As of 31.12.2020, 73% of Bulgaria's population or 5 043 186 people live in cities. Despite projections of overall population decline, the urban population is expected to reach 81% of the total population by 2050. This concentration in cities puts pressure on land, infrastructure and services and exposes more people to disaster risks due to the higher concentration of vulnerable groups.

Analysis of past and current weather events shows that Bulgarian cities have experienced an average annual increase in temperature and an increased number of days with intense rainfall, often accompanied by storms or hail and associated with an increasing number of floods that have caused significant damage in recent years.

There is a wide range of likely interrelated impacts in urban areas from future climate events. These include damage to buildings and urban infrastructure, health impacts, threatened key services including food and electricity supply, reduced mobility and accessibility, and stress on water use, as well as increased financial pressure on municipalities for infrastructure maintenance and for emergency response funds and personnel. Overall, climate change will have a greater impact in large cities. More vulnerable to extreme climate events will be central urban areas with higher densities, heavy traffic, reduced green and open spaces, and old infrastructure with limited capacity. Extreme weather events will also significantly affect more vulnerable groups, including those living below the poverty line, in poor standard housing, the homeless, the elderly and the sick.

Based on the risk assessment, vulnerability to urban climate change will be based on the following:

Extreme temperatures:

- Higher temperatures leading to the formation of heat islands, which will occur more frequently and last longer, will have the greatest impact on large cities with increased density and intensity of development

- Extremely cold temperatures and cold waves are not often expected, but can last for several days in a row and affect life in both large and small mountain towns. When combined with heavy snowfall, they can threaten vital services, including food supplies

Intense precipitation:

- Floods will increase in frequency and will affect all settlements causing damage in both large and small towns. The most vulnerable will be neighbourhoods located near watercourses and those of large cities built illegally on their periphery in flood-prone areas

- Hailstorms, which often combine with intense rainfall, will also cause urban flooding and damage buildings, vehicles, public transport and infrastructure

- Prolonged rainfall combined with rising groundwater levels or sewage intrusion and some additional anthropogenic factors will trigger landslides, especially those in the most sensitive areas of the Black Sea and Danube cities. Further aggravating factors in this respect are abrasion and erosion

- Landslides can also be triggered by earthquakes typical of the country. Although earthquakes are not linked to climate change, their major impact on the urban environment and people's lives must be taken into account in the adaptation process

Scarcity of water resources:

- High temperatures, combined with drought, will increase pressure in settlements where there are water shortages and outdated networks in which large amounts of water are lost