Tropical Tropospheric Temperature Trends, 1979-2025: The Epic Climate Model Failure Continues
As a follow-on to my recent post regarding global surface air temperature trends (1979-2025) and how they compare to climate models, this is an update on a similar comparison for tropical tropospheric temperature trends, courtesy of tabulations made by John Christy. It also represents an update to my popular “epic fail” blog post from 2013.
As most of you know, climate models suggest that the strongest warming response the climate system has to increasing anthropogenic greenhouse gas (GHG) emissions (mainly CO2 from fossil fuel burning) is in the tropical upper troposphere. This produces the model-anticipated “tropical hotspot”.
While the deep oceans represent the largest reservoir of heat energy storage in the climate system during warming, that signal is exceedingly small (hundredths of a degree C per decade) and so its uncertainty is rather large from an observational standpoint. In contrast, the tropical upper troposphere has the largest temperature response in climate models (up to 0.5 deg. C per decade).
This shown in the following plot of the decadal temperature trends from 39 climate models (red bars) compared to observations gathered from radiosondes (weather balloons); satellites; and global data reanalyses (which use all kinds of available meteorological data).
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Was tun, wenn Prognosen nicht eintreten? | Grenzen des Wissens
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Kennedy-Asser et al. 2026 im Fachblatt Climatic Change:
Do climate models agree on seasonal rainfall patterns and future changes over Southern Africa?
Understanding how rainfall will change over the southern Africa is a challenge, in part, due to large uncertainties in climate model projections. Using a large set of 201 global climate model simulations from the Coupled Model Intercomparison Project Phases 5 and 6 (CMIP5 and CMIP6) and 2018 UK Climate Projections (UKCP18), this study provides an in-depth investigation into future changes in southern African precipitation. Specifically, the spatial and temporal variation of model agreement, the intra- and inter-model uncertainties and the roles of interdecadal variability are examined. Model projections show agreement on drying over most of southern Africa in the dry season and the onset of the rainy season. Meanwhile in the main rainfall season, there is less agreement between models regarding the direction and magnitude of change over much of southern Africa, including in Zimbabwe, Mozambique, Zambia and Malawi. The range in future projections is not linked with biases in the historical climatology, and intra-model uncertainty analysis shows that multiple simulations of the same model often produce disagreeing projections in the sign of precipitation change when compared to the historical period. This highlights the importance of internal variability in influencing rainfall projections over southern Africa. For many models, this substantial interdecadal variability is greater than the projected future change. Given the large variability and uncertainty in models over southern Africa, impact and adaptation studies should consider the strong probability of both wet and dry years, and wet and dry decades, in the future.
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A new look at trends in human deaths due to climate extremes
A new study of climate extremes since 1988 finds that many regions have seen increases in deaths due to floods, storms and extreme temperatures. In human terms, the harm comes not just from deaths, but also from lost labor and property damage. (And this doesn’t consider damage to species and ecosystems.) A new look at trends and outliers has been published in Geophysical Research Letters.
How the study was conducted
B. B. Cael, of the Department of Geophysical Sciences at the University of Chicago, used data from the publicly available Emergency Events Database (EM‐DAT). He selected from a subset of 1,974 disasters by trimming the data in four ways: Events before 1988 were not considered, nor events after 2024.
Only events with 30 or more deaths were included, which Cael found accounted for 95% or more of all deaths; he found that the thresholds were not significantly sensitive to these limits. Only climate-related hazards were considered—climatological, hydrological and meteorological—with earthquakes, volcanoes, pandemics and infestations not included.