The Paris Agreement has set one of its targets that to pursue efforts to limit the temperature increase to 1.5℃ above pre-industrial levels (in short 1.5℃ target). The studies on 1.5℃ target are limited currently. According to existing researches, the 1.5℃ target, comparing with 2℃ long-term temperature goal, probably could reduce the climate risk for the earth systems but need more stringent global mitigation efforts. Although the Parties have committed their national determined contributions (NDC) till 2030 (2025), there is still a big gap with respect to the 1.5℃ target. Corresponding model simulations have shown that the global temperature rise by the end of the 21st century is in the range of 2.2-3.4℃ if the current NDC is fully implemented. There is still 467 Gt CO2 left under the 2℃ scenario, 17 Gt CO2 remaining under the 1.5℃ scenario. By 2030, the NDC-based emissions will have exceeded the target emissions of 1.5℃. According to the current pathway, the 1.5℃ target requests not only an immediate mitigation action and other actions related to decarbonization and carbon sequestration measures, but also a negative emission before 2100. Regardless the uncertainty from scientific communities, 1.5℃ target is more than just a direction for tackling climate change, but start an important way for the future global low-carbon sustainable development.
Based on the simulations of 18 CMIP5 models under there RCP scenarios, this article investigates the changes of the mean temperature and precipitation as well as their extremes over Asia in the context of global warming targets of 1.5℃–4℃, and further compares their differences between the 1.5℃ and the 2℃ targets. The results show that relative to the preindustrial ear, the mean temperature over Asia will increase by 2.3℃, 3.0℃, 4.6℃ and 6.0℃ at the warming targets of 1.5℃, 2℃, 3℃ and 4℃, respectively, with stronger warming in the high latitudes than in the low latitudes. The corresponding enhancement in the mean precipitation over the entire Asian region is 4.4%、5.8%、10.2% and 13%, but there are significant regional differences. Meanwhile, an increase in warm extreme, a decrease in cold extreme, and an augment in the variability of the extreme precipitation amount are projected. Compared with the case under the 2℃ target, the mean temperature will cool more than 0.5℃–1℃ over Asia at the 1.5 target, and the mean precipitation will reduce 5%–20% over most of the Asian areas while increase by about 10–15% over West Asia and western South Asia. The extreme high temperature will appear uniformly lower in the Asian region, and the extreme low temperature will decrease significantly in the high latitudes of Asia. Increase in the extreme precipitation will weaken over most of Asia but enhance over West Asia. Under the 1.5℃ and 2℃ warming targets, the probability of the occurrence of hot weather, extremely hot weather and extremely strong precipitation will increase respectively by at least one times, 10% and 10% as compared to the reference period (1861–1900).
In this study, the period that corresponds to the thresholds of a 1.5℃ rise (relative to 1861-1880) in surface temperature is validated using a multi-model ensemble mean from 17 global climate models in the Coupled Model Intercomparison Project Phase 5 (CMIP5). On this basis, the changes in permafrost and snow cover in the Northern Hemisphere are investigated under a scenario in which the global surface temperature has risen by 1.5℃, and the uncertainties of the results are further discussed. The results show that the threshold of 1.5℃ warming will be reached in 2027, 2026, and 2023 under three Representative Concentration Pathways (RCP2.6, RCP4.5, RCP8.5) respectively. When the global average surface temperature rises by 1.5℃, the southern boundary of the permafrost will move 1°-3.5°northwards, particularly in the southern Central Siberian Plateau. The permafrost area will be reduced by 3.43×106 km2 (21.12%), 3.91×106 km2 (24.10%) and 4.15×106 km2 (25.55%) relative to 1986-2005 in RCP2.6, RCP4.5 and RCP8.5, respectively, under a scenario of 1.5℃ warming. The snow water equivalent will decrease in over half of the regions in the Northern Hemisphere but increase only slightly in the Central Siberian Plateau. The snow water equivalent will decrease significantly (more than 40% relative to 1986-2005) in central North America, western Europe and northwestern Russia. The permafrost area in Qinghai-Tibet Plateau will decrease by 0.15×106 km2 (7.28%), 0.18×106 km2 (8.74%), and 0.17×106 km2 (8.25%), respectively, in RCP2.6, RCP4.5, RCP8.5. The snow water equivalent in winter (DJF) and spring (MAM) over the Qinghai-Tibet Plateau will decrease by 14.9% and 13.8%, respectively.
The Paris Agreement presents new challenges for the international community to address climate change, it also has a massive impact on China’s population, resources and environment under the background of global warming. Based on the 6th national census data in 2010, the shared socioeconomic pathways of IPCC and the population status and development policy in China were jointly considered to calibrate the parameters of population model. In this paper, the evolution and distribution of population in China by age, gender and education level are analyzed under global warming 1.5℃ and 2.0℃ targets. The research results show as follows: under global warming 1.5℃, the total population will increase by 44 million compared with 2010 under SSP1 and SSP4; under warming 2.0℃, the population will increase by 23 million and 67 million compared with 2010 under SSP2 and SSP3 respectively, and decrease by 12 million under SSP5. China’s population will peak in 2025?2035, the time period of 1.5℃ warming. Except the Northeast China, Sichuan and Anhui provinces, the majority of the provinces will have an increase in population compared with 2010 under warming 1.5℃; under global warming 2.0℃, population will increase in northwest, southwest and southeast coastal areas of China. In other parts of China the population will decrease. Population in most provinces will reach peak under global warming 1.5–2.0℃. Guangxi province will have the largest population under SSP3, up to 113 million. Guangdong province will have the largest population under all other pathways, up to 153 million. The proportion of elderly population over 65 will be higher in northeast than southwest of China. Under warming 1.5℃, the proportion of elderly population will reach 20% under SSP1 and SSP4. Comparing with warming 1.5℃, the aging trend will be further aggravated under warming 2.0℃. The proportion of elderly population will reach 36% under SSP5. Northeast China will face the most serious problem of aging. Pursue the target of limiting global warming well below 2.0℃ by adopting the green and sustainable development pathways (SSP1) is the scientific choice of future socioeconomic development strategy in China.
The Paris Agreement introduced a 1.5℃ target to control global temperature rising, but it didn’t make clear arrangements for feasible implementation pathways. Achieving 1.5℃ target sets up higher requirements on global emission reductions. Adding up NDCs (Nationally Determined Contributions) of all Parties is far from 1.5℃ target, while conventional emission reduction technologies and policies will also be difficult to fulfill the task. In this context, the discussion about geoengineering is heating up in the international area. The Paris Agreement in fact has already included afforestation, carbon capture, utilization and storage (CCS/CCUS), negative emission technologies such as bio-energy with CCS (BECCS), and all of these are carbon dioxide removal (CDR) technologies that belong to geoengineering. In addition, solar radiation management (SRM) which is more controversial also attracts more attentions in recent years. Geoengineering as an unconventional technical option is definately necessary in a series of researches and discussions on the impacts assessment, technical options, ethics, international governance, etc. under 1.5℃ target. On the basis of analyzing and discussing above-mentioned issues, this paper proposes some policy suggestions, such as enhancing scientific issues and governance problems research in geoengineering field for China.
Based on the national daily precipitation 0.5°× 0.5° gridded dataset, annual maximum (AM) samples and peaks over threshold (POT) samples were selected. The generalized extreme value distribution (GEV) and the generalized Pareto distribution (GPD) were employed to establish statistical models of precipitation extremes respectively. The goodness of fit of each model was evaluated by Kolmogorov-Smirnov test. The statistical analysis was performed. Extreme value distribution model of precipitation and threshold value selection criteria applicable to different areas were proposed. The results show that: (1) The simulated results of POT samples are superior to those of AM samples; (2) The method of sample percentile for determining threshold value is better than the others; (3) The geographical distribution pattern of optimization results is similar to the distribution of dry and wet regions in China. The 90?94 percentile is the fittest to determine threshold value in humid regions. The 94?97 percentile is better in semi-arid and sub-humid regions. The 97?99 percentile is the most suitable in arid regions.
The VIP eco-hydrological model and HIMS model were used to simulate hydrological processes from 1957 to 2012. Based on the ensemble projections of CMIP5 RCP2.6, RCP4.5 and RCP8.5 scenarios, the runoff in the two basins were predicted. The results show that in the past 50 years air temperatures in the two basins were continually increasing and the rates over the upstream plateau were higher than the lower downstream. The tendency of annual precipitation was not significant, while the precipitation in spring season was increasing. The total water resources were around 65 billion to 85 billion m3 and no noticeable tendency was detected. Spatially, the water resources kept the pattern of “higher in south and lower in north”. The variability of water resources in Lancang River was more significant than that of Nujiang River. In the future climate scenarios, it will become warmer and wetter, the runoff will increase with lower spatial variability. Being with high seasonal variability, there will still be challenges in the water resources security over the whole basins.
Based on the daily data on stroke morbidity and meteorological data in Lanzhou during 2010-2013, the association between temperature and the morbidity of stroke among the population was addressed using the distributed lag non-linear model, and the possible impacts of different temperature and different lag days on stroke morbidity were analyzed. The results show a close association between stroke morbidity and the meteorological factors. Analysis of correlation between the meteorological factors and patient characteristics of stroke show the daily number of stroke cases is correlated with temperature, atmospheric pressure and relative humidity. Temperature presented non-linear association with stroke over different lag days. Different types of stroke vary in their strength of association with temperature. For patients with cerebral hemorrhage, low temperature would demonstrate hazardous effect, the risk of morbidity would constantly rise with the increasing lag days before reaching the peak at 2?3 lag days, and could persist through 30 days after the occurrence of low temperature. The course of cerebral infraction presented certain differences from that of cerebral hemorrhage. Both high and low temperature could increase the risk of morbidity, and the temperature effect would occur on the same day and reach the peak within 3?5 lag days. Low temperature had greater impacts on women or those aged 19?64 years, while high temperature had greater impacts on those ≥65 years old. Low temperature had impacts on morbidity of various types of stroke, while high temperature only had impacts on morbidity of ischemic stroke. The impacts of temperature on stroke morbidity vary in different age groups and gender, and in different types of stroke. Temperature acts as an external etiological factor by affecting the organism’s functions.
The article reviews current studies in the field of causality analysis on the association between paleo-climate change and socio-economic dynamics, particularly from the quantitative results and achievements. These findings have justified the strong linkage between paleo-climate change and socio-economic development. Climate change has been proved as the fundamental factor affecting socio-economic process. No matter in the long term or short term, climate variation and climate change both could exert the effects on the human society. This progress has contributed to the knowledge on climate change and socio-economic development from both theoretical and methodological aspects. The research in this field has shown its value as the reference for policymakers in addition to its academic contribution.
Climate change, biodiversity loss and land desertification are three of the most serious global environmental challenges faced by humans. As these challenges involve global public goods, it is crucially important that the global society should strive to make synergies between the three most influential United Nations (UN) conventions, which are the UN Framework Convention on Climate Change (UNFCCC), Convention on Biodiversity and the UN Convention to Combat Desertification (UNCCD). This paper reviews the negotiation process under the three conventions, especially focusing on cross-boundary issues. By analyzing the focal concerns of main parties, this paper evaluates possible future scenarios on cross-boundary issues under the three conventions. The cross-boundary issues can be summarized in the following aspects: mitigation, adaptation, loss and damage, and strategic plans and initiatives. It will promote synergistic actions under three conventions based on the ecosystem approach. In the end, we propose the following strategies: (1) lead the negotiations of the cross-boundary issues initiatively; (2) construct and perfect the synergetic fulfillment mechanism of China; (3) improve the regional cooperation combining South–South Collaboration and the Belt and Road.
India’s energy and climate policy will have a significant impact both on the situation of the global greenhouse gas emission and the success of the global climate cooperation after Paris Climate Conference. To have a clear understanding about the dynamics and the targets of the energy and climate policy of India, this paper firstly introduces the current situation of Indian energy system as well as the economic and social development targets related. The second part deals with India’s energy policy context under the “New Policy Scenario”, including the future energy supply and demand. Finally, refer to the viewpoints on the Indian climate policy from national and international literature, this paper summarizes the main changes of the policy before and after the Paris Climate Summit. Comments and outlook on the future Indian climate policy are also forwarded from context of comparing analysis of Sino-India policies.
Based on the questionnaire survey and key informant interview conducted in Baoshan prefecture located in western Yunnan province, this paper explores, while government promoted farmers’ out-migration as a response to local drought, the impacts of out-migration on local farmers climate change adaptability, through a comprehensive and comparative study on the difference of income source, drought response, family income distribution between remittance-recipient families and non remittance-recipient families. Results show that the remittance brought back by out migrated farmers had a positive effect on the climate change adaptability of their families stayed in the origin. On the other hand, the mass out-migration of rural laborers also created potential problems, such as laborer shortage, for local agricultural development. It is suggested that in the future, vocational training for out-migration farmers, should include important courses such as family financial management, climate change and other related content to strengthen the climate change adaptability for farmers and rural communities; government should promote the concept of climate smart agriculture and localized adaptation strategies.