Summers are getting hotter. According to monitoring data from the European Union's Copernicus Climate Change Service (C3S), the past six years have been the hottest six years on record.

In the same few years, more than 37,000 species around the world are on the verge of extinction, and 8 million tons of plastic waste ends up in the ocean every year... The living conditions of the earth's creatures are not optimistic.

How many species are there on earth?

For centuries, humans have been dedicated to discovering and searching for the diversity of life on earth, from the depths of the earth’s crust to the tops of the Himalayas, from From the tropical rainforest to the deep blue sea, the classification of plants, animals, and microorganisms is becoming more and more detailed.

Although humans have spared no effort to explore the biological diversity of the earth, there is still no definite data on the specific species on the earth.

Although the science and technology of human society is constantly advancing, the acquisition of water, food, medicine, fuel and other resources still relies on the most basic ecological and natural systems. The epidemic swept the world in 2020, and the invasion of the virus made it more critical than ever to re-examine the relationship between humans and nature.

May 22 is the International Day for Biological Diversity. This year’s theme is “#ForNature, we are the solution to nature’s problems”, which once again emphasizes the importance of humans to the earth’s ecology and species diversity. Data shows that the earth's biodiversity has been declining in recent years. What role does humans play in this process?

In the past four decades, the earth's biodiversity has decreased by 68%

In September 2020, United Nations Secretary-General Guterres stated at the Biodiversity Summit that more than 60% of the world's coral reefs are endangered due to overfishing, destructive practices and climate change. Overconsumption, population growth, and intensive agriculture have drastically reduced wildlife populations. The rate of species extinction is accelerating, with 1 million species currently threatened or endangered.

According to the "Living Planet Report 2020" released by the World Wildlife Fund, from 1970 to 2016, the size of the monitored populations of mammals, birds, amphibians, reptiles and fish The average decrease was 68%.

Globally, Latin America, which has the world's largest tropical forest, has suffered the most obvious loss of biodiversity. In the past 40 years, species richness has dropped by 94%, making it the most serious region in the world. Changes in land and ocean use, including habitat loss and degradation, are the greatest threats to biodiversity.

Taking Latin America as an example, the Amazon tropical forest is one of the ecosystems with the richest biodiversity on earth. More than 3 million species live in the rainforest, and there are more than 2,500 tree species (about 10% of all tropical forests on earth). One third of the trees) support this vibrant ecosystem.

But also in this rainforest, the rate of species extinction is unprecedented. The United Nations estimates that 1 million species are on the verge of extinction. From August 2018 to July 2019 alone, the Amazon lost more than 9,842 square kilometers of forest, and the deforestation rate reached its highest peak in ten years.

Human occupation of land, expansion of industrial and agricultural land, and over-exploitation of grasslands, rainforests, and wetlands are the main reasons for the decline of species in the region.

Compared with oceans and forests, freshwater biodiversity is losing faster. According to the "Living Planet Index 2020", nearly 90% of the earth's wetlands have disappeared since 1700, which has had a profound impact on freshwater biodiversity. Of the 944 freshwater species included in the Living Planet Index (LPI) assessment, 3,741 populations, their numbers declined by an average of 84%.

Among these freshwater creatures, larger species are more vulnerable. Some creatures such as sturgeons, Yangtze finless porpoises, and otters that weigh more than 30 kilograms have experienced a sharp decline in population due to overexploitation by humans. Between 2000 and 2015, the catch of 78% of species in the Mekong River declined, and the decline was more obvious for medium and large species.

Although humans have been working hard to mitigate climate change in recent years, rising global temperatures, rising sea levels, and extreme weather have already had an impact on species diversity.

Ecology and species evolution are very slow. If climate changes are very drastic and biological evolution cannot adapt to this speed, the risk of species extinction will only be "forced" to accelerate.

Coral reefs are the most obvious example. Australian scholar Christopher Cornwall published a study in the Proceedings of the National Academy of Sciences on May 11, analyzing data from 183 coral reefs around the world and found that in the worst case scenario, 94% of coral reefs will die before 2050. .

The "Living Planet Report 2020" pointed out that global terrestrial biodiversity is currently in danger. The global average biodiversity integrity index is only 79%, which is far below the safe lower limit of 90%, and is still declining. decline.

In my country

The areas with the richest species are also the areas with the most endangered animals

my country is one of the countries with the richest biodiversity in the world, with higher plants There are more than 30,000 species, ranking third in the world, second only to Brazil and Colombia; there are more than 6,000 species of vertebrates, accounting for 13.7% of the world's total species.

The first edition of the "List of Biological Species of China" in 2008 included 49,000 species, including more than 10,000 animals, mainly animals, birds, fish and other vertebrates, invertebrates Animals and insects and more than 30,000 plants, as well as a small number of microorganisms.

But this is obviously not all species in our country. Over the next 12 years, new species were continuously added to the list.

In the "List of Chinese Biological Species 2020 Edition" released by the Biodiversity Committee of the Chinese Academy of Sciences, my country's biological species have reached 122,280 species, including 58,444 animal species, 44,905 plant species, 12,728 fungal species and bacteria , viruses and other species.

Although my country is one of the countries with the richest species in the world, it is also one of the countries where biodiversity is most seriously threatened. Due to the destruction and degradation of ecosystems, many species have become endangered and threatened species.

In 2020, there were more than 10,000 threatened species of higher plants, accounting for 29.3% of the total number of assessed species, and more than 6,500 threatened species of fungi, accounting for 70.3% of the total number of assessed species.

Among the 640 world-wide endangered species listed in the "Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)", there are 156 species in my country, accounting for about 25% of the total.

In June 2020, a paper on the changes in the living space of my country’s biodiversity published by the School of Environment and Ecology of Xiamen University, the Ecological Environment Research Center of the Chinese Academy of Sciences and other institutions showed that endangered species in my country are mainly distributed in Southwest and South China, including Yunnan, Sichuan, Guangxi and other places, while the number of threatened species in central and northeastern China is relatively small.

By comparing endangered species data with the spatial distribution of existing species in my country, we found that there is a high correlation between the number of threatened species and species richness. The Yunnan-Guizhou Plateau and forests in the southwest are the areas with the richest biodiversity in my country. Yunnan Province ranks first in species richness in the country, but it is also the place with the most endangered species.

Increasing environmental changes have brought multiple pressures to biodiversity conservation, and different provinces have different topography, climate, population, economic development levels and external pressure sources, causing different impacts on different biological species. . But overall, mammals, amphibians and reptiles are threatened at a higher proportion, with average proportions reaching 11.64%, 11.05% and 10.72%.

In the four regions with rich biodiversity, Yunnan, Sichuan, Guangxi and Guangdong, biological species are mainly threatened by climate change and global warming, as well as geological disasters, soil erosion and agricultural reclamation. Some studies have also shown that , Temperature changes in the climate induced by human activities are the main reason for the decrease in biodiversity in these areas.

Because the Yunnan-Guizhou region is mountainous, the valleys and mountains are relatively fragile, the complex terrain and geological structure, and the fragmentation of rocks and soil also make the region more susceptible to geological disasters and soil erosion.

By analyzing the damage caused by different stressors to biodiversity, we found that human activities inevitably threaten the number of biological species.

Greenhouse gas emissions are the main culprit of climate change. Activities such as night light, construction land, and cultivated land directly represent the intensity of industrial land and human activities. The advancement of humans and the retreat of animals will have a negative impact on the number of species. Great adverse effects.

Geological disasters and soil erosion generally affect the living space of organisms, and logically speaking, they will have an adverse impact on diversity. However, the destruction and isolation caused by soil erosion and geological disasters will also reduce the population density of the area, which will have a positive impact on the survival of biological species. Therefore, human activities are the main cause of biodiversity loss.

At the Biodiversity Summit, Guterres also pointed out that natural imbalances are punishing humans. The emergence of deadly diseases is an ongoing case, such as AIDS, Ebola, and the 2019 global outbreak. Coronavirus.

60% of all known diseases and 75% of new infectious diseases are zoonosis, that is, viruses are transmitted from animals to humans, which illustrates the relationship between the health of our planet and our own health close contact.

Biodiversity and ecosystems are crucial to human progress and prosperity. The degradation of nature is not a purely environmental issue. It covers many aspects such as economy, health, and social justice, and will intensify geopolitical tensions. Political tensions and conflicts.

At present, if no measures are taken, the global species extinction rate will "further accelerate", and the current extinction rate is already "at least thousands of times higher than the average of the past 10 million years."

Reference materials:

1World Wildlife Fund WWF, Institute of Zoology (Zoological Society of London), "Living Planet Report 2020"

2Yonglong Lu, Yifu Yang, Bin Sun, Jingjing Yuan, Minzhao Yu, Nils Chr. Stenseth, James M. Bullock, Michael Obersteiner, "Spatial variation in biopersity loss across China under

multiple environmental stressors", 2020.6

Data News Editor Chen Hualuo New Media Design Xu Xiao Proofreading Li Lijun