In January of this year, a landslide cleaved away an entire section of the city of Niscemi in Sicily, resulting in a massive two-and-a-half-mile-long chasm that left homes and other buildings teetering on a steep cliff.
Roads, cars, and structures were swallowed by the collapse of the hillside on which part of the city rested. The landslide was preceded by the torrential rains of Cyclone Harry. The storm that pounded Sicily is estimated to have been intensified by as much as 15 percent as a result of anthropogenic global heating. The landslide in Niscemi can hence be said to have been affected, at least in part, by global warming.
More heatwaves, floods, droughts and rising seas—these consequences of anthropogenic global warming were predicted as long as 50 years ago. Just glancing at headlines from around the world today proves those predictions to be painfully accurate.
Other consequences of our greenhouse gas emissions were not necessarily apparent when scientists first started to anticipate the results of our amped-up atmosphere. Few anticipated the number and magnitude of landslides would increase. Only well into the 21st century did researchers begin investigating the connection between landslides and global heating.
Landslides occur when rock and soil subside quickly from mountains or hills. They are caused by a number of factors, including volcanic and seismic activity and severe, climate-change-driven storms that saturate soil and rock formations. They can be inconvenient and costly, as they damage or destroy roadways, rail lines, and homes. Landslides can also be deadly, sometimes killing tens of thousands.
Perhaps having such disasters in mind, a team of Dutch and Italian researchers looked at Italy, with its northern region in the Alps, as well as the mountains that traverse the country from north to south, and assessed how much climate change would increase landslides. Their work was published this week in the journal Natural Hazards and Earth Systems Science, with a surprising result.
The scientists looked at two climate change scenarios: one of climate change caused by moderate greenhouse gas emissions and the other caused by more extreme, higher emissions. In examining these scenarios, the scientists found climate change will result in an overall drier climate throughout the Italian peninsula, but one with increasing rainfall variability. There will be longer periods of drought, but when it rains, the storms will often be more severe. Greater rainfall will increase the destabilization of rock and soil in Italy’s hills and mountains, causing more landslides.
Now the counterintuitive finding of this study was the scenario in which less warming caused more landslides. That doesn’t seem to make sense, but with less warming, the Italian countryside will not dry out as much. More moisture will already be in the soil when rains come, setting up conditions conducive to landslides.
And it was just last week that researchers at the University of Washington published the “Landslide Exposure Database,” a compilation of a broad range of data that rates 128 million buildings across the U.S. for their susceptibility to landslides. The research team also included socioeconomic data to rate folks’ vulnerability to the disruption caused by landslides as well as an assessment of how climate change will increase the number of landslides in the U.S. To read more about this database, earth.com has more on the story.
Other researchers throughout the world, though not directly linking climate change to increasing landslides, are making that connection in their climate change papers. A paper published this past April linked increased summer rainstorms in Beijing with climate change. The authors associated these rainstorms and resultant flooding with subsequent landslides.
Comments
Nothing yet. Say the first thing.
Sign in to join the conversation.