Population issues, resource issues, environmental issues and economic and social development issues are the four major issues that people in the world are increasingly paying attention to.

Among them, environmental issues are serious issues that restrict economic development and affect human life.

Environmental problems mainly refer to environmental damage and pollution caused by human production and life. Their essence is the contradiction between economic development and environmental protection, and the imbalance of the relationship between man and nature.

At present, the ecological and environmental problems faced by the world mainly include: Greenhouse effect The greenhouse effect refers to the phenomenon that carbon dioxide, nitrous oxide, methane, and fluoride are discharged into the atmosphere in large quantities, causing global temperatures to rise.

Currently, the world emits approximately 23 billion tons of carbon dioxide into the atmosphere every year.

An increase of 20% from the beginning of the 20th century.

It is still increasing at a rate of 0.5% per year, which will inevitably lead to global temperature warming, ecosystem damage and sea level rise.

According to relevant statistics and predictions, global sea level will rise by about 20cm by 2030 and 65cm by the end of this century, seriously threatening low-lying islands and coastal areas.

Destruction of the Ozone Layer The ozone layer is a layer with a high concentration of ozone in the high-altitude atmosphere. It can prevent excessive ultraviolet rays from the sun from reaching the earth's surface, effectively protecting the normal growth of all living things on the ground.

The destruction of the ozone layer is mainly caused by the chemical substance Freon used in modern life entering the stratosphere and decomposing under the action of ultraviolet rays to produce atomic chlorine through a chain reaction.

According to statistical analysis, if the ozone concentration decreases by 1%, skin cancer will increase by 4%, and the occurrence of cataracts will increase by 0.6%.

By the beginning of this century, the ozone layer over central Earth had decreased by 5%-10%, increasing the number of skin cancer cases by 26%.

Land degradation and desertification Land degradation and desertification refer to the process in which land quality declines and gradually becomes desertified due to the combined effects of human factors such as excessive grazing, farming, and indiscriminate reclamation and deforestation, and a series of natural factors.

15% of the global land area has been degraded to varying degrees due to human activities.

Due to land degradation and desertification, the number of hungry refugees worldwide has increased from 460 million to 550 million.

Waste material pollution and transfer Waste material pollution and transfer refers to the waste gas, waste liquid, solid waste, etc. discharged from industrial production and residents' lives into nature or to other countries, seriously polluting the air, the land environment of rivers, lakes, and oceans, and endangering human health.

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According to research, one AA battery can pollute 60 liters of water and make ten square meters of land lose its use value. The pollution can last for 20 years.

The contemporary "death in the sky" - acid rain, has been recognized for its impact and erosion on forest soil, lakes and various buildings.

The transfer of hazardous waste often turns into a political incident in international exchanges.

Reduction in forest area Forests are known as the "lungs of the earth" and "the master control room of nature" and have a significant regulating function on the environment.

Due to extensive imports by developed countries and land reclamation, logging, and grazing in developing countries, the forest area has been significantly reduced.

The reduction of forests leads to soil erosion, frequent floods, global warming, species loss, etc.

Biodiversity reduction Biodiversity reduction refers to all biological species, including animals, plants, and microorganisms, which continue to disappear due to the loss of the ecological environment, over-exploitation of resources, environmental pollution, and the introduction of alien species.

It is estimated that there are approximately 30 million species on Earth.

Since 1600, 724 species have become extinct, 3,956 species are currently endangered, 3,647 species are endangered, and 7,240 species are rare.

Most experts believe that 1/4 of all living things on earth may be at risk of extinction in the next 20-30 years. Between 1990 and 2020, 5%-15% of the world's species may become extinct, which means 40-140 species disappear every day.

The existence of biological diversity plays an irreplaceable role in the evolution and protection of the life-support systems of the biosphere.

Water resources are depleted. Water is the source of life. Water seems to be everywhere.

However, the shortage of drinking water threatens human survival.

At present, the world's annual water consumption has reached 7 trillion cubic meters. In addition, the discharge of industrial wastewater, the abuse of chemical fertilizers, the arbitrary dumping of garbage, and the sharp increase in domestic sewage have turned rivers into sewers and lakes into sewage lands;

Indiscriminate cultivation and deforestation have caused a large amount of water to evaporate and be lost, and drinking water has been drastically reduced.

Many scientists predict that water will become the most scarce resource for mankind in the 21st century.

Nuclear pollution Nuclear pollution refers to radioactive pollution caused by nuclear leakage or even nuclear explosion due to various reasons.

The damage range is large, the damage to surrounding organisms is extremely serious, the duration is long, and the subsequent treatment is dangerous and complicated.

For example, in April 1986, a nuclear leak occurred at the Chernobyl Nuclear Power Plant in the former Soviet Union. 130,000 people were evacuated and economic losses reached US$15 billion.

Ocean pollution The ocean is known as "the front line of national defense, a channel for trade, a treasure house of resources, the home of clouds and rain, and the cradle of life."

However, she is being severely contaminated.

Common marine pollution mainly includes crude oil pollution, floating debris pollution and organic compound pollution, as well as the red tide and black tide caused by them.

Marine pollution directly leads to the deterioration of the marine environment and the reduction of biological species.