For the first time, functioning of the planetary climate system is considered in terms of the self-organization laws with account of positive and negative feedbacks. It is shown that the maximum risks in the developme...For the first time, functioning of the planetary climate system is considered in terms of the self-organization laws with account of positive and negative feedbacks. It is shown that the maximum risks in the development of positive feedbacks that can lead the climate system to a planetary catastrophe, are associated with an unprecedented increase in the concentration of methane in the atmosphere. Over the last 30 years, its concentration in the atmosphere has increased by 2.5 times and continues to grow exponentially. In this review, we show that today the principal source for increase of methane concentration in the atmosphere is the self-accelerating decomposition of methane hydrates in the cryosphere of the Northern Hemisphere. In the history of the Earth, the emissions of methane into the atmosphere due to mass decomposition of methane hydrates led to climate-induced biosphere catastrophes. Paleo-reconstruction analysis of greenhouse gas concentrations in the atmosphere and its temperature over the last 420,000 years has allowed us to conclude that the self-organizing planetary climate system is currently in a state of dynamic chaos (close to the bifurcation point). This means that even a relatively weak impact on it, also of anthropogenic characters, is able to affect the planetary climate system to select its future development trajectory.展开更多
Permafrost regions of Qilian Mountains in China are rich in gas hydrate resources.Once greenhouse gases in deep frozen layer are released into the atmosphere during hydrate mining,a series of negative consequences occ...Permafrost regions of Qilian Mountains in China are rich in gas hydrate resources.Once greenhouse gases in deep frozen layer are released into the atmosphere during hydrate mining,a series of negative consequences occur.This study aims to evaluate the impact of hydrate thermal exploitation on regional permafrost and carbon budgets based on a multi-physical field coupling simulation.The results indicate that the permeability of the frozen soil is anisotropic,and the low permeability frozen layer can seal the methane gas in the natural state.Heat injection mining of hydrates causes the continuous melting of permafrost and the escape of methane gas,which transforms the regional permafrost from a carbon sink to a carbon source.A higher injection temperature concentrates the heat and causes uneven melting of the upper frozen layer,which provides a dominant channel for methane gas and results in increased methane emissions.However,dense heat injection wells cause more uniform melting of the lower permafrost layer,and the melting zone does not extend to the upper low permeability formation,which cannot provide advantageous channels for methane gas.Therefore,a reasonable and dense number of heat injection wells can reduce the risk of greenhouse gas emissions during hydrate exploitation.展开更多
【目的】探究不同水稻品种对稻田温室气体排放的影响,以期筛选出适宜重庆地区种植的高产、温室气体低排放水稻品种。【方法】通过田间试验,采用静态箱—气相色谱法连续观测重庆地区主推的6个水稻品种(中浙优H7、渝两优华占、Q香优352、...【目的】探究不同水稻品种对稻田温室气体排放的影响,以期筛选出适宜重庆地区种植的高产、温室气体低排放水稻品种。【方法】通过田间试验,采用静态箱—气相色谱法连续观测重庆地区主推的6个水稻品种(中浙优H7、渝两优华占、Q香优352、神农优446、渝香优8133、渝香203)甲烷(CH_(4))和氧化亚氮(N_(2)O)排放通量,收获期测定水稻产量,并对比其全球增温潜势和温室气体排放强度。【结果】在6个水稻品种中,仅中浙优H7的CH_(4)排放通量呈双峰趋势,峰值分别出现在抽穗期—灌浆期和成熟期—收获期;其余5个品种的CH_(4)排放通量均呈单峰趋势,且峰值均出现在抽穗期—灌浆期。不同品种的CH_(4)排放总量为175.77~274.10 kg/ha,其中,Q香优352的CH_(4)排放总量最低,而渝香优8133排放总量最高,二者间存在显著差异(P<0.05,下同)。N_(2)O的明显排放峰出现在稻田落干后,排放总量为-0.100~0.464 kg/ha,各品种间的N_(2)O排放总量无显著差异(P>0.05),其中渝香优8133的N_(2)O排放总量为负值。不同品种水稻产量为4.94~8.20 t/ha,其中Q香优352产量最高,渝两优华占产量最低,二者间存在显著差异。全球增温潜势分析显示,中浙优H7的全球增温潜势最高,达7.67 t CO_(2)e/ha,而Q香优352的全球增温潜势最低,为4.98 t CO_(2)e/ha。不同水稻品种的温室气体排放强度在0.61~1.54 t CO_(2)e/t,其中Q香优352的温室气体排放强度最低,显著低于其他品种,而中浙优H7的温室气体排放强度最高。【结论】综合考虑产量和温室气体排放情况,Q香优352产量最高,且CH_(4)排放总量和温室气体排放强度最低,更适宜在重庆及类似地区推广种植。展开更多
文摘For the first time, functioning of the planetary climate system is considered in terms of the self-organization laws with account of positive and negative feedbacks. It is shown that the maximum risks in the development of positive feedbacks that can lead the climate system to a planetary catastrophe, are associated with an unprecedented increase in the concentration of methane in the atmosphere. Over the last 30 years, its concentration in the atmosphere has increased by 2.5 times and continues to grow exponentially. In this review, we show that today the principal source for increase of methane concentration in the atmosphere is the self-accelerating decomposition of methane hydrates in the cryosphere of the Northern Hemisphere. In the history of the Earth, the emissions of methane into the atmosphere due to mass decomposition of methane hydrates led to climate-induced biosphere catastrophes. Paleo-reconstruction analysis of greenhouse gas concentrations in the atmosphere and its temperature over the last 420,000 years has allowed us to conclude that the self-organizing planetary climate system is currently in a state of dynamic chaos (close to the bifurcation point). This means that even a relatively weak impact on it, also of anthropogenic characters, is able to affect the planetary climate system to select its future development trajectory.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0904)the National Natural Science Foundation of China(Nos.42107190,41972287 and 42277144)。
文摘Permafrost regions of Qilian Mountains in China are rich in gas hydrate resources.Once greenhouse gases in deep frozen layer are released into the atmosphere during hydrate mining,a series of negative consequences occur.This study aims to evaluate the impact of hydrate thermal exploitation on regional permafrost and carbon budgets based on a multi-physical field coupling simulation.The results indicate that the permeability of the frozen soil is anisotropic,and the low permeability frozen layer can seal the methane gas in the natural state.Heat injection mining of hydrates causes the continuous melting of permafrost and the escape of methane gas,which transforms the regional permafrost from a carbon sink to a carbon source.A higher injection temperature concentrates the heat and causes uneven melting of the upper frozen layer,which provides a dominant channel for methane gas and results in increased methane emissions.However,dense heat injection wells cause more uniform melting of the lower permafrost layer,and the melting zone does not extend to the upper low permeability formation,which cannot provide advantageous channels for methane gas.Therefore,a reasonable and dense number of heat injection wells can reduce the risk of greenhouse gas emissions during hydrate exploitation.
文摘【目的】探究不同水稻品种对稻田温室气体排放的影响,以期筛选出适宜重庆地区种植的高产、温室气体低排放水稻品种。【方法】通过田间试验,采用静态箱—气相色谱法连续观测重庆地区主推的6个水稻品种(中浙优H7、渝两优华占、Q香优352、神农优446、渝香优8133、渝香203)甲烷(CH_(4))和氧化亚氮(N_(2)O)排放通量,收获期测定水稻产量,并对比其全球增温潜势和温室气体排放强度。【结果】在6个水稻品种中,仅中浙优H7的CH_(4)排放通量呈双峰趋势,峰值分别出现在抽穗期—灌浆期和成熟期—收获期;其余5个品种的CH_(4)排放通量均呈单峰趋势,且峰值均出现在抽穗期—灌浆期。不同品种的CH_(4)排放总量为175.77~274.10 kg/ha,其中,Q香优352的CH_(4)排放总量最低,而渝香优8133排放总量最高,二者间存在显著差异(P<0.05,下同)。N_(2)O的明显排放峰出现在稻田落干后,排放总量为-0.100~0.464 kg/ha,各品种间的N_(2)O排放总量无显著差异(P>0.05),其中渝香优8133的N_(2)O排放总量为负值。不同品种水稻产量为4.94~8.20 t/ha,其中Q香优352产量最高,渝两优华占产量最低,二者间存在显著差异。全球增温潜势分析显示,中浙优H7的全球增温潜势最高,达7.67 t CO_(2)e/ha,而Q香优352的全球增温潜势最低,为4.98 t CO_(2)e/ha。不同水稻品种的温室气体排放强度在0.61~1.54 t CO_(2)e/t,其中Q香优352的温室气体排放强度最低,显著低于其他品种,而中浙优H7的温室气体排放强度最高。【结论】综合考虑产量和温室气体排放情况,Q香优352产量最高,且CH_(4)排放总量和温室气体排放强度最低,更适宜在重庆及类似地区推广种植。
