Gradual increase of the Earth's surface temperature can cause many significant changes on the climate of our planet. This problem is progressively increasing. One of the main reasons for this phenomenon is the absorption of the Sun's energy and lack of proper reflection of emissions due to man-made activities, one of which is the increase in black surfaces. In this descriptive and cross-sectional research, black surfaces in Gonabad city and the average heat absorption in amount and the increase in average heat absorption due to these surfaces were calculated by physical formula. To date, we used the information obtained from Gonabad Isallobars Office (GIO) and other related offices in the region (from 1980-2009) and performed a simple experiment to support our claim. Many factors were found to be the cause of the increase in average surface temperature of earth, such as increase in black surfaces. These surfaces appear not only on residential buildings but also on roads which have increased (637%) during this 30-year period in Gonabad city. It was calculated that 864 m3 of the air should be replaced to cool 1 m2 of the black surfaces. The average heat of the land surface in desert cities seems to increase rapidly. Therefore, it deserves much attention on the part of local managers and city officials to design plans and make some decisions for reducing or alleviating the problem as soon as possible.