Climate change and its influence on lake navigation.

According to an international study, more than half of the world’s lakes have shrunk since the 1990s, unfortunately, the main cause is climate change.

These studies investigated the health of some of the world’s largest freshwater sources – from the Caspian Sea to Lake Titicaca – and the influence of climate change and human activities on water storage.

Lakes are often considered “sentinels of climate change”, integrating many climatic processes, precipitation, runoff, and evapotranspiration in their cycle. The amount of water that lakes accumulate therefore reflects both short- and long-term climate changes.

These changes affect every type of living being in the lakes, and the consequences are tangible. Many species will adapt, but many others will not.

But let’s see why the lakes are drying up and how this could be a problem for navigation.

According to an international study,“Satellites Reveal Widespread Decline in Global Lake Water Storage”, more than half of the world’s lakes have shrunk since the 1990s, unfortunately, the main cause is climate change.

This study investigated the health of some of the world’s largest freshwater sources – from the Caspian Sea to Lake Titicaca – and the influence of climate change and human activities on water storage.

These changes affect every type of living being in the lakes, and the consequences are tangible. Many species will adapt, but many others will not.

But let’s see why the lakes are drying up and how this could be a problem for navigation.

The lakes of the world are drying up, here’s the cause.

Scientists evaluated nearly 2,000 major lakes using satellite measurements combined with climate and hydrological models and found that unsustainable human use, changes in rainfall and runoff, sedimentation and rising temperatures have lowered lake levels globally. Between 1992 and 2020 it showed a decline in 53% of the lakes.

Human activities greatly influence water storage in lakes and are involved in their reduction.

The Surface Hydrologist of the University of Virginia, Fangfang Yao, affirmed in his research that 56% of the decline of natural lakes was driven by climate change leading to rising temperatures and human consumption of reservoirs.

We are talking about huge water basins, such as the Aral Sea in Central Asia and the Dead Sea in the Middle East, or the lakes in Afghanistan, Egypt, and Mongolia, affected by the increase in temperatures.

Italy

A future without water also awaits our Lake Como.

The increase in temperature is causing ever-greater summer droughts and is making it necessary to have greater availability of water, in the summer for irrigation of the fields but also the sustenance of livestock.

The potential increase in temperature and the estimated monthly variations in precipitation would lead to an overall reduction in the snowpack, visible above all at the end of the accumulation season, essentially coinciding with the month of April for most of the basin area. This variation in precipitation and temperature and the modified snow-glacial dynamics will have consequences on the water flows entering Lake Como.

Regarding the management of Lake Como in particular, but also of many other Italian lakes, sector studies show a general increase in the volume of water in the winter and a reduction in the summer.

New navigation and water use management strategies will therefore be needed, to be studied from now on, based on credible hydrological scenarios.

Lake Como, with its volume of 23.4 km3, is the third largest lake in Italy. The lake area is characterized by a temperate climate, while the contributing basin has an alpine climate, with cold and snowy winters at medium-high altitudes.

The regulation of the lake, at the Olginate dam, is necessary to provide for the seasonal irrigation needs downstream. Water is accumulated in winter, to be released in summer, limiting the risk of flooding along the lake shores as far as possible.

Therefore, the navigation can shortly need a change in the routes and maybe also in the departure times, according to the scenarios.

However, everything is unpredictable, which is why the economy that circulates the lakes is also affected and will be affected shortly.

Garda Lake: a suspended boat to raise awareness of climate change

In Manerba del Garda, a boat appeared suspended 75 cm above the water level, the same as the lake had lost in just four years. The cause? Prolonged periods of drought due to climate change. A problem that can no longer remain unnoticed. The suspended boat, created by Sicilian artist Domenico Pellegrino and part of an installation designed by E.ON Italia, is a palpable image of the consequences of the climate crisis and the human footprint on the environment. E.ON installed it in Manerba del Garda to raise awareness of the issue and play its part in making Italy a greener country. Just as the mantra goes: Make Italy Green.

With the aim of actively inviting everyone to take action against climate change, E.ON initiated an original flashmob near the island of San Biagio. E.ON employees and citizens joined in a human chain, symbolising the active and participatory movement. The flashmob is meant to symbolically represent the solution: a movement of people who, acting together, are able to reverse course, reducing their emissions and fighting climate change.

“Goletta dei laghi”

Another initiative is “Goletta dei laghi”, a campaign annually organised by Legambiente to monitor Italian lakes. In Italy, from north to south, twelve regions have been affected by the Legambiente campaign, in which hundreds of volunteers have worked in the territories to help sample lake water.

In Piedmont, there were three days of events, press conferences and citizen science activities to present data from micro-biological analyses carried out on Lake Maggiore (Piedmont shore), Lake Orta, the Avigliana lakes and Lake Viverone. Of the 23 points sampled on the lakes, 13 were above the legal limits.

Sources

https://environment.virginia.edu/news/satellites-reveal-widespread-decline-global-lake-water-storage

https://cires.colorado.edu/globallakes

https://www.nature.com/articles/s41586-021-03550-y.epdf?

www.ecologica.online/2022/07/26/laghi-vittime

La Goletta dei Laghi (Legambiente)

Goletta dei laghi

– Sara