Global warming, climate change, all these things are just a dream come true for politicians. I deal with evidence and not with frightening computer models because the seeker after truth does not put his faith in any consensus. The road to the truth is long and hard, but this is the road we must follow. People who describe the unprecedented comfort and ease of modern life as a climate disaster, in my opinion have no idea what a real problem is.
The Federal Judicial Centerโs โReference Manual on Scientific Evidenceโ is supposed to help federal judges understand scientific evidence and methodologies. Judges increasingly confront complex scientific questions and need reliable tools to evaluate expert testimony. The reference manual is one such tool โ or at least most of it is.
In a very anti-scientific turn, and without catching the irony, โHow Science Worksโ misleadingly suggests that broad consensus โ not reason, test results, or repeatability โ constitutes โthe highest level of certainty science has to offer.โ
Hand with black glove pushing on scale of justice in dark room with black background. Concept of injustice, espionage, partiality, law.
The Federal Judicial Centerโs โReference Manual on Scientific Evidenceโ is supposed to help federal judges understand scientific evidence and methodologies. Judges increasingly confront complex scientific questions and need reliable tools to evaluate expert testimony. The reference manual is one such tool โ or at least most of it is.
At the request of 27 statesโ attorneys general, the Federal Judicial Center recently removed the manualโs chapter on climate science because it did more to influence judicial outcomes than to help federal judges evaluate scientific evidence. And the reference guideโs chapter called โHow Science Worksโ is guilty of a similar offense.
Judicial reference manuals should teach judges how to evaluate scientific evidenceโnot tell them which scientific conclusions to draw. Unfortunately, โHow Science Worksโ does a lot more telling than teaching, putting a green-agenda thumb on the scales of justice. So, as The Buckeye Institute and other concerned public policy organizations expressed in a letter to the Federal Judicial Center, the dubious chapter has to go.
In a very anti-scientific turn, and without catching the irony, โHow Science Worksโ misleadingly suggests that broad consensus โ not reason, test results, or repeatability โ constitutes โthe highest level of certainty science has to offer.โ It then asserts that the hypothesis of man-made climate change has reached such โscientific consensus,โ despite that hypothesisโs many contested, untested, and controversial claims. The chapter goes on to contravene important legal authorities and doctrines that govern expert testimony.
Federal Rule of Evidence 702, for example, requires courts to determine whether expert testimony rests on sufficient facts or data, results from reliable principles and methods, and reflects a reliable application of those principles and methods to the facts of the case. The rule emphasizes that applying an expertโs methodology to the facts is critical to whether scientific evidence gets admitted in court. Similarly, in Daubert v. Merrell Dow Pharmaceuticals, a unanimous U.S. Supreme Court explained that scienceโs method of generating hypotheses and testing them to determine whether they can be falsified is what distinguishes science from other forms of inquiry. Daubert ruled that when it comes to scientific evidence, the quality of an expertโs methodology should trump consensus or โwidespread acceptance.โ The court may be surprised โ and not amused โ to learn that the federal Reference Manual on Scientific Evidence dismissively calls the scientific methodโs authoritative role a โmyth.โ
Elevating a so-called consensus over rigorous methodology when weighing scientific evidence in the courtroom risks serious, real-world consequences for litigants, especially in the energy sector. What federal judges read about scientific evidence in judicial reference guides will influence how they evaluate scientific evidence at trial, and those evaluations may mean billions of dollars in unwarranted liability.
As climate-related litigation marches across America and energy companies defend themselves and their business decisions against the charge of inflicting climate change, judges and juries should not be encouraged to rely on agenda-driven โconsensusโ to render their verdicts. Courts may be asked, for example, whether a particular climate model establishes causation; whether an attribution methodology supports a particular claim for damages; or whether an expertโs assumptions justify imposing liability on an energy company. Those questions should not be answered with โfour-out-of-five scientists agree,โ as if judges were shopping for a new toothpaste.
Instead, the Federal Judicial Center should remove the โHow Science Worksโ chapter from its reference manual, or else rewrite it to conform with Daubert and the centerโs own historical approach to judicial guides. When the first edition of the manual was published, the center explained that it was providing the bench with primers on scientific methods and identifying issues on which experts might disagree. The current edition strays far from that circumspect position, all but telling judges what to think rather than how to think about a contested scientific conclusion.
In October, the U.S. Supreme Court heard arguments in Suncor Energy Inc. v. Boulder County, a case in which climate activists hope to impose a very expensive net-zero carbon agenda nationwide. The parties and the country should hope that the Suncor decision adheres to science derived by the scientific method and eschews todayโs โwidely held beliefsโ that may or may not be so widely held tomorrow.
American energy depends on sound, objective science to fuel the future. And American litigants deserve an objective judiciary not primed with politically predetermined conclusions presented as scientific fact.
Santa Ana winds (also called Santa Anas or โdevil windsโ) are strong, hot, and extremely dry downslope winds that affect coastal Southern California and northern Baja California.
They are a type of katabatic (downslope) wind, similar to foehn or Chinook winds elsewhere.
Santa Ana winds have been observed and described in Southern California for centuries, though the specific name emerged in the late 19th century. They are a longstanding feature of the regionโs climate, driven by the same high- pressure patterns over the Great Basin and the topography of the coastal mountains and passes.
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Santa Ana winds (also called Santa Anas or โdevil windsโ) are strong, hot, and extremely dry downslope winds that affect coastal Southern California and northern Baja California.
They blow from inland desert regions (primarily the Great Basin of Nevada, Utah, and surrounding areas) toward the Pacific Ocean, descending the leeward (downwind) slopes of coastal mountain ranges. They typically arrive from the northeast or east and funnel through mountain passes and canyons such as Cajon Pass, the Santa Clara River Valley, Banning Pass, and Santa Ana Canyon.
High- pressure systems build over the cooler, higher- elevation Great Basin deserts (especially in fall and winter). Air flows clockwise out of these highs toward lower pressure near the coast. As the air descends thousands of feet, it is compressed and warms adiabatically, at roughly 10 ยฐC (about 18 ยฐF) per kilometer of descent, or roughly 5 ยฐF per 1,000 feet. This warming also sharply lowers relative humidity (often to single digits or teens). The air accelerates dramatically when squeezed through narrow canyons and passes (a venturi and gap- wind effect), producing strong gusts.
They are a type of katabatic (downslope) wind, similar to foehn or Chinook winds elsewhere.
Season and characteristics
Most common from early fall through early spring (roughly September- May), with a peak often in December- January, though they can occur outside this window.โ
Typical speeds: sustained winds around 20- 40 mph (30- 65 km/h), with common gusts of 40- 70 mph (65โ110 km/h). Extreme events can produce gusts exceeding 80- 100 and more mph in the windiest canyons and mountain locations.โ
They bring very low humidity, clear skies, and warm- to- hot temperatures (sometimes the hottest of the year for the season), even when originating from cooler desert air.
Events usually last 1- 7 days (average around 3), though longer ones occur. About 10- 25 events typically happen per year.
Impacts
The combination of heat, extreme dryness, and high winds creates critical fire weather: vegetation dries rapidly, and any ignition (power lines, sparks, etc.) can spread extremely fast. They have driven many of Southern Californiaโs most destructive wildfires. They can also cause wind damage, power outages/shutoffs, blowing dust, hazardous driving conditions, and aviation turbulence.
The name most likely derives from Santa Ana Canyon (between the Santa Ana Mountains and Chino Hills in Orange County), with written references dating to the late 19th century. Alternative folk etymologies involving โSantanaโ or โdevilโ winds exist but are less supported.โ
As of mid- to- late October 2026, Southern California experienced its first notable Santa Ana event of the fall season around October 15- 17, bringing red- flag fire weather warnings, strong gusts, heat, and several wildfires. By October 19 the winds had largely subsided, with a cooling trend and potential rain later in the week.
In short, Santa Ana winds are a dramatic and sometimes dangerous part of Southern Californiaโs climate, driven by regional pressure patterns and topography.
Santa Ana winds have been observed and described in Southern California for centuries, though the specific name emerged in the late 19th century. They are a longstanding feature of the regionโs climate, driven by the same high- pressure patterns over the Great Basin and the topography of the coastal mountains and passes.
Early Observations (Pre-Name Era)
Spanish and early American accounts described strong, dry northeast or east winds without using the modern name:
In 1812, a Spanish report from the San Diego Presidio noted northeast winds damaging wheat crops at San Juan Capistrano.โ
In 1836, Richard Henry Danaโs Two Years Before the Mast recounted a โviolent northeasterโ that forced his ship to seek shelter near Santa Catalina Island.โ
In January 1847, during the Mexican- American War, U.S. forces under Commodore Robert Stockton (and reports by Major William Emory) experienced a fierce gale near the mouth of Santa Ana Canyon while camped en route to Los Angeles. Descriptions called it a โhurricaneโ that filled the air with fine dust, made breathing difficult, and would have complicated loading firearms.โ
These accounts match classic Santa Ana characteristics: strong winds, dust, and dryness. Paleoclimate evidence from charcoal deposits in the Santa Barbara Basin indicates large fires under Santa Ana- like conditions occurring for at least 560 years (back to around A.D. 1425), with patterns linked to climate variability rather than major shifts from Indigenous, Spanish, or modern land-use practices.
Origin of the Name
The name almost certainly derives from Santa Ana Canyon (in present- day Orange County, between the Santa Ana Mountains and Chino/Puente Hills), where the winds often blow with particular force and appear to originate from the perspective of early settlers in the area. The canyon, river, and later the city of Santa Ana takes their name from the Portolรก expeditionโs entry into the valley on or near Saint Anneโs feast day in 1769.โ
The earliest known printed references appear in the Anaheim Gazette in 1871 (e.g., mentions of โwithering Santa Anaโsโ or a detailed October account of a hot, dusty wind sweeping through the canyon).โ
Another early citation is in the Los Angeles Evening Express on November 15, 1880 (โThe Philosophy of Sandstormsโ).โ
By the 1880s the term was in regular local use, and the U.S. Weather Bureau formalized it in publications around 1903.
Controversies and alternative theories:
Residents and the Chamber of Commerce of the city of Santa Ana disliked the association of their name with destructive winds and campaigned against it (proposing alternatives such as โRiverside Zephyrโ).
In 1922, a local resident suggested โSantanaโ, claiming it was an Indigenous word for a big or devil wind (later corrupted via Spanish โSatanรกsโ).
Linguists and historians have found no supporting evidence for an Indigenous term โSantana, sandanaโ, and the Spanish word for Satan is Satanรกs (or devil diablo).
Other weak folk theories link it to Mexican general Antonio Lรณpez de Santa Anna or Saint Anneโs Day itself. Most historical research (including by Orange County historians and folklorists such as Terry Stephenson in 1943) supports the canyon origin.
Historical Impacts and Notable Events
From the pioneer era onward, the winds damaged crops, orchards, wooden buildings, and infrastructure, raised blinding dust storms, and drove wildfires. Early settlers sometimes viewed milder events as beneficial (e.g., for drying raisins or clearing fog) or as harbingers of approaching rain.โ
They have fueled many of Southern Californiaโs largest and most destructive wildfires.
Examples include:
Late-19th- century fires such as the Santiago Canyon Fire of 1889.
20th- and 21st- century events including the Laguna Fire (1970), Cedar Fire and Old Fire (2003), Witch Creek Fire (2007), Thomas Fire (2017), and numerous others in which strong, dry Santa Ana conditions rapidly spread flames through dry vegetation, often starting from power lines, arson, or other ignitions.โ
Extreme wind events have also caused widespread power outages, structural damage, and hazardous conditions (e.g., very strong gusts recorded in mountain and canyon locations in events such as those in 1957, 2011, and others).
Cultural and Literary Significance
The winds feature prominently in Southern California literature and folklore, often linked to tension, irritability, or a sense of unease (sometimes exaggerated as โhomicidalโ moods). Classic depictions appear in Raymond Chandlerโs stories (notably โRed Windโ), works by Joan Didion, and others. Nicknames have included โdevil windsโ, โred windโ, or โnortheastersโ.โ
In summary, while the atmospheric phenomenon itself is ancient, the specific name โSanta Ana windsโ entered written English in the 1870s- 1880s, tied firmly to the geography of Santa Ana Canyon, and has remained the standard term despite local efforts to change it. The winds continue to shape the regionโs weather, fire history, and cultural identity.
Santa Ana winds create some of the most extreme wildfire conditions in Southern California by combining very low humidity, high temperatures (especially in โhotโ events), and strong, gusty winds that dry vegetation further and rapidly spread flames and embers.
Why the Fire Risk Is So High
Extreme dryness: The descending air warms by compression, and its relative humidity often drops below 10- 15% (sometimes under 5%). This desiccates grasses, shrubs (chaparral), and other fuels that are already dry after the long Mediterranean- climate summer with little or no rain. Overnight humidity recovery is also limited, so fuels stay critically dry.โ
Wind- driven spread: Gusts commonly reach 40- 70 mph and can exceed 80- 100 and mph in canyons and passes (e.g., Fremont Canyon, Cajon Pass). Winds push the fire front aggressively and, more critically, loft burning embers long distances (sometimes over a mile), starting new spot fires ahead of the main blaze. Fires under these conditions often spread through the air rather than solely through continuous vegetation.โ
Timing: Events peak in fall (especially October) into winter, precisely when fuels are driest. A single spark, from a downed power line, vehicle, equipment, arson, or other human source, can explode into a major fire within minutes. Firefighting becomes extremely difficult; aerial resources are often grounded, and crews focus on evacuation and protecting structures at the edges until winds ease.โ
โHotโ Santa Ana events (warmer and often longer- lasting) are especially linked to large fires; historically, about 90% of large (>100- acre) Santa Ana- spread wildfires and 95% of the associated burned area occurred during hot events.
Key Statistics and Patterns
Santa Ana wind (SAW) days account for a disproportionate share of destructive fall and winter fires. One analysis found they explain roughly 90% of the area burned by fall and winter wildfires in Southern California since 1950. Another long- term study (1948- 2018) showed SAW- ignited fires responsible for about 45% of total area burned in the region despite comprising fewer overall fire days.โ
Burned area per day is typically 3.5- 4.5 times larger on SAW days than non- SAW days.โ
Critically, ignitions matter more than the winds alone: Over 75% of SAW events produce no fires at all. Nearly 100% of SAW fires are human- caused. In recent decades, power- line failures have become a leading ignition source. Models show the number of ignitions is the strongest predictor of area burned, followed by wind intensity; short-term temperature or antecedent precipitation play smaller roles.โ
Major historical examples include the Laguna Fire (1970), Cedar and Old Fires (2003), Witch Creek Fire (2007), Thomas Fire (2017), Woolsey Fire (2018), and many others that destroyed thousands of structures and caused significant loss of life under strong Santa Ana conditions.
Climate Change Influence
Research indicates climate change is already reducing the frequency of weak- to- moderate Santa Ana events because deserts in the Great Basin are warming faster than the coastal ocean, shrinking the temperature and pressure contrast that drives the winds. By 2100 this could eliminate roughly 1 in 10- 20 events (mostly the milder ones).
However, the strongest, most dangerous fire-weather events show little sign of decreasing, and overall wildfire risk remains high or is increasing due to hotter baseline temperatures, drier fuels, extended fire seasons (now into winter), and greater fuel loads after wet years followed by drought.
Recent Context (October 2026)
The first notable Santa Ana event of the 2026 season (roughly October 15- 17) produced red-flag warnings across much of Los Angeles, Ventura, and surrounding counties, with gusts of 40- 70 and mph (isolated higher), very low humidity, and warm temperatures.
Several wildfires ignited or grew rapidly (including in Malibu, Orange County, and other areas), prompting evacuations, road closures, and public-safety power shutoffs affecting tens or hundreds of thousands of customers. By October 18- 19 the strongest winds had abated, allowing progress on containment, though rain later in the week raised secondary concerns about debris flows on burn scars.
Risk Reduction
Because ignitions are the limiting factor during wind events, utilities use public safety power shutoffs (PSPS), enhanced line inspections, and vegetation clearance around infrastructure. Homeowners and communities reduce risk through defensible space, home-hardening (ember-resistant vents, roofs, etc.), and preparedness plans. Forecasters issue Red Flag Warnings and the Santa Ana Wildfire Threat Index (SAWTI) to highlight the highest-danger periods.โ
In essence, Santa Ana winds turn ordinary sparks into fast- moving, hard- to-control disasters by creating a perfect storm of dry fuels and extreme wind. Reducing human ignitions remains one of the most effective ways to limit losses even as the climate evolves.
Santa Ana winds are forecast primarily by identifying the large- scale weather patterns that produce them and then refining the details with high- resolution models, pressure gradients, and specialized fire- weather tools.
The National Weather Service (NWS) offices in Los Angeles and Oxnard (LOX) and San Diego (SGX), along with Predictive Services and the U.S. Forest Service, lead this process.
Key Meteorological Indicators
Forecasters look for these classic ingredients:
Surface pressure pattern: High pressure (anticyclone) building over the Great Basin (Nevada and Utah deserts) and lower pressure near or off the Southern California coast. This creates an offshore pressure gradient that drives air from the northeast/east toward the ocean. A commonly monitored metric is the pressure difference between stations such as Los Angeles International Airport (LAX) and Daggett (DAG) or similar pairs; differences of about 5 mb or more (often 7- 9 and more mb in stronger events) signal significant Santa Ana potential.โ
Upper- level support: Northeasterly or easterly winds aloft (especially around 850 mb), often enhanced by a ridge of high pressure or an upper- level low positioned to the south/southwest (e.g., near Arizona). Cold- air advection in the lower troposphere over the deserts also strengthens the setup.โ
Terrain channeling: Once the large- scale flow is in place, air accelerates through mountain passes and canyons (Cajon, Santa Ana, Santa Clara River Valley, Banning/San Gorgonio, etc.) due to the venturi effect and downslope warming and drying.
Winds often peak overnight into the early morning as nighttime cooling over the deserts strengthens the pressure gradient.
Specialized Fire- Weather Products
Because the main hazard is wildfire, forecasts integrate fuel conditions:
Santa Ana Wildfire Threat Index (SAWTI): Produced by the USDA Forest Service and Predictive Services. It combines forecast wind speed and atmospheric moisture with dead fuel moisture, live fuel moisture, and the โgreennessโ of annual grasses. The result is a 6- day outlook of large- fire potential rated as No Rating, Marginal, Moderate, High, or Extreme.
Red Flag Warnings and Fire Weather Watches: Issued by the NWS when strong winds, low relative humidity (often single digits to teens), and dry fuels coincide. These highlight critical fire-weather periods.
Wind Advisories and High Wind Warnings: Focused on the wind hazard itself (gusts typically 40- 70 and more mph in favored areas, higher in mountains).
NWS Area Forecast Discussions (AFDs) provide detailed narrative explanations of the expected strength, timing, coverage, temperature/humidity impacts, and confidence levels.
Practical Forecasting Process
Monitor synoptic models for the developing high over the Great Basin and offshore gradients.
Assess upper- level winds and temperature advection.
Run or consult high- resolution and downscaled guidance for local wind speeds and direction.
Layer in fuel moisture data for fire potential (via SAWTI and similar tools).
Issue watches and warnings and update as observations confirm or models adjust the forecast.
Communicate via weather.gov, social media, and coordination with fire agencies and utilities (who may initiate public safety power shutoffs).
Forecast skill is generally good for the occurrence and broad timing of events several days out, though exact peak gust locations and strengths can still vary due to small shifts in the pressure gradient or upper flow. Continuous model improvements and specialized indices like SAWTI have enhanced both wind and fire-risk predictions in recent years.
The third annual State of Wildfires report went up as a discussion preprint in Earth System Science Data on August 3. It covers the fire season from March 2025 through February 2026. By the reportโs own count, global burned area was 18% below the 2002 to 2024 average, and fire carbon emissions were 20 to 31% below average.
The third annual State of Wildfires report went up as a discussion preprint in Earth System Science Data on August 3. It covers the fire season from March 2025 through February 2026. By the reportโs own count, global burned area was 18% below the 2002 to 2024 average, and fire carbon emissions were 20 to 31% below average.
That gets one sentence. The rest of the abstract goes region by region:
In the Midwestern Canadian Shield Forests, the epicentre of Canadaโs anomalous season, we find that anthropogenic climate change has doubled the likelihood of extreme fire weather in this region and made the observed BA around 61 times more likely during JulyโAugust 2025, while BA extent in the region is 46 times greater. Many parts of Europe also experienced record or high-ranking BA and fire C emissions, including in Spain, Portugal, and the UK, and a record USD 4.11 billion of physical assets were exposed to fire across the continent. Direct fatalities occurred in Tรผrkiye (17), Spain (8), Portugal (6), Cyprus (2), Greece (1) and France (1), and evacuations in Tรผrkiye, Spain, and Greece totalled over 110,000. In the Northwest Iberian Peninsula, we find that extreme fire weather over August 2025 was around 3 times more likely due to climate change. Under a high-emissions scenario (SSP3-7.0), fires of the same return interval are likely to burn about 78 % more area by the end of the century, with some projections within the same scenario suggesting increases of around sevenfold. In Chile and northwest Argentina, JanuaryโFebruary 2026 fires caused 23 fatalities, displaced 55,000 people and threatened a UNESCO World Heritage Site. In the Chilean Temperate Forests and Matorral, the epicentre, we find that BA was around 36 % larger due to anthropogenic climate change.
A below average year could be luck. So I went to the satellite record. NASAโs MODIS burned area product, MCD64A1, maps burn scars from the Terra and Aqua satellites every month at 500 meter resolution. The University of Maryland fire group, which produces it, also distributes a quarter degree version for climate work, MCD64CMQ, with the burned hectares already summed into each grid cell. I added up every month from January 2001 through December 2023, the last full year in the files.
Global area burned each year, 2001 to 2023. NASA MODIS MCD64CMQ.
The five years 2003 through 2007 averaged 450 million hectares burned. The five years 2019 through 2023 averaged 353 million. The fitted trend from 2003, when both satellites were flying, is a loss of about 1.5% per year, and it is not marginal: the odds of a trend like that turning up by chance are less than one in ten thousand. 2023, the year of Canadaโs record-breaking fire season, comes in 14th of 23 globally. The lowest year in the record is 2022.
None of this is a discovery. In 2017 Niels Andela and colleagues, using the same MODIS product along with the GFED4s database, reported in Science that โglobal burned area declined by 24.3 ยฑ 8.8% over the past 18 years.โ They traced most of it to farming, as agriculture spread into savannas and grasslands that used to burn. They also found that fire models could not reproduce the size or pattern of the decline, and suggested the models may overestimate fire emissions in future projections. At the time, MODIS alone gave them โ1.15% per year for 2003 to 2015, significant only at the 90% level. Eight more years of data have taken care of that.
MODIS at 500 meters misses a lot of small fires, so in 2023 the GFED team rebuilt the record. Chen et al. corrected MCD64A1 against Landsat and Sentinel-2 imagery, which see small burns MODIS doesnโt, and their total came out 93% higher. The decline survived.
From the abstract:
The global annual burned area during 2001โ2020 is estimated to be 774 ยฑ 63 Mha yrโ1 or 5.9 ยฑ 0.5 % of ice-free land. Burned area declined by 1.21 ยฑ 0.66 % yrโ1, a cumulative decrease of 24.2 ยฑ 13.2 % over 20 years. โฆ The global reduction is primarily driven by a decrease in fires in savannas, grasslands, and croplands. โฆ Forest, peat, and deforestation fires did not exhibit significant long-term trends.
So the raw satellite product, the Science paper and the corrected database all point the same way. About a quarter less land burns each year than at the start of the century.
The usual answer is that the decline is African grassland and doesnโt count. Africa is most of it. But I split the totals with a rough box around the continent, and the rest of the world is falling at about the same rate.
Burned area in a box around Africa and everywhere else, 2001 to 2023. NASA MODIS MCD64CMQ.
The right panel is noisier, and the trend there is weaker statistically, but it is down, not up. North of 50ยฐN, where the boreal forests are, the series jumps around with no significant trend in either direction. Its biggest year is still 2003.
The field has a response to all this. In June 2024 Calum Cunningham of the University of Tasmania and colleagues took roughly 30 million fires, kept the 2,913 most energetic, and found that these extreme events increased 2.2-fold from 2003 to 2023. Cunningham told the Washington Post the work began as a response to skeptics who asked how there could be a growing fire crisis while the area burned was shrinking. The increases are real and concentrated in temperate conifer and boreal forests. But the measure is about one fire in ten thousand, on a record that starts in 2003, and by Natureโs own account the study does not directly connect the trend to global warming.
Continued climate change is expected to intensify these hydroclimatic extremes, yet mitigation has already reduced projected end-of-century wildfire risk: under a high-end emissions pathway (SSP3-7.0), the extreme BA events in our focal regions are projected to be 4โ23 % smaller than they would have been under a worst-case emissions scenario no longer considered credible (SSP5-8.5).emphasis added
SSP5-8.5 was never the road we were on. Zeke Hausfather and Glen Peters pointed out in Nature in 2020 that it requires โan unprecedented fivefold increase in coal use by the end of the century,โ and that global coal use peaked in 2013.
There was nothing to mitigate.
Global burned area was 18% below average this past season and has been falling for two decades. Why is that one sentence?
If the fire models could not reproduce the decline in 2017, how much weight do their end-of-century projections carry now?
Burned area data: NASA MODIS MCD64CMQ Collection 6.1, monthly 0.25ยฐ burned area, January 2001 to December 2023, from the University of Maryland fire group (fuoco.geog.umd.edu). Annual totals are sums of the monthly BurnedArea field. โAfricaโ is the box 36ยฐS to 38ยฐN, 18ยฐW to 52ยฐE.
Yeah, whether the current (2026) El Niรฑo ranks as a record depends on the metric, region, and baseline used by different agencies.
The Relative Oceanic Niรฑo Index (RONI) is NOAAโs Climate Prediction Center (CPC) primary metric for monitoring and classifying El Niรฑo and La Niรฑa events, adopted officially in February 2026.
It improves on the traditional Oceanic Niรฑo Index (ONI) by better accounting for background tropical ocean warming due to climate change.
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Yeah, whether the current (2026) El Niรฑo ranks as a record depends on the metric, region, and baseline used by different agencies.
Britainโs Met Office has described this yearโs event as โunprecedentedโ, citing absolute (raw) sea- surface temperatures in the central equatorial Pacific that have surpassed levels from previous El Niรฑos.
Japanโs Meteorological Agency (JMA) declared it the strongest on record. In September 2026, the sea-surface temperature anomaly in the Niรฑo 3 region (eastern Pacific) reached +4.0ยฐC, exceeding the previous high of +3.6ยฐC from December 1997 (records back to 1949). JMA states the strongest conditions are virtually certain to continue into boreal winter.
U.S. NOAA (which primarily monitors the neighboring Niรฑo 3.4 region in the east- central Pacific) has not yet called it the outright record in its books.
It defines El Niรฑo via temperatures at least 0.5ยฐC above normal plus atmospheric coupling (e.g., weakened trade winds and shifted rainfall). Due to accelerating climate change and widespread ocean warming, NOAA now emphasizes the Relative Oceanic Niรฑo Index (RONI). RONI uses a 30- year baseline but measures how warm the east- central Pacific is relative to the rest of the tropical oceans, because that contrast better drives the weather impacts of interest.
NOAA projects a high chance (about 83% for the October- December 2026 average) that the three- month RONI anomaly will reach +2.5ยฐC or higher. That threshold would make it the strongest in NOAAโs records (back to 1950), surpassing the major events of 1982- 83, 1997- 98, and 2015- 16.
As of early October discussions, it was strengthening, with recent Niรฑo-region anomalies already very high (e.g., conventional weekly Niรฑo 3.4 readings around +3ยฐC or more in some reports).
Why the rankings differ
Regions: JMA focuses on Niรฑo 3 (farther east); NOAA on Niรฑo 3.4 (east- central).
Absolute temperatures vs. anomalies: Raw warmth can set records more easily in a warming climate; anomalies measure departure from a baseline.
Traditional vs. relative indices: Older Oceanic Niรฑo Index (ONI) approaches have been adjusted or supplemented by RONI (and similar relative measures used by other agencies) to better isolate the ENSO signal from background tropical warming. This can change how strong past and present events appear relative to one another.
Climate scientist Emily Becker of the University of Miami noted that by any measure it is a very strong El Niรฑo; only after it ends will its full ranking in historical context become clear. It remains an important opportunity to study a powerful event amid ongoing global warming.โ
In short, Japan and the UK are already treating aspects of it as record or unprecedented, while NOAA sees a strong- to- very- strong event with a high (but not yet locked- in) probability of setting a RONI- based record.
AI generated by Grok
The Relative Oceanic Niรฑo Index (RONI) is NOAAโs Climate Prediction Center (CPC) primary metric for monitoring and classifying El Niรฑo and La Niรฑa events, adopted officially in February 2026.
It improves on the traditional Oceanic Niรฑo Index (ONI) by better accounting for background tropical ocean warming due to climate change.
Why RONI Was Introduced
Traditional ONI measures sea- surface temperature (SST) anomalies in the Niรฑo 3.4 region relative to a fixed (but periodically updated) 30- year climatology. In a warming climate, this baseline lags, which can distort classifications,especially in real time,and weaken the link between the index and actual atmospheric impacts (e.g., rainfall shifts and teleconnections).
RONI addresses this by focusing on the relative warmth or coolness of the Niรฑo 3.4 region compared to the broader tropics, which better captures the ocean-atmosphere contrast that drives ENSO effects.
How RONI Is Calculated
Start with the Niรฑo 3.4 anomaly: Compute the monthly SST anomaly in the Niรฑo 3.4 region (5ยฐN-5ยฐS, 120ยฐ- 170ยฐW), relative to a 30- year base period (currently 1991- 2020 in many operational products; the base period follows WMO standards and is updated periodically). This is the same starting point as the traditional ONI. Data typically come from Extended Reconstructed SST (ERSST) versions (v5 or v6).โ
Subtract the tropical- mean anomaly: Subtract the average SST anomaly over the entire global tropics (20ยฐSโ20ยฐN) for the same period. This removes the broad-scale tropical warming signal, isolating the Pacificโs relative anomaly.โ
Apply a scaling (rescaling) factor: Multiply the difference by a factor so that the overall variance (standard deviation) of the relative index matches that of the traditional Niรฑo 3.4/ONI series. The scaling is often computed separately by calendar month or season (largest in March- May, smallest in July- August) using a historical reference period (e.g., 1950- 2020). The formula is approximately:โโwhere ฯ denotes the standard deviation.
Form the seasonal index: RONI is the three- month running mean (overlapping seasons: DJF, JFM, FMA, etc.) of the relative Niรฑo 3.4 values.
Classification Rules (Unchanged from ONI)
El Niรฑo: RONI โฅ +0.5ยฐC.
La Niรฑa: RONI โค โ0.5ยฐC.
Neutral: between โ0.5ยฐC and +0.5ยฐC.
A full โepisodeโ requires the threshold to be met for at least five consecutive overlapping three- month seasons. Strength categories (weak, moderate, strong, very strong) follow similar incremental thresholds (e.g., โฅ +2.0ยฐC often considered very strong/historic in forecasts).
Key Advantages and Effects
Reduced sensitivity to base period: Classifications of past events are more stable across different climatologies and less affected by the long- term warming trend.
Better physical relevance: More closely tied to the relative SST gradients that influence atmospheric circulation, rainfall, and teleconnections (e.g., sharper relationships with precipitation and upper- level heights over places like Australia and the U.S.).
Real- time reliability: Less lag from updating climatologies.
Impacts on historical record: Some events are reclassified (e.g., certain weak El Niรฑos disappear or weaken; some La Niรฑas strengthen or become continuous; the 2023- 24 El Niรฑo often appears moderate rather than strong under RONI). Overall variance is preserved by the scaling, so extremes are not systematically damped or amplified across the whole record.
RONI is based on work by van Oldenborgh et al. (2021) and formalized/extended for operational use by LโHeureux et al. (2024) in the Journal of Climate. NOAA maintains both RONI and traditional ONI data for continuity, with RONI now primary for advisories and forecasts. Official values and historical tables are available on the CPC website (updated monthly, with recent values potentially provisional due to data filtering).
In short, RONI keeps the familiar structure and thresholds of ONI while measuring the ENSO- relevant contrast rather than absolute regional anomalies, making it more robust in a warming world.
It’s a response to the Telegraph headline Wednesday: ‘Next financial crisis “to be triggered by uninsurable homes”‘ , warning that climate change is making British homes uninsurable, mortgages unobtainable, and properties unsellable, in a repeat of 2008.
Homes are covered by Flood Re. Businesses are not. And Tenbury’s problem is old: the Audit Commission flagged lack of flood defences in 2009, and the Environment Agency has now put the full scheme on hold.
Many scary numbers rely on RCP8.5, the implausible high-emissions pathway. Scientists behind the next IPCC scenarios have now dropped RCP8.5, SSP5-8.5 and SSP3-7.0 as “implausible”.
โIf it bleeds, it leadsโ is the oldest rule in the newsroom. Its climate-era corollary is that if it floods, burns or sinks, it sells. Wednesdayโs Telegraph ran the headline โNext financial crisis โto be triggered by uninsurable homesโโ, warning that climate change is making British homes harder or even impossible to insure, that mortgages will become unobtainable and that properties will become unsellable. Readers are reminded that the undermining of the mortgage market drove the 2008 crash, and informed that a wave of uninsured, high-risk homes could do the same.
There is no surer way to unsettle a reader than to tell him that his home, almost always a familyโs largest asset, is about to become worthless. That is precisely the point. For 15 years the climate story has been sold as โthe scienceโ that threatens the readerโs own front door: your house will burn (โglobal warmingโ), your street will flood (โrising sea levelsโ), your foundations will crack with land subsidence. In May 2013 Barack Obamaโs Twitter account told its 31 million followers that 97% of scientists agreed climate change was โreal, man-made and dangerousโ. The study behind the tweet said nothing about danger; that word was added by Obamaโs team. โReal, man-made and dangerousโ has nonetheless been the house style of the legacy media ever since, and the uninsurable home is simply its latest product line.
Whistleblowers, or a campaign?
The Telegraph describes its sources as senior City figures represented by โa whistleblowing organisation called Inside Trackโ, which has written to Ministers, the Financial Conduct Authority and the Bank of England claiming that insurers are under-pricing climate risk. The paper adds, almost in passing, that the group is backed by climate charities including the Esmรฉe Fairbairn Foundation, one of Britainโs largest grant-makers, whose 2020 strategy explicitly targets โthe causes and impacts of climate changeโ.
Inside Track Campaigns Ltd was incorporated in March 2025 as a company limited by guarantee whose registered business is public relations and communications. Its first accounts are not due until December, so the public cannot yet see who pays for it; its own FAQ says only that it has been funded by trusts and foundations. Nor does it deal in leaked documents, the stock-in-trade of genuine whistleblowers. Its website says plainly that it is not looking for confidential documents. It recruits anonymous senior professionals, collects their views on common industry practice, and then advises on which stakeholders should hear the message and how best to deliver it. That is a description of an advocacy campaign, as my colleague Paul Homewood describes. The template has been used before: an Inside Track group of food-industry executives issued a similar memo warning of climate risk to Britainโs food supply.
The anonymous insidersโ own words undercut the alarm. One former reinsurance executive complains that the industry does not care about climate risk more than a year ahead because it can โkeep repricing coverโ. That is not a scandal; it is how property insurance works. As Warren Buffett told Berkshire Hathaway shareholders in his 2015 letter, policies are written for a year and repriced annually, so a rising possibility of loss shows up promptly in premiums rather than in insolvency. An insurer that reprices every year is not quietly accumulating a 2008-style time bomb on its balance sheet.
The 2008 analogy fares no better. Stanford economist John Cochrane put it plainly in his testimony to the US Senate Banking Committee in March 2021: โClimate change poses no measurable risk to the financial system.โ As he explained, โโRiskโ means unforeseen events. We know exactly where the climate is going over the horizon that financial regulation can contemplate.โ The financial crisis was a sudden, unforeseen collapse in the value of leveraged mortgage securities; a slow, observable drift in weather statistics, repriced every year, is its opposite. Cochrane also warned that climate goals were being pursued through financial regulators โby regulatory subterfuge rather than aboveboard legislation or transparent agency rulemakingโ. A memo campaign aimed at the Bank of England and the FCA, rather than at voters, fits that description well. I made the same arguments last month about Brusselsโs plans for an EU-backed โclimate insuranceโ pool โ a climate protection racket as it were โ the very model the Telegraph now commends to Britain.
The โuninsurable townโ that isnโt about homes
The articleโs lead photograph shows flood water in Tenbury Wells, Worcestershire, โdubbed Britainโs first โuninsurable townโโ. But the Tenbury story is not about homes, and it is not new. What lost cover there were the town councilโs civic buildings and local businesses: Zurich withdrew flood cover from the Pump Rooms and the Regal Cinema in October 2025. Homes are a different matter. As the local MP Dame Harriett Baldwin pointed out to the Treasury Committee, the Flood Re scheme exists to help homeowners in flood-prone areas get insurance; what it does not cover is businesses.
Nor is the cause a sudden shift in the climate. As long ago as 2009 the Audit Commission flagged the lack of progress on Tenburyโs flood defences as one of only two red flags for Worcestershire, noting that some businesses already could not get insurance and that the national funding formula ranked the scheme low. Seventeen years later the Environment Agency has put the full scheme on hold. Tenbury is a monument to unbuilt flood defences, not to a broken climate. Even the Telegraph concedes that โscrapped flood defence investmentโ played its part.
Flood Re itself shows how the system is meant to work. Homes built after January 1st 2009 are excluded from the scheme, a cut-off designed to discourage developers from building on flood-prone land; owners of such homes buy cover at whatever price the risk commands. That is the price signal doing its job. Even the Association of British Insurers, quoted by the Telegraph, asks only for the obvious: more investment in flood defences, an end to building on flood plains and better building standards. None of that requires a climate emergency. It requires engineers, planners and premiums that are allowed to tell the truth.
Fifteen years of RCP8.5
Behind many of the headlines lies a single scenario. The high-emissions pathway known as RCP8.5 with projected catastrophic outcomes, and for over a decade journalists and regulators treated it as โbusiness as usualโ. As early as 2020, Zeke Hausfather and Glen Peters warned in Nature that this framing was misleading. In April this year the scientists who design the scenarios feeding the IPCCโs next assessment went further, declaring the old high-end emission levels โimplausibleโ and dropping RCP8.5, SSP5-8.5 and SSP3-7.0 from the new framework. Even the European Commissionโs climate website now concedes that RCP8.5 is no longer considered plausible.
Yet the numbers built on these scenarios live on in the property pages. The Telegraph tells readers that one in 10 homes could be affected by subsidence by 2070. That figure matches the British Geological Surveyโs projection under RCP8.5: 11%, or 4.2 million properties. Under RCP4.5, the pathway the BGS itself says current emissions are closest to, the share is around 5%; under the Paris-aligned scenario, about 500,000 properties. The BGSโs earlier, widely cited subsidence maps used RCP8.5 alone. The scariest number, as ever, is the one that reaches the reader.
The Telegraphโs August data feature on climate threats to homes, which the paper recommends at the foot of this weekโs article, follows the same formula. Its interactive map finds that fewer than one in 20 British properties is spared high exposure to at least one of five threats: drought, heat, wildfires, flooding and coastal erosion. A measure that captures 95% of the country tells you about the threshold, not the risk. Read further and the threats shrink. Some 10,000 properties are at risk from coastal erosion over the next 80 years, out of a national stock of tens of millions. Wildfires, the article concedes, are mostly started by human hands, from barbecues and campfires to discarded cigarettes โ a point I made about Britainโs wildfires this summer.
What the loss data actually show
The insurance figures are presented in the same way. The Telegraphโs chart shows domestic claims for subsidence and weather damage rising from about ยฃ437 million in 2021 to just over ยฃ1 billion in 2025. That is five years of raw totals in nominal pounds, with no adjustment for inflation in repair and rebuilding costs or for the growing number and value of insured homes. A short window of unadjusted claims is not a climate signal.
The longer, global record tells a different story. Roger Pielke Jrโs analysis of Munich Re data shows that total economic losses from weather and climate disasters have fallen as a share of world GDP, from about 0.25% in 1990 to under 0.2%. Insured losses do grow, by 5-7% a year in real terms according to Swiss Re, but the reinsurer names the main driver as rising exposure: economic and population growth, building in hazard-prone areas and construction-cost inflation. Nor is the market buckling. Swiss Reโs sigma report says reinsurers can absorb even a one-in-10 peak year of $300 billion or more in insured losses.
Swiss Reโs own press release makes the point with Hurricane Katrina. A repeat today would still be very costly because of higher housing and construction costs, but improved flood defences and a 20% fall in the local population along the stormโs path have significantly reduced exposure. Adaptation works. That is the lesson of Tenbury too.
Swiss Reโs Chief Executive Andreas Berger tells a different story when he goes on television. In a CNN interview last summer, against footage of European wildfires, he declared that the frequency and severity of natural catastrophes are increasing, that conventional measures are no longer sufficient, and that governments, the public and industry must โcome togetherโ in a tripartite arrangement. His host opened with the firmโs claim that around 480,000 people a year die from extreme heat. Those are modelled mortality estimates, not insured losses, and say nothing about whether a home in Kent can be insured. A reinsurer whose business grows with perceived risk has every reason to talk the risk up on CNN while its research department attributes the rising bill to exposure. Readers may weigh the two accordingly. Of course, it does not occur to Berger to mention cheap air-conditioners as an appropriate mitigation option for households in summer heat.
Who benefits from fear?
If the facts are this thin, why the drumbeat? Partly because fear is the product. A postcode map of personal peril, published in the money pages, travels further than a chart of losses relative to GDP. As we found during Covid, fear has avid customers. Every โprotection gapโ story strengthens the case for a public-private scheme in which taxpayers backstop risks that premiums ought to price: a bigger and longer-lived Flood Re, the EUโs new โclimate insurance allianceโ that the Telegraph holds up as a model, or the EU-backed catastrophe protection racket I criticised last month. It strengthens the hand of central bankers who have doubled down on climate regulation even as green finance collapses. And it sustains a foundation-funded campaign ecosystem that turns anonymous testimony into memos to ministers and government regulatory authorities such as the FCA.
There is a final irony. The industryโs real failing, according to Inside Trackโs insiders, is that it has gone quiet: fewer people, one complains, are now prepared to stand up and say they are scared by what they are seeing. In the climate debate, fear is no longer a by-product of the evidence; it has become the evidence. As I argued in a recent piece on the so-called Planetary Health Check, doom never goes out of fashion.
The homeowner in Worcestershire or Kent deserves better than a map telling him that his house sits beneath five climate threats at once. He deserves flood defences that are actually built, planning rules that stop new estates going up on flood plains, and insurance priced honestly, year by year, as it always has been. The Telegraphโs readers were offered a financial crisis in their homeownership instead. Fear sells, but the scenario on which 15 years of it were built has now been retired. As with Covid, so with climate: sooner or later, truth will out. Franklin Delano Rooseveltโs first inaugural speech, delivered in March 1933 on the East Portico of the US Capitol at Washington DC, was called โThe Only Thing We Have to Fear is Fear Itselfโ. Truer words have seldom been spoken.
Dr Tilak K. Doshi is the Daily Scepticโs Energy Editor. He is an economist, a member of the CO2 Coalition and a former (cancelled) contributor to Forbes. Follow him onSubstackandX.
New research from White Sands National Park in New Mexico shows that early humans were present during the Last Glacial Maximum (roughly 23,500- 21,700 years ago) and lived through repeated, rapid climate shifts, including drought and major landscape changes.
Dansgaard- Oeschger (D-O) events are abrupt, large- scale climate oscillations that occurred repeatedly during the last glacial period (roughly the past 120,000- 11,000 years). They are named after Danish geophysicist Willi Dansgaard and Swiss geophysicist Hans Oeschger, who identified them in Greenland ice-core records.
D -O event 2 (also called Greenland Interstadial 2 or GI- 2) is one of the later events in the sequence. It began around 23.3- 23.2 thousand years ago (ka), during the Last Glacial Maximum (the coldest phase of the last ice age, ~26.5- 19/20 ka).
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New research from White Sands National Park in New Mexico shows that early humans were present during the Last Glacial Maximum (roughly 23,500- 21,700 years ago) and lived through repeated, rapid climate shifts, including drought and major landscape changes.
The findings come from an October 2026 Science Advances paper (and a related popular article by co-authors Matthew Robert Bennett and Sally Christine Reynolds in The Conversation). Expanded excavations identified 20 distinct sediment layers (horizons) containing human footprints, spanning nearly 2,000 years at the height of the last ice age. This builds on earlier (2021 and later) dating of the famous White Sands footprints that placed people in North America thousands of years earlier than many traditional models allowed.
Environmental reconstruction
Sediments, pollen, and plant- leaf waxes (biomarkers) reveal a dynamic setting quite unlike todayโs desert:
Early in the record, a large perennial lake (Lake Otero) filled much of the basin. Nearby mountains held conifer forests, and average temperatures were about 4ยฐC colder than today.
From around 23,600 years ago the lake began shrinking as temperatures rose. Conifers declined and were replaced by oak and sagebrush steppe; the basin grew drier due to higher evaporation.
Around 23,200 years ago a short but severe drought struck: rainfall dropped, the lake became more saline, and drought- tolerant plants expanded. This local aridification matched a rapid Northern Hemisphere climate shift (Dansgaard- Oeschger event 2) recorded in Greenland ice cores.
People were present during these transitions, the earliest expanded footprint horizons appear around the drought/climate shift, and tracks continue at intervals as the lake retreated.
Interpreting the footprint record
The authors caution against over- interpreting the pattern.
An agent- based computer model of people moving around a fluctuating lake showed that preservation is highly selective: footprints survive mainly when mud is exposed (e.g., during drying) and then quickly buried by rising water or sediment.
As a result:
Footprint- rich surfaces tend to cluster around climatic and hydrological transitions (exactly the pattern seen at White Sands).
Gaps between layers do not prove people were absent, and dense tracks do not necessarily mean a population boom, a few people crossing soft mud repeatedly can leave many prints.
The record therefore interleaves a human history (repeated use of the landscape amid changing conditions) with a geological filter that preserved only certain moments.โ
In short, the study strengthens evidence that humans occupied the southern United States during the peak of the ice age and demonstrates they experienced abrupt, noticeable environmental change (lake recession, vegetation turnover, centennial- scale wet, dry swings) over roughly two millennia. It does not claim people only appeared during droughts, but shows they were resilient in a rapidly shifting world.
Footprints found at White Sands, New Mexico, were dated to the height of the last ice age. Credit: National Park Service
Dansgaard- Oeschger (D-O) events are abrupt, large- scale climate oscillations that occurred repeatedly during the last glacial period (roughly the past 120,000- 11,000 years). They are named after Danish geophysicist Willi Dansgaard and Swiss geophysicist Hans Oeschger, who identified them in Greenland ice-core records.
General characteristics
Each D- O event typically features:
A very rapid warming phase (over decades, sometimes just a few years to decades) in the North Atlantic region, especially Greenland. Temperatures there could rise by 5- 15 ยฐC (9- 27 ยฐF), roughly half the full glacial- to- interglacial difference.
This is followed by a more gradual cooling over centuries to millennia, often ending with a sharper drop back into cold (stadial) conditions.
These produce a characteristic โsawtoothโ pattern in temperature proxies (especially oxygen isotope ratios, ฮดยนโธO) from Greenland ice cores. About 25 such events are recognized over the last glacial cycle; roughly 13 well- dated ones fall between ~45,000 and 11,600 years ago, with an average spacing near 1,470 years (though exact regularity is debated).
They are most strongly expressed around the North Atlantic but have global or hemispheric effects, appearing in records from Europe, Asia, the Americas, and the Southern Hemisphere (often with some lag or opposite polarity via ocean and atmospheric teleconnections).
Causes
The precise triggers remain uncertain, but the leading explanation involves shifts in the Atlantic Meridional Overturning Circulation (AMOC), the large- scale ocean current system that transports heat northward.
Weakened AMOC (linked to expanded sea ice, freshwater input from melting ice, or other factors) produces cold stadials; a sudden reinvigoration produces the abrupt warmings. Sea- ice extent in the North Atlantic, atmospheric circulation changes, and possible external pacing (e.g., solar or orbital influences) are also implicated. Exact mechanisms are still actively researched.
Dansgaard- Oeschger event 2 specifically
D -O event 2 (also called Greenland Interstadial 2 or GI- 2) is one of the later events in the sequence. It began around 23.3- 23.2 thousand years ago (ka), during the Last Glacial Maximum (the coldest phase of the last ice age, ~26.5- 19/20 ka).
In Greenland ice cores (on the GICC05 timescale), it marks a relatively short interstadial warming. Recent high-resolution work, including from White Sands National Park in New Mexico, places its peak or expression at approximately 23.2 ยฑ 0.3 ka.
At White Sands, this interval coincided with a short but severe regional drought: reduced rainfall, increased lake salinity in ancient Lake Otero, expansion of drought- tolerant vegetation, and shrinkage of the lake that exposed shoreline areas. This local aridification is interpreted as a teleconnected response to the broader Northern Hemisphere climate shift associated with D- O 2.
D- O 2 is notable because it occurred deep within the Last Glacial Maximum, when large ice sheets still dominated the Northern Hemisphere, yet it still produced detectable, rapid environmental changes far from Greenland, including in the American Southwest.
In short, D- O events illustrate that even during full glacial conditions the climate system could flip rapidly between cold and warmer states on human- relevant timescales, driven largely by ocean- atmosphere interactions centered on the North Atlantic. Event 2 is a specific instance of this behavior dated to ~23.2 ka.
Reconstruction of life at White Sands at the height of the last ice age. Credit: Davide Bonadonna, Bournemouth University
Dansgaard- Oeschger (D- O) events, including event 2 (~23.2 ka), produced rapid, widespread climate impacts far beyond Greenland and the North Atlantic, though the strongest signals occurred in the Northern Hemisphere.
These effects arose mainly from changes in the Atlantic Meridional Overturning Circulation (AMOC), shifts in atmospheric circulation (including the Intertropical Convergence Zone, or ITCZ, and storm tracks), and interhemispheric heat redistribution via the bipolar seesaw.
Northern Hemisphere
Europe and western Mediterranean: Interstadial (warm) phases brought warmer and wetter conditions. Vegetation expanded (more temperate forests or woodland), and lake levels or precipitation proxies often rose. Stadials were colder and drier. Temperature swings were smaller than in Greenland but still significant (several degrees).
Eurasia (including central and eastern Europe, western Asia): Largest land- based warming during interstadials occurred here according to pollen- based reconstructions. Winters warmed more than summers, reducing seasonality. Moisture responses varied but often included wetter conditions in many areas.
East Asia and Asian monsoon regions: Northern Hemisphere summer monsoons typically strengthened during interstadials (more rainfall in China and surrounding areas, recorded in speleothem ฮดยนโธO). Southern Hemisphere monsoons weakened in a seesaw pattern.
North America: Patterns were spatially complex. Eastern or more continental areas often warmed and sometimes became wetter during interstadials. Western North America (including the Southwest) frequently showed cooling or increased aridity in some reconstructions. For D- O event 2 specifically, multiproxy evidence from White Sands (New Mexico) and other southwestern U.S. sites records a short but severe aridification: reduced rainfall, higher lake salinity, recession of Lake Otero, and a shift toward drought- tolerant vegetation (conifer forest giving way to sagebrush/oak steppe). This matched the Greenland timing of D- O 2 and allowed humans and megafauna to traverse newly exposed lake margins.โ
Tropics and low latitudes
The ITCZ shifted northward during Northern Hemisphere interstadials. This increased rainfall in northern tropical regions (e.g., Caribbean, northern South America, parts of Africa and Asia) and decreased it in southern tropical areas. Speleothem and lake records across the tropics consistently show these hydroclimate flips, often with little lag relative to Greenland.
Southern Hemisphere
Antarctica and Southern Ocean: Temperature changes were typically out of phase with Greenland (the bipolar seesaw). Antarctic warming (Antarctic Isotope Maximum events) often led or lagged Greenland warmings by centuries, driven mainly by slower oceanic heat transport changes. Atmospheric teleconnections were faster: mid- latitude storm tracks and westerly winds shifted within decades of North Atlantic changes, altering moisture sources for Antarctic precipitation (seen in deuterium- excess records).
Southern extratropics more broadly often cooled or showed muted/opposite responses relative to northern warming.
Spatial and temporal patterns
Impacts diminished with distance from the North Atlantic but remained detectable globally. Warming was strongest in northern extratropics (especially Eurasia), with antiphasing between northern and southern extratropics.
In North America a west- east contrast (cooling and aridity in the west, warming farther east) appears in some pollen syntheses. Moisture (precipitation) changes did not always mirror temperature changes and were regionally specific. Most teleconnections outside the high southern latitudes operated rapidly (decades or less) via the atmosphere; oceanic links to Antarctica were slower (centuries).
These patterns hold across multiple D- O events, including weaker ones like event 2 during the Last Glacial Maximum, although signal strength and coherence are greatest for the larger events. Proxy records (ice cores, speleothems, pollen, marine sediments, lake levels) and climate models consistently support this global reorganization of atmospheric and oceanic circulation.
Map of early archaeological sites in North America. Credit: The Conversation
Humans experienced abrupt environmental changes at White Sands during the Last Glacial Maximum
Key findings
Expanded excavations at White Sands National Park (WHSA) Locality 2 (Tularosa Basin, New Mexico) uncovered 20 stratigraphic horizons containing in situ human footprints, megafaunal trackways (mammoth/Proboscidea, ground sloth, canids, possible ursids, rare birds), and linear features interpreted as travois (drag marks from poles used to transport resources).
Refined chronology (using improved radiocarbon dating of conifer pollen and aquatic Ruppia seeds, plus supporting OSL ages):
Footprint- bearing sequence spans 23.5 to 21.7 thousand years ago (ka).
Firmly within the Last Glacial Maximum (LGM).
Paleoenvironmental reconstruction (pollen, leaf- wax biomarkers and hydrogen isotopes, stratigraphy):
The setting began as a shallow perennial lake (pluvial Lake Otero) with surrounding conifer forests and cooler temperatures.
It underwent a complete environmental overturn to a lake- margin and wet- playa system.
A major aridification episode at ~23.2 ka coincided with Dansgaard- Oeschger event 2 (a rapid Northern Hemisphere climate oscillation recorded in Greenland ice cores). Rainfall declined, the lake shrank and became more saline, and vegetation shifted toward drought- tolerant sagebrush and oak steppe.
Centennial- scale swings in hydroclimate continued afterward.
Lake recession during the aridification exposed shoreline areas that humans and megafauna repeatedly traversed for nearly two millennia.
This provides a high-resolution terrestrial record showing that early humans in North America experienced marked, abrupt environmental changes (including severe drought) during the height of the last ice age. The earliest track horizons occur around the D- O 2 transition.
The paper strengthens the LGM age of the White Sands footprints (previously debated) and demonstrates human presence and activity (including possible resource transport with travois) amid a dynamic glacial climate.
Journal:Science Advances, 14 October 2026, Vol. 12, Issue 42, eaeh0707
Authors: Kathleen B. Springer, Jeffrey S. Pigati, Jessica E. Tierney, et al. (including Sally C. Reynolds and Matthew R. Bennett)
Abstract
Expanded excavations at White Sands National Park have unearthed 20 stratigraphic horizons containing in situ human footprints, megafaunal trackways, and linear features created by travois. Advances in radiocarbon dating of conifer pollen, combined with ages of aquatic seeds, refines the chronology of the footprint-bearing sequence to between 23.5 and 21.7 thousand years ago (ka). Biomarker, pollen, and stratigraphic evidence indicate a complete overturning of the environment from a perennial lake to a playa and capture a large aridification episode coincident with Dansgaard-Oeschger event 2 at 23.2 ka, which shrank pluvial Lake Otero and allowed people to traverse the former shoreline area for nearly two millennia. This well-dated and highly resolved paleoclimate record provides compelling evidence that humans in North America experienced marked environmental changes during the Last Glacial Maximum.
People repeatedly crossed this landscape for almost two millennia while the regional climate swung between wetter and exceptionally dry conditions. Credit: National Park Service
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