Global warming caused by greenhouse effect is an important and thorny hot issue facing mankind, and it is also a huge challenge facing mankind in the 2 1 century. It is directly related to the survival and development of mankind.

1 The greenhouse effect leads to global warming.

Gases in the atmosphere, such as CO2, CH4, nitrogen oxides, etc., can let sunlight and visible light pass through, but hinder the infrared rays released by the earth to the universe and convert them into heat, thus increasing the humidity of the earth's surface. This phenomenon is called the greenhouse effect. The gas that forms the greenhouse effect is the greenhouse gas. Carbon dioxide is the main greenhouse gas, accounting for about 60%. The higher the concentration of greenhouse gases, the higher the temperature near the surface. Without greenhouse gases, the temperature on the earth would be very low. For hundreds of millions of years, the earth has benefited from the greenhouse effect, because it has created an environment suitable for living things.

However, human activities have intensified the greenhouse effect and even affected the climate. Since the industrial revolution, resources and energy have been greatly consumed, especially the CO2 content emitted by the burning of coal, oil, natural gas and other antiquities has increased. It is estimated that at present, the global annual CO2 emission to the atmosphere is about 24 billion tons. Trace gases such as methane also rise with various human activities. According to the research results recently released by the United Nations Intergovernmental Panel on Climate Change (IPCC), since 1000 years ago, the current global average temperature has increased by 0.3 ~ 0.6℃. In the previous 1 10,000 years, the average temperature of the earth did not change more than 2℃. The United Nations agencies also predicted that by 2050, due to the increasing energy demand, the global carbon dioxide emissions will increase to 70 billion tons, and the global average temperature will rise by 65,438 0.5 ~ 4.5℃.

2 the impact of greenhouse effect on biodiversity

Global warming will seriously threaten biodiversity. Because living things can't bear this huge change of rapid addition.

2. 1 Impact of global warming on biodiversity Global warming is not a new phenomenon. In the past 2 million years, the earth has experienced 10 cycles of alternating cold and warm. During the warm period, the polar ice sheet melted, the sea level was higher than today, and the species distribution extended to the polar regions and migrated to high altitude areas. On the contrary, during the transformation to Xinhua News Agency, the ice sheet expanded, the sea level dropped, and species moved to the equator and low altitude areas. There is no doubt that many species will go extinct in this process of repeated changes, and the existing species are the products of these changes. Can species adapt to past changes, but can they adapt to the future climate changed by human activities? This is an open question. But what is certain is that the natural fluctuation of latitude and longitude of global warming caused by human factors in the past is much faster, so the impact of this change on biodiversity will be enormous.

2. 1. 1 Impact on temperate biodiversity With the continuous increase of temperature, the north temperate zone and the south temperate zone will expand to the poles. Climate change will inevitably lead to species migration. However, according to the speed table of natural diffusion, many species seem to be unable to keep up with the rapid climate change at high migration speed. It is clear by comparing the species mobility of deciduous broad-leaved forests in eastern North America. After the recent Pleistocene Ice Age, the temperature rose and the trees moved back to North America at the speed of 10 ~ 40 km/world. According to the estimation that the temperature will rise 1.5 ~ 4.5℃ in 2 1 century, trees will move 5000 ~ 10000 km to the north. Obviously, it is impossible to spread at a speed of dozens of times in the natural state. Moreover, habitat fragmentation caused by human activities can only reduce species mobility. Therefore, many species with limited distribution or poor diffusion ability will undoubtedly go extinct during migration. Only widely distributed and easily diffused species can establish their own communities in new habitats.

2. The impact of1.2 on the biodiversity of tropical rain forest; Tropical rainforests have the greatest species diversity. Although the impact of global temperature change on the tropics is far less than that on the temperate zone. However, climate warming will lead to changes in tropical rainfall and rainfall time, and forest fires and hurricanes will also become frequent. These factors will have a great influence on species composition and plant reproduction time, thus changing the structural composition of tropical rain forest.

2. 1.3 Impact on biodiversity of coastal wetlands and coral reefs Wetlands and coral reefs are biodiversity-rich ecosystems, but they are also threatened by climate warming. Rising temperatures will melt alpine glaciers and shrink Antarctic ice. In the next 50 ~ 100 years, the sea level will rise by 0.2 ~ 0.9 meters or even higher. Sea level rise will inundate wetland communities in coastal areas. The sea level is changing so fast that many biological species have no time to migrate to suitable areas with the rise of sea water. In particular, houses, roads and flood control dams built in wetland areas will become direct obstacles to species migration.

Sea level rise is very harmful to coral reef species. Because corals have strict requirements on the combination of seawater illumination and water flow. If the sea water rises at the budgeted rate, even the fastest growing corals can't adapt to this change. In addition, the rising temperature of seawater will also do great harm to corals. This will cause a large number of corals to sink and die.