Global warming will have a serious impact on the environment. Do you know the cause of global warming?

Since 1880 was recorded, the temperature level of the earth has been rising steadily. Then, the speed of global warming accelerated in the middle of the 20th century, and accelerated again at the end of the 20th century. Therefore, the earth is now experiencing the warmest climate in modern history.

0 1 causes of global warming

The sun is the main heat source of the whole solar system. Solar radiation and global average temperature usually rise and fall together. But at least in the past 40 years, this has not been the case.

The Physical Meteorological Observatory of Davos World Radiation Center is one of the institutions that track solar radiation. According to the peer-reviewed journal Solar Variability and Planetary Climate, their instruments confirmed that the solar energy level was rising and falling, but during the period from 1978 to 2007, even if the global average temperature soared, the average level declined slightly.

NASA also released a chart showing solar radiation and global temperature data in 2020, indicating that solar radiation is not the cause of global warming.

If the sun is not the cause of global temperature rise, what is it?

02 causes global warming

As the United States Environmental Protection Agency (EPA) explained, global warming is mainly caused by greenhouse gases carbon dioxide, methane, nitrous oxide and a small amount of synthetic chemicals called hydrofluorocarbons, which absorb the heat generated by solar radiation near the earth's surface and prevent it from leaving the earth's atmosphere and entering space.

Global warming caused by greenhouse gases is mainly man-made.

Part of the reason for global warming is that geological events such as volcanoes have increased carbon dioxide in the atmosphere, and this amount is not small. The US Geological Survey (USGS) estimates that volcanoes emit about 260 million tons of carbon dioxide into the atmosphere every year.

However, most scientists believe that global warming is mainly caused by human activities. In 20 16, the peer-reviewed journal Environmental Research Express reported that among the climate scientists who published their papers, 90% to 100% thought it was mainly human factors.

This echoes the early research results published by this journal on 20 13. A team of nine climate scientists studied 1 1944 peer-reviewed published papers. Among those papers that express opinions on the causes of global warming, 97. 1% describe it as caused by human beings.

How do greenhouse gases make the world warm?

According to the US Environmental Protection Agency, most greenhouse gases are emitted into the atmosphere when fossil fuels are burned in industrial or agricultural processes, although some (hydrofluorocarbons) are emitted into the air through refrigeration, air conditioning, building insulation materials and fire protection products.

Although methane absorbs heat in the earth's atmosphere 28 times more efficiently than carbon dioxide, the US Environmental Protection Agency considers carbon dioxide to be the most important greenhouse gas that causes global warming. This is mainly because it is the most abundant and has existed in the atmosphere for 300- 1000 years.

Greenhouse gases absorb solar radiation near the earth and warm the oceans, waterways and the earth's surface, just like plants growing in artificial greenhouses are heated by glass insulation panels, so they are called "greenhouse effect" in climate change terminology.

05 Deforestation

Although human activities emit greenhouse gases into the atmosphere, which leads to global warming, human beings also deprive the earth of its natural ability to remove greenhouse gases and regulate temperature.

Photosynthesis is a metabolic process in which plants convert light into glucose as energy. As part of this process, plants breathe, inhale carbon dioxide in the atmosphere and exhale oxygen. By absorbing carbon dioxide in the air, plants play an important role in fighting global warming.

According to a report of FAO in 2020, forests cover 365,438+0% of the global land area. FAO estimates that since 1990, about 420 million hectares (more than 10 billion acres) of forests have been deliberately destroyed, and the agricultural expansion of large profit-making companies is the main reason for this destruction.

Due to deforestation, the earth is losing one of the main ways to prevent the temperature from rising sharply.

Impact of global warming

Global warming destroys the terrestrial waters and habitats on the earth's surface, endangering life. However, to some extent, the ocean is the main victim of rising temperature.

07 ocean

The ocean covers 70% of the earth's surface, and it is estimated that the ocean will suffer 70% damage. On the contrary, the impact on them is staggering. 202 1 10 The National Oceanic and Atmospheric Administration (NOAA) reported that since the 1970s, more than 90% of the excess heat inside and outside the earth has been absorbed by the ocean.

Changes in ocean systems usually take a long time to complete. Unfortunately, as warned by the US Environmental Protection Agency, these changes may take as long to correct.

1) threatens marine life

In the 10 survey, which ended on 20 10, more than 2,700 scientists from 80 countries participated in 540 marine expeditions, and made statistics and cataloguing of marine species. According to the investigation, there are 15629 1 species in American waters only. According to the National Oceanic and Atmospheric Administration, this figure may be 9 1% lower.

Whether known or unknown, most marine life occupies a specific space in the food web on which human beings depend. The rising temperature has caused great pressure on marine habitats and greatly endangered a large number of marine life.

2) Causing drought, flood and unstable weather.

The ocean creates the weather of the sea and the land. Ocean currents bring breezes, storms, trade winds and weather fronts. Seawater evaporates to form clouds and finally forms rain.

The National Oceanic and Atmospheric Administration reported that if global warming continues, the global wind speed is expected to increase. The increase of wind speed will cause greater disturbance to seawater, thus increasing the possibility of hurricane development and rainfall.

Great ocean changes may lead to feedback cycles of hot and cold weather, some of which are extreme and most of which are disastrous and unpredictable. The increase of seawater evaporation may cause catastrophic floods and change the precipitation pattern, which is enough to create new desert areas.

3) The sea level rises and the Arctic expands.

The National Oceanic and Atmospheric Administration predicts that sea levels around the world will continue to rise with global warming and melting polar sea ice. Unfortunately, as outlined in an article in the peer-reviewed journal Nature Communications, a destructive feedback loop called Arctic amplification may also continue to exist, especially near the North Pole.

Usually, the reflectivity of white sea ice is very high, and about 80% of sunlight will be reflected to the sun immediately after reaching the sea ice. This keeps the ocean cold.

Unfortunately, maintaining a low ocean temperature is an arduous task, which cannot be solved by ice alone. In recent summers, the unusually warm air near the North Pole is melting the sea ice, exposing the bare black ocean.

The dark ocean absorbs sunlight easily. When this happens, the ocean temperature rises and the sea ice in the adjacent area begins to melt from below. This forms a feedback loop: the newly disappeared ice absorbs more sunlight, warms more oceans, melts more ice from below and absorbs more sunlight from above. Wait a minute.

In the past forty years, the temperature in the Arctic has risen two to three times faster than that in other parts of the world. As the temperature difference between the poles and the mid-latitude area becomes smaller and smaller, the jet may weaken and the front may stagnate.

According to the comments published by the National Aeronautics and Space Administration (NASA), many scientists trace the Arctic amplification to high temperature and extreme weather events in the mid-latitude region of the earth.

4) Protect the earth but harm corals and shellfish.

Although the ocean is threatened by global warming, it plays a great protective role: according to NASA, the ocean is a carbon sink, which has stored carbon dioxide for millions of years and completely excluded it from the atmosphere.

However, the ocean has extraordinary carbon sequestration capacity, which also has an unfortunate side effect. Carbon will cause the pH balance of seawater to drop, making seawater more acidic. The National Oceanic and Atmospheric Administration explained that the acidity of the ocean has increased by 30% since the industrial revolution. In this case, the exoskeletons and shells of marine animals such as corals and shellfish become thinner and are more likely to be eaten by predators.

The risk of global warming

Global warming brings risks to almost all systems on earth. Its impact on the environment can already be seen, and it is expected to worsen in the next few decades. Some prominent risks are:

1) The sea level is rising. NASA predicts that the sea level may rise by 8 feet by 2 100. If so, many coastal areas will be flooded forever, and cities and large areas of farmland will disappear. This may lead to a large-scale migration crisis and destroy the global food supply.

2) Extreme weather events. In 2020 and 20021year, global warming triggered deadly hurricanes, resulting in flooding in coastal and inland areas. The first street foundation research lab, a non-profit organization composed of 180 cooperative research laboratories and business partners, warned that within 30 years, about 25% of key infrastructures, such as police stations, airports and hospitals, will be flooded by devastating floods.

3) drought. The National Aeronautics and Space Administration (NASA) predicts that unstable weather will continue to lead to various droughts, which have recently plagued Russia, Central Asia, Southeast Asia, Africa, Australia and the western United States.

4) Forest fire. The number and intensity of wildfires may increase. Drought will cause wildfires. Unfortunately, burning increases the content of carbon dioxide in the atmosphere in arid areas.

5) Biological extinction. Land and marine species will continue to be extinct. A study published in the peer-reviewed journal Science Progress 20 15 shows that the extinction rate of vertebrate species is 100 times faster than that of 200 years ago.