Satellite images have revealed that the consequences of global warming can be seen from space as the Alps turn greener.
The European mountain range is covered by a blanket of snow for most of the year, attracting skiers and snowboarders from all over the world.
But new data has found that vegetation above the tree line has increased by almost 80% in the Alps over the past 38 years.
While new plants can help reduce carbon dioxide, a greenhouse gas, this is threatening biodiversity in the mountains.
Shrubs that are better adapted to new climatic conditions will outnumber many alpine plants, researchers from the University of Lausanne and the University of Basel said.
They also found that snow cover had decreased significantly by almost 10% of the measured area.
Lead author and assistant professor Sabine Rumpf concluded that the observations were the result of climate change and are likely to get worse.
Satellite images reveal that the consequences of global warming can be seen from space as the Alps turn greener. Aerial photographs of the Alps taken in 1998 (left) and 2021 (right) show an increase in vegetation because it is slightly greener.
This is a black and white aerial photograph of the Swiss Alps taken in 1984 when the study began. Over the next 38 years, global warming caused an increase in vegetation and a decrease in snow cover, as scientists in Switzerland have pointed out.
Graphs showing vegetation and snow cover changes in the European Alps from 1984 to 2021; A – Vegetation productivity, B – Summer snow, C – Snow all year round. The D bar graph shows these changes as the proportion of colored pixels in the graphs
He said: “The scale of change has turned out to be absolutely massive in the Alps.
“Greener mountains reflect less sunlight and therefore cause overheating and, in turn, greater shrinkage of the reflective snow cover.”
Mountain landscapes are points of biodiversity and provide a number of important ecosystem services.
For example, the melting water of alpine glaciers and snow provides almost half of the world’s freshwater resources.
However, mountain environments are also more susceptible to climate change and are warming at about twice as fast as the global average.
This is suspected to be the result of the loss of the tops of its snow-white layer that reflects solar radiation, and is replaced by a darker-colored soil that absorbs heat.
The new coloring is believed to complement the heat-capturing effect of greenhouse gases and heat up more quickly relative to land that has never had snow cover.
However, while the melting of glaciers has become a symbol of climate change in the Alps and Arctic regions, snowfall is not the biggest consequence in the mountains, according to researchers.
Vegetation above the tree line in the Alps has increased by almost 80% in the Alps, while snow cover has decreased by almost 10% of the area measured, since 1984.
This graph shows the “green” and “darkening” in the Alps for the last 38 years. Green pixels are proportional to the increase in vegetation, and brown pixels represent a decrease in vegetation. Frozen areas are transparent as they were not considered in the study
Professor Rumpf of the University of Basel, together with Professor Grégoire Mariéthoz and Professor Antoine Guisan of the University of Lausanne, investigated vegetation change using Landsat images from 1984 to 2021.
His study found that plant biomass above the tree line increased by more than 77% of the observed area.
This growth is called ‘greening’, and is due to the fact that plants are colonizing new areas of the Alps and the vegetation is generally denser and taller.
It is a consequence of changes in rainfall and longer periods of vegetation as a result of rising temperatures, and predominates in warmer areas.
In addition, less than one percent of the observed alpine area experienced “reddening,” where plant productivity declined.
“Alpine plants are adapted to harsh conditions, but they are not very competitive,” said Professor Rumpf.
As environmental conditions change, he says, these specialized species lose their advantage and are outgrown.
He added: “Therefore, the unique biodiversity of the Alps is under considerable pressure.”
The new study has been published in the journal Science.
GLOBAL WARMING AND MOUNTAINS
Some gases in the atmosphere, such as carbon dioxide, trap heat in a manner similar to the glass roof of a greenhouse, and are called greenhouse gases.
During the day, the Sun shines through the atmosphere and the Earth’s surface heats up in the sunlight
At night, the Earth’s surface cools, releasing heat back into the air, but some of the heat is trapped by the greenhouse gases in the atmosphere.
Human activities, such as burning fossil fuels such as coal and oil, bring more carbon dioxide into our atmosphere.
Too much of these greenhouse gases can cause the Earth’s atmosphere to catch more and more heat, causing the planet to heat up.
Since the pre-industrial period, human activities have been estimated to have increased the average global temperature of the Earth by about 1.8 ° F (1 ° C), a figure that is currently rising by 0.36 ° F (0.2 ° C). C) per decade.
Permafrost, glaciers and ice sheets struggle to keep up with warmer weather
Some animal and plant species are highly dependent on the cold and migrate to higher altitudes to find suitable habitat.
This is putting great strain on ecosystems as more animals and more species live in an increasingly small region.
In addition to environmental pressure, the lack of ice in the mountains is greatly increasing the risk of landslides and volcanic eruptions.
Permafrost, glaciers, and ice sheets struggle to keep in touch with the warmer weather that is a consequence of the greenhouse effect.
Along with colleagues from the Netherlands and Finland, scientists also used high-resolution satellite data to study snow cover reduction over the past 38 years.
Excluding regions below 1,700 meters, glaciers and forests, they looked at satellite imagery to see which areas had become “snow-free” over time.
The results found that the change in snow cover above the tree line had decreased significantly by almost 10% of the area.
This peaked in colder temperatures, driven mainly by changes in precipitation caused by climate change.
Antoine Guisan said: “Previous analysis of satellite data had not identified any such trends.
“This may be because the resolution of the satellite images was insufficient or because the periods considered were too short.”
They could not use the images to draw conclusions about the depth of the snow, but claim that previous studies of measurements on the ground have shown a decrease.
As global warming increases, the “green” will also contribute to the snow recession along with the rise in temperature.
More glaciers will melt, which could cause landslides, rock falls and mudslides, and thawing permafrost could release “blocked” greenhouse gases.
This is likely to have consequences for snow sports, tourism and drinking water supply, as well as threatening fragile alpine plant and animal communities.
Mountain environments are also more susceptible to climate change and are warming at about twice as fast as the global average, which is thought to have been reflected by the sun’s rays, but is now melting due to rising temperatures. .
Climate change has drastically altered the Swiss Alps, transforming glaciers into nearly 1,200 new lakes since 1850, and 1,000 of them still exist today.
A team of scientists from the Swiss Federal Institute of Aquatic Science and Technology (Eawag) combined data from aerial photographs of the massive mountain range and years of data on the glaciers of Switzerland to determine the inventory of the lakes.
The analysis also revealed that 180 of the existing lakes had only been created between 2006 and 2016, when 18 new bodies of water appeared each year.
According to scientists, glaciers lost 2% of their volume in 2020 alone.
Climate change has drastically altered the Swiss Alps, transforming glaciers into nearly 1,200 new lakes since 1850, and 1,000 of them still exist today. In the photo, Steisee sings from Bern
Scientists have warned that the growing number of glacial lakes increases the risk of such eruptions and therefore the danger of flood waves for the settlements below. In the photo, Griesseeli, Uri corner, between Clariden and Klausenpass
A quarter of the newly formed lakes have shrunk or disappeared altogether.
For the study, the team recorded the location, elevation, shape, and area of the 1,200 lakes at different times, along with the type and material of the dam, surface drainage, and the recorded development of the lake.
The assessment showed that there was an initial peak in glacial lake formation in the Swiss Alps between 1946 and 1973, when almost eight new lakes appeared on average each year.
From there, a brief decline was observed, but then it recovered again between 2006 and 2016, when an average of 18 new lakes appeared each year, while the water surface increased by more than 4,300 feet. squares annually.