Marc Alessi
@marc-alessi.bsky.social
PhD Climate Scientist, Union of Concerned Scientists | Colorado State/Cornell alum | Syracuse, NY | opinions my own #JoinYourUnion
"This Super El Niño will no doubt significantly impact the Southwestern US this winter, with effects from record-high sea levels and coastal erosion to the potential for excessive rainfall and consequent flash flooding throughout the southern half of the country."— @marc-alessi.bsky.social
Strongest El Niño on Record Triggers California State of Emergency and Is Already Affecting Global Weather Patterns
And it’s only September— El Niño doesn’t typically peak until November-January.
blog.ucs.org
I would actually say it’s the combination of attribution science AND the fact that fossil fuel companies knew about the dangers of climate change and began a campaign of disinformation/deception while continuing to push fossil fuels on the world, profiting off its destruction
The New York Times@nytimes.com · 5d agoIn @nytopinion.nytimes.com “The age of accountability for the fossil fuel industry has just begun and has a bright future,” Jeff Goodell writes in a guest essay. “The reason for that is the emergence of a powerful field of climate science known as attribution science.”
The Super El Niño is breaking charts as well as records, including Climate Reanalyzer's, which previously went to 30 degrees C but had to be updated today. SSTs in this part of the Pacific are in unprecedented territory - and rising - roughly two months before the typical El Niño peak.
My new blog on the Super El Niño will hopefully answer some questions you might have on: ONI vs RONI, how El Niño impacts global weather patterns, and the state of emergency announcement in California
Strongest El Niño on Record Triggers California State of Emergency and Is Already Affecting Global Weather Patterns
And it’s only September— El Niño doesn’t typically peak until November-January.
blog.ucs.org
To my fellow @cornelluniversity.bsky.social alums out there, please sign this petition and withhold all donations until the demands are met: c.org/gwTNKbmcCf
Sign the Petition
CORNELL ALUMNI SUPPORTING JANE DOE
c.org
New Commentary out in Nature Climate Action: we now live in a fundamentally different climate system due to the burning of fossil fuels. Because of this, any extreme weather event now occurs in a changed climate and is influenced by fossil fuel-driven climate change to some degree.
The next phase of climate attribution - npj Climate Action
Attribution science has transformed our understanding of how anthropogenic emissions shape extreme weather events, yet the field remains constrained by repeatedly demonstrating anthropogenic influence...
nature.com
There’s some chatter about this weekend’s nor’easter going “subtropical.” If you’re wondering what that means, I have a blog for you!
Hurricanes, Nor’easters, Subtropical Storms! What’s the Difference?
Different types of storms explained.
blog.ucs.org
The world’s oceans have overheated due to fossil fuel-driven climate change, and we’re seeing the impacts of it right now. In the US, there are 3 examples of extreme precip: a tropical system bringing torrential rain to Hawaii; heavy monsoon rains in NM; and a strong, early-season Nor’easter.
No doubt this marine heatwave is contributing to the absolutely insane humidity values being observed in SoCal
tomwellborn3rd@wellborn.net · last mo.Waters off Baja are running 14 degrees above normal, a severe to extreme marine heatwave by NOAA's own scale, and that heat is riding straight into SoCal's record-humid summer. This is climate collapse in real time while the current administration guts the agencies athat track it.
According to new data, August 2026 was the hottest Aug on record globally, tying July 2023 as the hottest month in recorded history. The heat is in part due to record ocean temperatures across the globe from the burning of fossil fuels and the developing Super El Niño. @copernicusecmwf.bsky.social
How will the predicted "Super El Nino" affect California and beyond? We discuss on Your Call today at 10am PT w/@marc-alessi.bsky.social @ucs.org & @edwardsanthonyb.bsky.social @sfchronicle.com Comment here w/any q's for our guests. Stream live @kalwradio.bsky.social: www.kalw.org/show/your-ca...
How will the predicted “super” El Niño impact California and beyond?
According to NOAA, a “Super” El Niño now has a 95% chance of developing this year, which scientists warn could be one of the largest weather events in living memory.
kalw.org
The latest HRRR is predicting quite the squall line over Western and Central New York this evening with an enhanced risk of severe weather from the SPC (and quite a significant high wind risk). Hopefully NYS Fair is monitoring...
Some morning severe thunderstorms on their way to cuse
Why is this so important? The Arctic permafrost stores almost 1,700 billion tons of frozen and thawing carbon-- and it's unclear how much of that carbon will be released as fossil fuel-driven climate change worsens.
Dr. Aaron Thierry@thierryaaron.bsky.social · last mo."Active layer thickness increased significantly at 55% and 38% of sites in the Arctic and Antarctic regions, at more than 90% European mountain and high elevation Asian sites, and at sites in South America, demonstrating worldwide permafrost degradation during the first quarter of this century"
Fossil-fueled climate change is causing glacial ice in the Himalayas to melt rapidly, raising the risks of these kinds of disasters.
Hindu Kush Himalaya glaciers losing ice at double the rate since 2000, new ICIMOD report confirm - ICIMOD
Kathmandu, 18 March 2026 – Glaciers across the Hindu Kush Himalaya (HKH) are melting at an accelerating rate, with ice loss rates doubling since the year 2000, according to two new landmark reports th...
icimod.org
The world has never been hotter for this time of year in recorded history. According to the latest data from the Climate Change Institute at the University of Maine, the average global surface air temperature is over 1.0C above the historical average:
It’s been so nice to be working from the Max Planck Institute for Meteorology in Hamburg this month. Just gave a seminar on my research this morning!
It’s over 100F for the second time this year in London
Met Office - weather and climate@metoffice.gov.uk · 2mo agoTemperatures provisionally reached 38.1°C at Kew Gardens, making it the hottest day of the year so far. This is the second time this year we have reached 38°C. The only other time this has happened twice in one year was in 2022. It also makes it the 5th hottest day on record.
Another reason why we need to invest more in NOAA to keep people safe. Congress must stand up to the Trump administration's attacks on NOAA's budget and staffing www.cnn.com/2026/08/12/w...
A software glitch prevented weather warnings from going out as deadly storms struck Midwest | CNN
An unusually long and far-reaching communications outage hobbled the National Weather Service just as deadly severe thunderstorms were tearing across the Midwest and Ohio Valley on Tuesday evening.
cnn.com
Had a lovely time visiting the @metoffice.gov.uk and giving a seminar on my @ucs.org fellowship research (filling in data gaps in Global South countries using machine learning)!
My third solar eclipse from Exeter, UK! I think we reached about 97% coverage here
The Trump administration is cancelling federal support for #NOAA’s Arctic Report Card, an essential scientific report that shows how fossil fueled climate change is having an alarming effect on the vital signs of this unique region of the world.
Government Pulls Funding for the Arctic Report Card - Eos
The Trump administration is pulling funding from NOAA’s Arctic Report Card, an annual, peer-reviewed report about the state of the region, which is warming more quickly than anywhere else on Earth.
eos.org
The world’s oceans experienced their hottest July on record, thanks to a combination of the developing Super El Niño in the Pacific Ocean and fossil fuel-driven climate change. www.bbc.com/news/article...
bbc.com
No doubt we're on track for a record breaking El Niño event in the Pacific. While, yes, El Niño is part of a natural cycle in Earth's climate system, what's happening now is a combination of El Niño + ocean warming and marine heatwaves from fossil fuel-driven climate change.
Zeke Hausfather@zekehausfather.com · 2mo agoThe rise in Niño 3.4 region sea surface temperatures over the past few weeks has been nothing short of astonishing. We are now hotter than any days during the 1997/1998 super El Niño event, and we are still many months from the peak.
Totally normal things happening in the Pacific Ocean 🙃
Zeke Hausfather@zekehausfather.com · 2mo agoThe rise in Niño 3.4 region sea surface temperatures over the past few weeks has been nothing short of astonishing. We are now hotter than any days during the 1997/1998 super El Niño event, and we are still many months from the peak.
If you've ever wondered why not to use the jet color scheme in manuscript figures, I was just pointed to this excellent article with great examples of colorbars that do work: www.nature.com/articles/s41...
Ok, I'm starting a thread of climate and weather extremes that are eye-popping that I will continuously add to (reminder that Big Oil continues to take in record profits at the expense of our planet):
Check out this great blog by my colleague at UCS. The climate isn't just changing-- it's already changed. And Big Oil is announcing record profits while the world is on fire...
UCS Climate & Accountability Campaigns@ucsclimate.bsky.social · 2mo agoA catastrophic global wildfire season is underway, while fossil fuel companies announce record profits and push for legislative immunity. Hear more from @ucs.org Policy Director Rachel Cleetus on fires in a changed climate.
Also worth flagging that there's a near 50% chance (according to the NMME) we'll cross a +2.0F global temperature anomaly for multiple months later this year into 2027...
Zeke Hausfather@zekehausfather.com · 2mo agoI'm not sure folks have realized just how crazy the second half of 2026 and 2027 will be for global temperatures – on the back of a record-smashing El Niño event. Here is my latest estimate of where both years will end up compared to global temperatures since 1850.
