How is climate change caused?

The IPCC's third assessment report shows the climate change in the past 1765-2 100, and predicts the future temperature change. At present, scientists all over the world know that more than 90% of climate change may be the responsibility of human beings, and the decisions and choices we make today will affect the direction of climate change.

Climate change is an indisputable fact. Today, our earth is hotter than in the past two thousand years. If the situation continues to deteriorate, the temperature of the earth will climb to the highest level in two million years by the end of this century.

Why do we cause climate change?

For one hundred years, mankind has been relying on fossil fuels such as oil and coal to provide energy for production and life. Carbon dioxide and other greenhouse gases emitted by burning these fossil fuels are the main reasons for enhancing the greenhouse effect and triggering global climate change. About 1/5 of greenhouse gases are emitted due to destroying forests and reducing the ability to absorb carbon dioxide. In addition, some special industrial processes, agriculture and animal husbandry will also have a little greenhouse gas emissions.

In China, coal occupies a dominant position in the total energy consumption. From 1979 to 2005, the average proportion of coal resource consumption in the total energy consumption was 72.4%. In the relative changes of various energy consumption, although the proportion of coal in the total energy consumption shows a slow downward trend, its absolute consumption is on the rise. At present, coal consumption accounts for about 67%, and China's energy efficiency is not high, so it is unsustainable to rely on coal for development. Facing the increasingly serious problem of global warming, we have only one choice: we must take immediate action.

Our understanding of the causes of climate change

Understanding of the process, severity and impact of climate change on different regions is still deepening, but scientists have confirmed the following points:

Some gases, such as carbon dioxide, form a greenhouse effect in the atmosphere, preventing heat from reflecting back into space, and increasing the temperature of the earth.

Burning fossil fuels (such as coal and oil) will release more carbon dioxide into the atmosphere.

Although carbon dioxide is not the strongest greenhouse gas, the content of carbon dioxide produced by human activities has greatly increased, which has become the chief culprit in enhancing the greenhouse effect.

The concentration of carbon dioxide in the atmosphere has reached the highest level in 650 thousand years.

The 1990s can be regarded as the hottest decade in history, and 1998 is the hottest year.

The following points have also been widely recognized:

Due to the emission of greenhouse gases such as carbon dioxide, it seems inevitable that the global average temperature will rise by 65438 0.3 degrees Celsius compared with that before the industrial revolution. Limiting the increase to 2 degrees Celsius is the only way to prevent climate change from causing more serious disasters.

If the emission of greenhouse gases is not controlled, the speed of climate change will be the fastest in human history.

The climate feedback mechanism is likely to bring about a drastic and irreversible chain reaction, and no one knows to what extent climate change will lead to the "end of the world".

Greenhouse gases are the culprit.

The earth's atmosphere is composed of gas layer, which covers heat and maintains life on earth. However, the burning of fossil fuels and deforestation have enhanced the greenhouse effect, and the original gas canopy has caused more heat to be covered up. As a result, the global temperature rises, making the world climate out of balance.

Forest destruction

Forest destruction is also one of the important sources of carbon dioxide emissions. Plants absorb carbon dioxide to grow, but it will be released after withering, rotting or burning. Plant decay can also produce methane, which is a stronger greenhouse gas than carbon dioxide. Therefore, when the number of trees that can absorb carbon dioxide decreases at the same time, greenhouse gases (such as forest fires or burning firewood) will be released. Deforestation and degradation can be said to be a double destruction. In the past 150 years, 30% of carbon dioxide emissions came from forest harvesting, but this is still a small amount compared with the global forest storage carbon. Temperate forests in Canada and Russia alone store 40% of the global carbon storage.

scientific knowledge

In fact, scientists all over the world have reached a consensus that the ongoing global climate change is mainly caused by human activities, including burning fossil fuels. If it is not stopped in time, the consequences will be unimaginable. In addition, scientists unanimously call on us to take action to stop the drastic climate change.

Intergovernmental Panel on Climate Change

In 2007, the United Nations Intergovernmental Panel on Climate Change (IPCC) issued the fourth assessment report "Climate Change 2007" in four volumes, which issued the severest warning to world leaders: human activities, especially the uncontrolled use of fossil energy, are the chief culprit of climate change, and the threat of global warming is imminent. IPCC won the 2007 Nobel Peace Prize for its great contribution to promoting climate change policies and raising public awareness.

IPCC's fourth assessment report, Climate Change 2007, embodies the most authoritative knowledge of thousands of scientists around the world in the past six years on the causes, extent and future changes of climate change, its impact on nature and human society, and countermeasures evaluation. In its first volume, Climate Change in 2007: Scientific Basis, it reveals the important knowledge of global scientists:

1.Most of the global warming observed since the mid-20th century is probably due to the increase of greenhouse gas concentration caused by human activities. Compared with the third assessment report, "most of the warming phenomena observed in the past 50 years may be due to the increase of greenhouse gas concentration". Among them, the use of fossil fuels accounts for about two-thirds of the total greenhouse gases.

According to the current progress trend, in the worst case, the global average temperature may rise by 6.4 degrees Celsius by the end of this century.

In the past 50 years, the global temperature has been rising continuously. In the past 12 years, 1 1 was the hottest year on record.

China's attitude towards climate change.

In June 2007, Ma Kai, director of China's National Development and Reform Commission, stressed at the press conference of China's National Plan to Address Climate Change that although there are still differences in details, the mainstream views on climate change have tended to be consistent, that is, global climate change has become an indisputable fact and has had serious consequences on the environment, and its formation is closely related to human activities, especially the use of fossil fuels.

Zhao Zongci, a researcher at the National Climate Center of China Meteorological Bureau and a member of the IPCC China Expert Group, pointed out, "Global warming is a general trend, and China is not immune. In the recent 65,438+000 years, the climate in China has become warmer and warmer. Especially in the past 50 years, the average extent of climate warming in China is 0.6 ~ 0.9 degrees higher than the average level of global warming. " China has recognized the tremendous impact of climate change from the perspective of scientific and social development, and is actively responding to it.

Causes of climate change

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20 10-4-28 18:55:28

Summary: The earth on which human beings live is an extremely complex system, and the climate system is an important part of the earth system. According to scientific research, changes in solar radiation, changes in the Earth's orbit, volcanic activity and changes in the atmosphere and ocean circulation are natural factors that cause global climate change.

Causes of climate change

The earth on which human beings live is an extremely complex system, and the climate system is an important part of the earth system. In the long history of the earth, the climate is always changing, and the reasons can be summarized into two categories: natural climate fluctuation and human factors.

According to scientific research, changes in solar radiation, changes in the Earth's orbit, volcanic activity and changes in the atmosphere and ocean circulation are natural factors that cause global climate change. However, human activities, especially those since the industrial revolution, are the main causes of climate change characterized by global warming, including greenhouse gas emissions such as carbon dioxide caused by human production and life, land use and urbanization.

At the first World Climate Conference held in Geneva, Switzerland from 65438 to 0979, scientists warned that the increase of atmospheric carbon dioxide concentration would lead to global warming, and climate change was put on the agenda for the first time as a concern of the international community. 1988, the United Nations Intergovernmental Panel on Climate Change (IPCC) was established to assess climate change and its impact.

Since its establishment, IPCC has published four climate change assessment reports, and the formulation process of these reports represents the gradual deepening of human understanding of climate change. At the same time, there have been some views in the scientific and business circles that the warming that the earth is experiencing is part of the natural climate fluctuation in a wider range, rather than caused by human activities. However, the fourth assessment report published by IPCC in 2007 pointed out that the possibility of global temperature rise caused by human activities exceeded 90%.

The report, completed by about 2,500 scientists from more than 30 countries and regions around the world, points out that since 1750, the global atmospheric greenhouse gas concentration has increased significantly due to human activities, and now it has far exceeded the level of hundreds of thousands of years before the industrial age, with the carbon dioxide concentration reaching the highest point in 650,000 years. After a detailed calculation of the impacts of various human activities on the climate, the report believes that it is certain that the net impact of human activities on the climate since the industrial age is the increase in temperature.

Keywords click: climate change

Xinhuanet Beijing165438+1October 29th (Reporter Li) When it comes to climate change, many people will simply understand it as wind, rain, sunny and cloudy weather changes. But in fact, the significance of climate change is not the case.

Weather refers to meteorological phenomena that occur in a short period of time (several minutes to several days), such as thunderstorm, hail, typhoon, cold wave and strong wind. Climate, on the other hand, refers to the average or statistical situation of weather in a long period (month, season, year, year or even hundreds of years), which is usually characterized by the average value and deviation from the average value in a certain period, and mainly reflects the basic characteristics of a region such as cold, heat, dryness and humidity, that is, the comprehensive performance of various weather processes in a certain period on earth.

Climate change refers to the statistically significant changes of climate mean and climate deviation, such as the changes of average temperature, average precipitation, maximum temperature, minimum temperature and extreme weather events. It is often said that global warming is one of the important manifestations of climate change.

According to Luo Yong, deputy director of the National Climate Center, the causes of climate change may be natural internal processes, external compulsion, or man-made continuous changes in atmospheric composition and land use.

The United Nations Framework Convention on Climate Change defines "climate change" as "climate change caused by human activities directly or indirectly changing the composition of the global atmosphere after a long period of observation." This distinguishes "climate change" that changes the atmospheric composition due to human activities from "climate variability" attributed to natural causes.

Climate change has both positive and negative effects, and the latter is particularly concerned, which has seriously affected the earth's natural ecosystem and human life. Climate change is not only a scientific and environmental issue, but also an energy, economic and political issue.