July 9, 2025
by Francesco Ramella
Among the many endangered species, there is one in particular: natural disasters not caused by climate change. The massive landslide triggered by the collapse of the Birch Glacier, which almost entirely buried the village of Blatten in Valais, Switzerland, has been no exception.
This, for example, is the headline of the Turin newspaper La Stampa: “The Swiss glacier disaster: how climate change wiped out Blatten”. But is it really so?
What we know for sure is that snow and ice avalanches, debris flows, rockfall and rock avalanches have always shaped the alpine valleys.
In Switzerland, the largest natural disaster in historical times happened on September 2, 1806: a massive landslide of rock and debris from the Rossberg mountain submerged Goldau and the nearby villages, destroyed 111 houses and two churches, killing 457 people.
The most serious event of the last century happened on August 30, 1965 when a two million cubic metres landslide broke off the Allalin glacier in canton Valais, burying the Mattmark dam construction site. Eighty-eight people died. In the last few decades alone, three events (Brienz, Bondo, Randa) of comparable or greater size than the one at the end of May have taken place.
Now, is climate change really increasing the frequency of these phenomena? The answer is that we don’t know. The authors of an article that summarizes three decades of scientific literature (from the mid-1990s to early 2024) claim that only one third of the relevant studies found a measurable impact of climate change on the alpine mass movement .
The main author, Mylène Jacquemart, physical geographer and remote sensing specialist at ETH Zurich said that while “smaller landslides occur more frequently, especially at high altitudes, linking the increase in temperatures to larger landslides, like the one in Blatten, is premature because our systematic observations span a period of about twenty years, which is too short to determine whether these are exceptional events or if a statistically significant change is underway”. She also stated that: “the event would probably have happened even without climate change”.
What scientific research tells us about alpine mass movements is also true for most natural phenomena. The IPCC (Intergovernmental Panel on Climate Change), a United Nations body established in 1988 to assess the impacts and risks of climate change, states that climate change has increased the Earth’s average temperature and the frequency of heatwaves. Moreover, it has reduced the periods of anomalously cold weather. However, contrary to what we are used to reading in the media, the IPCC also asserts that there is a mere 20% probability that climate change affects beyond natural variability the most extreme events, including heavy rainfall, hail, drought, windstorms, tropical cyclones, and coastal flooding. This also applies to the worst-case and less plausible future scenarios.
What happened in Blatten is also emblematic of another development on a global scale. Thanks to early warnings systems, 300 residents were evacuated in an orderly manner with no known injuries; as we write, only one person is missing. As regards property, the canton where the disaster occurred does not require mandatory insurance for natural catastrophes. Yet, it seems that few property owners were without it. This is also because banks require that the buyers of property have insurance, if they want to get a mortgage.
Certainly, the human consequences would likely have been much worse if the same event had occurred a century ago. The global average mortality due to climate disasters dropped by 6.5 times from 1980-1989 to 2007-2016. In the same period, damages in the areas affected decreased nearly 5 times. There is a clear negative relation between vulnerability and wealth, which is strongest at the lowest income levels. This has narrowed gap between poorer and richer countries, which remains considerable.
Moreover, although the effects of climate change are overall negative, there are also some positive outcomes. In the case in question, for example, with the further increase in temperature, snow and ice related hazards will strongly diminish by the end of the century. Similarly, deaths caused by cold, which today are ten times those caused by heat, will decrease.
Many people who regularly claim that we should “follow the science” and accuse those who challenge the prevailing scientific hypothesis of denialism have usually no objections if, unscientifically, all natural disasters are blamed on climate change while the positive effects are ignored.
A typical case of double standard.