LHASA, July 4 (Xinhua) -- The average temperature in Tibet for the first four days of July is up to five degrees higher than the average temperature on the plateau region in previous years.

    Temperatures were three to five degrees higher in Xigaze Prefecture, Shannan Prefecture and areas around Lhasa over the past four days, He Xiaohong, a senior engineer with the region's meteorological station, said on Wednesday.

    The temperature in Lhasa on Monday reached a high of 29 degrees,the highest in 30 years for July.

    Low rainfall and dry, hot weather have resulted in drought in some areas such as Xigaze and Shannan, but the situation is not serious, He said.

    Global warming has decreased the thickness of frozen earth on the Qinghai-Tibet Plateau by four to five meters in the last 50 years.

    The plateau, regarded as a barometer for the world's climatic conditions, has seen its glaciers melt at an annual average rate of 131.4 square kilometers over the past three decades.

    And the situation is set to worsen. Tibet experienced its third"warm winter" in the last seven years this year, with a temperature rise of nine degrees more than average in some areas.