China Net/China Development Portal News The latest assessment of the Intergovernmental Panel on Climate Change (IPCC) shows that since the industrial revolution, carbon emissions caused by anthropogenic activities such as fossil fuel use and deforestation have increased atmospheric carbon dioxide (CO2). The concentration increased from 285 ppm before the industrial revolution to 417 ppm in 2022, causing the global average temperature to increase by about 1.1°C. In order to slow down climate warming caused by the increase in concentration of CO2 as the main greenhouse gas, the international community has successively formulated the United Nations Framework Convention on Climate Change (1992 Year), “Kyoto Protocol” (1997), “Copenhagen Agreement” (2009), “Paris Agreement” (2015), “Glasgow Climate Agreement” (2021), “United Nations Framework Convention on Climate Change” (2022) ) and other international conventions have set the goal of controlling temperature rise to 1.5°C by the end of the 21st century. As a major global action to reduce carbon emissions, the world’s major economies have successively announced “dual carbon” (carbon peak, carbon neutral) emission reduction targets.
China is an active promoter of the “double carbon” Zelanian sugar action, which the Chinese government announced in September 2020 , will strive to “peak carbon” in 2030 and achieve “carbon neutrality” (that is, CO2 net emissions will be 0) before 2060. As a big country like China that is in the process of realizing industrialization and modernization, “carbon peak” and “carbon neutrality” “There is only an interval of 30 years, and we will inevitably face huge challenges in industrial transformation, technologicalZelanian sugarupgrading, and ecosystem carbon sequestration and increase in sinks. . Currently, the main paths to achieve “carbon neutrality” include reducing carbon emissions caused by fossil fuel use and land use changes (emission reduction), increasing carbon absorption in land and sea ecosystems (increasing sinks) and widespread use of carbon capture and carbon storage ( CCUS) technology.
Newzealand Sugar Increasing ecosystem carbon sinks is the most green, economical and feasible way to achieve “carbon neutrality” . 2Newzealand Sugar012-2021, the global terrestrial ecosystem carbon sink is approximately 11 billion tons of CONewzealand Sugar2/year, it offsets about 32% of human fossil fuel carbon emissions and plays an irreplaceable role in achieving the goal of “carbon neutrality”. However, ecosystem carbon sinks are fragile and are not only affected by ecosystem type, soil and climate factors, but also by human interference.
Wildfire is one of the most important natural disturbance processes in global ecosystems and a major threat to forests and grasslands NZ EscortsNZ Escorts
a> Natural disturbance type that plays an important role in the carbon cycle of terrestrial ecosystems. Fire destroys surface vegetation, releases large amounts of greenhouse gases, particulate matter and other trace gases, exacerbating Zelanian Escort soil erosion and air pollution, and is a global issue. One of the important drivers of environmental and climate security. From 2002 to 2020, the average annual global wildfire emissions were (73.2±7.32) billion tons of CO2, which is approximately the CO2, which contributes significantly to the increase in atmospheric CO2 concentration. At the same time, wildfire carbon emissions experience large interannual variability as a result of climate change. Sugar Daddy For example, in the 1997-1998 El Niño year, wildfire emissions reached 11.712 billion tons of CO2, and from 2001 to 2009, the average annual wildfire emissions were 5.86 billion tons of CO2, Therefore, wildfire carbon emissions are one of the main factors leading to changes in terrestrial carbon sinks. Although post-fire vegetation recovery can offset some of the direct carbon emissions of wildfires, Zelanian EscortWith a warming climate, shorter fire cycles, and increased intensity, it will take longer for vegetation to offset carbon releases. Especially in boreal forests and tropical rainforests, climate warming and drying and human activities have led to an increase in the frequency, area and intensity of forest fires, and a sharp increase in carbon emissions from forest fires. As a result, it will take more than a hundred years for forest vegetation to recover to offset the carbon emissions caused by forest fires. The release lags within the time frame set by the target of keeping temperature rise at NZ Escorts 1.5°C. Therefore, when evaluating the carbon accounting system in the context of “dual carbon”, wildfire carbon emissions cannot be ignored.
The role of forest fire carbon emissions in the global carbon cycle
Global forest fire area and carbon emission trends
Wildfires mainly occur in the three major ecosystems of grassland, savanna and forest, and the wildfire area on the African continent accounts for more than 3/4 of the global fire area. Satellite data show that the global wildfire area has generally shown a downward trend since 2000, mainly due to farmland management leading to a decrease in the burned area of African grasslands and savannas. However, forest fires are on the rise globally, especially in western North America, Australia and other regions, where the frequency of catastrophic fires is increasing. Forest fires account for about 5% of the global burned area, but due to the high forest biomass, forest fire carbon emissions account for 20% of global wildfire CO2 emissions. The average annual emissions are about 1.5 billion tons of CO2. In recent years, affected by climate warming and human activities, the CO2 emitted by forest fires has reached an annual rate of about 1% (about 15 million tons of CO2 sub style=”text-indent: 32px; text-wrap: wrap;”>2) is growing at a rapid rate and has become a source of carbon emissions that cannot be ignored.
Especially in northern coniferous forests, as climate warming and drought intensify, the frequency of forest fires has shown a significant increase. 2Zelanian Escort000—In 2020, carbon emissions from boreal forest fires accounted for global wildfire CO2 emissions; due to climate warming, the proportion will reach 23% in 2021, releasing 1.76 billion tons of CO2 . Moreover, high-latitude tundra areas where wildfires rarely occur have also begun to burn frequently, causing the permafrost to melt and exacerbating the emission of strong greenhouse gases such as methane and nitrogen oxides.
Factors affecting the occurrence of forest fires
The occurrence of forest fires is affected by meteorological conditions, combustible characteristics and fire sources. Climate warming leads to high temperatures, heat waves and droughts, causing the moisture content of combustibles to decrease and increasing the frequency of atmospheric thunderstorms , the frequency, spread speed and energy release of forest fires also increase. At the same time, rising temperatures are beneficial to the growth of high-latitude plants, increase the load of combustibles, and further increase the intensity of forest fires. Due to climate warming, there is an “Arctic” “Amplification effect” (that is, the climate warming rate in high latitudes is higher than the global average), so high temperature heat waves and drought events in high latitudes in the northern hemisphere may be more severe in the futureZelanian sugar is frequent, and the frequency and intensity of extreme wildfires may continue to increase. The positive feedback mechanism between climate warming and wildfire carbon emissions may make high latitudes areas with high incidence of fire carbon emissions.
Estimation of carbon emissions from extreme forest fires in Canada in 2023 and their impacts
Forest fires are an indispensable natural disturbance process in boreal forests and are important for maintaining the diversity of forest ecosystems. It is an important factor in sex and health. It regulates the tree species composition, age structure and spatial (landscape) pattern of the forest ecosystem in various forms from ground fire to crown fire. May to October every year is the active period of forest fires in Canada. Global climate Changes have led to continued high temperatures in North America. In the spring of 2023, the temperature in some Canadian provinces Zelanian Escort was higher than the same period in previous years. The unusually hot and dry climate increased forest risk. The frequency and intensity of fires. According to data from the Canadian Forest Fire Center, as of August 29, local time, a total of 5,900 fires have occurred in the country in 2023, with a total fire area of approximately 150,000 square kilometers. Such large-scale and high-intensity forest fires It may lead to damage to the ecosystem and loss of biodiversity, causing irreversible degradation of the ecosystem Zelanian sugar.
Fires release a large amount of particulate matter, which is transported to the United States and Europe with westerly circulation, causing serious air pollution and endangering the health of people in the United States, Canada, Europe and even the entire northern hemisphere. At the same time, forest fires releaseA large amount of greenhouse gases (CO2, methane and nitrogen oxides) will further increase the concentration of atmospheric greenhouse gases and intensify the global climateNZ EscortsWarming will cause difficulties for international climate governance and “double carbon” emission reduction targets.
Methods for estimating forest fire carbon emissions
The main methods for calculating forest fire carbon emissions include emission factor method, remote sensing observation method, model simulation method, Monitoring inversion method, etc. Emission factor method, Zelanian Escort remote sensing observation method, model simulation method, etc. are “bottom-up” methods, mainly through fire area or radiation Sugar Daddyradiation power, combined with biomass, combustion coefficient, emission factors and other parameters to calculate the different greenhouse gases produced by the consumed combustible biomassZelanian EscortEmissions with high spatial resolution (hopefully. 100 m2—1 km2NZ Escorts) and other advantages, but requires accurate data on burned area, biomass, emission factors, etc. The monitoring inversion method is a “top-down” method. It is mainly based on the greenhouse gas concentration and meteorological field data of atmospheric observations, combined with the atmospheric chemical transport model, and through the data assimilation method, the emissions of forest fires can be obtained relatively quickly through data assimilation. However, this method has low spatial resolution (> 0.25°) and is difficult to quantify source-sink changes in CO2 emissions due to the influence of the atmospheric boundary layer. Since it is not yet possible to accurately grasp the forest structure, stand density, burning proportion and other information in burned areas in Canada, there are certain differences in estimations made by different methods.
Remote sensing data is currently an effective means of estimating carbon emissions from large-scale forest fires. This study is based on the fire carbon release intensity method, which can quickly and accurately conduct a preliminary assessment of forest fire carbon release. This method first calculates the Canadian regional fire carbon emission intensity map through the Global Forest Fire Carbon Release Database (GFED) (Figure 1). The GFED database is a highly accurate and internationally accepted forest fire carbon emission data set, and is the main data source for IPCC to estimate fire carbon release; then, combined with remote sensing observations andAccording to the fire data released by the Canadian state, as soon as she finished speaking, she heard Wang Da’s voice from outside. The cumulative carbon release from fire is estimated at this time (Fig. 2).
This study uses fire carbon release data provided by the Copernicus Atmosphere Monitoring Service (CAMS) Global Fire Assimilation System (GFAS) as verification. GFAS is based on medium-resolution imaging spectroscopy for She was embarrassed to leave her daughter waiting outside the door for too long. “Fire radiant power (FRP) data observed by MODIS instrument, use the emission factor method to convert FRP into dry matter (DM) consumed by fire, and then combine it with published data to calculate fire carbon emissions. GFAS has been widely used Monitoring fire carbon emissions, air quality forecasting and atmospheric chemistry simulation, it is one of the internationally authoritative fire carbon emission databases.
This study estimates that as of August 29, fires in Canada have accumulated CO emissions in 20232 is about 1.268 billion tons, which is about 9% lower than the estimated value of CAMS (1.394 billion tons) and is the CO for the same period from 2002 to 20222 is more than five times the average emissions (Figure 2); this emission has exceeded the annual energy-related CO emissions of Canada and Germany in 20212 emissions (according to 2022 data from the International Carbon Plan, Canada and Germany’s energy-related CO2 emissions are “Son, you areYou are asking for trouble. No matter why Mr. Lan married your only daughter to you, ask yourself, what is there to covet in the Lan family? Without money, power, fame or fortune, there are 546 million tons and 674 million tons; among them, Germany ranks 7th in the world).
The impact of Canadian forest fires on air quality
Canadian forest fires release CO2. Greenhouse gases such as methane also produce a large amount of particulate matter, including fine Sugar Daddy particulate matter (Sugar Daddy Air pollutants such as PM2.5), respirable particulate matter (PM10), black carbon (BC), and volatile organic compounds (VOCs); these air pollutants Pollutants have a significant impact on air quality in local and downstream areas, directly affecting human health. Based on the Earth System Model (IAP-AACM), this study simulated the impact of Canadian forest fire air pollutants on global PM2.5 concentrations. The results show that PM2.5 released by forest fires in Canada is affected by westerly circulation and weather dynamics, causing long-distance cross-border transmission. It not only affects the eastern United States, but also spreads across the Atlantic to densely populated areas such as Western Europe and Eurasia, leading to Widespread air pollution. There are four main cross-border transmission processes with greater impact, namely May 17-26, June 6-19, June 23-30, and July 15-20, 2023Zelanian sugar (Figure 3). These four processes have significantly Sugar Daddy affected air quality in the United States (PM2.5 concentration can reach more than 50 micrograms/cubic meter), Among them, the high concentration of PM2.5 released by forest fires from June 27 to 30 significantly affected Europe (above 5 micrograms/cubic meter). Canadian forest fires also have an impact on PM2.5 concentrations in North Africa and Asia. Blue’s mother was so frightened by her daughter’s nonsense that she turned pale and quickly moved the stunned daughter Zelanian Escort‘er pulled her up, hugged her tightly, and said loudly to her: “Hu’er, don’t make any noise, and it will affect meZelanian EscortWestern region of the countryarea, the concentration contribution is less than 5 micrograms/cubicSugar Daddym. As of July 20, 2023, forest fires in Canada have caused PM2.5 to exceed standards in more than 3 million square kilometers of land, affecting more than 80 million people.
Current status of carbon emissions from forest fires in China
my country’s ongoing Ecological management measures such as afforestation and forest protection have achieved “double growth” in forest area and stock volume for more than 30 consecutive years. According to the ninth national forest resources inventory data, my country’s natural forest area is 140 million hectares, and artificial forest area is 80 million hectares. The coverage rate is about 23%. Among the newly added green areas in the world from 2000 to 2017, about 1/4 came from China, ranking first in the world and making a huge contribution to increasing foreign exchange. The “14th Five-Year Plan for National Economic and Social Development of the People’s Republic of China and the Outline of Long-term Goals for 2035” proposes that during the “14th Five-Year Plan” period, the forest coverage rate will increase to 24.1%.
The continuous growth of forest area and stock volume has made a huge contribution to carbon sequestration and improvement of the ecological environment. It also brings huge challenges to forest fire prevention. Despite the severe challenges faced by the combination of natural factors and social factors, with the joint efforts of many parties Zelanian sugar, my country’s forest and grassland fire prevention work has still made great progress. , the comprehensive fire prevention and control capabilities have been significantly improved. From 2000 to 2021, the average annual number of forest fires in my country was 6 088 ± 3 948, of which more than 95% were less than 100 hectares in area Newzealand Sugar fire, the forest affected area was (72,000 ± 12,000 hectares). Especially since 2010, the number and area of forest fires have dropped significantly (Figure 4). The reduction in forest fire area has significantly reduced the amount of carbon emissions from forest fires. The annual carbon emissions from forest fires in my country are (1 500 ± 1.6 million) tons of CO2. Therefore, my country’s forest ecological engineering measures of “increasing greening and sequestering carbon” and the fire prevention policy of “prevention first, combining prevention and rescue” have made great contributions to global environmental governance, increasing carbon sinks and reducing forest fire carbon emissions.
Strengthen forest fire carbon research and reduce carbon emissions from natural processes
Forest fires have become a source of carbon emissions that cannot be ignored, especially in recent years when extreme forest fire events have occurred frequently (such as 2019 Amazon forest fires, Australian forest fires in 2019-2020, Siberian forest fires in 2022, and Canadian forest fires in 2023) directly emit large amounts of greenhouse gases. At the same time, forest fires also release large amounts of strong greenhouse gases such as methane and nitrous oxide by accelerating the melting of permafrost. Other volcanoes and active faults are also sources of greenhouse gas emissions. Therefore, it is urgent to strengthen research on carbon emissions from forest fires and reduce carbon emissions from natural processes. Here are 3 suggestions.
Incorporate forest fire carbon emissions into the national emissions inventory. Establish a comprehensive, objective and fair carbon emission monitoring and measurement system, taking into account both human activities (fossil fuel emissions, industrial emissions) and natural process carbon emissions, and include greenhouse gases emitted by natural processes, including forest fires, into the national emissions inventory. Let’s jointly establish a global climate governance system that is fair, reasonable, cooperative and win-win.
Take effective measures to reduce carbon emissions from natural processes. Although the prediction and control of forest fires is a difficult problem for academia and the forestry department, scientific and effective methods can be adopted to prevent forest fires. For example, combustible material treatment is implemented in the forest to reduce the combustible material load. The treatment methods include planned fire, mechanical clearing, stand dredging and natural fire utilization, and increasing fire prevention forest belts. At the same time, we can consider adjusting the tree species composition of the forest to form a forest belt that is resistant to forest fires and build a natural “green fire road.” In May 2023, my country issued the “Opinions on Comprehensively Strengthening Forest and Grassland Fire Prevention and Extinguishing Work under the New Situation”, which reflects the determination of the Party Central Committee and the State Council to resolve major forest and grassland fire risks and fully safeguard the safety of people’s lives and property and ecological security.
Strengthen international cooperation. The impact of extreme forest fires is not limited to a certain region. It has become an emergency event affecting the global environment and climate governance. It is urgent for all countries to pay close attention toAttention; by strengthening cooperation, jointly responding, and implementing practical measures to reduce carbon emissions caused by natural factors. In response to the global problem of predicting and preventing extreme forest fires, scientific researchers should be organized to further study and build a technical system for forest fire risk identification, early warning prediction and prevention and control, and strengthen research on carbon emissions in forest fire processes to establish a more scientific, comprehensive and independent Controllable carbon accounting system.
(Author: Liu Zhihua, Shenyang Institute of Applied Ecology, Chinese Academy of Sciences; He Hongshi, Northeast China School of Geographical Sciences, Normal University; Xu Wenru, Liang Yu, Zhu Jiaojun, Wang Gaofeng, Shenyang Institute of Applied Ecology, Chinese Academy of Sciences; Wei Wei, Shanghai Institutes for Advanced Studies, Chinese Academy of Sciences; Wang Zifa, Institute of Atmospheric Physics, Chinese Academy of Sciences; Han Yongming, China Institute of Earth Environment, Academy of Sciences; contributed by “Proceedings of the Chinese Academy of Sciences”)