Tom Di Liberto

@tdiliberto

Climate scientist and science communicator who dabbles in comedy. Creator of NOAA's Teek and Tom cartoon series focused on weather, climate and ocean science. If in Washington DC, come check out my science improv troupe at Washington Improv theater

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Tom Di Liberto@tdiliberto· 17d

But remember, we are always talking about record-breaking temperatures because of human-caused climate change! Not El Nino. Confused? Kids book time! Who was more responsible for getting that dump truck out of the mud? The animals + the little blue truck (climate change) or the frog (El Nino)?

Children's book illustration of a little blue truck and animals pushing a dump truck out of the mud.

Tom Di Liberto@tdiliberto· 17d

Oh and expect global temperatures to be bonkers by the end of the year and into 2027. We're talking record-breaking global surface temperatures month after month potentially. nmme.earth.miami.edu/figures/inde...

line graph split into two sections. Left is observations with a red line. Right is forecast with a red line and lots of orange lines showing different potential outcomes.

Tom Di Liberto@tdiliberto· 17d

Who should be most concerned? Start with the places noted below. I'd be preparing for a topsy turvy year. Not all of these places will see these anomalies (because El Nino isn't the only thing happening). But these places do have a higher chance of climate extremes occurring.

Map of planet with green and tan blotches representing where El Nino causes wet or drier than average conditions.

Tom Di Liberto@tdiliberto· 17d

What about the forecast? This event has a very good chance of ending up in the pantheon of El Nino events in the last 75 years! Maybe even the strongest! That's not good! It will have all sorts of major impacts globally! There's no need to actually hype this thing up even more!

Forecast for El Nino using bar graphs with different colors. Dark red indicates a very strong event. Highest chance in OND

Tom Di Liberto@tdiliberto· 17d

What does the atmosphere show? Equatorial Southern Oscillation Index (EqSOI) - 5th place, although the top events are pretty clustered. Interesting. This El Nino is definitely impressive, but not unprecedented. So far, it's perfectly precedented.

Atmospheric circulation shown across the tropics using arrows indicating where air goes up and thunderstorms occur and where it sinks.

Tom Di Liberto@tdiliberto· 17d

The RELATIVE Oceanic Nino Index (RONI) DOES take into account the rest of the tropical ocean and does a much better job at reflecting the ACTUAL strength of El Nino. So why isn't that being cited more often? If I was cynical, I'd say it's because that # isn't nearly as record-breakingly high.

Two maps of the Pacific Ocean stacked. One shows traditional ocean temperature anomalies. The other shows relative anomalies which take into account the warming of the oceans.

Tom Di Liberto@tdiliberto· 17d

#3 first. If you are interested in how strong the ocean-atmospheric climate phenomena known as El Nino is, you just can't use the ocean anomalies in the Nino3.4 region. The warming trend has added an extra boost to those numbers so it doesn't actually reflect the strength of El Nino. Analogy 🔽

Bar graph showing comparison of traditional and relative nino3.4 index. Blues are when relative was warmer, and red is when traditional was warmer. Warming trend is key

Tom Di Liberto@tdiliberto· 17d

El Nino thread! 🌊 My Key Takeaways: 1. This event is well on its way to being a very strong event rarely seen in the last 75 years. 2. Right now, it's most likely not the strongest on record. 3. The warming of the nino3.4 region due to climate change does not add to El Nino strength!

Line graph showing ocean temperatures in nino3.4 region. Current temperatures are record breaking hot

Tom Di Liberto@tdiliberto· Jul 8

🎧⚽️@climatecentral.org's Curiously Climate podcast takes on the World Cup! @shelwinkleywx.bsky.social and I chat World Cup with @ftblforfuture.bsky.social about extreme heat & how climate change is impacting the game & pitch. 🟢Spotify open.spotify.com/episode/7F5h 🔴YouTube youtu.be/_k_835kB36k

Tom Di Liberto@tdiliberto· Jun 21

Always cool seeing an analogy you created spur of the moment 5 years ago for an ENSO Blog post at Climate . gov (long live @climate.us !) get re-used in a NY Times piece on El Nino and Climate Change! www.nytimes.com/2026/06/19/c...

Tom Di Liberto@tdiliberto· Jun 12

The first #WorldCup match in Miami is scheduled for 6pm on June 15. Hmm, a late afternoon/early evening game in south Florida in June? What's that weather forecast like? Oh just a high of 87F, dewpoint of 76F, a heat index of 98 with thunderstorms likely. forecast.weather.gov/MapClick.php...

Tom Di Liberto@tdiliberto· Jun 2

Could climate change slow down the 2026 #FIFAWorldCup? Join @climatecentral.org to explore how rising temps could impact player performance, health, and match strategy during the tournament. 📅Wednesday, June 3, 2026 ⏰12 PM ET / 9 AM PT Don't make me give you a 🟥 Register ➡️ lnkd.in/ekdj5tQg

Tom Di Liberto@tdiliberto· Apr 22

And do me a favor, next time you see someone using the ONI instead of the RONI, ask them if we were in a La Nina this past winter. If they say yes, let them know that's only true if you use the RONI. So why are they picking and choosing which metric to use? www.cpc.ncep.noaa.gov/products/ana...

Numbers in a table colored blue and red occasionally.

Tom Di Liberto@tdiliberto· Apr 22

Let's look at 2014 vs. 2015 to illustrate this. This is what the subsurface of the tropical Pacific looked like in March 2014 vs. March 2015. Quick, which year developed into one of the strongest El Ninos since 1950, while the other year didn't even see an El Nino?

Tom Di Liberto@tdiliberto· Apr 22

Here's another example. Look at that WWB early in the spring in the year on the right! I bet that caused a super-duper, mega Godzilla, Charmander El Nino. Narrator: The year was 2014, and it did not.

Hovmoller showing 2026 vs 2014. Initial red shows a WWB in image on right in 2014 but no El Nino forms. 2026 on left only has data through March and shows one WWB.

Tom Di Liberto@tdiliberto· Apr 22

Let's compare this year to past strong El Ninos to put this into perspective. Look at all those WWBs (in red)! We need to see this play out a lot more. And there is no guarantee that it will.

Hovmoller showing 2026 vs 1982. Reds as you go down chart which means an increase in time show lots of westerly wind anomalies. 2026 on left only has data through March and shows one WWB.

Hovmoller showing 2026 vs 1997. Reds as you go down chart which means an increase in time show lots of westerly wind anomalies. 2026 on left only has data through March and shows one WWB.

Hovmoller showing 2026 vs 2015. Reds as you go down chart which means an increase in time show lots of westerly wind anomalies. 2026 on left only has data through March and shows one WWB.

Tom Di Liberto@tdiliberto· Apr 22

For El Nino, we want to see the trade winds, which blow east to west across the Pacific, weaken. Not all at once, but ideally in a series of spurts called Westerly Wind Bursts (WWBs). This cools the western Pacific and lets warm water slide eastward. And this happened! That's the red at the bottom

Tom Di Liberto@tdiliberto· Apr 22

"But Tom, I saw a forecast that said the tropical pacific is going to be so hot it'll start boiling, thus releasing Godzilla to do something. I don't know what. But it'll be BAD." I mean, this event could be a very strong El Nino at peak strength (25%) IN WINTER! But also, that's very far away.

bar graph of El Nino forecast with different shades of red indicating strength

Tom Di Liberto@tdiliberto· Apr 22

Current Status: No El Nino Future Status: ~60 chance El Nino forms during May-July period. ~90% chance El Nino sticks around through winter. Strength? From CPC: "The possible outcomes range from ENSO-neutral to a very strong El Niño during the upcoming winter" www.cpc.ncep.noaa.gov/products/ana...

Bar graph showing chances for El Nino this year. Red bars are very large indicating increasing chances.

Tom Di Liberto@tdiliberto· Apr 8

OH! Also. A Supercalifragilisticexpialidocious El Nino doesn't guarantee the US sees typical El Nino impacts. Some places won't. See below. (Yikes look at how different the 2015-16 Megazoid Mothra Pikachu El Nino was vs. the expected El Nino pattern.)

Map of precipitation anomalies for the contiguous US during 7 strongest el ninos. Blue meaning above-average precip generally covers the southern US but not always.

Bar graph showing the match between observed winter precipitation and the expected El Nino pattern

Tom Di Liberto@tdiliberto· Apr 8

I'm gonna keep saying this. If you're interested in what's forecast for this potential El Nino, you really should not be using the Oceanic Nino Index. Use the RELATIVE Oceanic Nino Index. nmme.earth.miami.edu/figures/inde... #FriendsDontLetFriendsUseONIandOldClimatologies

Line graph with different colors showing forecast of ENSO through rest of the year.

Tom Di Liberto@tdiliberto· Mar 17

Regardless, if an El Nino does form, expect global temperatures to go nuts. It wouldn’t surprise me in the least if global temps in 2026 and 2027 break records. And that’s probably true for any strength El Nino.

global temperatures colored by ENSO status. Red parts which are warmer are El Nino. Blue is La Nina. Gray is neither.

Tom Di Liberto@tdiliberto· Mar 17

ENSO forecasters now use the RELATIVE Oceanic Nino Index (RONI) which considers the warming across the entire tropics. It gives a MUCH better sense on the strength of El Nino/La Nina events. I know because I’m the 13th (and last!) author on the paper that describes it. Let me show that pic again.

Two graphs stacked vertically. Top is line graph showing old vs. new way of measuring ENSO. Bottom is the difference between the two

Tom Di Liberto@tdiliberto· Mar 17

El Nino is a lot more than just ocean temperatures in one part of the central/eastern Pacific. Remember, it’s an ocean/atmosphere climate phenomenon. It’s the difference in warming compared to normal between the East and West Pacific that cause the atmosphere to go wacky.

Schematic of tropical atmosphere during El Nino.

Tom Di Liberto@tdiliberto· Mar 17

What is the responsible thing to say then? There’s a ~60% chance of El Nino forming in June-August. But LOTS of uncertainty on strength when it peaks next fall/winter. 1/3 chance of this event being strong. But what does that mean?

Tom Di Liberto@tdiliberto· Mar 17

GODZILLA HAS BEEN DEFEATED?!?☠️🦖 No…also stop that! Just stop with Godzilla. And Super. It makes it seem like El Nino is a “storm” that hits your house. It’s not. It makes certain conditions averaged over a season more likely. But it’s not a rainstorm. Or a prehistoric creature.

Globe focused on North America with schematics showing usual impacts of El Nino during winter months.

Tom Di Liberto@tdiliberto· Mar 17

So GODZILLA IS NIGH?!?! 🦖 No…stop that. It’s wayyyyyy too early to be saying anything with confidence about the strength of a potential El Nino. It’s March. Not a great time historically for predicting these things. Some reading: www.climate.gov/news-feature... www.climate.gov/news-feature...

Bar graph showing how hard it is to predict ENSO strength in spring for following winter

Tom Di Liberto@tdiliberto· Mar 17

It’s underneath the surface that tells the story, though. There is a lot of warmer-than-average water making their way eastward and upwards across the Pacific. A classic sign of an ending La Nina and potentially foretelling a future El Nino.

Tom Di Liberto@tdiliberto· Mar 17

What’s really going on? Right now, we’re still in La Nina. SSTs reflect this. But 1) it’s expected to end in the next month. And El Nino is likely to develop this summer (We’re in an El Nino Watch!).

Tom Di Liberto@tdiliberto· Mar 11

To put this data gap in Africa into perspective for those in the US, here's DRC, Sudan, South Sudan, Ethiopia and Somalia overlayed on the United States.