What causes climate change? How does the climate change?

climate is the average or statistical state of meteorological elements and weather phenomena for a long time, and the time scale is months, seasons, years to hundreds of years. Climate is measured by the characteristics of cold, warm, dry and wet, and is usually characterized by the average value and deviation value in a certain period. Climate is the general state of the atmosphere in a certain area of the earth for many years. It is a comprehensive expression of various weather processes in this period. Various statistics (mean value, extreme value, probability, etc.) of meteorological elements (temperature, precipitation, wind, etc.) are the basic basis for expressing climate. The formation of climate is mainly caused by the change of heat, so there are three main factors for the formation of climate: First, radiation factors solar radiation is the source of heat energy on the ground and in the atmosphere. The balance of ground heat budget is an important reason that affects the formation of climate. For the whole earth, the balance of ground heat budget is zero, but for different regions, the heat received by the ground is different, which will have an impact on the formation of climate. At the same time, after receiving heat, the ground continuously exchanges heat with the atmosphere. The components in the process of heat balance also have an important influence on climate formation. Second, geographical factors' influence on climate formation is manifested in geographical dimensions, land and sea distribution, topography and ocean currents, and the influence of geographical factors on climate formation can be attributed to radiation factors in the final analysis. Different geographical dimensions receive different heat, resulting in different climates; Because the ocean and the mainland have different thermodynamic properties, such as volume heat capacity and thermal conductivity, the ocean and the mainland are significantly different in climate. Comparatively speaking, the diurnal range and annual range on the mainland are larger than those on the ocean. The annual range of temperature is an important indicator to distinguish the continental climate from the maritime climate. Moreover, the mainland is a heat source in summer and the ocean is a heat source in winter, and the heat source is conducive to the formation and strengthening of low-pressure systems. The cold source is beneficial to the formation and strengthening of the high pressure system. The distribution of land and sea divides the planetary wind belt into several high and low pressure activity centers, which have an important influence on the climate formation. In addition, the different distribution of land and sea also affects the weather changes. The influence of topography on climate formation lies in that at high altitude, the direct solar radiation increases, the scattered radiation decreases, the temperature decreases and the humidity decreases. Different topography also has different effects on climate, and the plateau has obvious effects on climate. The influence of ocean currents on climate is also caused by heat, and the ocean is an important storage of heat on the earth's surface. Third, circulation factors include atmospheric circulation and weather system. The average temperature of the earth seems to have been very stable in the past 1, years, with fluctuations of less than 1 C. It enables human civilization to flourish at the current comfortable temperature of 15℃. However, the success of human civilization itself poses a destructive threat to the climate that has taken care of us so far. The greenhouse gas "protective blanket" naturally formed in the troposphere (less than 1% in the whole atmosphere) plays an important role in regulating the earth's climate. When solar energy reaches the earth in the form of visible light, It will warm the earth's surface. The earth, which is much colder than the sun, will reflect this energy back into space in the form of infrared radiation or thermal radiation. Greenhouse gases can prevent infrared radiation from directly entering space. The resulting "natural greenhouse effect" makes the earth's temperature 3℃ higher than that without this effect, which is essential for the living conditions as we know it. The problem we are facing now is that since the beginning of the industrial revolution 25 years ago, Our greenhouse gas emissions have been making this protective blanket thicker and thicker at an unprecedented rate. This has brought about the most dramatic changes in the atmospheric composition for at least 65, years. Unless we make great efforts to reduce greenhouse gas emissions, the global climate will continue to warm rapidly in the next decades or even longer.