This article is selected from the journal of the Chinese Academy of Engineering, China Engineering Science, Issue 5, 2022
Authors: Shu Zhangkang, Li Wenxin, Zhang Jianyun, Jin Junliang, Xue Qing, Wang Yintang, Hu Qingfang, Wang Guoqing
Source:Historical changes and future trends of extreme precipitation and high temperature in China[J].Strategic Study of Chinese Academy of Engineering,2022,24(5):116-125.)
Editor's note
Global warming is an indisputable fact, and extreme precipitation and extreme heat waves seriously endanger the safety of human life and property. In the case of frequent extreme climate events, it is of great significance to understand and grasp the temporal and spatial changes of extreme events, reveal the historical evolution of extreme precipitation and high temperature in the continent under the background of global warming, and predict the possible changes of extreme climate events in the future.
The research team of Academician Zhang Jianyun of the Chinese Academy of Engineering published the article "Historical Changes and Future Trends of Extreme Precipitation and High Temperature in China" in the 5th issue of the journal of the Chinese Academy of Engineering, China Engineering Science in 2022. Based on CN05.1 national grid meteorological data and 11 global climate models of the Sixth International Coupled Model Intercomparison Project (CMIP6), this paper analyzes the evolution characteristics of historical extreme precipitation and high temperature events in the continent from 1975 to 2014, studies the changes of extreme events from 2015 to 2054, and puts forward policy suggestions for coping with extreme events.
The results show that: (1) From 1975 to 2014, the heavy precipitation in China showed a spatial pattern of increasing from northwest to southeast, decreasing and increasing, and the risk and danger of extreme precipitation in the east of the Hu Huanyong line were greater, and under the two selected comparison scenarios, extreme precipitation in the mainland would generally increase and intensify from 2015 to 2054, with a large increase in extreme precipitation events in North China and Northeast China, and a further increase in heavy precipitation in Northwest China. (2) The number of warm night days and warm days in mainland China from 1975 to 2014 showed a significant increasing trend, and the increase in the number of warm night days was higher than that of warm days. In order to mitigate the impact of climate change and cope with the risk of extreme events in the future, this paper suggests that the risk response and emergency management capabilities of flood disasters and high temperature and heat waves should be further improved, international cooperation should be strengthened, and relevant climate change adaptation strategies should be formulated according to local conditions, so as to prevent and respond to extreme disasters caused by global warming.
I. Preface
Since the Industrial Revolution, the concentration of carbon dioxide in the atmosphere has increased significantly, with an annual average of 414.7 ppm of carbon dioxide in 2021, an increase of about 2.3 ppm compared to 2020 and the highest value recorded by modern instrumental observations. Continued emissions of greenhouse gases such as carbon dioxide have led to a significant increase in the global average temperature, increasing the risk of extreme weather events around the world. According to the Global Climate Risk Index 2021, there have been about 11,000 extreme weather events in the past 20 years, resulting in about 475,000 deaths and economic losses of nearly $2.56 trillion. Global warming caused by greenhouse gas emissions has significantly affected the process of regional hydro-atmospheric cycle, resulting in the frequent occurrence of disasters such as extreme drought, torrential rain and floods, high temperature and heat waves, sea level rise, glacier degradation and permafrost melting, which have seriously restricted the balanced development of regional economy, society and ecological environment.
According to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the global average temperature from 2011 to 2020 increased by about 1.09 °C compared with that from 1850 to 1900. According to the Clausius-Clapeyron thermodynamic equation, a significant warming of the atmosphere will lead to an increase in the saturated water vapor pressure in the atmosphere, which will increase the frequency and intensity of extreme precipitation events. The frequent occurrence of extreme precipitation events will cause regional floods and threaten the safety of urban and rural residents, while the reduction of food production caused by heavy rainfall disasters will also exacerbate the global food crisis and trigger a series of secondary disasters. Extreme heat wave events will increase the incidence of heat stroke, cardiovascular and cerebrovascular, respiratory, and nervous system diseases, and directly threaten human health. To mitigate the effects of global warming, the Paris Agreement proposes to limit global warming to 1.5 °C and strive to limit warming to 2 °C. Previous studies have pointed out that the global average temperature increased by 0.24 °C from 2011 to 2020, and the simulation of the finite amplitude impulse response (FalR) climate model shows that under the 2021 immediate cessation of carbon emission scenario, the global average temperature is still 42% likely to exceed the 1.5 °C temperature limit target around 2029, and the projections based on various climate models show that global warming of 1.5 °C and 2.0 °C may occur in 2030 and 2.0 °C, respectively. Around 2040, the temperature change in continental regions will be higher than the global average.
Global warming is an indisputable fact, and climate change will have an important impact on the continent's resources, ecology, and economy and society. The sub-project "Water Balance Relationship and Evolution of Water Cycle Elements in Key Regions" (2020) in the consulting project of the Chinese Academy of Engineering "Research on the Strategy of Coordinated Development of Water Balance and Land Space (Phase I)" focuses on sorting out the evolution of water balance factors and analyzing the impact of climate change on regional water balance. Among them, the changes of extreme events under global warming are directly related to the economic, social and people's property security of the continent, revealing the historical evolution law of extreme precipitation and high temperature in the continent under the background of global warming, and predicting the possible changes of extreme climate events in the future are of great significance for coping with climate change risks. In view of this, this paper combines the CN05.1 national grid meteorological data and the global climate model simulation climate data of the Sixth International Coupled Model Intercomparison Project (CMIP6) to analyze the historical extreme precipitation and high temperature changes and future trends of the continent, and put forward policy recommendations for coping with extreme events and mitigating the impact of climate change.
2. Research data and methods
(i) Research data
In this study, the CN05.1 grid meteorological data (precipitation, maximum temperature, minimum temperature) from 1975 to 2014 were used as the measured information to analyze the variation trend and spatial characteristics of historical extreme precipitation and high temperature events. CN05.1 meteorological data is generated by interpolation of data from more than 2,400 weather stations across the country and provided by the National Climate Center. The future precipitation, maximum temperature, and minimum temperature data are projected using global climate models, which are selected from the newly released CMIP6 plan, including ACCESS-CM2, ACCESS-ESM1-5, CanESM5, EC-Earth3, EC-Earth3-Veg, EC-Earth3-Veg-LR, GFDL-ESM4, KACE-1-0-G, MRI-ESM2-0, A total of 11 climate models were developed in NorESM2-LM and NorESM2-MM. These models have good performance in the simulation of extreme precipitation and temperature, and the ability of CMIP6 to simulate extreme climate is improved compared with CMIP5.
CMIP6 provides historical climate simulation data from 1850 to 2014 and future climate projections from 2015 to 2100, and in order to correspond to the time of historical observation information of the continent, this paper takes 1975-2014 as the historical reference period and 2015-2054 as the future projection period, and selects two different shared socio-economic pathway scenarios (SSP1-2.6 and SSP5-8.5) for comparative analysis. The SSP1-2.6 scenario indicates that the radiative forcing in 2100 is stable at 2.6 W/m2 under the sustainable development pathway, and the SSP5-8.5 scenario indicates that the radiative forcing in 2100 is as high as 8.5 W/m2 under the traditional fossil fuel-based pathway.
(ii) Research methodology
Due to the differences in the resolution of the historical and future climate projections involved in this paper, bilinear interpolation is used to unify the resolution of all historical and future projected data to a 0.5°×0.5° grid. In this study, the historical data of CN05.1 were used as a reference, and the daily deviation correction method (DBC) was used to correct the deviation of the historical and future data of the climate model.
Heavy precipitation (R95TOT), precipitation intensity (SDII), number of warm night days (TN90p) and number of warm days (TX90p) were selected to analyze the changes of extreme climate events for extreme precipitation and high temperature. Table 1 shows the meaning of each extreme indicator. The threshold of extreme event indicators in the historical period was determined by the CN05.1 dataset from 1975 to 2014, and the threshold of extreme event indicators in the future was determined by the model data of the climate models selected above from 1975 to 2014 under different emission scenarios.
Table 1 Determination of extreme weather event indicators
The Theil-Sen trend estimation method and the Mann-Kendall (MK) nonparametric rank test were used to analyze the evolution trend and significance of historical extreme weather indicators from 1975 to 2014. For the trend estimation of future extreme events, the future trend of extreme events is characterized by the change of multi-year average extreme indicators in the future projection period relative to the average value of the historical reference period, in which the relative percentage of extreme precipitation and the absolute change of extreme high temperature are used. In order to facilitate comparative analysis, according to the geographical location of provincial-level administrative regions, the country is divided into seven regions: Northwest, North China, Northeast China, Southwest, Central China, East China, and South China.
3. Historical climate change in the mainland
(i) Changes in historical extreme precipitation
Fig. 1 shows the box plots of the change rates of R95TOT, SDII indices and MK trend values in different regions from 1975 to 2014. From the perspective of change rate, from 1975 to 2014, the spatial pattern of R95TOT trend was similar to that of the continental summer precipitation trend (Fig. 1(a)), and the pattern of increase, decrease, and increase from northwest to southeast was generally present. The specific results are as follows: more than 75% of the areas in Northwest China show an increasing trend, with an increase rate of 0~30 mm per 10 years, the increase rate of R95TOT is the most obvious in Northeast China, Central China, East China and South China east of the Hu Huanyong Line, and the increase rate of R95TOT is 10~80 mm per 10 years in more than 75% of the regions, and the decreasing areas of R95TOT are mainly distributed in North China and Southwest China, with a decrease rate of 0~40 mm per 10 years.
Fig. 1 The change rate of R95TOT, SDII index and MK value of extreme precipitation in mainland China from 1975 to 2014
From the perspective of the significance of the MK spatial trend, the R95TOT index did not change significantly in most parts of the continent, and the area with a confidence level of less than 95% (MK value between ±1.96) accounted for about 81.4% of the study area (see Fig. 1(b)). The area of the area with a significant increase in R95TOT accounts for about 17.2% of the total area, and most of them are distributed in the northwest and northeast regions, among which the heavy precipitation in the densely populated area east of the Hu Huanyong line generally increases, and the risk and harm of extreme rainfall are greater, and the area of the area with a significant decrease in R95TOT is less than 2% of the total area, which is distributed in the southwest region.
For the SDII index, the change pattern is similar to that of R95TOT, and the spatial pattern of "two increases and one decrease" is generally presented (see Fig. 1(c)). Specifically, there are more regions with an upward trend in Northeast China, East China and South China, and more regions with a downward trend in North China and Central China. The area with an upward trend of SDII accounts for about 47.0% of the total area of China, of which the area with a change rate of more than 0.2 mm/d per 10 years accounts for about 5.1% of the total area, and the area with a change rate of less than -0.2 mm/d per 10 years accounts for about 10.9% of the total area. From the perspective of MK trend value, the trend of SDII in most areas of China was not significant, and the area with MK value between ±1.96 accounted for about 85.5% of the total area of the study area (Fig. 1(d)). The area of the area with a significant increase in SDII accounted for about 6.3% of the total area, and the area with a significant decrease accounted for about 8.2% of the total area. In general, the intensity and total amount of extreme precipitation in the densely populated areas along the eastern coast of mainland China have increased, and the risk and danger of extreme precipitation are relatively high, which is basically consistent with the existing research.
(ii) Changes in historical extreme high temperatures
Fig. 2 shows the boxplots of the change rates of TN90p and TX90p indices and MK values in different regions of mainland China from 1975 to 2014. The changes of TN90p and TX90p indices characterize the changes in the frequency of extreme heat events at night and during the day, respectively. From the perspective of change rate, the TN90p and TX90p indices in most areas of the country have increased to varying degrees, and the area with an upward trend of the two has reached 99.4% and 97.3% respectively. The spatial distribution of the change rates of TN90p and TX90p was generally similar, and the change rates were larger in Northwest, North China, Southwest China and South China, and smaller in Central and East China. In general, the average rate of change of TN90p per 10 years was 5.9 d for TN90p and 4.0 d per 10 years for TX90p. The spatial characteristics of the change rate of TN90p and TX90p are consistent with the existing studies: the change rate of TN90p in Northwest China, Qinghai-Tibet and Southwest China is larger, and the change rate of TX90p in Sichuan, Chongqing, Gansu, Shaanxi and coastal areas is larger.
Fig. 2 The change rate and MK value of TN90p and TX90p indices in mainland China from 1975 to 2014
From the perspective of MK trend value, the significance level of TN90p and TX90p is consistent with the rate of trend change, and the larger the change rate, the higher the significance level, accounting for 82.8% and 72.2% of the regions with a significant upward trend, respectively. It is worth noting that the overall trend of the two types of extreme heat indices in northwest Xinjiang is quite different from that of the whole of Northwest Xinjiang, and the change rates of TN90p and TX90p in these areas range from 0~5 d and \u20122~3 d per decade, respectively, which is much smaller than the average change rate per 10 years in Northwest China (the increase rates of TN90p and TX90p are 5~13 d and 3~7 d, respectively), and the TX90p index in a few regions shows a significant downward trend (Fig. 2(d)).
4. Prediction of future extreme events in the mainland
(i) Projections of extreme precipitation in the future
Figure 3 shows the percentage change of future R95TOT and SDII in different regions of the continent relative to the base period, and the percentiles are determined by the 50% quantile of the model set, and each box in the figure is composed of the 50% quantile projections of each grid in the region. As can be seen from Figure 3, R95TOT will increase in the future under different scenarios, and most regions show this increasing signal. Under the SSP1-2.6 scenario, from 2015 to 2054, the increase of R95TOT in the northwest and southwest of the Tibetan Plateau is the largest, with the increase of more than 15% in most areas, followed by 10%~20% in North China and Northeast China, 5%~15% in Central China, 0~10% in East China and South China, and the smallest increase in heavy precipitation in Yunnan, Guangxi and Guangdong, which is 0~5%.
Fig. 3 Relative percentage change of continental extreme precipitation from 2015 to 2054 under SSP1-2.6 and SSP5-8.5 scenarios (relative to 1975-2014)
The spatial mode of heavy precipitation change in R95TOT predicted in the SSP5-8.5 scenario is basically consistent with that in the SSP1-2.6 scenario, and the distribution characteristics of the Northwest China, North China, Northeast China and Southwest Tibetan Plateau regions are larger, and the southern region has a smaller increase. Compared with the SSP1-2.6 scenario, the extreme heavy precipitation in the northern part of the mainland will further increase under the SSP5-8.5 scenario, especially in the cold and arid areas of Northwest China, Qinghai-Tibet, and Northeast China. This also indicates that high carbon emissions will further exacerbate the risk of extreme events and threaten the security of the cold and drought ecological fragile areas and economic core areas of the mainland.
For the SDII index, the precipitation intensity will increase in most parts of the continent under different development scenarios, and only the northwest and southwest regions will show a decreasing trend. The SSP1-2.6 scenario shows that from 2015 to 2054, the largest increase in SDII in North China and Northeast China is about 6%~12%, followed by Central China and East China, with an increase of 2%~6%, and South China is the smallest, with an increase of 0~4%. The spatial modes of precipitation intensity change in SDII projected in the SSP5-8.5 scenario are basically consistent with those in the SSP1-2.6 scenario, and the distribution characteristics are generally characterized by a large increase in North China and Northeast China, the smallest increase in South China, and a decrease in Northwest China. Compared with the SSP1-2.6 scenario, the precipitation intensity in the northern part of the continent will further increase under the SSP5-8.5 scenario, and the SDII decrease trend in the northwest region will be more obvious, but the prediction results of different climate models in the northwest region are quite different, and there is a large uncertainty in the projections.
In recent years, the relevant observational data show that the western part of the northwest has shown a certain trend of warming and humidification, the western part of the northwest has been continuously wetting since 1961, and the eastern part of the northwest has changed from a dry trend to a humid trend in 1997, which is related to the synergistic strengthening of the westerly circulation and the East Asian summer monsoon circulation since the 21st century. Climate model simulations also show that precipitation events will increase and intensify in Northwest China in the future. Previous studies have shown that under the global warming of 2.0 °C, the continuous dry days in the northwest of the continent will be significantly reduced, especially in the Tarim and Qaidam basins. SDII is the ratio of the total annual precipitation to the number of wet days, due to the drought and lack of rainfall in Northwest China, precipitation events are scarce, but due to the influence of global climate change, precipitation events and events exceeding the 95% quantile threshold will increase significantly, resulting in a decrease in precipitation intensity in Northwest China compared with the base period in the future.
(ii) Prediction of extreme heat in the future
Figure 4 shows the absolute change of extreme heat index (TN90p and TX90p) under different scenarios from 2015 to 2054 relative to the base period. As can be seen from Figure 4, TN90p will increase in the future under different scenarios, and this increase signal is shown in all parts of the country. The SSP1-2.6 scenario shows that the TN90p increase is the largest in southwest China and South China, with an increase of more than 40 days in most regions, followed by 20~45 days in Northwest, North China and Central China, and the smallest increase in Northeast China and East China (20~30 days).
Fig. 4 Relative changes of continental extreme heat index from 2015 to 2054 under SSP1-2.6 and SSP5-8.5 scenarios (relative to 1975-2014)
The spatial modes of TN90p change projected in the SSP5-8.5 scenario are basically consistent with those in the SSP1-2.6 scenario, and generally show the spatial characteristics of large increases in South China, Southwest China, Northwest China, North China and Central China. Compared with the SSP1-2.6 scenario, the extreme high temperature at night in the mainland will be further aggravated under the SSP5-8.5 scenario, and the risk of high temperature at night will increase significantly.
For the number of warm days TX90p, the number of warm days in the whole mainland will increase in the future under different development scenarios. The SSP1-2.6 scenario shows that from 2015 to 2054, the northwest, southwest and south China regions of mainland China have the largest increase of TX90p, with an amplitude of about 20~45 days, followed by North China and Northeast China, with an increase of about 20~30 days. Central China and East China had the smallest increase, about 15~30 days. Compared with the SSP1-2.6 scenario, the TX90p spatial modes estimated in the SSP5-8.5 scenario are basically consistent with those in the SSP1-2.6 scenario, and both show that the number of warm days increases in Central and East China is the lowest. Compared with the SSP1-2.6 scenario, the risk of extreme high temperature in the mainland during the day under the SSP5-8.5 scenario will further increase, especially in southwest and southern China, where the number of locally warm days will increase by more than 50 days.
Comparing TN90p and TX90p under different scenarios, it can be seen that the warming amplitude of TN90p under different scenarios is significantly greater than that of TX90p, which is basically consistent with the variation law of historical extreme high temperature. Under the high-carbon emission SSP5-8.5 scenario, the extreme heat increase is more obvious, which means that the nighttime temperature increase of the continent is significantly higher than that of the daytime temperature increase in the context of global warming. Previous studies have shown that the lowest temperature in history has warmed more significantly than the maximum temperature, and the warming rate has been faster. This also shows that the impact of global warming on the regional minimum temperature is more obvious, and the simultaneous increase in the risk of extreme heat between day and night and the continuous high emission of greenhouse gases will aggravate the risk of future heat waves to a greater extent, further threatening human survival and the earth's ecology.
5. Suggestions for responding to and mitigating extreme precipitation and high temperature events
Under the background of global climate change, continental extreme precipitation and high temperature events show certain spatial and temporal differences. The results show that from 1975 to 2014, the heavy precipitation in mainland China showed a spatial pattern of two increases and one decrease, that is, from northwest to southeast, the precipitation intensity and heavy precipitation increased in the north of the Tianshan Mountains, Northeast China, East China and South China. From 2015 to 2054, under the influence of global warming, extreme precipitation on the continent will further increase and intensify. From 1975 to 2014, the frequency of diurnal extreme heat events in China generally increased, and the number of warm days and warm nights in the north and southwest regions changed greatly, and the high temperature and heat wave events increased significantly, and from 2015 to 2054, the number of diurnal extreme heat events in mainland China will further increase and intensify, and the risk of high temperature and heat wave events will increase, especially the simultaneous increase of diurnal extreme heat will further aggravate the disaster degree of extreme weather events in the future.
Global warming has exacerbated the probability of extreme precipitation and high temperature events in the region, resulting in frequent floods and heat waves. On the one hand, the response to extreme disasters such as floods and heat waves can be carried out from two perspectives: engineering measures (infrastructure construction) and non-engineering measures (information construction, emergency management). On the other hand, climate change has a profound impact on the global climate and is a common problem faced by all mankind, and the disaster chain caused by it has a huge impact on human society. Therefore, this study combines specific engineering and non-engineering measures and puts forward the following suggestions from three perspectives: flood response, high temperature and heat wave disaster response, and climate change response (see Figure 5).
Fig.5 Impacts of extreme precipitation and high temperature events and countermeasures
(1) Enhance flood risk response and emergency management capabilities
Global climate change will increase the probability of extreme rainstorm events in the region, leading to an increase in the risk of multiple disasters such as excessive floods, reservoir dam failures, flash floods and landslides, and urban waterlogging in river basins, threatening national water security and public safety. In view of flood disasters, firstly, it is necessary to strengthen engineering measures such as engineering design, river basin flood control project construction and urban flood control infrastructure, and secondly, non-engineering measures such as river basin, urban and engineering disaster prevention informatization and river basin safety management should be strengthened to build resilient river basins and resilient cities in an all-round way.
1. Strengthen disaster prevention and mitigation infrastructure in a changing environment
(1) Strengthen the basic research on engineering hydrological calculations in the changing environment, comprehensively review the design flood of reservoirs and dams, and consider the impact of extreme rainstorm and high temperature events on water conservancy projects in engineering design, and improve engineering design standards.
(2) Based on the river basin and the urban and rural areas as a whole, accelerate the construction of flood control projects for major rivers and flood storage and detention areas in the river basin, strengthen the management of small and medium-sized rivers and the prevention and control of mountain floods, and accelerate the work of removing and reinforcing dangerous reservoirs for existing reservoirs.
(3) Promote the construction of sponge cities in new and old urban areas, and fully mobilize the city's water storage capacity through measures such as expanding the area of green space and building artificial wetlands, so as to achieve source emission reduction and rainstorm runoff regulation and storage while ensuring the ecological base. Comprehensively investigate and solve the dredging and drainage blockages, and build large-scale drainage facilities and urban deep projects for urban flood disasters that exceed the standard, so as to improve the city's drainage and waterlogging capacity.
2. Strengthen the construction of flood disaster prevention informatization
(1) To improve the level of water conservancy informatization, apply advanced sensing, communication and other modern information technology to establish a three-dimensional hydrometeorological flood control and drought control system for air, space and ground, apply big data and artificial intelligence technology, and jointly optimize the multi-objective joint optimization and dispatch of cascade reservoirs in the river basin, develop an integrated flood control forecasting and dispatching system for complex river basins, and build a command system integrating forecasting, early warning, pre-planning, and rehearsal.
(2) Improve the research and judgment mechanism of urban extreme weather, realize the dynamic monitoring of the whole process of extreme rainstorm and flooding in cities, establish an integrated cloud platform for forecasting and early warning of urban rainstorm and waterlogging, and strengthen the ability to release forecast and early warning information.
(3) Accelerate the informatization construction of water conservancy project safety monitoring, so that the monitoring is real-time and the report is timely. Improve the level of communication, computing and control, build a digital twin platform for large-scale water conservancy projects in combination with the big data system, realize the informatization of the management and supervision platform of water conservancy projects, strengthen the safety guarantee capacity of reservoir dams, and improve the ability of reservoirs and dams to withstand heavy rain and respond to disasters.
3. Enhance river basin safety management and national awareness of disaster prevention
(1) Strengthen the daily management of reservoirs and dams, improve the level of emergency rescue, and strengthen the preparation of emergency plans for flood control and flood control. Based on the basic principle of "safety first, prevention first, and comprehensive rescue", we will avoid risks in advance and improve our ability to respond to sudden disasters, so as to reduce the possible post-disaster impact in an all-round way.
(2) Strengthen urban planning and construction that adapts to the flood mentality, avoid and restrict the development and construction of flood-prone areas in advance, improve the disaster prevention and emergency repair capabilities of lifelines such as communications, transportation, power supply, and water supply, and ensure the normal operation of cities and the smoothness of emergency rescue and disaster relief.
(3) Strengthen the daily popularization of disaster prevention and mitigation science and enhance the awareness of disaster prevention among the whole people.
(2) Strengthen mitigation and response measures for high temperature and heat waves
The continuous emission of greenhouse gases has led to a significant increase in global temperature, triggered abnormal atmospheric circulation, led to frequent high temperature and heat wave events in weather systems, and the heat island effect caused by urban construction has contributed to the heatwave disaster, which makes the urban areas with concentrated populations have higher heat exposure and danger under heat wave disasters, and the threat to life and property caused by them is much higher than that of other extreme events. To cope with the high temperature and heat wave disasters, firstly, we should start with the engineering measures to optimize the urban layout and reduce the risk of urban heat exposure, and secondly, we should strengthen the informatization level of heat wave monitoring and early warning and improve the non-engineering measures such as high temperature policies.
1. Strengthen infrastructure to mitigate the risk of urban heat waves
(1) Rationally plan the layout of urban construction, control the density of population and buildings, scientifically plan urban ventilation corridors, and introduce cold air from the suburbs into urban areas.
(2) Improve the urban green coverage rate and reduce the urban heat exposure, build a water system around the city and regulate the urban climate, innovate the design of building structures, and promote the central cooling technology in public areas.
(3) Reduce artificial heat dissipation, improve energy efficiency, develop and utilize new clean energy, and improve the performance of building insulation materials.
2. Build a monitoring and early warning emergency response system for high temperature and heat waves
(1) Comprehensively lay out the high-temperature weather observation network, build a multi-source monitoring information channel for high-temperature weather, and realize all-round coverage monitoring and early warning in general areas and refinement in key areas.
(2) Establish an accurate and real-time integrated system for high temperature forecasting and early warning, strengthen the ability of urban high temperature forecasting, and improve the timeliness of agricultural high temperature forecasting.
(3) Develop multi-source publicity channels for high temperature forecast information, and give full play to the communication capabilities of network technology and communication technology, so as to achieve comprehensive and meticulous monitoring, accurate and timely forecasting, and rapid and extensive dissemination.
3. Improve heat policies and enhance the public's ability to cope with high temperatures
(1) Improve the labor security and heatstroke prevention subsidy system during high temperature and heat waves, reduce heat exposure caused by outdoor work during high temperature and heat waves, and improve high temperature policies to protect human health.
(2) Strengthen publicity and education on the hazards of high temperature and heat waves, scientifically popularize heat disease prevention methods and self-help and mutual rescue measures, especially strengthen the popularization of science for workers in high temperature places.
(3) Do a good job in health care, strengthen personal heat-resistant exercises, and improve their ability to adapt to extreme heat.
(iii) Global climate change response and mitigation
Climate change is a common challenge facing the whole world, which is related to the survival and development of mankind. The extreme events brought about by climate change have affected the global ecological environment and economic and social balance, and through the knock-on effects on agriculture, animal husbandry, fisheries and agriculture, the livelihood costs in poor areas have increased, and the impact of climate change is most serious. To cope with global warming, we should first strengthen international cooperation and assistance from a state-to-state perspective, and secondly, we should establish climate change adaptation strategies from a region-to-region perspective to address the vulnerable areas of climate change.
1. Strengthen international cooperation and assistance
(1) Addressing climate change requires the international community to work together to build a global community with a shared future, actively promote the goals of the Paris Agreement, and strengthen the common responsibility to address climate change.
(2) Developed countries are the main responsible countries for global climate change and historical carbon emissions, while developing countries are in the inevitable stage of high-carbon emission development.
2. Improve the capacity of poor areas to adapt to climate change
(1) Actively promote the Belt and Road Initiative, strengthen South-South cooperation, improve the economic level of poverty-stricken areas, accelerate energy transition, and enhance climate change response capacity.
(2) Carry out a meteorological information service sharing mechanism, transport and train talents related to climate change and meteorological forecasting, and improve the ability of extreme weather forecasting and early warning in poor areas.
(3) Provide new ideas for water-saving and efficient agriculture, renewable energy technologies and water resource management and development solutions for poor areas, and improve energy conservation and emission reduction capabilities.
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About the Author:
Zhang Jianyun
He is an expert in hydrology and water resources, an academician of the Chinese Academy of Engineering, and a foreign academician of the Royal Academy of Engineering.
He is mainly engaged in scientific research in hydrology and water resources, flood control and drought relief, climate change impact, water conservancy informatization, water environmental protection and governance, etc.
Note: The paper reflects the progress of research results and does not represent the views of Chinese Journal of Engineering Science.