When was it in ancient times, 500 years ago, 1,000 years ago or 5,000 years ago? In short, since Lantian ape-man then, the highest temperature in summer will not be as high as it is today. First, there are many forests. Before the industrial revolution, people cultivated by hand, and the trees and forests were not cut down in large quantities. The forests regulated the climate, and the extremely high temperature was lower than now. Second, there is more water. Because there are many forest vegetation and sufficient water conservation, there are rivers and streams everywhere. Water is of great help to the stability of temperature. Extremely low temperature and extremely high temperature will be effectively limited. Third, there are few people. The population in the world is increasing, and people&;s food, clothing, housing and transportation always consume forests, water, energy and heat. For example, air conditioners, cars and high-rise buildings generate heat or absorb reflected sunlight, which causes the surrounding environment to heat up. 4. Industry. Industrial production, such as boilers, heat treatment, power generation, steelmaking, power transmission, etc., will generate a lot of heat, which will &”;add fuel to the fire&”; to the high temperature in summer. El Nino phenomenon. People&;s production and life make the earth have a greenhouse effect. In summer, the temperature is getting higher and higher, and there are more and more extremely hot weather, which lasts longer and longer. This is the reason why people in Xi &;an scramble to drill into the Qinling Mountains every hot weather, looking for forests and river valleys and waterfalls, which also proves that it is not as hot as it is now in ancient summer. This is true not only in Xi &;an, but also in the whole country and people all over the world. In summer, they escape from cities to rural fields and enter mountains to live in old forests for the summer. Therefore, it is extremely wise to say that green mountains and green waters are Jinshan Yinshan. This is not only related to people&;s happiness today, but also affects the well-being of future generations. If we don&;t protect the environment and carry out ecological construction, it will be more than 40 degrees today, and hundreds of thousands of years later, will our future generations bear the high temperature of 4 or 50 degrees? Don&;t underestimate our daily habits. Every person saves a drop of water, a grain, and electricity every day. How much do 780 million people around the world save? Sand accumulates into a tower, and streams gather into rivers. Let&;s work together for our tomorrow!