Lake Como and Climate Change

Forest Fire Varese

Forest Fire on October 30th on Campo Dei Fiori, Varese

Man’s impact on our natural environment through climate change is becoming frighteningly dramatic in many instances. The recent flooding in Indonesia and the devastation of the forest fires in South Eastern Australia are clearly a concern to all except for the more sociopathic of the world’s leaders. Yet the impacts of climate change are not just visible on the grand scale. Even on Lake Como there is reason to be concerned that recent patterns of weather are having a negative impact on the lake’s ecosystem. 

water level

Water marks on the lake walls show the variety in water levels.

Back in June 2018 the combined Como and Lecco Chambers of Commerce held a conference to kick off a project raising awareness of what climate change is doing to our lake.  They asked what we should be doing to ensure a sustainable future for all those who live or visit the area and gain either social or economic benefits from the lake’s natural environment. Proteus, a local environmental association, was entrusted with the responsibility of raising awareness amongst the young. In turn they set up a group called ‘Resilario’ whose slogan is to re-appropriate our lake. Locals can often be heard talking proudly of OUR lake and Resilario have been astute in selecting the use of that pronoun to elicit local pride and a sense of ownership in the hope that this inspires a communal sense of responsibility.

Como Futuribile

Waterfall Moltrasio

Waterfall above Moltrasio – the mountain streams become raging torrents at times of high rainfall

Resilario and their initiative now called ‘Como Futuribile’ are still in the consciousness-raising phase of the project. As part of this, local geologist Filippo Camerlenghi recently addressed a meeting at the Universita Popolare to outline exactly how climate change is impacting the lake. And the very first thing he mentioned was the change in the distribution of annual rainfall. This last November saw 25% of total annual rain fall in the one month. Apparently our annual rainfall totals have remained constant but there is now a marked variation between wet and dry periods with a concentration of rain in the Spring and Autumn. There are a number of issues that arise from this since the level of the lake can now vary considerably during the year and we are not prepared for the impact of a distribution of this sort.

Water levels

faggeto water level

Low water levels in Faggeto lario

The lake is renowned for its many villas with their gardens descending down to walled lakeside terraces. These walls were constructed with the expectation of constant pressure from the lake’s waters corresponding to the contrasting pressure outwards from the terraced land. That balance does not exist when the water level is low and so the whole aesthetic fabric of the lakeside is under threat due to the changing need to deploy structures more designed for tidal seafronts. The weakening of these traditional lakeside walls has created crevices to appear in them at low water which then allow water to enter and permeate the shore line at high water. This water, isolated from the main mass of the lake, then freezes in the winter causing further damage to lakeside structures such as roads and pavements. This causes the sort of damage experienced recently on the Como lakefront when a massive hole opened up on the road to Villa Geno. Further evidence of accelerated erosion can be seen on the any of the walks on Como’s lakefront where the pavements suffer from subsidence and distortion.

Street damage

Lakeside erosion in Como

Agone, Laverello and Other Lake Fish


Missoltino, a local ‘delicacy’

The increased variation in water levels is also responsible for risking the recovery of the lake’s fish population, in particular the ‘agone’ – the small fish also known as fresh water sardines – which when dried and pickled are known as ‘missoltini’. If the water level drops after the agone have lain their eggs in the shallow lakeside waters, these eggs are then exposed as water levels drop and so fail to spawn. 


Mountain stream in full flow above Cernobbio

Camerlenghi was keen to point out that we need to consider the health of the lake as part of an ecosystem that includes the surrounding mountainsides. Excess rain before the cold temperatures of winter reduces the amount of precipitation stored as snow on the mountains and increases the runoff containing sand and silt carried by the two rivers that feed the lake, the Adda flowing down the Valtellina and the Nera from the  Val Chiavenna. This sand residue does not directly pollute the lake but it does coat the bottom in its upper reaches with additional quantities of silt reducing the ability of the fish to feed. The resulting local reduction in the fish population there may be one of the causes for the increase in alghi in the summer months. Alghi may also flourish due to the growing numbers of the non-native fresh water mussels which have the effect of clearing the water in shallow areas. This may appear to be a positive sign of clean and attractive water for swimming but it allows for increased penetration of sunlight and heat which again can encourage the growth of more alghi. These are just a few examples of how the lake’s ecosystem, like all ecosystems, is so delicate and thus at risk from the effects of climate change. 

Economic Impact


Summer time swimmers may well be encouraged by the clear waters filtered by the increase in fresh-water mussels. Neither do they have need to fear bacteria levels since these are all well within safety limits around the lake. These attacks on the ecosystem do not result in any increase in pollution. But the economic interests of the seventy licensed fishermen and the number of restaurants offering produce from the lake are at risk if spawning and feeding grounds for the fish population continue to be threatened. Even the Navigazione Laghi who manage the ferries across the lake have suffered some economic disadvantage. At low water they can no longer deploy the larger ferry boats transporting vehicles from and to Bellagio and Menaggio. The smaller vessels maintain the service but at a higher cost.

Lake and mountain

In normal years, precipitation during the winter is held as snow on the mountains as here on Monte San Primo.

On the 23rd August 2017 a massive landslide on the borders of Switzerland and the Val Chiavenna to the north of Lake Como claimed the lives of eight people and made over one hundred inhabitants homeless. (Dramatic video of the landslide). This event followed a torrential summer storm. The land acts like a massive sponge seeking to absorb the precipitation that falls on it. There comes a point though when the mountainsides can no longer support the weight of the additional water they have absorbed. The result is a landslide. This November saw a relatively small landslide on the hills above Cernobbio close to one of George Clooney’s favourite restaurants, the Gatto Nero in Rovenna. Fortunately there were no fatalities as in the Val Bregaglia but the only road up to Rovenna was cut off. If we continue to see excessive rainfall in months like November, there will be a need to review the whole of the communications infrastructure in the lake’s surrounding mountain communities. The danger to life is real and the potential costs of revising the infrastructure are enormous.

Is Flooding a Problem?


Como floods in 1917

Como has had its own scandal running for years on a smaller scale but similar in aspect to Venice’s attempts to construct flood defences across its lagoon. Como’s scandal resulted from the contract to build flood defences along its lake frontage. The contract was awarded to the same constructors building the Venice defences. One may want to question why flood defences were ever needed since the levels of the lake are controlled at the end of the Lecco leg as the lake runs out into the continuation of the River Adda which eventually flows into the River Po near to Lodi. Those responsible for managing the dam in Lecco are constrained by law to only take two factors into consideration when deciding how much water to release out of the lake into the lower reaches of the Adda.

water level 4

Sign in Via Diaz showing where the flood of 1673 arrived.

These factors are firstly the needs for irrigating agricultural land in the Lombardy plain and secondly maintaining sufficient flow to operate the hydro electric power plants on the river past Brivio. They are prevented by law from taking any other factor into consideration including the possible risk of flooding in Como or anywhere else on the lake. Having said that, even the record-breaking rainfall this November only caused the lake to break its banks to trickle slightly over onto Piazza Cavour – nothing like the flood levels recorded in the past. 

However the plans for Como’s flood defence became ever more extensive and costly and, clearly with the prospect of rich pickings to be made, were finally deemed illegal. The council and contractors had decided to take a chunk out of the lake without permission hoping to increase land on the lakefront which would then be highly attractive commercially and bound to sell at a high price. Some of those responsible for this speculation now face jail terms and Como still has an incomplete, useless and probably unnecessary flood defence system. Como does not need to spend massive amounts on managing high water levels but it does need to spend to counter the effects of massive water level variation. This is in effect a much more complex and less visible issue. One can only hope that our local politicians are up to facing such a challenge.

Small car ferry

One of the smaller car ferries the Navigazione Laghi are constrained to deploy when water levels are low

The Future

The Lecco and Como Chambers of Commerce are to be complimented on kicking off this initiative to raise awareness and foster the knowledge and determination to confront the issues of climate change on the lake. The Como Futuribile project will see ongoing efforts to increase local awareness and knowledge of the lake’s ecosystem and promote all forms of sustainable development. In March they and Proteus plan a live broadcast filming underwater just to let us all see what exactly is going on below the water’s surface. In one sense the concentration of rainfall in months like November, one of the quietest months for tourism, might be seen as a positive. Certainly I would advise visitors to plan on visiting the lake at any other time of year. However the impact of such heavy rainfall on the mountainsides with the associated risks of more landslides and accelerated erosion will be very costly to manage. As will be the need to secure the lakefront structures from the erosion arising from increased variations in water levels.  These impacts may all be relatively small scale but they affect the whole region and so could become a heavy financial burden. Similarly the economic impact on the lake’s seventy fishermen might be dismissed as hardly significant but those seventy are supplying the much larger catering sector who provide residents and visitors alike with an authentic lakeside culinary experience. Although personally I am no fan of missoltini, just consider how poorer the region would be if this small pickled fish disappeared from local menus. 

water level 3

This spit of land formed from the silt and sand brought down by the River Cosia only appears at very low water levels.

Finally we might be grateful that we have not experienced any of the more dramatic impacts caused by climate change such as the forest fires currently raging in Australia. However, our woods and forests do get very dry over the summer months and a repeat of the Varese fires in 2017 is always a possibility. We cannot afford any degree of complacency.


About comocompanion

I am an Englishman in Como, Northern Italy - definitely both a Euro and Italophile with an interest in modern history, walks in the hills and mountains, and food and wine. I favour 'slow' tourism alongside of 'slow' food.
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2 Responses to Lake Como and Climate Change

  1. John Doherty says:

    What a load of rubbish. Climate Change is a scam. Como has just experienced massive flooding despite CNN saying that the lake levels were falling. Como has always experienced extremes in both weather and lake water levels. Stop trying to make out that it has something to do with mankind’s carbon emissions.


    • I am not a scientist but I am open to listen to scientists. From your tone I am assuming you also are not a scientist and I gather you are neither open to listening to them. Now I am not going to tell you personally to stop ignoring science since you seem more than convinced in your views. I hope for all our sakes that few others follow your example. For the record my article presents the scientific argument that climate change has affected the distribution rather than the overall volume of rainfall on Lake Como. A very real example of this occurred this week when a month’s normal precipitation for July fell in just 24 hours. A number of lakeside communities around Como were severely damaged.


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