Global climate warming,disasters increasing and agricultural productivity safeguarding

Three periods were clearly divided based on decadal mean temperatures of global surfacetem peratures in recent 120 years(from 1880 to 1997) The first ogre was the period of lower temperature(from 1880 to 1919，at least 40 years)．the second one was the period of transition (fluetuation oftemperature was not too big，from 1920 to 1979，about 60 years)，the third one was the period of temperature increasing．We understand the temperature of the Little Ice Age was lower than that of the period from 1880 to 1919 according to the references of the Little Ice Age(from 1450 or 1490 to 1850 or 1880．about 400 years )．Therefore we imagined the duration of lower temperature is about 450 years．The variations of temperature for the recent 450 years are the kind of the process of unidirectional，gradual change．Another three periods may be also divided according to the situation of EI Nino emerging in 20st century The first period that of EI Nino accidental emerging from 1900 to 1940 The second period was that of E1 Nino middle emerging from 1940 to 1980，the global temperature was increasing at faint or middle level for this period．The third period is that of frequendy emerging of El Nino trom 1980 to 1998，the global warming is ohviousiy．In recent 100 years，the situation of El Nino emerging is similar with the process of unidirectional，gradual change for global temperature．The new viewpoint，that is to pay cLose allention to the influences on the piled effects of greenhouse effect and El Nino，is given out after the thermal inertia of ocean being considered．We think the El Nino will be frequently emerged and global teraperature,gill also kept warmer for several decades or longer periled in the future．The natural disasters，such as flood，drought，bio-calamities etc．,will be frequently took place following El Nino and global warming．Therefore,we should do the works for taking precautions against and reducing natural calamities,and safeguard the sustainable agriculture productivity．