introduction
Kilimanjaro is the highest mountain of volcanic origin on the continent of Africa, which is characterized by a distinct cone–shaped shape composed of a large number of layers of lava, volcanic ash and tephra. Thus, Kilimanjaro is a stratovolcano. It consists of three main peaks: Shira, Kibo, and Mawenzi. The volcano has not fully erupted since 2008 and is currently extinct and inactive [Scoon 2016: 61].
In recent decades, the volcano has attracted the special attention of environmental scientists. A tropical glacier has been formed at the top of Kilimanjaro, which is currently in the process of rapid melting. You can even notice strong changes in its size from photographs. In 1912, the glacier covered an area of 12.1 km2, and in 2006 – 2 km2 (Fig.1) [Thompson].
 
Figure 1. Kilimanjaro in 1915 and 2006 [Thompson]
The glacier on Mount Kilimanjaro is included in the UNESCO Heritage List and, according to this institution, it will completely disappear by 2050. This ecological disaster will lead to changes in the structure of the flora and fauna of Tanzania, as well as threaten the shallowing and drying up of Africa's largest freshwater sources – the Nile and the Congo. Thus, the problem of the melting of the Kilimanjaro glacier is one of the most pressing environmental and economic problems of the continent [UNESCO]. 
The aim of the work is to predict the melting of the glacier by 2100 and to develop methods for its conservation.
The tasks are:
1. To identify the degree of change in the glacier area.
2. To assess the risks and possible consequences of this process.
3. Predict the melting of the glacier by 2100 while maintaining the current conditions in the region.
4. Recommend ways to solve this environmental problem.
5. Predict the melting of the glacier by 2100, taking into account all the ways to preserve it.
 
CHAPTER I. THE CURRENT STATE OF THE GLACIER ON MOUNT KILIMANJARO
1.1. General information about the state of the glacier.
The earliest reports on the state of the glacier date back to 1888. They say that one of the peaks, Kibo, is completely covered with an ice cap. This conclusion was made by Hans Meyer, who with his team made the first ascent to the top of Kibo and measured its real height. The report also recorded the area of the glacier – about 20 km2, which extended to a height of 4,500 m. The next study of the glacier took place in 1938 using an aerial photograph: at that time the glacier occupied an area of 11.4 km2. [Scoon, 2016: 68]
You can visually trace the dynamics of the glacier using Google Earth. Figure 2 shows satellite images for 1984, 1994, 2003, 2014 and 2019, and Table 1 shows data on the size of the glacier by year [Google Earth].
 

Table 1. The trend of interannual variability in the size of the Kilimanjaro glacier
According to research over the past 100 years, the glacier has been melting by 1% per year, and since 1998 there has been a 40% decrease in the area [Scoon, 2016: 69].
The glacier on Mount Kilimanjaro is tropical and therefore its melting process differs from the melting processes at the peaks located in the middle latitudes, closer to the poles. Glaciers in the middle latitudes are melting due to an increase in temperature, that is, under the influence of ambient air and with the transformation of solid ice into liquid water. At the top of Kilimanjaro, the temperature reaches its maximum at -3 ° C, so it is more correct, from a physical point of view, to call this process sublimation, since water immediately passes from a solid state into water vapor [Thompson]. 
1.1. The causes of glacier melting.
 To date, there are two main causes of glacier melting on Mount Kilimanjaro. 
The first reason is climate change and global warming. Between 1961 and 1990, temperatures in Africa increased by about 0.2°C per decade, and from 1991 to 2021, temperatures increased by 0.3°C per decade. The year 2021 was one of the hottest on record in Africa (Fig. 3). (1) Kilimanjaro is located near the equator, which makes it more vulnerable, as the air warms up faster [Meteoblue].
 
Figure 3. Change in average temperature in Africa from 1980 to 2020. Blue color - temperature below average, red - temperature above average [Meteoblue]
The second, but no less dangerous reason for the melting of the glacier is the deforestation of the slopes of Mount Kilimanjaro. Most of the moisture comes from mountain forests, so their deforestation leads to a decrease in humidity, which prevents glaciers from growing and maintaining their original size [Schatz]. 
In addition to these reasons, the glacier is affected by the growth of tourism – it leads to an increase in external influences, including environmental change and pollution. These actions accelerate the melting of the glacier, as the reflectivity of the ice decreases and solar radiation increases.
1.2. Consequences of glacier melting.
The consequences that a complete loss of a glacier can lead to are diverse. First, there is climate change. Mountains play an important role in the formation of climate and circulation of air masses. The reduction of the glacier and its complete disappearance will significantly affect weather conditions both in the surrounding areas and in the region as a whole. 
Further, the melting of the glacier will lead to the loss of unique ecosystems. There are microecosystems adapted to constantly low temperatures and access to meltwater. Accordingly, changing environmental conditions will have a detrimental effect on biodiversity. 
The likelihood of landslides and floods will also increase. A large amount of ice that melts and slides down the slopes threatens both people and the flora and fauna of the foothill areas, and can lead to the destruction of infrastructure. 
In general, the melting of the glacier on Mount Kilimanjaro has serious consequences for the ecology, water supply, climate and economic development of the region, as well as for local communities and public infrastructure. This requires urgent measures to combat climate change and preserve the environment.

 
CHAPTER II. FORECASTING GLACIER MELTING BY 2100
2.1. Calculation of the glacier area in 2100. 
Taking into account the statistics on ice melting at the top of Mount Kilimanjaro, described in chapter I, it is possible to predict by which year the glacier will cease to exist without changing the current conditions in Tanzania. 
To calculate the area of the glacier by 2100, data on average temperatures in the studied area will be required. The average air temperature is taken from the climatic data of the city of Moshi, as it is the closest to the object under study. The average air temperature in the hottest month (February) is 32°C, the average air temperature in the coldest month (July) is 16°C. Thus, we will take 24 °C as the average temperature per year.
Given that the temperature rises by 0.3 °C every decade, let's calculate how many degrees the average air temperature in Moshi will rise by 2100 (in 77 years):
0.3°C * (77 years / 10 years) = 2.31°C
Therefore, by 2100, the average air temperature in Moshi will be 24 °C + 2.31 °C = 27.4°.
Now it is possible to calculate the theoretical area of the glacier in 77 years, given that its annual reduction is 1%:
2 sq.km * (1 – 1% * 77 years) = 2 sq.km * (1 – 0,01 * 77 years) = 0.46 sq.km
Based on these calculations, it can be concluded that by 2100 the area of the glacier will be 0.46 sq.km. This means that in 77 years the glacier will occupy only 3.8% of its original size in 1912.
2.2. Aggravation of already existing problems related to the reduction of the glacier.
Due to the decrease in the glacier area, the environmental problems described above will worsen. 
1. Climate change. 
As described above, glaciers play an important role in climate formation. They reflect the sun's rays, preventing them from directly hitting the earth, that is, they reduce the amount of heat reaching the earth. The reduction of the glacier on Mount Kilimanjaro will lead to a decrease in the reflective effect, which will lead to an increase in air temperature in the region. 
Also, the glacier is an important source of nutrition for the rivers of the region, provides local water supply. Its reduction will also lead to a reduction in precipitation, which will negatively affect vegetation, wildlife and water distribution in the region. During periods of heavy rains, more floods will occur, as the glacier will not be able to hold enough water. And during periods of drought, when water is needed, there will be a shortage of it.
It is not possible to make accurate calculations of changes in temperature and precipitation in the region, since in addition to the glacier, a large number of factors affect the climate, however, scientists predict that the reduction of the glacier may lead to an increase in temperature by 1-2 degrees and a decrease in precipitation by 10-15% in the region.
2. Reduction of biodiversity.
The shrinking of the Kilimanjaro Glacier may also have a serious impact on biodiversity in the region. Firstly, as already mentioned, this will lead to climate change, and consequently to droughts, deforestation of some parts of the mountain, the destruction of familiar ecosystems, and in the future, the extinction of some plant and animal species. In addition, the reduction of the glacier will lead to the loss of a large amount of fresh water, which is a necessary resource for many species, therefore, it will also lead to extinction or migration to other areas in search of water. Migration is also a negative consequence, as species will occupy already occupied ecosystems and displace the species living there.
 

There are about 1,000 plant species on Mount Kilimanjaro, 250 of which are endemic. Many of them are currently under threat of extinction due to habitat loss, climate change and human activity. Many of them grow in the tropical forests of Kilimanjaro, but there are also unique plants from the wastelands and the Arctic zone of the mountain. For example, the plant Dendosenecio kilimanjari, also called the "giant lily of the valley", which reaches 12 meters in height. 
Also, endangered and endemic animal species are found on the mountain, such as Cephalophus spadix – Abbott's duiker, red book antelope, Ceropithecus mitis – blue monkey. 
All these endemic species are part of the unique ecosystem of Kilimanjaro and their extinction can seriously affect the biodiversity of the region. 
3. The economy of the region.
The reduction of the Kilimanjaro Glacier will have a strong impact on the region's economy. Firstly, as previously mentioned, there will be a reduction in water levels in rivers and lakes, which will negatively affect agriculture and fishing. This can lead to a reduction in production and income of local residents, as well as an increase in food prices.  Secondly, Mount Kilimanjaro, and in particular the glacier, is one of the most popular tourist attractions in Africa, attracting about 600 thousand tourists from all over the world every year. The reduction of the glacier can negatively affect the uniqueness of this place, its landscape and environmental attractiveness, which will affect the number of tourists and the region's income from tourism. For example, if the glacier disappears completely, this may lead to a reduction in tourist routes and complication of access to some of them.
In addition, the reduction of the glacier will lead to increased spending on infrastructure and environmental protection measures, which will also affect the region's economy. 
Therefore, the preservation of the Kilimanjaro glacier is not only an ecologically important task for the conservation of biodiversity and ecological balance, but also important for the economic well-being of the region.
 
CHAPTER III. POSSIBLE WAYS TO PRESERVE THE GLACIER
3.1. Artificial precipitation of snow and ice.
It is possible to solve the environmental problem for a short period by artificially depositing snow or ice on the mountain tops using special technologies. In 1959, ice was delivered from the city of Mu-i-Rana (Norway) to Libreville (Gabon) for the purposes of an advertising campaign. Engineers calculated that 800 kg of glass wool would be needed to reduce the natural melting of 3,000 kg of ice by 10%. Thus, this solution is quite possible, but not long-term and allows only to preserve biodiversity [Folkestad].
Artificial snow is also used in most ski towns at the moment. Crystals of perfect shape are created from water. 
 
Thus, the Carosello-Tonale team builds up the snow mass on the Presena glacier every year with the help of snow cannons. According to the developers, the process of artificial ice creation is as close as possible to the natural one. One such snow cannon is ready to produce about 90 m3 per hour, with costs in the form of 36 thousand liters of water and 23 kW of energy per hour. As of March 2023, water and electricity prices in Moshi, Tanzania are as follows: $ 0.05 / liter of running water and $0.095 / kW of energy. Therefore, the hourly operation of the snow cannon will cost $ 1,800 for water and $2,185 for electricity. TechnoAlpin has installed an artificial snow deposition system in Switzerland that runs entirely on hydroelectric power, which is a more environmentally friendly and cheaper method, and the possibility of using wind turbines as an energy source is also being considered.
3.2. The use of a textile tarpaulin.
Nowadays, it is also popular among ski resorts to preserve glaciers in the hottest months with the help of tarpaulins. In 2008, this method was used for the first time in Italy. Tarpaulin is an artificial fabric covering that allows you to reflect the sun's rays and maintain a low temperature. Since the first use of this technique, 70% of the glacier has been preserved. In 2021, specialists used 70 meters of tarpaulin, covering 11.7 hectares of the surface. At the moment, the same method is used in Switzerland to preserve the Rhone Glacier in the Alps and the Helags glacier. The method is also used in China. Researchers from the Northwestern Institute of Ecology covered the Sichuan Glacier with a tarpaulin in 2020. After 2 months, they noted that the glacier in the covered part had shrunk by less than 1 meter in the uncovered part.
 

To reduce the negative impact on the environment, a biodegradable canvas was created. It has already been tried on the Helags glacier. 
3.3. International cooperation.
In the long term, first of all, the solution to the problem will be the conclusion of international agreements on glacier protection and reduction of greenhouse gas emissions. The fundamental point should be the transition to renewable energy sources (solar panels, wind turbines). The fight against global warming and climate change cannot take place only on one continent, in one region – this is a global problem that requires a joint solution. It is also worth raising awareness of the problem of climate change and melting glaciers at the international level. This will allow more people to realize the importance of minimizing their carbon footprint.
It is important to create such conditions in the region to reduce the melting of the glacier in order to achieve a reduction in the consumption of meltwater. That is, the maximum use of rainwater for irrigation, as well as the use of drip irrigation systems in agriculture. 
3.4. Tourism regulation.
Since tourism is one of the main sources of income in the Kilimanjaro area, it causes considerable harm and therefore the regulation of tourism plays an important role in solving the problem. The introduction of restrictions on the number of visits, the length of stay and the development of strict security measures to minimize the negative impact of tourism on the glacier. 

 
conclusion
So, analyzing the problem of glacier melting on Mount Kilimanjaro, we come to the need to take measures to solve it. Forecasts indicate that in the coming decades, the glaciers of Kilimanjaro may disappear completely, which will lead to serious consequences for the environment and the local ecosystem.
The main risks associated with melting ice include reduced availability of fresh water, changing climatic conditions in the region and threats to biological diversity. 
Comprehensive measures must be taken to solve the problem of the melting of the Kilimanjaro glacier. First, it requires global action to reduce greenhouse gas emissions and combat climate change at the global level. Secondly, it is necessary to create certain conditions for life in the surrounding areas, without using melt water. It is also important to implement educational programs aimed at raising public awareness of the importance of glacier conservation.
In general, solving the problem of glacier melting on Mount Kilimanjaro requires not only concrete actions at the local level, but also international cooperation. Only through joint efforts will we be able to stop the melting of the ice on Kilimanjaro and preserve this unique corner of nature for future generations.

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