1. What are the main environmental problems facing humanity today?

The main environmental problem facing humanity today is severe global pollution； Resources per capita are insufficient, and some resources have been depleted ； Widespread ecological damage and a decline in biodiversity.

Global environmental pollution is severe； Resources per capita are insufficient, and some resources have been depleted ； Widespread ecological damage and a decline in biodiversity.

As humanity seeks to develop, it tends to pollute the environment. Currently, development is occurring too rapidly, and there is a lack of balance between environmental protection and development; humans are damaging the air, water, and soil. If proper measures are not taken, humanity could transform into monsters.

The main environmental problems facing humanity today include acid rain, ozone layer depletion, a sharp decline in species diversity, deforestation, global warming, land desertification, the expansion of deserts, waste, noise, electromagnetic radiation pollution, and air pollution.

The most fundamental issue is the excessive number of humans. Humans are at the top of the food chain, and there is a certain proportional relationship between the numbers of organisms at various levels of this chain. With so many humans, they first squeeze out the living space of other species that also occupy the top positions in the food chain. It now seems that humans are becoming the only species at the top of this chain; next, they will likely take over the living space of the organisms that exist at lower levels in the food chain. So, individually, each environmental problem seems solvable, but in reality one problem is resolved only for another to arise; it’s impossible to solve all environmental problems, and even controlling them is very difficult.

The most significant issues are air and water pollution; once these two problems are resolved, everything else, such as the melting of ice caps, will be easily addressed.

The main environmental problems facing humanity today: Apart from waste and water pollution, the environmental issues that have so far threatened human survival and are recognized by humans include global warming, ozone layer depletion, acid rain, energy shortages, a sharp decline in forest resources, land desertification, the accelerated extinction of species, and pollution caused by toxic chemicals, among many others. 1. Global warming refers to the rise in global temperatures. Over the past 100 years or so, the global average temperature has experienced two fluctuations of cold–warm–cold–warm, showing an overall upward trend. After entering the 1980s, global temperatures rose significantly. Between 1981 and 1990, the global average temperature rose by 0.48°C compared to 100 years earlier. The main cause of global warming is humanity’s extensive use of fossil fuels such as coal and oil over the past century, which has led to the emission of large amounts of various greenhouse gases including CO2. Since these greenhouse gases are highly transparent to short-wavelength radiation from the sun, but highly absorbent to long-wavelength radiation reflected by the Earth – which is what is commonly referred to as the greenhouse effect – they cause global warming. The consequences of global warming include a redistribution of global precipitation, the melting of glaciers and permafrost, and rising sea levels. These factors not only disrupt the balance of natural ecosystems but also threaten humanity’s food supply and living conditions. 2. Ozone layer depletion: There is an ozone layer in the stratosphere, about 20–30 kilometers above the Earth’s surface, where the concentration of ozone accounts for one ten-thousandth of the total amount of gases at that altitude. Although its concentration is extremely low, ozone has a strong ability to absorb ultraviolet rays; therefore, it can prevent the harmful effects of solar ultraviolet radiation on Earth’s organisms, protecting all life on the planet. However, some pollutants emitted as a result of human production and daily activities, such as chlorofluorocarbons used as refrigerants in refrigerators and air conditioners, as well as fluorobromocarbons used for other purposes, can be activated upon exposure to ultraviolet light. These activated particles react with the ozone (O3) in the ozone layer, converting it into oxygen molecules (O2). This reaction occurs in a chain reaction, leading to a rapid depletion of ozone and thus damage to the ozone layer. The ozone hole over Antarctica is one of the most prominent signs of ozone layer depletion. By 1994, the area of ozone layer depletion over Antarctica had reached 24 million square kilometers. The ozone layer over Antarctica took 2 billion years to form, but 60% of it was destroyed in just one century. The ozone layer over the Northern Hemisphere is also thinner than ever before; it has decreased by an average of 10–15% over Europe and North America, and by as much as 35% over Siberia. Therefore, scientists warn that the extent of ozone layer depletion over the Earth is much more severe than most people realize. 3. Acid rain is acidic precipitation with a pH value of less than 5.6, caused by acidic pollutants such as sulfur dioxide (SO2) and nitrogen oxides (NOx) in the air. In areas affected by acid rain, a range of serious environmental problems have arisen, including soil and lake acidification, damage to vegetation and ecosystems, and corrosion of building materials, metal structures, and cultural relics. Acid rain first appeared in Northern and Central Europe in the 1950s and 1960s; at that time, it was the result of acidic industrial emissions from Central Europe reaching Northern Europe. Since the 1970s, many industrialized countries have taken various measures to prevent air pollution in urban areas and industries. One important measure has been to increase the height of chimneys. Although this approach has effectively improved the air quality in the areas where emissions occur, it has also exacerbated the problem of long-distance transport of air pollutants. These pollutants cross national borders and reach neighboring countries, sometimes traveling great distances, thus giving rise to more widespread transnational acid rain. Furthermore, the continuous increase in the global use of fossil fuels is also contributing to the expansion of areas affected by acid rain. Regions heavily affected by acid rain worldwide include Europe, North America, and East Asia. In the 1980s, acid rain mainly occurred in the southwestern region of our country; by the mid-1990s, it had spread to a wide area south of the Yangtze River, east of the Qinghai-Tibet Plateau, and in the Sichuan Basin. 4. Shortages of resources and energy: At present, shortages of resources and energy exist in most **regions of the world, and even on a global scale. The emergence of this phenomenon is mainly due to humanity’s unplanned and irrational large-scale exploitation. In the early 1990s, the total global energy consumption was approximately 10 billion tons of standard coal, and it is predicted that this figure will double by the year 2000. Judging from the current development of oil, coal, hydropower, and nuclear energy, it is very difficult to meet such demand. Therefore, until significant breakthroughs are achieved in the development and utilization of new energy sources (such as solar energy, fast neutron reactor power plants, nuclear fusion power plants, etc.), the world’s energy supply will become increasingly strained. In addition, the reserves of other non-renewable mineral resources are also decreasing steadily, and these resources will eventually be exhausted. 5. Rapid forest decline: Forests are an important component of the ecosystem on which humanity depends for survival. There were once 7.6 billion hectares of forests on Earth; by this century that figure had dropped to 5.5 billion hectares, and by 1976 it had further decreased to 2.8 billion hectares. Due to the growth of the world’s population, there is an increasing demand for arable land, pastureland, and timber, which leads to excessive deforestation and land conversion, causing forests to be damaged like never before. According to statistics, about 12 million hectares of forests disappear worldwide each year, the vast majority of which are tropical rainforests that are crucial for the global ecological balance. The destruction of tropical rainforests mainly occurs in developing countries in the tropics, with the situation in Brazil’s Amazon being the most severe. The Amazon rainforest is the largest among the world’s tropical rainforests. However, by the early 1990s, the forest coverage in this region had decreased by 11%, an area equivalent to 700,000 square kilometers; on average, a forest area the size of a football field disappeared every 5 seconds. Furthermore, the tropical rainforests in the Asia-Pacific region and Africa are also being destroyed. 6. Land desertification: Simply put, land desertification refers to land degradation. The 1992 United Nations Conference on Environment and Development defined the concept of desertification as follows: “Desertification is the degradation of land in arid, semi-arid, and dry sub-humid regions due to factors such as climate change and unsustainable human economic activities.” On June 17, 1996, the second World Day to Combat Desertification and Drought, the Secretariat of the United Nations Convention to Combat Desertification issued a statement stating that desertification in the world is still on the rise. More than 1.2 billion people worldwide are directly threatened by desertification, of whom 135 million are at risk of losing their land in the short term. Desertification is no longer merely an ecological and environmental issue; it has evolved into an economic and social problem, bringing poverty and social instability to humanity. By 1996, the area of land affected by desertification worldwide had reached 36 million square kilometers, accounting for one-quarter of the Earth’s total land area – an amount equivalent to the combined land areas of Russia, Canada, China, and the United States. More than 100 countries around the world are affected by desertification. Although people in various countries are fighting against it, desertification continues to expand at a rate of 50,000 to 70,000 square kilometers per year, an area equivalent to that of Ireland. By the end of the 20th century, the world will lose about one-third of its arable land. Among the many environmental problems facing humanity today, desertification is one of the most severe disasters. For those threatened by desertification, it means the loss of their most fundamental basis for survival—the disappearance of land that is capable of production. 7. Accelerating species extinction refers to biological species. There are 5 to 10 million species of organisms living on Earth today. Generally, the rate of species extinction should be balanced with the rate of species formation. However, human activities have disrupted this balance, accelerating the rate of species extinction. According to the World Natural Resources Conservation Outline, thousands of plant and animal species go extinct each year, and by the year 2000, 10–20% of Earth’s plant and animal species, that is, 500,000 to 1 million species, will have disappeared. Moreover, the rate of extinction is accelerating. The World Wildlife Fund issues a warning: one bird species goes extinct each year this century, and at least one species disappears daily in the tropical rainforests. The extinction of species will pose a threat to the global food supply, and the losses and impacts on human societal development will be unpredictable and irreparable. 8. There are approximately 70,000 to 80,000 chemicals on the market that are toxic. There are about 35,000 species that are harmful to human health and the ecological environment. Among them, there are over 500 types that have carcinogenic, teratogenic, and mutagenic effects. With the development of industrial and agricultural production, 1,000 to 2,000 new chemicals are introduced to the market each year. Due to the widespread use of chemicals, the world’s atmosphere, water bodies, soils, and even living organisms have been polluted and poisoned to varying degrees, with even penguins in Antarctica not being spared. Since the 1950s, pollution incidents involving toxic and hazardous chemicals have been on the rise, and if no effective preventive and control measures are taken, they will cause serious harm to humans as well as animals and plants. It causes severe harm.