extreme event trends.

Further, machine learning (ML) approaches have shown promising results for providing more reliable bias adjustment of climate model output. These are based on methods from image processing and are better in retaining the relationships between variables compared to more traditional quantile-mapping approaches. This is particularly important when analyzing risks and impacts from compound extremes. ML techniques could also assist in detecting nonlinear and regime-changing behavior in the ocean–atmosphere–land–vegetation system and provide causality where common drivers experience strong coupling and feedbacks (9, 74). Beyond using ML for analysis, recent advances in ML-driven weather forecasts exemplify its potential in climate modeling (75, 76). In addition, ML might offer accurate and less computationally costly solutions for resolving important subgrid processes (77, 78), compared to purely numerical frameworks. ML approaches, however, must be combined with others that can physically explain and understand the causal flows identified by ML. New assimilation techniques that integrate observational datasets and exploit advanced interpolation frameworks have been proven to improve the depiction of extremes compared to reanalysis datasets (79) and provide climate information at a higher resolution.

While our findings provide many avenues for interesting and relevant new research, the authors stress that the best way to reduce both uncertainty in and exposure to climate impacts is a rapid transition of relevant societal sectors away from fossil fuels to stabilize global temperature rise.

[Typhoon Tip]

One aspect that intrigues me about that final/ending statement, "While our findings provide many avenues for interesting and relevant new research, the authors stress that the best way to reduce both uncertainty in and exposure to climate impacts is a rapid transition of relevant societal sectors away from fossil fuels to stabilize global temperature rise",   is that the climate response has actually lagged behind the anthropomorphic contributed forcing.  Or in other words, the latter has outpaced the former.

I keep reading statements - no fault to the author as it's not specific to their study - like this, where it "seems" or intimates a 1::1 causality in time.   As though if the ideal reality could ever be achieved, where there were a sudden and abrupt cessation of fossil fuel use, there would thus begin an immediately response and stabilizing climate.  

That is unfortunately not the case. 

In any such idealized state of affairs, the Earth would like keep warming until it satisfies the total thermal regulation/balance.  Another way to look at it is, there is room for the present atmospheric chemistry to store yet more thermal energy that it is.

Another possibility ( intuitive speculation) is that the modulating aspect of the global oceanic quasi coupling to this mess we are in, might also continue to absorb the lion's share of the warming human activity should otherwise have realized.  90% of which has sunk into the oceans (btw) since the Industrial Revolution.  So in simpler terms, it's possible that a sudden stoppage of fossil fuel combustion might register more slowing of the warming due to this factor.

[frontranger8]

4 hours ago, bluewave said:

Another extreme heatwave matching the findings of this recent paper. 
 

 

 

It's interesting that 2 of the 3 areas that have seen the biggest increase in extreme heatwaves, western North America with a focus on BC/the PNW and NW Europe, have pretty similar climates. Traditionally very temperate and mild in both the winter and summer, and similar latitude.

[donsutherland1]

The Paris-Montouris station, for which records go back to 1872, has recorded its first case of two consecutive 40°C (104°F) or above days. Paris-Jardin du Luxembourg topped out at 41.2°C (106.2°F). Jersey (Maison St. Louis: 39.3°C/102.7°F) and Switzerland (Basel: 38.0°C/100.4°F) set national all-time records. The UK (Merrifield: 36.7°C/98.1F) set a national June monthly record.

[donsutherland1]

Today was another day of furnace-like heat in France, Jersey, and the UK. The extreme heat will shift eastward over the next few days. 

[ChescoWx]

A really interesting statistic for the entire USA which exactly mirrors the data I share here from the philly burbs of Chester County. This below analysis measures not the typical metric of 90+ days but unusual hot periods of at least 4 days on average across the entire country where the average temperature reaches a level based on historical records that would be expected to only occur once every 10 years. Look how much hotter the entire nation was back in 1930's and 1940's compared to today! No matter how much we hear about how hot it is today we have still not reached that peak heating from the 1930 through 1942 period which matches the hottest period here in Chester County PA.

[donsutherland1]

Excerpts from World Weather Attribution concerning Europe's record-breaking June heatwave:

Fossil fuel emissions have rapidly worsened European heatwaves in just a few decades

• Over the region studied this heatwave is the most severe ever recorded. 
• In 1976, when some of the previous European records were set, the 2026 temperatures would have been virtually impossible to occur in June, while also highly unlikely at any time of the year. In 2003, the first major heatwave of this century, daytime heat like this would still have been very rare, about 10 times less likely than today, while nighttime temperatures such as this June would have been more than a hundred times less likely in 2003. 
• Across large parts of Western Europe, June is warming faster than any other month. In addition, daily maximum temperatures are warming faster than night time temperatures, though both are warming much faster than global warming. The hottest daily temperatures are warming at about triple the rate of global warming and night time temperatures at about twice the rate. Many capital cities are experiencing not only their hottest June 3-day period but also the hottest three-day period since 1950, according to the ERA5 dataset. However, due to global warming, these very high temperatures are now expected regularly during the summer months in many capitals. 
• This means that a similar heatwave in June would have been about 3.5°C cooler during the day in 1976 and about 2°C cooler in 2003. The nighttime temperatures would have been about 2.4°C cooler in June 1976 and about 1.3°C cooler in June 2003. 
• This June 2026 heatwave occurred under a circulation pattern broadly similar to historical analogues – Southerly Flow. However, a similar circulation pattern now produces significantly hotter temperatures than it did in the mid-20th century because the climate baseline has warmed...
• This summer shows that at 1.4°C of global warming, extreme heat is already reaching the limits of our societies’ ability to cope. Our analysis here shows that intense heat is increasing rapidly even in living memory, with such events tens to hundreds of times more likely since only 2003 and virtually impossible just 50 years ago. A rapid phase-out of fossil fuels is critical if we are to avoid even higher temperatures and their consequences in the future.

https://www.worldweatherattribution.org/fossil-fuel-emissions-have-rapidly-worsened-european-heatwaves-in-just-a-few-decades/

[Silver Meteor]

The deeper you look the more you find narrative-driven quackery.

https://grokipedia.com/page/World_Weather_Attribution

[donsutherland1]

Today was another day of crushing inescapable heat in much of Europe. Saarbrücken, Germany (41.3C/106.3F) and Basel, Switzerland (38.8C/101.8F) set new national all-time heat records. Locations in France also set additional all-time records. Santon Downham (37.3C/99.1F) set a national UK June record.

 

[Typhoon Tip]

2 hours ago, donsutherland1 said:

Today was another day of crushing inescapable heat in much of Europe. Saarbrücken, Germany (41.3C/106.3F) and Basel, Switzerland (38.8C/101.8F) set new national all-time heat records. Locations in France also set additional all-time records. Santon Downham (37.3C/99.1F) set a national UK June record.

 

Don   if you wanna look brilliant, I'd go and start suggesting if now outright warning western Europe to watch the July 4 weekend .. signal's grown across 7 consecutive model cycles as trend on top of a background hemispheric foot that's not actually changed the non-linear/synergism

[donsutherland1]

55 minutes ago, Typhoon Tip said:

Don   if you wanna look brilliant, I'd go and start suggesting if now outright warning western Europe to watch the July 4 weekend .. signal's grown across 7 consecutive model cycles as trend on top of a background hemispheric foot that's not actually changed the non-linear/synergism

The forecast heat dome is looking more and more impressive. The NBM shows a peak of 105° +/- 5° at Washington, DC.  The all-time mark is 106°. This situation will merit watching.

[Typhoon Tip]

33 minutes ago, donsutherland1 said:

The forecast heat dome is looking more and more impressive. The NBM shows a peak of 105° +/- 5° at Washington, DC.  The all-time mark is 106°. This situation will merit watching.

Well, yeah that but I was talking about Western Europe a resurgence scenario. That ridge I annotated west of the Iberian Peninsula is in a critical mode/danger of engulfing the region episodically.

[donsutherland1]

2 hours ago, Typhoon Tip said:

Well, yeah that but I was talking about Western Europe a resurgence scenario. That ridge I annotated west of the Iberian Peninsula is in a critical mode/danger of engulfing the region episodically.

On that, I also agree. Summer 2026 is becoming much like Summer 2019 with wave after wave of intense heat in Europe.

[ChescoWx]

You will no doubt see and hear a lot of alarmist news stories later this week saying the current heatwave is "unprecedented" across the Eastern US. However, as confirmed in a new peer reviewed study in the Journal of Theoretical and Applied Climatology, Christy (2026)

“The results indicate that extremes in heat-related metrics for daily TMax in the summer have not increased and in fact often show modest declines since 1899, due mostly to the early heat events during 1925-1954”

Those period of years are also the hottest period here in Chester County PA. So over the last century, there has been no evidence of an increase in heatwaves in the United Stares no matter what you will see on your TV later this week. It is simply called summer!! Stay cool!!  

 

[RCC]

3 hours ago, ChescoWx said:

You will no doubt see and hear a lot of alarmist news stories later this week saying the current heatwave is "unprecedented" across the Eastern US. However, as confirmed in a new peer reviewed study in the Journal of Theoretical and Applied Climatology, Christy (2026)

“The results indicate that extremes in heat-related metrics for daily TMax in the summer have not increased and in fact often show modest declines since 1899, due mostly to the early heat events during 1925-1954”

Those period of years are also the hottest period here in Chester County PA. So over the last century, there has been no evidence of an increase in heatwaves in the United Stares no matter what you will see on your TV later this week. It is simply called summer!! Stay cool!!  

 

 

" Heat Wave Days"   vs. Temperature anomalies broken out by seasons.  Trend lines are similar- rising steadily as a whole. 

[donsutherland1]

June 2026 in France and much of Europe isn't merely "hot." Hot is a beach day, lemonade, and open windows. This is different. Stoked by rising atmospheric greenhouse gases, the air is seemingly breathing fire in one's face. The shade is failing to offer much relief. 

Today, France saw additional all-time records. The Czech Republic, Denmark, and Germany set all-time national records.

[frontranger8]

Breathing fire, eh? Extreme, unprecedented hyperbole warning!

[donsutherland1]

11 minutes ago, frontranger8 said:

Breathing fire, eh? Extreme, unprecedented hyperbole warning!

It’s a metaphor, not literal description.

[GaWx]

 

 Per DMI, the daily mean temp in the Arctic N of 80N has still not reached 0C! As of today (6/27), it’s still barely <0C at -0.35C:

 

 Going all of the way back to 1958, the previous latest to first exceed 0C was a full week earlier, June 20th, and that was in 2013:

 

 

So, even if it finally exceeds 0C tomorrow, that would still be a whopping 8 days later than the previous latest on record of June 20th! I checked every year.

https://ocean.dmi.dk/arctic/meant80n.uk.php

 

[donsutherland1]

The historic June 2026 heatwave finally began to release its grip on France. Nevertheless, a few locations set monthly and all-time records. Germany (41.7C) and Czechia (41.9C) also set all-time heat records. 

As a result of the heatwave, June 2026 accounts for the most all-time records for the month of June and 2026 accounts for the second most all-time records for any calendar year. The clustering of all-time records in recent years is consistent with a warming climate from fossil fuel-driven anthropogenic climate change.

 

[donsutherland1]

The updated June monthly record for the UK during the most recent climate change-enhanced heatwave is 37.7C (99.9F).

Key contextual point from World Weather Attribution:

This June 2026 heatwave occurred under a circulation pattern broadly similar to historical analogues – Southerly Flow. However, a similar circulation pattern now produces significantly hotter temperatures than it did in the mid-20th century because the climate baseline has warmed...

[GaWx]

25 minutes ago, donsutherland1 said:

The updated June monthly record for the UK during the most recent climate change-enhanced heatwave is 37.7C (99.9F).

Key contextual point from World Weather Attribution:

This June 2026 heatwave occurred under a circulation pattern broadly similar to historical analogues – Southerly Flow. However, a similar circulation pattern now produces significantly hotter temperatures than it did in the mid-20th century because the climate baseline has warmed...

 Absolutely, Don. It still would have been another historic heatwave even without AGW but not near as historic as it got due to the added effects from AGW. A larger portion of this extreme heat was very likely due to the pattern, itself, as opposed to AGW, itself. But AGW means a higher baseline as your quote said.
 

 The global baseline average has warmed ~2.5F since the late 1800s and not far from that even since just the mid-20th century if I’m not mistaken with the Arctic significantly higher and the tropics lower. How much do you figure the W Europe climate baseline has warmed?

[donsutherland1]

12 minutes ago, GaWx said:

 Absolutely, Don. It still would have been another historic heatwave even without AGW but not near as historic as it got due to the added effects from AGW. A larger portion of this extreme heat was very likely due to the pattern, itself, as opposed to AGW, itself. But AGW means a higher baseline as your quote said.
 

 The global baseline average has warmed ~2.5F since the late 1800s and not far from that even since just the mid-20th century if I’m not mistaken with the Arctic significantly higher and the tropics lower. How much do you figure the W Europe climate baseline has warmed?

The latest estimates I have seen is 2.19C-2.26C (3.9F-4.1F):

European land temperatures have increased even faster over the same period by 2.19 to 2.26°C, depending on the dataset used.

https://www.eea.europa.eu/en/analysis/indicators/global-and-european-temperatures

[donsutherland1]

In the wake of Europe's record-setting June heatwave and the guidance suggesting that parts of the U.S. Mid-Atlantic and southern New England regions could challenge July monthly and even all-time heat records, the climate change denial movement is desperately trying to frame the heat as ordinary summer heat. One example from a fossil fuel advocacy group's policy analyst in attacking a meteorologically sound post:

In the past week, Belarus, Czechia, Denmark, Germany, Poland, and Slovakia set all-time national heat records. Austria, France (with 292 cities setting all-time records), Switzerland, and the United Kingdom set June monthly records. 

But to the ignorant, that's just "summer."

The latest guidance suggests that the July 1-4 period could see locations in the Mid-Atlantic and southern New England regions challenge July monthly and even all-time records.

But again to the ignorant, that's just "summer."

And finally the ignorant policy analyst's claim that nationally-recognized meteorologist Jeff Berardelli should use the "correct terminology" instead of "heat dome," proves incorrect. It's the policy analyst who has no clue.

From the AMS Glossary of Meteorology:

Rather than making wild claims about subject matter with which he obviously is unfamiliar, he should brush up on the basics and put aside a belief system that is a repudiation of both science and reason. Arrogance and ignorance are a toxic combination for any profession. 

In any case, the extraordinary June heatwave is consistent with the warming global climate, including the rapid warming in Europe. No ranting, raving, or other forms of deflection or projection can erase what happened, much less undermine the science that is based on overwhelming and unequivocal evidence.

[donsutherland1]

"It's called 'summer'..."--CFACT policy analyst

Meanwhile from Météo-France:

The recent heatwave saw France record, on a national basis, three highest daily mean temperatures, four highest mean high temperatures, and four highest mean low temperatures on record. "Summer" doesn't describe this extraordinary climate change-driven heat. 

The reality from France:

A warmer baseline climate makes hot patterns hotter. Key points from a recent World Weather Attribution rapid analysis:

• Across large parts of Western Europe, June is warming faster than any other month. In addition, daily maximum temperatures are warming faster than night time temperatures, though both are warming much faster than global warming. The hottest daily temperatures are warming at about triple the rate of global warming and night time temperatures at about twice the rate. Many capital cities are experiencing not only their hottest June 3-day period but also the hottest three-day period since 1950, according to the ERA5 dataset. However, due to global warming, these very high temperatures are now expected regularly during the summer months in many capitals. 
• This means that a similar heatwave in June would have been about 3.5°C cooler during the day in 1976 and about 2°C cooler in 2003. The nighttime temperatures would have been about 2.4°C cooler in June 1976 and about 1.3°C cooler in June 2003. 
• This June 2026 heatwave occurred under a circulation pattern broadly similar to historical analogues – Southerly Flow. However, a similar circulation pattern now produces significantly hotter temperatures than it did in the mid-20th century because the climate baseline has warmed.

Key Points:

1) The heat was record-setting, not typical summer warmth

2) Human induced climate change contributed to the extreme nature of the heat

3) Interest-driven policy analysts are poor sources of weather/climate information; they seek to advance their employers' interests and some even resort to pushing misleading information to undermine public knowledge e.g., the flippant dismissal of the heat as "summer." 

[GaWx]

18 hours ago, donsutherland1 said:

In the wake of Europe's record-setting June heatwave and the guidance suggesting that parts of the U.S. Mid-Atlantic and southern New England regions could challenge July monthly and even all-time heat records, the climate change denial movement is desperately trying to frame the heat as ordinary summer heat. One example from a fossil fuel advocacy group's policy analyst in attacking a meteorologically sound post:

In the past week, Belarus, Czechia, Denmark, Germany, Poland, and Slovakia set all-time national heat records. Austria, France (with 292 cities setting all-time records), Switzerland, and the United Kingdom set June monthly records. 

But to the ignorant, that's just "summer."

The latest guidance suggests that the July 1-4 period could see locations in the Mid-Atlantic and southern New England regions challenge July monthly and even all-time records.

But again to the ignorant, that's just "summer."

And finally the ignorant policy analyst's claim that nationally-recognized meteorologist Jeff Berardelli should use the "correct terminology" instead of "heat dome," proves incorrect. It's the policy analyst who has no clue.

From the AMS Glossary of Meteorology:

Rather than making wild claims about subject matter with which he obviously is unfamiliar, he should brush up on the basics and put aside a belief system that is a repudiation of both science and reason. Arrogance and ignorance are a toxic combination for any profession. 

In any case, the extraordinary June heatwave is consistent with the warming global climate, including the rapid warming in Europe. No ranting, raving, or other forms of deflection or projection can erase what happened, much less undermine the science that is based on overwhelming and unequivocal evidence.

Hey Don,

  My point in thanking you for your post was agreeing with you about Chris Martz. Chris is both openly dismissing the contribution of AGW in these cases and is also dead wrong about the use of the term “heat dome”.

 But at the same time, I disagree with Jeff B. in calling this US heatwave one of the most “expansive”. It’s quite intense with record highs likely for a couple of days, but certainly not in a large portion of the country:

 This is the largest extent of the heat dome at H5 expected to produce record heat in and near the Mid-Atlantic states:

 

 Compare that to this significantly more expansive heatwave over the U.S.: 594 dm from E coast to Rockies and also N to MSP in addition to it peaking at ~600 vs the current one peaking at ~597:

 There are others, including the Dust Bowl years, especially July of 1936, that had some days of 100++ over a much larger portion of the U.S. In contrast, the current one is forecasted at its peak extent to have 100+ only mainly from E GA to the NYC/Hartford areas, which is not one of the most expansive in US history:

 

[bluewave]

On 6/25/2026 at 1:25 PM, frontranger8 said:

It's interesting that 2 of the 3 areas that have seen the biggest increase in extreme heatwaves, western North America with a focus on BC/the PNW and NW Europe, have pretty similar climates. Traditionally very temperate and mild in both the winter and summer, and similar latitude.

I suspect the climate models aren’t good enough yet to detect all of the circulation changes that are resulting from warming the climate. We are warming the planet at faster rate than our current level of technology can keep up with 

So we get these repeated 500mb ridges which keep getting stuck in places for long durations leading to these increasing record heat extremes.

It’s quite possible that the repeating omega block itself which is a part of the record heat pattern in Europe is also related to the warming climate.
 

From The Atlantic:

https://geography.dartmouth.edu/news/2025/01/climate-models-cant-explain-whats-happening-earth

Climate Models Can’t Explain What’s Happening to Earth

Fifty years into the project of modeling Earth's future climate, we still don't really know what's coming. Some places are warming with more ferocity than expected. Extreme events are taking scientists by surprise. Right now, as the bald reality of climate change bears down on human life, scientists are seeing more clearly the limits of our ability to predict the exact future we face. The coming decades may be far worse, and far weirder, than the best models anticipated.

This is a problem. The world has warmed enough that city planners, public-health officials, insurance companies, farmers, and everyone else in the global economy want to know what's coming next for their patch of the planet. And telling them would require geographic precision that even the most advanced climate models don't yet have, as well as computing power that doesn't yet exist. Our picture of what is happening and probably will happen on Earth is less hazy than it's ever been. Still, the exquisitely local scale on which climate change is experienced and the global purview of our best tools to forecast its effects simply do not line up.

Today's climate models very accurately describe the broad strokes of Earth's future. But warming has also now progressed enough that scientists are noticing unsettling mismatches between some of their predictions and real outcomes. Kai Kornhuber, a climate scientist at Columbia University, and his colleagues recently found that, on every continent except Antarctica, certain regions showed up as mysterious hot spots, suffering repeated heat waves worse than what any model could predict or explain. Across places where a third of humanity lives, actual daily temperature records are outpacing model predictions, according to forthcoming research from Dartmouth's Alexander Gottlieb and Justin Mankin. And a global jump in temperature that lasted from mid-2023 to this past June remains largely unexplained, a fact that troubles Gavin Schmidt, the director of NASA's Goddard Institute for Space Studies, although it doesn't entirely surprise him.

"From the 1970s on, people have understood that all models are wrong," he told me. "But we've been working to make them more useful." In that sense, the project of climate modeling is a scientific process that's proceeding normally, even excellently. Only now the whole world needs very specific information to make crucial decisions, and they needed it, like, yesterday. That scientists don't have those answers might look like a failure of modeling, but really, it's a testament to how bad climate change has been permitted to get, and how quickly.

The Earth is an unfathomably complex place, a nesting doll of systems within systems. Feedback loops among temperature, land, air, and water are made even more complicated by the fact that every place on Earth is a little different. Natural variability and human-driven warming further alter the rules that govern each of those fundamental interactions.

Some of these systems such as cloud formation are notoriously poorly understood, despite having a major bearing on climate change. And, like clouds, many parts of the Earth system are just too localized for climate models to pick up on. "We have to approximate cloud formation because we don't have the small scales necessary to resolve individual water droplets coming together," Robert Rohde, the chief scientist at the open-source environmental-data nonprofit Berkeley Earth, told me. Similarly, models approximate topography, because the scale at which mountain ranges undulate is smaller than the resolution of global climate models, which tend to represent Earth in, at best, 100-square-kilometer pixels. That resolution is good for understanding phenomena such as Arctic warming over decades. But "you can't resolve a tornado worth anything," Rohde said.

Models simply can't function on the scale at which people live, because assessing the impact of current emissions on the future world requires hundreds of years of simulations. Modeling the Earth at one-square-kilometer pixels would take "like a hundred thousand times more computation than we currently have," Schmidt, of NASA, told me. Still, global climate models can be of local use if combined with enough regional data and the correct expertise, and more people now want to use them that way, in order to understand risk to their properties and investments, or to make emergency plans and build infrastructure. "We are asking a lot of the models. More than we have in the past," Rohde said.

For nonscientists, coaxing useful information from climate models requires professional help. Climate scientists have been working for years with New York City to help direct choices such as where to put infrastructure with sea-level rise in mind. But, Schmidt said, "there's just not enough scientists to be on the advisory board of every locality or every enterprise or every institution or every company," helping them access the right climate data or pick which models to rely on. (Some are better at simulating certain variables, such as day-to-night temperature variation, than others.) Often governments end up turning to private-sector companies that claim to be able to translate the data; Schmidt would rather see his own field produce work that is more directly useful to the public.

At the same time, now that the models are running up against the reality of dramatic climate change, some of their limits are showing. When this scientific endeavor first started, the models were meant to imagine what global temperatures might look like if greenhouse-gas emissions rose, and they did a remarkable job of that. But models are, even now, less capable of accounting for secondary effects of those emissions that no one saw coming, and that now seem to be driving important change.

Some of those variables are missing from climate models entirely. Trees and land are major sinks for carbon emissions, and that this fact might change is not accounted for in climate models. But it is changing: Trees and land absorbed much less carbon than normal in 2023, according to research published last October. In Finland, forests have stopped absorbing the majority of the carbon they once did, and recently became a net source of emissions, which, as The Guardian has reported, swamped all gains the country has made in cutting emissions from all other sectors since the early 1990s. The interactions of the ice sheets with the oceans are also largely missing from models, Schmidt told me, despite the fact that melting ice could change ocean temperatures, which could have significant knock-on effects. Changing ocean-temperature patterns are currently making climate modelers at NOAA rethink their models of El Niño and La Niña; the agency initially predicted that La Niña's cooling powers would kick in much sooner than it now appears they will.

Biases in climate models go in both directions: Some overestimate risk from various factors, and others underestimate it. Some models "run hot," suggesting more warming than what actually plays out. But the recent findings about temperature extremes point in the other direction: The models may be underestimating future climate risks across several regions because of a yet-unclear limitation. And, Rohde said, underestimating risk is far more dangerous than overestimating it.

To Kornhuber, too, that models already appear to be severely underestimating climate risk in several places is a bad sign for what's ahead and our capacity to see it coming. "It should be worrying that we are now moving into a world where we've kind of reached the limit of our physical understanding of the Earth system," Kornhuber said.

While models struggle to capture the world we live in now, the planet is growing more alien to us, further from our reference ranges, as the climate keeps changing. If given unlimited time, science could probably develop models that more fully captured what we're watching play out. But by then it would be too late to do anything about it. Science is more than five decades into the modeling endeavor, and still our best tools can only get us so far. "At the end of the day, we are all making estimates of what's coming," Rohde said. "And there is no magic crystal ball to tell us the absolute truth." We're left instead with a partial picture, gestural in its scope, pointing toward a world we've never seen before.

Access Original Article here.

Illustration by The Atlantic

WRITTEN BY

Zoë Schlanger (The Atlantic)

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[frontranger8]

I think to me what really stands out is the heat just isn't spread out evenly. And the climates that have seen the most summer warming tended to be fairly similar.