2023 Amazon drought

[Tom Goreau]

• Article
• Open access

• Published: 09 October 2025

Moisture and temperature sources were key drivers of the anomalies for the record-breaking of 2023 Amazon drought

• José C. Fernández-Alvarez, 
• Raquel Nieto, 
• Sergio M. Vicente-Serrano, 
• David Carvalho & 
• Luis Gimeno 

Communications Earth & Environment volume 6, Article number: 801 (2025) 

The record-breaking 2022–24 Amazon-drought, which extended into the Orinoco and Cerrado regions, was characterized by severe-dry conditions during the dry-to-wet transition-season of the 2023–24 hydrological years (September-November/2023). This situation was not driven by a moisture-deficit from either remote sources or the region itself, although oceanic moisture sources exhibited negative anomalies. It was caused by the prevailing atmospheric stability, which inhibited convection and therefore precipitation in this region, and by extremely high temperatures having as its main driver the transition from 2022–23 La Niña to 2023–24 El Niño, which amplified the anomalies in the variables. Although atmospheric moisture was anomalously high, it was insufficient to compensate for the high temperatures, which led to reduced relative humidity values and enhanced atmospheric evaporative demand. Moisture that did not precipitate in the region was transported to areas where there was sufficient instability for convection, resulting in high precipitation and floods in the Uruguay/Brazilian-South-Atlantic-Marginal river basins in September-October/2023. The temperature anomaly over the target region had two sources: a local one contributing to warming and an external one contributing to cooling. The results show the importance of adiabatic warming due to subsidence in the region itself and outside the region.

 

[rob de laet]

Hi Tom, 

thank you for this article. I understand their argument that El Niño and a stable “lid” on the atmosphere mattered, but it was not the only process that caused the record drought and local temperatures and boosted global temperatures: part of the drought was likely caused by the faltering of the forest’s own cooling and rehydrating engine, in a self-reinforcing feedback loop: high temperatures slow/stop photosynthesis, which slows cloud seeding, convection and surface/canopy cooling. 

In the 2023–24 heat, leaf-level stress spiked. I remember sawing top of canopy temperatures above 40 C. At that level the heat stress can even lead to the denaturation of proteins that disrupts cell membranes, irreversibly shutting down photosynthesis in those leaves. Before that leaves already close their stomata to avoid moisture loss. This stops photosynthesis, evapotranspiration and bioaerosol emissions. This means that convection weakens even if enough moisture is around in the air column. This slows/stops cloud seeding and convection. So less condensation means less biotic pump activity and moisture recycling via precipitation down wind. The moisture simply rides the remaining slower winds uncondensed and only rains out farther south where lower temperatures did not inhibit these processes. These areas still have a lot of natural vegetation despite huge pastures and monocropping areas. So the supersaturated winds caused large flooding in Southern Brazil and Uruguay. It was moisture that never got recycled over the Amazon. If the Amazon had functioned normally, temperatures would never have risen that far and the down wind floods would not have occurred. 

This also shows how quickly the situation in the Amazon can change when temperatures spike. The Amazon is right now balancing at the edge of the tipping point of dieback and needs to be brought back from there. The sudden heating up and drying out is a self-reinforcing feedback loop that could trigger the largest forest fires we have ever seen in a similar occurrence, which under the current circumstances could happen very soon. Once that happens, the forests and its cooling and rehydrating capacity are toast and so is the food and water security for a whole continent and even beyond. Take out the cooling capacity of the Amazon/Orinoco rainforests and global temperatures can spike up to 2.5 C above IPCC trajectories. The global  temperature spikes of 23/24 were to a large extent caused by the record droughts over the Amazon. From a risk management perspective it means that we are playing with fire to not bring back the forest from the brink. 

The project I lead is designed to reverse that risk. We propose to facilitate rewarding everyone in the forest to protect and restore the forest and with that increase the cooling and rehydrating capacity both locally and downwind as it will reinvigorate the biotic pump. 

For more: Cooling the Climate. 

Best, 

Rob de Laet 

Project Lead Cooling the Climate

Member of the EcoRestoration Alliance

Fellow of Global Evergreening Alliance

Fellow fo the Schumacher Institute

Planetary Solvency Taskforce

Co-founder of Senang Eco Services

WhatsApp: +55 71 992617846

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[Tom Goreau]

To be sure this is a phenomenological study of the atmospheric impacts of one extreme event, not a predictor of what will happen to biological feedbacks stretched past the breaking point, so it is an underestimate of the impacts of the next extreme record event.

 

The climate catastrophe devastating my island Jamaica today by the worst hurricane in our history will be far worse than the previous records set by Charlie, Flora, Allen, Gilbert, and Ivan, a trend directly caused by global warming.

[Sue Lennox]

Thanks Rob - this is valuable information. Can I quote you or better still can you give me reference?

Hope you are keeping well in these challenging times.

I am wondering if you have come across any young people (aged 14-35), who could be interested in getting involved in Youth Leading the World (YLTW). YLTW is an OzGREEN initiative that seeks to train and support local facilitators to run the youth environmental leadership program in their own region, connected to other youth globally. To date we have trained over 1300 Facilitators from around the world.

It would be wonderful to have the voice of youth from the Amazon sharing their story as part of a global platform of youth working for change. I am part of the Local Organising Committee for the upcoming 13th World Environmental Education Congress (WEEC), coming up 21-25 September 2026 in Perth. My focus has been on youth engagement and youth voice in this program. We have established an amazing Youth Leaders Committee (YLC) of 26 young people from around the world. 

We have a YLTW Facilitator Training coming up in the next month, focused on Oceania and Americas. We are just in the process of making a date to suit the most people. We have an amazing Spanish speaking mentor based in Colombia who is supporting youth from the region. 

I have attached some background info about YLTW and links to 13th WEEC are above.

Let me know if this is of interest and we can make a time to talk.

On the flip side the El Nina in Australia = more rain. I think we are coming into the 4th or 5th year of La Niña (unprecedented). But at present it is being out competed by the Antarctic Sudden Stratospheric Warming event and we have unprecedented hot and dry conditions.

With love, Sue

Sue Lennox AM
2020 NSW Senior Australian of the Year
Co-Founder OzGREEN
Founder Youth Leading the World (YLTW)

Phone + 61 408 027 995
Email: sle...@ozgreen.org.au

Website: www.ozgreen.org

Jagun yaam Gumbaynggirrgundi. 

I live and work in Gumbaynggirr Country. 
I give my love and respect to Elders past, present and emerging. 
I acknowledge that sovereignty was never ceded.

[Michael Pilarski]

Why does warming lead to bigger hurricanes? 

Higher surface ocean temperatures?

My understanding is that precipitation leads to a release of heat into the atmosphere and a lot of it escapes to space.  Ie. precipitation is one of the main ways the planet can cool itself 

The planet is overheating and big hurricanes with lots or rain are one of the ways the planet can cool itself.  Is this giving the Earth too much credit for knowing what it is doing?  or what are the scientific explanations? 

Michael "Skeeter" Pilarski

Earth Repair - Permaculture - Agroforestry - Wildcrafting - Medicinal Herbs

Global Earth Repair Foundation

Friends of the Trees Botanicals

Friends of the Trees Society

NW Herbal Fair

Fairy Congress

PO Box 1133
Port Hadlock, WA 98339
# (360)-643-9178

I acknowledge that I live on the stolen lands of the Chemacum, S'Klallam and Klallam PeopleWhy does ws.

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.

[Bru Pearce]

Hi Sue,

 

Having just read your below email I thought you might be interested to connect with my friend Johann Hoschtialek and the project he is leading 195 in 365 see attached.

 

Best wishes

 

 

 

Bru Pearce

E-mail   b...@envisionation.org  

Mobile  +44 7740 854713

Web      www.envisionation.org  

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[Tom Goreau]

The amount of water the air can hold (the water vapor pressure) increases exponentially with temperature so the warmer it is the more latent heat of evapotranspiration is in the air, which drives buoyancy and winds. A 1C rise in average temperature can result in up to 7% more heat content. The hotter it is the power of the hurricane rises exponentially. My island, Jamaica, was devastated yesterday by the worst hurricane in our history, it will take a long time before the damage can even be assessed.

[Tom Goreau]

To be sure, the Clausius Clapeyron relationship is an equilibrium one, and the eye of a hurricane is very dynamic!

 

From: healthy-planet-...@googlegroups.com <healthy-planet-...@googlegroups.com> on behalf of Bruce Melton -- Austin, Texas <bme...@earthlink.net>
Date: Wednesday, October 29, 2025 at 12:38
To: Tom Goreau <gor...@globalcoral.org>, rob de laet <robd...@yahoo.com>, healthy-planet-action-coalition <healthy-planet-...@googlegroups.com>, EcoRestoration Alliance <ecorestorat...@googlegroups.com>, Anastassia Makarieva <ammak...@gmail.com>
Cc: Peter Bunyard <peter....@btinternet.com>, Ali Bin Shahid <a...@paanisubkayliay.com>, Antonio Donato Nobre <anob...@gmail.com>, Foster Brown <fbr...@woodwellclimate.org>
Subject: Re: [HPAC] Re: [ERA] 2023 Amazon drought

Positive energy to you and your fam, friends, and colleagues in Jamaica Tom, and everyone else impacted by Melissa too.

The Clausius–Clapeyron moisture-temperature relationship of a 7% percent increase in moisture per degree C of warming is widely misused in the media to represent the increasing precipitation caused by climate warming. The dynamics of the heat of condensation you mentioned are far more important than Clausius–Clapeyron. I logged a couple of works into my database on the topic after Hurricane Harvey. See below,

MeltOn

 

Harvey and Atlas 14
Rainfall Frequency and Intensity increase intensity
Rainbombs

Most of us have heard that atmospheric moisture increases in quantity at a rate of seven percent per degree C of warming. The media almost always presents this number as a metric to identify how much more extreme a rainfall event can be because of climate warming. This is a valid piece of physics but taken in context and poorly interpreted by the media. It only applies to the laboratory evaluated water-holding capacity of air. Many more physical relationships affect the amount it actually rains with one degree C of warming. When air rises in a storm, its moisture condenses out and falls as rain. Condensation creates heat and this extra heat then causes extra lift that causes more air in the storm to rise faster, allowing more condensation faster, that creates more lift faster in a feedback loop. As a comparison, academic work on Hurricane Harvey's rainfall showed that the dynamic factors involved with that storm increased rainfall volume by 38 percent, not the 7 percent increase allowed by the climate change increased capacity of moisture in the atmosphere alone. (Risser and Wehner 2017)

 

Harvey’s rainfall was 38 percent more intense than in our normal climate, not 7 percent per degree C… The study looked at a 200-mile ellipse along the Texas and Louisiana coasts from southwest of Houston to Lake Charles LA and extending 100 miles inland for a seven-day duration with widespread 32-inch radar estimated totals. Harvey was just a five-day event, but this eval used the more common 7-day to look at history. Not included in this ellipse were reported widespread 40 inches totals and three 60-inch bullseyes. The large complete storm analysis had an ellipse 300 miles along the coast and 150 miles inland with totals down to 5 to 6 inches and an increase in rainfall of up to 22 percent.
Risser and Wehner, Attributable Human-Induced Changes in the Likelihood and Magnitude of the Observed Extreme Precipitation during Hurricane Harvey Geophysical Research Letters, December 23, 2017.
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/2017GL075888

World Weather Attribution Network Harvey’s precipitation increase was up to nearly 20 percent more, based on a three-day, 24-inch rainfall… Harvey’s increase in precipitation up to almost 20 percent based on weather station data the authors consider to underestimate with about 24 inches total.
Climate change fingerprints confirmed in Hurricane Harvey’s rainfall, World Weather Attribution, August 2017.
https://www.worldweatherattribution.org/hurricane-harvey-august-2017/

 

Bruce Melton PE
Director, Climate Change Now Initiative, 501c3
President, Melton Engineering Services Austin
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[rob de laet]

Hi Johann, will be there from 9-15 Nov, who else? 

Rob de Laet 

Project Lead Cooling the Climate

Member of the EcoRestoration Alliance

Fellow of Global Evergreening Alliance

Fellow fo the Schumacher Institute

Planetary Solvency Taskforce

Co-founder of Senang Eco Services

WhatsApp: +55 71 992617846

On Wednesday 29 October 2025 at 22:59:07 CET, Johann Hoschtialek <joh...@195in365.com> wrote:

thanks Bru,

its a pleasure connecting with you all. Are any of you heading down to Brazil for COP30

Johann

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From: Bru Pearce <b...@envisionation.org>
Sent: Wednesday, October 29, 2025 5:51 AM
To: Sue Lennox <sle...@ozgreen.org.au>; rob de laet <robd...@yahoo.com>; Johann Hoschtialek <joh...@195in365.com>

Cc: healthy-planet-action-coalition <healthy-planet-...@googlegroups.com>; EcoRestoration Alliance <ecorestorat...@googlegroups.com>; Anastassia Makarieva <ammak...@gmail.com>; Tom Goreau <gor...@globalcoral.org>; Peter Bunyard <peter....@btinternet.com>; Ali Bin Shahid <a...@paanisubkayliay.com>; Antonio Donato Nobre <anob...@gmail.com>

Subject: RE: [ERA] 2023 Amazon drought - YOUTH VOICE

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