Our globally changing climate
Our globally changing climate
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发表时间：
2016
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影响因子：
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通讯作者：
D. Wuebbles;D. Easterling;K. Hayhoe;T. Knutson;Robert E Kopp;J. Kossin;K. Kunkel;A. Legrande;
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作者：
D. Wuebbles;D. Easterling;K. Hayhoe;T. Knutson;Robert E Kopp;J. Kossin;K. Kunkel;A. Legrande;
1. 与整个地球历史上发生的气候自然变化的速度相比，全球气候继续迅速变化。全球平均温度、海平面上升、上层海洋热含量、陆基冰融化、北极海冰、季节性永久冻土融化深度和其他气候变量的趋势为地球变暖提供了一致的证据。这些观察到的趋势是强有力的，并已得到世界各地多个独立研究小组的证实。（非常高置信度）在世界大多数大陆区域，极端高温和强降水事件的频率和强度正在增加（非常高置信度）。这些趋势与对气候变暖的预期生理反应是一致的。气候模式研究也与这些趋势相一致，尽管模式往往低估了观测到的趋势，特别是对于极端降水事件的增加（温度的置信度很高，极端降水的置信度很高）。随着全球温度的升高，未来极端温度事件的频率和强度几乎肯定会增加（高置信度）。在世界大部分地区，极端降水事件的频率和强度很可能继续增加（高置信度）。其他一些类型的极端事件，如洪水、干旱和严重风暴，观测到的和预估的趋势具有更多的区域变化特征。3. 许多证据表明，人类的影响极有可能是20世纪中期以来观测到的变暖的主要原因。1951年至2010年期间的正式探测和归因研究发现，观测到的全球平均地表温度变暖处于同一时期人类对变暖可能贡献范围的中间位置。我们没有发现令人信服的证据表明，自然变率可以解释工业时代观测到的全球变暖程度。对于上个世纪的这段时间，没有令人信服的替代解释得到观测证据的支持。在过去的一个世纪里，太阳输出变化和内部变率对观测到的气候变化的贡献微乎其微，我们在观测记录中没有发现令人信服的证据表明自然周期可以解释观测到的气候变化。（高置信度）预计全球气候将在本世纪及以后继续变化。未来几十年气候变化的幅度将主要取决于全球排放的温室气体（吸热气体）的数量，以及地球气候对这些气体敏感性的剩余不确定性（非常高置信度）。随着温室气体排放的显著减少，全球年平均气温上升可能被限制在3.6华氏度（2摄氏度）或更低。如果不大幅减少这些排放，到本世纪末，相对于工业化前时代，全球年平均气温的增幅可能达到9华氏度（5摄氏度）或更高（高置信度）。5. 自然变率，包括厄尔尼诺Niño事件和其他海洋大气相互作用的循环模式，影响温度和降水，特别是区域性的，持续数月至数年。然而，自然变率的全球影响仅限于几十年来观测到的气候趋势的一小部分。（高置信度）过去几个世纪和几千年的长期气候记录表明，近几十年来世界大部分地区的平均温度比过去1700年或更长时间的任何时候都要高得多，而且在这段时间内上升得更快，而过去1700年或更长时间是可以重建全球地表温度分布的时期。（高可信度）CSSR 5OD：最终许可第一章以最终编辑为准2017年6月28日38。全球气候变化
1. The global climate continues to change rapidly compared to the pace of the natural variations in climate that have occurred throughout Earth’s history. Trends in globally averaged temperature, sea level rise, upper-ocean heat content, land-based ice melt, Arctic sea ice, depth of seasonal permafrost thaw, and other climate variables provide consistent evidence of a warming planet. These observed trends are robust and have been confirmed by multiple independent research groups around the world. (Very high confidence) 2. The frequency and intensity of extreme heat and heavy precipitation events are increasing in most continental regions of the world (very high confidence). These trends are consistent with expected physical responses to a warming climate. Climate model studies are also consistent with these trends, although models tend to underestimate the observed trends, especially for the increase in extreme precipitation events (very high confidence for temperature, high confidence for extreme precipitation). The frequency and intensity of extreme temperature events are virtually certain to increase in the future as global temperature increases (high confidence). Extreme precipitation events will very likely continue to increase in frequency and intensity throughout most of the world (high confidence). Observed and projected trends for some other types of extreme events, such as floods, droughts, and severe storms, have more variable regional characteristics. 3. Many lines of evidence demonstrate that it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. Formal detection and attribution studies for the period 1951 to 2010 find that the observed global mean surface temperature warming lies in the middle of the range of likely human contributions to warming over that same period. We find no convincing evidence that natural variability can account for the amount of global warming observed over the industrial era. For the period extending over the last century, there are no convincing alternative explanations supported by the extent of the observational evidence. Solar output changes and internal variability can only contribute marginally to the observed changes in climate over the last century, and we find no convincing evidence for natural cycles in the observational record that could explain the observed changes in climate. (Very high confidence) 4. Global climate is projected to continue to change over this century and beyond. The magnitude of climate change beyond the next few decades will depend primarily on the amount of greenhouse (heat-trapping) gases emitted globally and on the remaining uncertainty in the sensitivity of Earth’s climate to those emissions (very high confidence). With significant reductions in the emissions of greenhouse gases, the global annually averaged temperature rise could be limited to 3.6°F (2°C) or less. Without major reductions in these emissions, the increase in annual average global temperatures relative to preindustrial times could reach 9°F (5°C) or more by the end of this century (high confidence). 5. Natural variability, including El Niño events and other recurring patterns of ocean– atmosphere interactions, impact temperature and precipitation, especially regionally, over months to years. The global influence of natural variability, however, is limited to a small fraction of observed climate trends over decades. (Very high confidence) 6. Longer-term climate records over past centuries and millennia indicate that average temperatures in recent decades over much of the world have been much higher, and have risen faster during this time period, than at any time in the past 1,700 years or more, the time period for which the global distribution of surface temperatures can be reconstructed. (High confidence) CSSR 5OD: FINAL CLEARANCE Chapter 1 Subject to Final Copyedit 28 June 2017 38 1. Our Globally Changing Climate 1