The Hong Kong Observatory forecasts that four to six typhoons are expected to hit Hong Kong this summer, but it is difficult to estimate their scale.

Speaking at a radio talk show Saturday morning, Hong Kong Observatory Director Lam Chiu-ying said high temperature is a normal phenomenon in July and August in Hong Kong, especially whenthere are typhoons in the southeast which will draw the hot air current from the mainland in the north.

"The high temperature that continued for some time a few days ago was brought about by severe tropical storm Mindulle," he said.

Lam pointed out that Hong Kong's rising temperature is in line with the trend of global warming and it is also a result of the city's high building density.

"The world's average temperature reached a record high in 1998,while that for 2002 ranked second and 2003 ranked third. It shows that the global temperature is gradually on the rise," he said.

"In Hong Kong, the population growth, the high building densityand the increasing electricity consumption are factors for the rising temperature," he said.

"At night time, the concrete buildings will release heat which makes it difficult for the temperature to drop," he added.

On the rising sea level, Lam said there was an annual increase of only about 2.3 mm in the past 50 years. As works departments have already taken this factor into account in coastal construction, there should be no worry about flooding.

He said the increase in temperature fluctuation, another phenomenon of global warming, should raise concern. It affects theecological system and the life-cycle of microorganisms, which willcause food and health problems for the world and lead to socio-economic problems.