Breaking News: Hunga Tonga temperature impact
Lightfoot and Ratzer
Good Science is based on the Scientific Method.
In this case, the Hypothesis is that the current spike in global temperatures as measured by the University ofAlabama at Huntsville (UAH) has been impacted by the Hunga Tonga submarine volcano explosion on 15th January 2022.
From 2022 to 2024 the media has been having a field day saying these are the hottest years “evah”!
In 2022 there was a rise in the water vapor in the Stratosphere, after the massive explosion in the Western Pacific. This included 146 million metric tonnes of water blasted some 60 km into the air. This water froze into ice crystals. Usually, the Stratosphere has a low water vapor content, but the Hunga Tonga eruption added some extra 10%.
Here are three graphics to better understand what has happened over the last 3 years. The first one is an overview of the initial eruption and the fast action of NOAAto get a team of researchers out into the Indian Ocean on the Island of Reunion in a matter of a week after the explosion. Start at the lower right-hand side of the graphic and follow the arrows up and to the left to see where the island of Reunion and the data collection site is. The inset in the graphic shows a vertical cross-section profile of the Stratosphere up to 31 km high. This graph, when integrated, is where the accurate estimate of the 146 million tonnes of water vapor comes from.
And what is the longer-term effect of this once-in-a-lifetime event?
The above updated data record is from the NASAAura satellite. This documents the water vapor in the Stratosphere and a very clear increase in 2022 can be seen in the dark patch. It took the best part of a year to spread around the globe, first in the Southern Hemisphere and then to the north. Looking at the end of the data series –one can see that in the middle of 2024, the dark patch was beginning to lighten up, showing a reduction in the water vapor content, now spread evenly around the globe. The dissipation continues.
So, what is the impact on global temperatures? We consider the 45-year UAH satellite temperature record to be the best available data with one reading per month. The complete record through May 2025 is available at the foot of this article.
Below is a chart of those data points for the last few years, starting in 2015. The blue squares are the January readings and usually fall between the red readings taken in July. In the next chart, there are annotations which further explain the important point of the hypothesis that Hunga Tonga was the driver of the latest temperature spike.
The baseline along the x-axis is the Pre-industrial temperature from circa 1850. The optimistic temperature IPCC goal (Paris Agreement target) of a 1.5°C rise is shown as “IPCC 2030”, on the right margin. Also shown is the start of Solar Cycle 25 and the Grand Solar Minimum in 2020. Adownturn in the temperature record can be seen starting in 2020. Then the July 2022 reading is an outlier – which we assert was due to the extra Water Vapor (WV) in the Stratosphere. From July 2023 onwards there are 20 red dots for the monthly readings which are at or above the 1.5°C IPCC/Paris guideline. Did you see the red dot forApril 2024, the spike maximum, which is 1.9°C above the Pre-industrial baseline?
These 20 UAH readings form a very clear spike, which is indeed one of the highest temperature spikes over the last 100 years and longer. The red dots for February and May 2025 are right on the 1.5°C above Pre-industrial, the March andApril ones are a bit higher. The dashed line pointing down to the “Sun”, in the chart
above, is the prediction from the research of Valentina Zharkova. Is this where we are heading?
So, we agree that 2024 was a very hot year, but not from the slow rise of CO2. The attribution of the heat spike to the Hunga Tonga volcano is based on several different empirical data sources and meets the standard of the Scientific Method.
There are four references after the chart, which support this assertion and add more details. Reference 3 is by Javier Vinos is a recent one and recommended reading by Judith Curry.
Comments are welcome!
Douglas Lightfoot and Gerald Ratzer 19th June 2025
References:
1. https://www.youtube.com/watch?v=tsYgCxVVICM
2. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JD041296
3. https://judithcurry.com/2024/07/05/hunga-tonga-volcano-impact-on-recordwarming/
4. https://acp.copernicus.org/articles/25/3623/2025/