Researchers at the University of Graz provide evidence of climate change in the atmosphere

The expansion of the troposphere is presumably linked to changes in weather patterns on Earth. Photo: Rawf8 - stock.adobe.com

Human-induced climate change is leaving clear traces in the atmosphere. Using satellite data, researchers at the Wegener Center at the University of Graz proved that the troposphere has expanded by up to 500 meters in some regions over the last two decades. The increase was most pronounced in the mid-latitudes of the northern hemisphere. This is also likely to be a sign of changes in the strong westerly winds, known as jet streams, and thus influences weather patterns. The new findings were recently published in the research journal Atmospheric Chemistry and Physics.

The tropopause is a good indicator of climate change. It forms the boundary between the troposphere – the weather layer – and the stratosphere above it. It lies at an altitude of eight to 17 kilometres above the Earth's surface, with the distance being greatest over the tropics and least over the poles. With temperatures between -40 and -80 degrees Celsius, the tropopause is one of the coldest places in the atmosphere. When the weather layer warms up, for example due to rising CO₂ emissions, it expands. This causes the boundary to the stratosphere to move upwards.

A new study shows: “Over the past 23 years, the tropopause has risen worldwide by between 100 and almost 500 metres, depending on the region. The shift was most pronounced in the mid-latitudes of the northern hemisphere, particularly over Asia in autumn and winter. The development over the last years is particularly striking, with the weather layer above the tropics warming unusually strongly,” reports Florian Ladstädter, lead author of the publication. The geophysicist is part of the Global Climate Analysis research group led by Andrea Steiner at the Wegener Center at the University of Graz. Using satellite data from radio occultation measurements, the scientists have documented global changes in the tropopause over more than two decades. “Our study provides, for the first time, a reliable, seasonally and spatially high-resolution picture that reveals both regional details and differences over the course of the year,” says Andrea Steiner, emphasising the significance of the publication.

According to the researchers, it can be assumed that the observed trend indicates changes in both the jet streams in the troposphere and global circulation in the stratosphere – with consequences for global meteorological phenomena as well as for weather patterns at the regional level.

Publication
Ladstädter, F., Stocker, M., Scher, S., and Steiner, A. K.: Observed changes in the temperature and height of the globally resolved lapserate tropopause, Atmos. Chem. Phys., 25, 16053–16062, https://doi.org/10.5194/acp-25-16053-2025

If you want to understand how the climate and other natural phenomena work, studying physics is a good choice.

Gudrun Pichler

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