On September 27, 2013, the decision makers (SPM) of the Fifth Assessment Report (AR5) of the First Working Group of the UN Intergovernmental Panel on Climate Change (IPCC) released the IPCC Fifth Assessment Report. The prologue was released one after another. The 12th meeting of the IPCC's fifth Climate Change Assessment Working Group I Working Group was held in Stockholm on the 26th. National government representatives signed the first IPCC Working Group I decision-maker on climate change basic science reports in Stockholm on the 27th. The full report was announced on the 30th. The new report combines the efforts of 259 authors from 39 countries, citing more than 9,200 scientific papers and a large amount of scientific data, and has conducted reviews by experts and government agencies. The AR5 report made a new assessment of the new progress in climate change research since 2007 and provided new scientific support for a new round of international climate change policies and actions.
The IPCC was established in 1988 by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) to assess scientific, technological, and socio-economic related information, to recognize the risks and potential impacts of human activities that cause climate change, and to mitigate Adapt to choices. IPCC itself does not carry out scientific research on climate change, nor does it engage in the monitoring of climate-related data. It only evaluates and carefully publishes scientific research and technical data on climate change that have been carefully reviewed and published in the world. It was issued to summarize the "existing knowledge" of humans regarding climate change. The IPCC consists of three working groups: the first working group to address the scientific issues of the climate system and climate change; the second working group to address the vulnerability of socio-economic and natural systems to climate change, and the climate change impact and adaptation program; The three working groups deal with solutions that reduce greenhouse gas emissions and climate change mitigation. IPCC's main work products include assessment reports, special reports, method reports, and technical reports. These reports have become the authoritative products in the field of climate change, and are widely used by policy makers and scientists from all over the world. Since its establishment in 1988, IPCC has played a unique role in the global governance of climate change with its unique expertise and authority, and has built a platform for communication and exchange between government decision makers and scientists around the world. The IPCC has won great respect through its previous assessment report and won the 2007 Nobel Peace Prize for supporting climate policy and increasing global public awareness.
1 Treatment of uncertainties in climate change assessment Because natural climate systems are extremely complex and inherently chaotic, they include nonlinear feedback at various time scales. Therefore, there are uncertainties both in observations and estimates of climate change. Some uncertainties can be expressed in terms of certain numerical ranges, while other uncertainties can be expressed as the reliability of experts’ knowledge of certain scientific discoveries. According to the guidance provided by the main authors of the IPCC Fifth Assessment Report on Uncertainty in Uncertainty, the report relied on two metrics to convey the degree of certainty of important findings: 1) Based on the type, quantity, quality, and compatibility of the evidence (eg, Mechanism recognition, theory, data, model, expert judgment) and degree of consistency, reliability of the validity of a finding. Confidence is expressed in a qualitative manner; 2) The uncertainty of a certain discovery is quantified and expressed in terms of probability.
It is difficult to directly compare the uncertainty assessments found in the fifth assessment report with the uncertainty assessments in the IPCC Fourth Assessment Report because the fifth assessment uses the revised uncertainty guidance. , And covered new information, improved scientific understanding, conducted uninterrupted analysis of data and models, and there are specific differences in the methods used in the evaluation study. According to the above rules, special terms are used to evaluate and express the uncertainty of the key findings: 1) The type, quantity, quality and consistency of the evidence are expressed as “limitedâ€, “medium†or “conclusiveâ€; the degree of agreement is expressed “Lowâ€, “Medium†or “High†in general, the evidence is most conclusive when there are multiple independent high-consistent, high-quality evidence; 2) Different qualifiers are used to indicate the reliability level: “Very Low The “lowâ€, “mediumâ€, “highâ€, and “very high†reliability combined with the author’s team’s judgment of the validity of the results was determined by evaluating the evidence and consistency. The results of "low" and "very low" reliability should be presented in areas of major concern, and the reasons for these conclusions should be carefully interpreted. Confidence should not be explained from the perspective of probability, it is different from the "reliability in statistics"
Use "possibility" to quantify uncertainty. Table 1 provides an estimate of the probability of description. "Possibility" can be based on statistical analysis or simulation analysis, expert opinion or other quantitative analysis.
Probability of results 33% 66% probability 033% probability 010% probability 01% probability Note: Other terms that may be used in the fifth assessment report as appropriate (extremelylikely, 95% 100% 2 GHG emission scenarios used in the fifth assessment report The GHG emission scenarios are the basis for future climate change projections. The scenarios that were applied in the past were designed to be completed in the year 2000 and will need to be updated and supplemented. The fifth assessment report was adopted. A new generation of scenarios is called the "Representative Concentration Pathways (RCPs)" scenario. Here, rep-resentative represents just one of many possibilities. Using concentration instead of radiative forcing emphasizes concentration as the goal. Pathways refer not only to a certain quantity but also to the process of reaching this quantity. The four scenarios are called RCP8.5 scenario, RCP6 scenario, RCP4.5 scenario and RCP2.6 scenario: RCP8.5 scenario. This is the highest Greenhouse gas emissions scenario: scenario assumes the largest population, low technological innovation rate, and slow energy improvement, so income growth is slow, which will lead to long time Energy demand and high greenhouse gas emissions, and lack of policies to deal with climate change, compared with past scenarios, there are two important improvements: 1) establish a spatial distribution map of air pollution estimates; 2) strengthen land use and land Changes in estimates.
RCP6 scenario. This scenario reflects long-lived global greenhouse gas emissions and short-lived material emissions, as well as land-use/land-surface changes that lead to a stable radiative forcing of 6.0 Wm-2 by 2100. According to the Asian-Pacific comprehensive model observation changes Assessment of Human Contribution Possibility of Future Changes 21st Century Early 21st Century (Large and warmer nights and/or less of most land areas in 2016 are likely to be almost certain of the warmth and warm nights of most land areas. More frequent or likely more likely to be almost certain of warm periods/heat waves: the increase in the frequency and/or duration of the occurrence in most land areas is of medium confidence on a global scale; in some areas (eg, most of Europe, Asia, and (Australia) is likely to be (through a number of heat wave cases to see a large increase in the probability of possible human impacts in some places) without a formal assessment (the model predicts the period, intensity, and extent of recent heat waves and warm periods are increasing) is likely to be a strong precipitation event : Increased frequency, intensity, and/or precipitation of heavy precipitation may increase more land on land than increase In mid-North America it is very likely that medium confidence is possible on many lands in some areas, but in most parts of the mid-latitude lands and humid tropical regions it is very likely that the intensity of drought and/or dry periods increase in Low confidence on a global scale; in some areas it is possible (drought frequency and intensity may increase in the Mediterranean and West Africa but may decrease in North America and northwest Australia) low confidence and low confidence (due to soil moisture Estimated low reliability) is possible from the regional to global scale (medium confidence) The estimated soil moisture at the regional to global scale is reduced, and agricultural drought is currently arid area in the RCP 8.5 scenario to the end of the 21st century. (Medium confidence) will increase. Stronger tropical cyclone activity is less reliable in long-term (century-scale) changes; but since 1970 there has been almost certain low confidence in the North Atlantic. In some ocean basins it is more likely to be extreme. High sea level triggering since 1970 is possible without evaluating the likely event and/or amplitude increase Note: AR5 estimates are relative to 1986-2005 except for special Note that the scenario uses a new Typical Concentration Target (RCP) scenario.
In addition, extreme weather has also been frequent (Table 3). Globally, it has been observed that days with colder days and nights are decreasing, while days with warmer days and nights are increasing, and more frequent or more severe precipitation events occur in North America and Europe. It has been observed that most cold and warm nights on land are warmer and/or lesser, while hot and hot nights are warmer and/or more frequent; at the same time, the frequency of warm periods/heat waves occurring on most of the land and The duration is also increasing, and the frequency of heat waves in Europe, Asia, and Australia is increasing. In more and more areas on land, the frequency, intensity, and/or precipitation of heavy precipitation are increasing. To be sure, the strong tropical cyclone activity in the North Atlantic has been increasing since 1970. Globally, the events and/or magnitude caused by extreme high sea levels may also increase.
3.2 Marine Observations The fact that ocean warming leads to an increase in stored energy in the climate system accounts for more than 90% of the stored energy in 1971-2010 (high confidence).
The upper part of the ocean (~700m) almost certainly warmed in 1971*2010, and it was possible to warm up in the 1970s to 770th.
From a global scale, the largest warming of the oceans is that seawater at sea depths of nearly 000m may have warmed; however, no obvious warming trend has been observed in the ocean depth of 1992 000m, but below the water depth of 3000m until the sea-temperature of the seabed. During the period, the temperature is rising, and the area where the deepest seawater temperature rises most is in the Antarctic sea.
This shows that 90% of the newly added climate system energy is stored in the warmer ocean. From the linear trend estimate, 1971, since the 1950s, salinity in high-salinity areas where evaporation predominates in the ocean is even higher, and seawater in predominantly low-salinity areas has become less dim, providing indirect evidence that oceans Evaporation and precipitation have changed.
3.3 Observations of the Cryosphere In the past 20 years, the ice sheets of Greenland and Antarctica have largely disappeared, and glaciers worldwide have continued to shrink. Arctic sea ice and snow cover in the northern hemisphere have been continuously reduced (high confidence).
Loss of glacier ice outside the glacier around the global deicing cover, the average rate between 1971 and 2009 is likely to be 226X 109ta-1 per year, but during 1993-2009 the average rate is likely to reach 275X 109ta-S per year. Global glaciers retreat faster.
The average rate of ice loss in the Greenland ice sheet has increased rapidly from the rate of loss of ice in the ice sheet in the Mt. The average rate of ice loss in the Antarctic ice sheet ranges from 1992 to the Amundsen Sea in the west.
The speed of 5% 4.1% is decreasing (equivalent to 45X10451X104km2 sea ice area per 10a). In the summer, the area of ​​sea ice is the smallest, but the area of ​​multi-year ice in this period is also reduced by 9.4% and 13.6% per 10a (equivalent to 73X104107X104km2 sea ice area per 10a). The retreat of sea ice in the Arctic summer over the past 30 years and the increase in sea temperature have been abnormal since at least 1450a. The Antarctic sea ice area is on the contrary increasing. During the period of 1979-2012, the Antarctic sea ice area is likely to increase by an average of 1.2% 1.8% per 10a (equivalent to the decrease in snow cover in the Northern Hemisphere since the middle of the 20th century). Between 1967 and 2012, the Northern Hemisphere snow cover area ranged from 1.6% per 10 years in March and April, and 35 volumes compared to June's northern hemisphere with an area of ​​11.7% per 10 years. Since the early 1980s, the temperature of permafrost has increased in most regions, and it has been observed that the temperature in the northern part of Alaska increased by 3°C from the early 1980s to the mid-2000s, and the temperature in northern Russia increased by 2°C in 1971–2010. Among them, the thickness and area of ​​permafrost in the northern part of Europe in Europe in 1975 3.4 sea level observation facts Since the middle of the 19th century, the rate of sea level rise has been higher than the average rate of the past two thousand years.In the period of 1901-2010, the global sea The average plane elevation has risen by 019m. From the end of the 20th century, since the end of the 20th century, the end of the 19th century and the beginning of the 20th century are the transitional periods of sea level change, which have changed from the relatively low average rate of increase in the previous two thousand years to the relatively high rate of increase. The global average rate of sea-level rise continues to increase, and the average rate of global average sea-level rise during the period 1901–2010 was a high rate of 1. a - 1. Since 1920, there have been 75 reasons for sea-level rise observed since the 1970s. % can be attributed to the thermal expansion of the ocean and loss of glacier material (high confidence).In 1993a-1, glacial changes contributed 0.33mma-1 to the Greenland ice sheet, and the Antarctic ice sheet contributed 0. a-1 to land. Water storage contributes to a plane that lasts for at least 5m longer than it is today, but not more than 10m, when the temperature is at least 2C higher than the current average temperature. During the last interglacial, the melting of ice sheets from the Greenland ice sheet caused sea level rise. 1.44. 3.5 Carbon and other biogeochemical geochemistry at the highest level since 800 ka C (h concentration has risen by 40% from the pre-industrial level, mainly due to fossil fuel combustion emissions, followed by net emissions from land-use changes. 30% of people have C2 emissions, resulting in ocean acidification.
Since 1750, atmospheric concentrations of C2, CH4, and Team 0 have increased due to human activities. By 2011, the concentration of C2, CH4, and Team 0 in the atmosphere has reached 391 mL m-3, which is 40%, 150%, and 20% higher than before the industrial era; compared with the CO2, CH4, and N20 components in the ice core. The concentration of these greenhouse gases has exceeded the highest concentration in the past 800ka, which is unprecedented. The average rate of greenhouse gas concentration increase in the past 100 years has not been exceeded in the past 22ka.
Annual C2 emissions from cement production reach 8.3 GtCa-, and in 2011, C2 emissions reached 9.5 GtCa-, which is 54% more than the global emission level of 1990. In 2002, it reached an annual average of 0.9 Gt Ca-1 in terms of total volume. Between 1750 and 2011, the burning of fossil fuels and the production of cement contributed 365 GtC, and deforestation and other land-use changes estimated that 180 GtC was released, with a total of anthropogenic emissions of 545 GtC. Among the emitted greenhouse gases, 240 GtC remained. In the atmosphere, 155 GtC exists in seawater, and 150 GtC accumulates in the natural ecosystem of the land. After the seawater absorbs C2, the pH value gradually changes. Since the era of industrialization, the pH of seawater has decreased by 0.1, and the relative hydrogen ion concentration has increased. 4 Causes and Causes of Climate Change After giving evidence of global warming, the report discusses the causes of global warming. Scientists use Radiative Forcing (RF) to measure the impact of different factors on climate change. The radiative forcing of an influencing factor refers to the change in energy flow caused by the tropopause or the top of the atmosphere, in units of W*m -2. A positive radiative forcing indicates that this factor will lead to an increase in surface temperature, whereas a negative value will cause a decrease in surface temperature. . The increase in total radiative forcing has led to energy intake in the climate system, and the greatest contribution to total radiative forcing has been caused by the increase in atmospheric C2 concentrations since 1750.
Compared with 1750, the radiative forcing caused by human activities in 2011 reached 2.29 Wm-2, which was 43% higher than the assessment in 2005 in the Fourth Assessment Report (AR4). Greenhouse gases (C2, CH4, N2O and halogen Substitution of hydrocarbons contributed to the emission of radiative forcing of C2, which was 1.82W m-2, and that of halogenated hydrocarbons related to the hole of ozone layer was 0. 18W-0+2. Radiative forcing of aerosols such as cloud fog and black carbon aerosols. A contribution of 0.9Wm-2. In contrast, natural factors such as changes in solar activity (contributions of 0. m-2) and volcanic eruptions (influence only in individual years) are minimal.
On the basis of existing research results, AR5 gave a more complete climate model. According to the model, during the period of 1951-2010, the greenhouse gas emissions contributed 0.51.3°C of the average surface temperature increase; other man-made influences, such as the increase of aerosol, contributed 0.60.1°C; The influence of natural factors is between 0.10.1C. This model explains well the warming of 0.60.7C during this period. Changes in the global water cycle, the melting of ice and snow, rising sea levels and changes in certain extreme weather are also closely related to human activities. Therefore, the report believes that human activities are extremely likely (over 95% probability) to cause most of the global surface temperature increase since the 1950s.
5 Future projections of global and regional climate change 5.1 Projections of future air temperature Surface temperature of the ball may change by 15°C from the end of the 21st century to 1850-1900; in the context of RCP6 and RCP8.5, it compares to 1850-19 (0 years may exceed 2C; under the RCP4 scenario, it is more likely not to exceed 2C. Under all RCP scenarios except the RCP2.6 scenario, the warming will continue, but the decadal variability will continue to show. And regional changes are uneven.
The scope of 7C.
According to the simulation results of the CMIP5 model (Table 4), under the RCP2.6 scenario, the 2081 at the end of the 21st century is in the 0.31.7C range; under the RCP4.5 scenario, the temperature increase may be in the 1.12.6C range; under the RCP6 scenario, The warming may be in the 1.43.1C range; under the RCP8.5 scenario, the warming may be as high as 2.64.8C. At the same time, the rate of warming in the Arctic region will be faster than the global average, and the warming of the land will be faster than the rate of warming of the oceans.
The increase in the average temperature of the local surface can almost confirm that in most places, there will be more days of high temperature and fewer days of freezing in the weekday and seasonal time scales (Table 3). The frequency of heat waves will likely increase and the duration will increase, but sporadic cold winters will still occur. 5.2 Prediction of the future of the water cycle In the 21st century, changes in the global water cycle in response to climate warming will not be uniform. Although there may be regional anomalies, the contrast between wet and dry areas, and between rainy and dry seasons will be stronger.
Under the 5 scenarios, the annual precipitation in the Gaoweidu area and the tropical Pacific will increase, and in many humid areas with medium Weis, the average precipitation will also increase. However, the average precipitation will decrease in the dry areas of Zhongweidu and the subtropical areas.
Under the global trend of continuous warming, by the end of the 21st century, extreme rainfall events in most of the land areas of the Weifang region and tropical regions will likely be more intense and frequent.
Table 4 The relative base period in the middle and late 21st century is the projected variable for the global average temperature and the global average sea level rise from 1986 to 2005 2046–2065 2081-2100 Average Possible Range Average Possible Range Global Average Surface Temperature Change/*RCP2. 61.00.41. On a global scale, regions affected by the monsoon system may increase by the end of the 21st century, and monsoon intensity may weaken, but monsoon precipitation may be more severe. The onset of monsoon may be earlier or unchanged, but the monsoon season may be prolonged because of the delay in the end of the monsoon.
With global influence, it will remain the most important factor affecting the inter-annual changes in the tropical Pacific in the 21st century. As a result of the increase in water vapor, the precipitation associated with the El Niño-Southern Oscillation will be likely to increase in some regions.
5.3 Prediction of Future Air Quality Globally, surface warming will reduce near-surface ozone. Under the RCP8.5 scenario, an increase in CH4 concentration will cause the increase in surface ozone to be greater than the reduction in warming, and by 2100 the concentration of ozone will increase by 25% over that of other scenarios. Under all other conditions, When the surface air temperature in the polluted area is warm, ground ozone and PM2.5 concentrations will increase.
5.4 Estimates of the future of the ocean The global ocean will continue to warm in the 21st century. Heat will penetrate from the ocean surface to the deep sea and affect the ocean circulation.
The areas with the most obvious increase in surface seawater temperature are located in the oceans of tropical and northern hemisphere subtropical regions, but the most obvious warming of deeper seawater temperatures is in the southern hemisphere. By the end of the 21st century, the ocean warming of about 100m deep in the upper layer will be about 0.6°C to 2.0°C (RCP8.5 scenario), and the seawater temperature will be about 0.3°C deeper in seawater of about 1000m (RCP2.6 scenario ) to 5 scenarios).
It is likely to weaken, with a reduction of approximately 11% under the RCP2.6 scenario and approximately 34% under the RCP8. 5 scenario. Due to the internal dynamics of the AMOC, AMOC will decrease around 2050, and in some years Will increase. In the 21st century, AMOC may not suddenly change or disintegrate. However, if the trend of continuous warming continues, AMOC may still be disintegrated.
5.5 Prediction of the Future of the Cryosphere As the global average surface temperature rises, Arctic sea ice coverage will very likely continue to shrink and thin, and snow cover in the northern hemisphere will likely decrease in the spring. Global glacial volume will be further reduced.
Through the multi-model average, Arctic sea ice is projected to shrink by the end of the 21st century. Among them, the Arctic sea ice area will decrease by 43% in the September RCP2.6 scenario and by 94% under the RCP 8.5 scenario. The Arctic sea ice area will decrease by 8% in the February RCP2.6 scenario and 34% under the RCP8. 5 scenario. Based on a partial assessment of the current model of the Arctic Sea Ice Coverage simulation closest to that of the RCP8. Under the .5 scenario, the ice-free Arctic in September will probably appear before 2050. With rising global temperatures, by the end of the 21st century, the Antarctic sea ice area and volume may decrease to the end of the 21st century, and the estimated global glaciers (including glaciers around the Antarctic ice sheet) will be reduced by 15% under the RCP2.6 scenario. 55 %, and under the RCP8.5 scenario will be reduced by 35% and 85%. According to the model average, the estimated snow cover area in the northern hemisphere at the end of the 21st century will decrease by 7% under the RCP2.6 scenario and decrease under the RCP8.5 scenario. 25%. It is certain that with the increase of the global average surface temperature, the area of ​​permafrost near the surface of the high altitude in the Northern Hemisphere will decrease. It is estimated that by the end of the 21st century, the permafrost area near the ground (upper 3. 5m) in the high Weiwei area of ​​the Northern Hemisphere will be further reduced by 5.6 compared to the end of the 20th century. The future of sea level is estimated during the 21st century, the global average sea level will continue to rise . Under all RCP scenarios, the rate of sea-level rise is likely to exceed the observations of 1171-2210. The sea level rise observed during 1971-22 was caused by further ocean warming and material loss from glaciers and ice sheets.
From Table 4 on future sea level projections under the four RCP scenarios, compared with 1986-2005, the highest sea level will rise from 2081 to 2100. Under the 5 scenarios, the sea level will rise about 0.520.98m. In all RCP scenario projections, the main reason for global average sea level rise in the 21st century is the impact of seawater thermal expansion, which accounts for about 35% and 55%, and glacial melting accounts for about 15% and 35%. The increase in the surface ablation of the Greenland ice sheet will exceed the increase in snowfall. The balance of surface ice and snow masses will positively contribute to the rise of the sea surface in the future; the Antarctic ice sheet will have less ablation and snowfall will increase, and its material balance will play a negative role in the future rise of the sea surface. However, the combination of the melting ice of the Greenland ice sheet and the Antarctic ice sheet will increase the sea level by 0.030.20m by 2018-2100. 5.7 Prediction of carbon and geochemical cycles will increase atmospheric CO2 concentrations. The way affects the carbon cycle process. Further uptake of carbon by the ocean will increase ocean acidification.
Absorption of artificial C2, and the higher the C2 concentration of the scenario, the more absorbed. However, in the future, the carbon sequestration capacity of the land is still uncertain. Some models point out that due to the effects of warming and land use changes, the role of land-based carbon sequestration will be weakened. According to the results of the Earth System Model (ESM), the feedback between the climate and the carbon cycle in the 21st century is positive. Climate change will partially offset the land and ocean carbon sink mechanisms, and the human-caused emissions of C2 will remain in the atmosphere. In all RCP scenarios, ESM estimates that by 2100, the pH of the seawater will be reduced by 0.06 in the most conservative manner; while under severe warming scenarios, the seawater pH will decrease by 0. Based on the 15 Earth system models (ESM). According to the estimation results of the four scenarios, cumulative C2 emissions in the world from 2012 to 2100 will be at least 140 GtC, up to 1910 GtC, indicating that human carbon emissions will continue to grow.
To limit and reduce global warming can only be done with RCP2.6, the annual C2 emissions by 2050 will be slightly lower than 1990 emissions (about 4% 96%). According to this situation, by the end of the 21st century, half of the model inferred that the carbon emissions of all humans would be close to zero; the other half of the models inferred that the existing atmospheric C2. 5 scenario must be removed and released by the melting of permafrost by the end of the 21st century. Either C2 or CH4 will determine the climate stability, climate change commitments and irreversible cumulative C2 emissions up to 50250 GtC 6 to a large extent determining the global average surface temperature increase in the 21st century and beyond. Many aspects of climate change will continue for many centuries, even if CO emissions are stopped. This represents a century-long commitment to climate change from past, present and future C2 emissions.
The rate of warming of surface air temperature is basically proportional to the cumulative C2 emissions in the atmosphere. Therefore, the cumulative emissions of all anthropogenic greenhouse gases must be controlled within 1000 GtC to have a probability of >66% compared with 1861–1880. The annual average temperature controls the temperature rise at the end of the 21st century to below 2°C. If other non-C2 warming is taken into account, at least the emissions will be reduced to 800 GtC. However, by 2011, 531 GtC has been emitted by humans, and it is increasingly difficult to achieve the target of temperature control.
Most of the anthropogenic climate changes caused by the increase in C2 emissions are irreversible on a time scale of a hundred years to a thousand years. At the same time, according to different scenarios, nearly 15% of C2 emissions will remain in the atmosphere for more than 1000 years. If we look at the RCP2.6 scenario, we can be sure that the sea level will continue to rise with global warming after 2100; it is expected that by 2300, if the concentration of CC2 in the atmosphere reaches 500mL m-3, the sea The height of the plane is less than 1m above the pre-industrial level; however, under the scenario of RCP8.5, the concentration of thorium 02 between 7001 planes will rise by 1m to more than 3m. The global large-scale reduction of ice sheet material may result in higher sea levels. As the plane rises, the reduction of some ice sheets has become an irreversible process. When the local surface warming exceeds a certain threshold, the ice sheet may melt completely in millennia or longer, which will cause the sea level to rise more than 7m. Currently, the estimated critical value is compared with Before the Industrial Revolution, it was higher than 1C, but less than 4C. 7 Conclusions The fifth assessment report of Climate Change 2013: The Foundation of Natural Science was published by the first working group of IPCC. It was completed by several hundred scientists for 3 years. Other working groups have The mitigation part and comprehensive report will also be released next year. IPCC this assessment report gives data that the facts of climate warming are more conclusive. This assessment report provides a more objective and scientific analysis of the entire climate system. Compared with the past, the observed data used today have obviously improved in quality and quantity, and can describe the scientific facts in a more comprehensive, multi-perspective and diverse manner. . At the same time, in terms of climate models, more influencing factors were considered, carbon cycle and dynamic vegetation were added, and a deeper understanding of human activities was gained. The IPCC report played an important role in promoting the adoption and implementation of the UN Framework Convention on Climate Change by all governments.
Acknowledgments: After the release of the Fifth Assessment Report of the IPCC Working Group I, many media, agencies and experts reported and interpreted the report, which provided us with good understanding and in-depth interpretation of the assessment report. When we read the report, we read the relevant materials and quoted the relevant interpretations. Since the sources of the information are multiple approaches, we cannot mark them one by one. We hereby express our sincere gratitude to the relevant institutions and experts.
Ferro Calcium Silicon Lump,Ferro Calcium Silicon,High Performance Ferro Silicon Calcium,High Performance Calcium Silicon
NINGXIA HELANSHAN METALLURGY CO., LTD. , https://www.nxhlsyjferrosilicon.com