与气候变暖相联系的极端天气、气候事件及其影响的研究正日益受到重视,极端事件与气候变化直接相关,而极端事件的影响还与人类的适应行为密切相关。本文以农业对温度变化最敏感的黑龙江省为例,分析了变暖对夏季低温冷害事件的影响。结果显示,变暖后夏季出现低温冷害临界气温的概率减小;但由于人们追求更高经济效益的适应行为,在变暖的情况下种植更适应较暖气候条件的农作物,低温冷害的发生的频率和强度并不一定随变暖而减少,但作物单产期望值还是会增加。

More and more importance has been attached to the extreme weather and climate events related to climate warming and their impacts. Changes of extreme events are directly related to climate change, while the impact of the extreme events is as well as depended on the adaptation behavior of human being.A case study is made in this paper on change of cool summer hazard under an adaptation behavior to the climate warming in Heilongjiang Province, Northeast China. Heilongjiang Province in Northeast China located in the highest latitudes of China is one of theriod (1990-1999), almost no cool summer hazard happened. Theoretically the risk of crops planting impacted by the cool summer hazard will be decreased accordingly. However, it does not mean that the frequency and intensity of the cool summer hazard rea lly decreased. Because farmers may change the variety of the crop or the crop's structure to adapt to the climate warming in order to obtain more economicbene fits. In fact, human regions where agriculture is most sensitive to temperature variations in China. The impact of climate warming and adaptation behavior to the cold summer hazard in Heilongjiang Province is analyzed in this paper. It is found that the growth period mean temperature increased and the standard deviation of the temperature decreased. In theory, the probability of extreme low summer temperature would decrease accordingly. If the planting mode was kept unchanged, that is, the criterion of cool summer hazard was not changed, the frequency of cool summer hazard would be reduced to about 10% in the warm period (1980-1999) and about 30% in the cold period (1960-1979) in most parts of Heilongjiang Province. In the intensive warming pe being's adaptation interfered the impact of climate warming on the probability of cool summer hazard. In general, people seek for maximal economic benefits instead of the minimal risk. When climate warms up, people would select plant varieties more suitable to warmer climate to obtain more economic benefits, but the probability and intensity of cool summer hazard might not always decrease as climate warms.