In brief:

  • Scientists expect dramatic swings between active and inactive hurricane seasons in the future.
  • The risk of back-to-back hurricanes is growing. 
  • Hurricanes are expected to get more damaging and deadly. 

Wild year-to-year swings — from punishing hyperactive seasons to quiet years with little activity — could well become the norm for future Atlantic hurricane seasons, according to recent climate change research. 

The latest science paints a complex but alarming future, as the unprecedented amount of heat that humans are supplying to the climate system disrupts the fundamental atmospheric circulation pattern in which we designed our civilization. 

During the coming busy seasons, death and destruction from unprecedented hurricane catastrophes will probably grow much more commonplace, because even as risks grow, people have continued to build in risky flood-prone regions. But eventually, the coming hurricane catastrophes will pose an increasing threat to the viability of living in many coastal areas, particularly in the Caribbean.

Hurricane seasons will likely grow more erratic

The year-to-year variability of Atlantic basin hurricane activity already is the largest of any of the globe’s tropical cyclone basins. And climate change will make extreme swings between active and inactive hurricane seasons the norm, according to a 2024 paper, Projected increase in the frequency of extremely active Atlantic hurricane seasons. 

The high-resolution climate models used in the study projected a 36% increase by 2050 in the variance of Atlantic tropical cyclone activity. The main causes: an increase in the variability of wind shear (strong upper-level winds that tend to tear a storm apart), and major swings in how stable the atmosphere is in the tropical Atlantic. One good thing is that the study found that the increased activity during hyperactive seasons would be focused farther from land over the eastern and central Atlantic, with less activity over the Caribbean.

A 2022 study, Extreme Atlantic hurricane seasons made twice as likely by ocean warming, found that ocean warming from 1982 to 2020 doubled the probability of extremely active hurricane seasons over that time period. However, the authors did not clearly separate out how much of that change resulted from increased heat-trapping greenhouse gases and how much was caused by a reduction in planet-cooling air pollution particles called aerosols. These particles are not likely to change much in the future, while greenhouse gases will be increasing, so it is important to know their relative impacts on ocean warming.

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On the death of RCP8.5

Posted on 26 May 2026 by Zeke Hausfather

This is a re-post from The Climate Brink by Zeke Hausfather, Glen Peters, and Piers Forster

With the release of the new van Vuuren et al 2026 paper on the emissions scenarios that will be used in the upcoming IPCC 7th Assessment Report, the internet has been abuzz with debate over the implications of the formal retirement of the RCP8.5/SSP5-8.5 scenario. The president of the United States even weighed in over the weekend in his own unique style, posting that “the United Nations TOP Climate Committee just admitted that its own projections (RCP8.5) were WRONG! WRONG! WRONG!”.

van Vuuren et al justify this move by noting that “the CMIP6 high emission levels (quantified by SSP5-8.5) have become implausible, based on trends in the costs of renewables, the emergence of climate policy and recent emission trends,” citing the paper that we published in Nature back in 2020.

Actual global CO2 emissions (black) compared to different generations of emissions scenarios featured in IPCC reports. Updated by Glen Peters through 2025.

Others have pointed out that RCP8.5 was never particularly plausible, and have criticized claims that the move away from using these scenarios reflects actual progress on reducing emissions.

So what actually happened here? It turns out that two things can be true at the same time:

  • RCP8.5 (and its successor SSP5-8.5) were designed to be a worst case emissions scenario, not the most likely outcome even in a world that did nothing to address climate change. We were probably never headed to a tripling of global emissions by 2100 (to say nothing of a five-fold increase in coal use), even in the absence of climate policy.

  • Rapid declines in clean energy costs have bent the curve of future emissions downward, with new scenarios designed to reflect current policies notably lower than most baseline scenarios in the literature. The 21st century is now unlikely to see a continued expansion of fossil fuel use globally, with current policy scenarios reflecting relatively flat global emissions going forward.

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RCP8.5 Update

Posted on 25 May 2026 by Ken Rice

This is a re-post from And Then There's Physics

If you’ve been paying attention to the climate debate on social media you might have noticed the RCP8.5 debate rearing it’s ugly head again. This is because a new set of emission/concentration projections have been developed for the climate modelling community (CMIP7). These new projections no longer include an RCP8.5-like projection and so all of those who have been critical of its use are now crowing about this proving them right.

I’ve written about RCP8.5 numerous times before. My views have probably evolve somewhat over time, but my previous posts are probably a reasonably good reflection of them. So, if you do want to know them, you could read some of these earlier post. I don’t want to delve too much into the re-invigorated “debate” but instead thought I’d post links to other posts/articles that I think explain the situation pretty well. If you want to read alternative takes, they’re not all that difficult to find. You can probably guess the authors.

I will, though, repeat the sub-heading of Gavin’s Realclimate post:

The fantasy version of the normal updating of scenarios for a new round of CMIP simulations doing the rounds is bad faith BS.

Links to other posts:

Scenarios, Schemarios – Gavin Schmidt at Realclimate.
On the death of RCP8.5 – Zeke Hausfather, Glen Peters and Piers Foster at Climate Brink.
Factcheck: Trump’s false claims about the IPCC and ‘RCP8.5’ climate scenario – multiple authors at Carbon Brief.
IPCC does not create scenarios – Reto Knutti at Linkedin
Sorry, climate change is still dangerous, no matter what nonsense Trump emits – Bulletin article by Genevieve Guenther

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2026 SkS Weekly Climate Change & Global Warming News Roundup #21

Posted on 24 May 2026 by BaerbelW, Doug Bostrom

A listing of 28 news and opinion articles we found interesting and shared on social media during the past week: Sun, May 17, 2026 thru Sat, May 23, 2026.

Stories we promoted this week, by category:

Climate Policy and Politics (6 articles)

Climate Change Impacts (5 articles)

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Skeptical Science New Research for Week #21 2026

Posted on 21 May 2026 by Doug Bostrom, Marc Kodack

Open access notables

A desk piled high with research reports

Attribution of UK Temperature Changes to Anthropogenic and Natural Factors, Amos et al., Atmospheric Science Letters

Understanding the extent to which human activities have influenced regional climate is a key scientific and policy challenge. The UK is one of the world's best observed regions climatically, with a long and reliable temperature record that makes it an important test case for regional detection and attribution. Here, for the first time, we apply optimal fingerprinting to UK mean 2-m air temperature changes using the Estimating Equations method, HadUK-Grid observations, and CMIP6 simulations. We assess the extent to which observed UK temperature changes can be explained by natural internal variability, anthropogenic forcings, and natural external forcings. We detect a significant anthropogenic influence on warming in recent decades and identify greenhouse gases as the main driver. We also detect a cooling contribution from other anthropogenic influences in the mid-twentieth century, likely dominated by sulphate aerosols. These results update earlier UK-focused work and demonstrate that human influences, both warming and cooling, are detectable even at the national scale.

Sustained deoxygenation in global flowing waters under climate warming, Guan et al., Science Advances

Dissolved oxygen (DO), as a vital material sustaining aquatic ecosystems, has declined markedly in oceans, lakes, and coastal waters, yet unbiased understandings of changing DO concentrations in each individual river segment globally remain a challenge. Here, we estimate DO concentrations in 21,439 rivers globally between 1985 and 2023, based on Landsat observations and climatic data, and examine their patterns and trends. We find sustained deoxygenation in global rivers, at a rate of −0.045 mg liter−1 decade−1, with 78.8% experiencing fluvial deoxygenation, driven mainly by oxygen solubility and temperature. Moreover, short-term heatwaves and dam impoundment exert non-neglecting influence on these changes. Future projections demonstrate that global fluvial DO concentrations decline by 1.1% ± 1.6% under SSP1–2.6 and 4.7% ± 2.7% under SSP5–8.5 throughout the 21st century. Our study provides an unbiased baseline for escalating deoxygenation in global fluvial ecosystems that underscores targeted measures to mitigate deoxygenation threats and protect ecosystem health.

Emergent constraints on future methane emissions from global wetlands, Zhang et al., Nature Geoscience

Future methane (CH4) emissions from natural wetlands are predicted to increase due to global warming, leading to positive feedback on climate change. However, the magnitude of this increase remains highly uncertain. Here we present novel ensemble simulations of seven state-of-the-art terrestrial biosphere models to estimate wetland CH4 emissions (eCH4) during the twenty-first century. Our estimates suggest that for every 1 °C increase in global land surface temperature, there is a 24 ± 10 Tg CH4 yr−1 increase in eCH4. We also identify an emergent relationship between contemporary temperature dependence and projected eCH4. When constrained by 163 site-year eddy-covariance measurements of eCH4, we show that wetland emissions can increase by 50–60% by the 2090s relative to the 2010s under a high-warming scenario. The projected decadal increase in eCH4 from the 2010–2019 baseline to the 2030s would very likely (90% probability) offset an amount equivalent in scale to 8–10% of anthropogenic eCH4 at the 2020 level, comparable to the reductions committed under the Global Methane Pledge. However, the constraint is dominated by mid- and high-latitude observations, with limited tropical coverage, and uncertainties in projected wetland inundation contribute substantially to uncertainty in eCH4. Our findings reduce the uncertainty in projected wetland methane–climate feedback and highlight its potential impacts on methane mitigation efforts to slow global warming.

Challenges and opportunities of the full phase-out of fossil fuels under the 1.5 °C goal, Mori et al., Nature Communications

The COP28 decision called for transitioning away from fossil fuels, sparking a growing interest in their full phase-out. However, energy system transformation pathways towards a phase-out of fossil fuels, which may reduce the reliance on carbon dioxide removal to meet the 1.5 °C goal, remain unclear. Here, we employ two global energy system models to explore energy system transformations and the challenges and opportunities associated with attaining a full phase-out of fossil fuels. We found that phasing out fossil fuels by 2050 would require accelerating direct and indirect electrification, involving 1.6–1.8-fold increases in power generation compared to the conventional cost-effective 1.5 °C pathways. This transition from cost-effective to fossil fuel phase-out pathways would increase energy supply investments by up to 34% over this century and require accelerated deployment of solar and wind power, as well as electrolysers. Despite opportunities including lower reliance on carbon dioxide removal and increasing probability of returning to 1.5 °C after temperature overshoot, these additional requirements imply that international society must approach the transition towards zero-fossil energy systems with strong determination.

Scientific authority cues increase the spread of misinformation, Harrando et al., Proceedings of the National Academy of Sciences 

Misinformation continues to circulate on social media, often because people unintentionally share posts without verifying their accuracy. We show that references to scientific entities, what we call Scientific Authority Cues, play an important role in this problem. Analyzing 8.7 million posts on Twitter (X), we find that these cues are associated with an increase in sharing, especially when sharing low veracity content, and when users lean politically to the right. A preregistered experiment with U.S. adults shows that attributing claims to scientific entities increases people’s willingness to share them by making claims seem more accurate. These findings reveal an important tension: Signals of scientific authority can also make misinformation more credible and thus easier to spread.

From this week's government/NGO section:

The AI Climate Hoax: Behind the Curtain of How Big Tech Greenwashes Impacts, Ketan Joshi, Beyond Fossil Fuels, Standearth, Climate Action Against Disinformation et al

The analysis collected the most prominent AI climate claims and determined a) what types of AI were referred to and b) what evidence was presented to back up those claims. The author found that 1. Most claims of climate benefit relate to ‘traditional’ AI, which has a much lower environmental impact than consumer generative AI tools. Even if these benefits are real, they are unrelated to - and dwarfed by - the massive expansion of energy use from the generative AI industry. 2. Where claims of traditional AI climate benefits are made, they tend to rely on weaker forms of evidence, such as corporate websites, rather than published academic research. Only 26% cited published academic research while 36% did not cite any evidence at all. This analysis shows that to bring the deployment of digital services in bounds with the physical limits of the planet, tech companies investing in AI should implement actual sustainability measures rather than masking ever-worsening damage to the climate and environment with vague terms and weak evidence.

Survey: U.S. and Canadian Business Confidence in Climate Action Remains Strong, Melissa Fifield, BMO Climate Institute

The fourth edition of the BMO Climate Institute Business Leaders Survey was conducted in January 2026 and included 741 respondents, including 370 in Canada and 371 in the U.S. Survey respondents include individuals in a senior role at their company (e.g. C-suite, President, Vice-President, Executive Director or General Manager) and who consider themselves to be senior decision makers. Companies range from those with at least five employees to more than 500 employees. Nearly three-quarters (73%) of respondents say they have or are developing plans to address climate-related risks, up from 69% in 2025. Extreme and unpredictable weather is a top concern for business leaders considering the impact of climate-related risks on their companies. Competitive pressure, customer expectations, and regulatory change are expected to drive further climate action. Three?fifths of respondents say AI is already used in daily operations or climate planning. Costs remain the most frequently cited obstacle to developing an effective climate plan.

101 articles in 48 journals by 751 contributing authors

Physical science of climate change, effects

Future changes of upscale ocean kinetic energy transfer under greenhouse warming, Wang et al., npj Climate and Atmospheric Science Open Access pdf 10.1038/s41612-026-01429-1

Mean State Change-Induced Differential Responses Between Strong Positive and Negative Events Reduce Indian Ocean Dipole Asymmetry Under Greenhouse Warming, Wang et al., Journal of Geophysical Research Atmospheres 10.1029/2025jd045190

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What’s a ‘super El Niño’? And other El Niño questions, answered

Posted on 20 May 2026 by Guest Author

This is a re-post from Yale Climate Connections by Bob Henson

The odds are in El Niño’s favor right now.

This natural weather phenomenon, part of the El Niño-Southern Oscillation, or ENSO, occurs when warmer-than-average water extends throughout most of the equatorial Pacific Ocean just below the surface. That’s happening now. And powerful bursts of westerly wind have pushed immense amounts of warm water eastward, toward the Niño3.4 region where sea surface temperature, along with other atmospheric conditions, is used to assess the state of ENSO.

On May 14, in its monthly ENSO outlook, the NOAA/National Weather Service Climate Prediction Center gave an 82% chance that El Niño will be in place for the period May through July, which implies that it’ll be here within weeks.

How do experts know when El Niño has arrived?

El Niño conditions are declared when the atmosphere and ocean are in sync and the Niño3.4 sea surface temperature is at least 0.5 degrees Celsius (0.9°F) warmer than the seasonal average.

But just as hurricanes can and do stray from the “cone of uncertainty” at times, it’s vital to remember that El Niño can do much the same. Preparing for the prototypical outcomes is a smart move, as long as you keep in mind that forecasting the El Niño-Southern Oscillation is more a matter of probabilities than certainties.

NOAA now uses a Relative Oceanic Niño Index, or RONI, in which the Niño3.4 value is adjusted relative to the world’s tropical oceans as a whole; the goal is to keep global warming from smudging the signal of El Niño and La Niña events themselves.

Read: A new and better way to keep tabs on El Niño and La Niña

Nearly all seasonal forecast ensembles used to predict ENSO at agencies around the world now concur that the imminent event is likely to bring Niño3.4 warming of at least 1.5°C, which would push it into the “strong” category. And some of the ensemble averages are now going well above 2°C, even for the adjusted RONI index. That would put it in the ballpark of the biggest El Niño events in the NOAA database going back to 1950.

Individual ensemble members still cover a fairly broad range, with outcomes varying from a weak event to a record-stomping one, but as shown below, they’re about as close to being unanimous on a significant El Niño as you’re likely to see. (This output is mainly using the traditional pre-RONI index, which tends to run slightly hotter on recent El Niño events.)

What’s a ‘super El Niño’ – and will we get one?

Back in 2003, a group of researchers from Australia’s national science agency, CSIRO, invoked the term “super El Niño” in a Monthly Weather Review paper. They used it to describe events where the Niño3.4 departure from average was at least 3°C. The phrase has since been used more loosely around the world, especially in news articles and social media, but it’s not part of the toolbox of most professional ENSO forecasters.

“While ‘Super El Niño’ is sometimes used informally, it is not a scientific term,” said senior climatologist Felicity Gamble in a statement from Australia’s Bureau of Meteorology, which avoids the “super” moniker in its products.

The same is true of NOAA, which is going with “weak,” “moderate,” “strong,” and “very strong.” NOAA’s monthly ENSO outlooks now include month-by-month odds that a predicted El Niño event will fall into each of these four brackets. The odds of a “very strong” event peak at 37% in the November-to-January period.

Summing these categories, the odds that we will have El Niño at any strength are now greater than 90% from this summer through winter 2026-27, according to NOAA.

A bar chart shows the NOAA CPC ENSO strength probabilities issued May 2026Figure 1. Probabilities from NOAA’s May 14 outlook that the expected El Niño event of 2026-27 will fall into various strength categories during each overlapping three-month period through December-February. El Niño events typically build in northern summer and fall, peak in the winter, and fade by spring. Unlike La Niña, El Niño rarely persists or recurs for two or more years in a row, though that occasionally happens. (Image credit: NOAA/NWS/CPC)

Jan Null of Golden Gate Weather Services, a California-based forensic meteorologist and former National Weather Service forecaster, began using “very strong” when the 2015-16 event arrived, so he’s happy to see NOAA doing the same. As Null puts it, “Everyone sees a forecast plume that looks like the liftoff of Artemis and goes crazy, and somehow early on attached the ‘super’ superlative to it.”

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Fact brief - Does electromagnetic radiation from wind turbines pose a threat to human health?

Posted on 19 May 2026 by Sue Bin Park

FactBriefSkeptical Science is partnering with Gigafact to produce fact briefs — bite-sized fact checks of trending claims. You can submit claims you think need checking via the tipline.

Does electromagnetic radiation from wind turbines pose a threat to human health?

NoElectromagnetic fields (EMFs) from wind turbines are well below international exposure safety limits.

Wind turbines produce EMFs mainly from their electrical equipment. Multiple studies have found their strength to be lower than everyday exposure to many common household appliances, such as microwaves and vacuum cleaners.  

In a field study at a Canadian wind farm, average magnetic fields at the base of operating turbines were around 0.1 microtesla (µT) and dropped to background levels within 2 meters. Turbines under high wind and low wind conditions emitted equivalent levels of radiation. Another 2020 study found wind turbines produced under 0.1 µT at 4 meters distance.

For comparison, an electric can opener measures about 60 µT at 6 inches but 0.2 µT at 4 feet. International guidelines set a safety reference level of 100 µT at 50 Hz, far above the turbine measurements reported in field studies.

Go to full rebuttal on Skeptical Science or to the fact brief on Gigafact

This fact brief is responsive to quotes such as this one.

Sources

Environmental Health Measuring electromagnetic fields (EMF) around wind turbines in Canada: is there a human health concern?

Radiation Protection Dosimetry EXTREMELY LOW FREQUENCY ELECTROMAGNETIC FIELD EXPOSURE MEASUREMENT IN THE VICINITY OF WIND TURBINES

World Health Organization Radiation: Electromagnetic fields

Frontiers in Human Health Wind Turbines and Human Health

Columbia Law School Sabin Center for Climate Change Law Rebutting 33 False Claims About Solar, Wind, and Electric Vehicles

Please use this form to provide feedback about this fact brief. This will help us to better gauge its impact and usability. Thank you!

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Five things you need to know about El Niño’s likely comeback

Posted on 18 May 2026 by Guest Author

This is a re-post from Yale Climate Connections by Rafael Méndez Tejeda

El Niño is (probably) coming back later this year.

And this time, it’s unfolding against a backdrop of unusually warm oceans and an even warmer climate system than the last time we experienced this natural climate pattern.

Here is what you need to know about it.

What is El Niño?

The term El Niño is part of a broader phenomenon called El Niño-Southern Oscillation, or ENSO. It’s a recurring climate pattern involving changes in sea surface temperatures across the central and eastern tropical Pacific.

Copernicus, a European climate data service, reported that in March 2026, the average sea surface temperatures in the Pacific reached 20.97°C – the second-highest value ever recorded for March, which suggests a likely transition toward El Niño conditions.

The El Niño-Southern Oscillation is one of the planet’s most important natural mechanisms through which the ocean and atmosphere exchange energy and reorganize the global climate from year to year.

The phenomenon has three phases: the warm phase is El Niño, the cool phase is La Niña, and between the two lies a neutral or transitional phase, when neither dominates clearly. The changes occur in the tropical region of the Pacific Ocean, within 700 miles of the equator.

The consensus among climate models – including those from NOAA – indicates with high probability the onset and subsequent intensification of El Niño starting in fall 2026, with some models suggesting it could be an unusually intense event.

We can anticipate more heat waves with a strengthening El Niño, along with more extreme events ranging from heavy rainfall to drought. El Niño tends to intensify the subtropical jet stream, favoring wetter conditions and greater storm activity across the southern United States and northern Mexico, while the northern United States and Canada experience a relatively warmer and drier pattern, affecting snow cover and water availability. At the same time, the effects of El Niño usually reduce the frequency and intensity of hurricanes in the Atlantic Ocean.

The return of El Niño is not synonymous with climate change

El Niño is a natural phenomenon of the ocean-atmosphere system. But when it coincides with a planet already warmed by human activity, its effects can be amplified. The World Meteorological Organization warned that during the last El Niño period (2023–2024), the combination of El Niño and climate change hit Latin America and the Caribbean with greater force, worsening droughts, heat waves, wildfires, extreme rainfall, and other impacts with significant human and economic costs.

El Niño affects more than the Pacific region

Although El Niño originates in the equatorial Pacific Ocean, its effects extend to other regions of the planet through processes known as climate teleconnections – atmospheric links that allow massive cloud formations to develop as a result of the enormous evaporation generated by the warming of ocean waters.

El Niño disrupts what is known as the Walker Cell or Walker Circulation, a tropical atmospheric circulation system that transports heat, moisture, and energy on a large scale. These disturbances propagate through the atmosphere in the form of planetary waves, modifying global pressure and wind patterns. As a result, El Niño’s influence reaches the Atlantic Ocean and the Caribbean, where significant changes in regional climate occur.

Among these effects are a tendency toward drier conditions in certain periods due to descending air and a redistribution of heat that contributes to higher temperatures and more intense heat waves. In short, even though El Niño occurs far from where most Yale Climate Connections readers live, its impact is clearly felt because Earth’s climate system is interconnected, and atmospheric disturbances can travel vast distances.

During El Niño, increased variability in wind direction and speed – which inhibits hurricane formation – can act as a buffer against hurricane activity. However, hurricane formation in the Atlantic depends on multiple factors, including conditions in the Atlantic itself – such as sea surface temperatures, atmospheric moisture, and the Azores High, a large semipermanent center of high atmospheric pressure that sits over the North Atlantic near the Azores islands. And when it comes to hurricanes, we should never let our guard down completely.

A graphic of the Americas showing the effects of El Niño.How El Niño affects hurricane formation in the Pacific and Atlantic Oceans. (Image credit: NOAA / Climate.gov)

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2026 SkS Weekly Climate Change & Global Warming News Roundup #20

Posted on 17 May 2026 by BaerbelW, Doug Bostrom

A listing of 28 news and opinion articles we found interesting and shared on social media during the past week: Sun, May 10, 2026 thru Sat, May 16, 2026.

Stories we promoted this week, by category:

Climate Change Impacts (10 articles)

Climate Science and Research (4 articles)

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