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标题: IPCC: 气候变化比原来认识的更严重 [打印本页]

作者: 橡树村 时间: 2013-10-3 03:35
标题: IPCC: 气候变化比原来认识的更严重
本帖最后由橡树村于 2013-10-3 15:36 编辑

2013年9月27日，联合国政府间气候变化专门委员会IPCC发布了第五次评估报告第一工作组的决策者摘要。第一工作组的任务是就气候变化的相关科学问题进行分析阐述，对气候变化的原因进行归因，并对未来的变化趋势进行预估。与2007年发布的第四次评估报告相比，新的评估报告认为，气候变化要比原来认识到的更加严重，而有95%以上的把握认为气候变化是人类的行为造成的。

气候变化的相关研究非常复杂，涉及到多个学科，不过对于普通人来讲，可以归结到四个问题：全球气候真的在变暖吗？导致气候变化的原因都有什么，哪个是主要的？气候变化会带来什么样的后果？人类如何应对气候变化？IPCC使用三个工作组来回答人们的这些疑问，其中前两个问题由第一工作组来回答。

新的报告坚持了以往报告的说法，认为气候变暖是明确的。这个结论有多方面的观察结果支持，地表气温是最直接的指标。报告指出从1950年代以来的变化是千年以来所未见的；从有详细气象记录以来的1850年代开始，刚刚过去的三个年代每一个都刷新了气温最高的纪录。从1983到2012年这三十年，至少在北半球是1400年以来最热的三十年。在1880年到2012年间，陆地与海洋表面的气温已经升高了0.85摄氏度，而2003到2012年十年的平均气温与1850到1900年五十年的平均气温比较，也高出了0.78摄氏度。

1850到2012年间全球陆地海洋表面平均温度变化情况

地球表面绝大多数被海水覆盖，实际上海水具有比大气更大的热容，也就会比大气吸收更多的能量。报告指出从1971年到2010年四十年间，地表所积累的能量的60%被700米深度以内的上层海水所吸收，30%被700米深度以下的海水所吸收，加在一起海洋存储了90%地表积累的能量。75米深度以内的浅层海水平均温度在1971到2010年间以每个年代0.11摄氏度的温度在上升。对海水温度变化的观测与地表气温变化的观测一致。

另外一个重要的全球变暖指标就是冰川的变化。1971年到2009年间，陆地冰川平均每年损失2260亿吨冰，而在1993年到2009年间，损失速度已经达到平均每年2750亿吨，冰川消融速度在增加。格陵兰和南极的冰盖损失也终于能够估算，其中格陵兰的冰盖损失已经从1992年到2001年的平均每年损失340亿吨增加到了2002年到2011年间的平均每年2150亿吨；而南极冰盖损失也已经从1992到2001年间的平均每年300亿吨增加到了2002年到2011年间的平均每年1470亿吨。

北冰洋的海冰覆盖面积也是一个很明显的指标。1979到2012年间，北冰洋冰层覆盖面积以平均每十年3.5-4.1%的速度减少，或者说每十年损失45到51万平方公里的冰面；而夏季最小冰面面积也在以每十年9.4-13.6%的速度在减少。同样在北半球，春季积雪的覆盖面积也在减少。1967到2010年间，春季积雪覆盖面积平均每十年减少1.6%，六月份积雪面积则平均每十年减少11.7%。北半球北部还观察到了明显地的冻土温度上升，以及冻土层厚度减少。这些都与气候变暖的趋势相吻合。

北极夏季海冰存量变化

海冰的减少并不会影响海平面位置，但是冰川和冰盖的消融直接对海平面上升作出了贡献，同时海洋温度升高本身带来的热胀冷缩也会导致海平面上升。从1901年到2010年，全球平均海平面上升达到了0.19米，平均每年1.7毫米；而1971年到2010年的海平面平均上升速度是每年2.0毫米，1993年到2010年间速度则达到了平均每年3.2毫米，海平面上升速度在提高，比以前预想的要严重。在数据翔实的1993年到2010年间，海平面上升的程度基本上与估计的冰川消融程度、海水温度升高的程度以及陆地水储存总量相符合，也就是说气候变暖基本上可以解释海平面上升的原因。这也是支持全球变暖的强有力证据。

全球平均海平面高度变化

在观测到全球变暖的同时，大气中的温室气体含量也在继续增加。二氧化碳在大气中的浓度已经比工业化之前高出了40%，同样是温室气体的甲烷浓度已经比工业化之前高出了150%，氮氧化物含量也增加了20%。现在这三种气体在大气中的含量都已经是八十万年以来的最高，并且浓度还在以很快的速度上升，这个上升速度至少在过去的2.2万年的时间里是没出现过的。

大气二氧化碳浓度变化

这其中化石燃料的使用贡献最大。从1750年到2011年，化石燃料使用以及水泥行业总共排放了3650亿吨碳，同时森林减少以及其它土地用途改变造成的碳排达到1800亿吨。二者加在一起导致人类总量达到5450亿吨的碳排（每吨碳排折合3.67吨二氧化碳），可以肯定观察到的大气二氧化碳浓度迅速增高是人类活动造成的。现在土地变更造成的碳排比例已经显著降低，2002至2011年十年间，化石燃料燃烧造成的二氧化碳排放平均是每年95亿吨碳，土地用途的变化每年平均仅贡献9亿吨碳排。人类活动排放的二氧化碳并没有完全留在大气。地表的生态系统吸收了1500亿吨碳，大气保留了2400亿吨，其余的1550亿吨碳被海洋吸收。海洋在缓解大气中二氧化碳浓度做出贡献的同时也开始酸化，pH值已经平均下降了0.1。这个数字看起来很小，但是换一个说法，海水中氢离子浓度已经增加了26%，大约就能看出严重性了。

大气中的温室气体浓度增加会造成地表温度上升是有充分科学依据的，不过影响气候的主要因素还有几个，要研究造成全球变暖的原因，就需要比较各种不同因素做出的贡献。这些因素对气候的影响程度使用一个叫做“辐射强迫”的指标来衡量，正的辐射强迫就会导致地表温度增加，负的则代表会导致地表温度降低。在人类活动有能力影响气候之前，主导气候变化的一直是大自然。

大自然影响气候的方式主要是两个，一个是太阳自身的辐射的变化，一个是火山喷发。太阳的辐射一直不是一成不变的，历史上的太阳辐射变化可以通过各种方式去寻找痕迹，而现代太阳的辐射变化则可以通过卫星监测。1978年开始的卫星监测的太阳辐射数据显示最后的一个太阳极小值要比前两个低，2008年的极小值与1986年的极小值相比，辐射强迫为-0.04W/m2，显示太阳辐射在最近三十年有一个轻微的减弱。工业化以来，太阳的辐射变化造成的辐射强迫为0.05W/m2，对升温略有贡献。大规模的火山喷发也会短期对气候造成影响。火山喷发释放的颗粒物进入大气后能够反照太阳辐射，从而减少到达地面的辐射，所以火山喷发之后的一段时间会产生一个负的辐射强迫，时间长短取决于火山的喷发程度。总的来说，在上一个世纪，自然本身仅仅贡献了一个很小的辐射强迫，在这个期间内，平均下来对气候的贡献不大。定量的估算为，自然导致的影响在温升-0.1度到0.1度之间，与现在观察到的实际温升情况相差甚远。

那么就需要在人类活动上面找原因了。工业化以来大气温室气体浓度增高所造成的辐射强迫增加达到了3W/m2，二氧化碳排放一项就达到了1.68W/m2。不过人类活动不仅仅增加温室气体排放，各种工业污染排放的颗粒物是有能力降低地表温度的。人类活动排放的气溶胶，加上炭黑，考虑的云的影响之后，贡献了-0.9W/m2的辐射强迫。综合下来，与1750年相比，2011年人类活动造成的辐射强迫达到2.29W/m2，这个数值在1970年以后增长迅速，甚至与2005年估算的数值相比，2011年估算的辐射强迫也增加了43%。与此同时，目前所观测到的气候变化的形式，表现出来的一些具体特征，也与人类活动对气候产生影响的形式和特征相符合。综合下来温室气体浓度变化导致1951-2010年期间平均气温增高0.5-1.3度，其他的人类影响则产生了-0.6到0.1度之间的变化，而自然导致的影响在-0.1至0.1度之间，人类活动对气候造成的影响超出了自然本身的影响。所以这次评估报告下结论说，人类活动对气候的影响已经很清晰，也有了95%以上的把握认为人类活动是造成气候变化的主要原因。

IPCC第一工作组也对未来气候变化的趋势做出了预测。预估显示如果太阳辐射没有显著变化，没有大的火山喷发这些会显著影响气候的自然因素，与1986年到2005年的平均气温相比，2016到2035年的平均气温会高出0.3-0.7摄氏度，升温的趋势仍然会继续。

更加远期的预估就会受到人类发展各种因素的影响，IPCC根据经济和政策的不同状况推出了四个未来情景来进行预估，这里面有大幅度减排，使得温室气体排放在21世纪中期达到顶点然后下降的RCP2.6情景，也有对温室气体完全没有控制的RCP8.5情景。不过无论什么样的情景，大气中的温室气体浓度在21世纪仍然会继续上升，气候变暖的大趋势也不会改变，只是程度不同。到本世纪末的2081-2100年，碳减排力度最大的RCP2.6模式也会导致相对1986-2005年平均的0.3-1.7摄氏度的温升，不进行减排的模式则会导致2.6-4.8摄氏度的温升，21世纪的全球变暖程度非常可能超过1.5度，比20世纪的温升幅度要高出不少。

全球平均表面温度变化预估

温升会导致极端气候发生的频率强度增加，北冰洋冰面继续萎缩，陆地冰川和冰盖继续消融，而海平面的上升速度也会加快。减排强度最大的预估情景中，到21世纪末，海平面也要比20世纪末升高0.26-0.55米，而对于没有减排的情景，海平面则会在21世纪升高0.45-0.82米。到那个时候，海岸线会与现在非常不同。

全球平均海平面上升情况预估

作者: 李根 时间: 2013-10-3 03:45
不是说北冰洋夏季冰盖面积不减反增吗？南极冰盖面积也在增加

作者: 橡树村 时间: 2013-10-3 03:56

李根发表于 2013-10-3 03:45
2 J: q) o) q7 W; b不是说北冰洋夏季冰盖面积不减反增吗？南极冰盖面积也在增加

气候的年计变化非常大，高于平均变化，所以气候变化要看至少十年的平均，看的是大趋势，而不是某年的变化。

作者: 潜客 时间: 2013-10-3 04:05

李根发表于 2013-10-2 14:45 0 X3 O# E: D0 ]' r2 K
不是说北冰洋夏季冰盖面积不减反增吗？南极冰盖面积也在增加

南极冰盖面积在增加，但是北冰洋冰盖是在减小

作者: 七月群山 时间: 2013-10-3 04:09
很严重啊，看得让人心惊肉跳的，很想说“不是我干的”

作者: MacArthur 时间: 2013-10-3 04:42

到21世纪末，海平面也要比20世纪末升高0.26-0.55米，而对于没有减排的情景，海平面则会在21世纪升高0.45-0.82米。到那个时候，海岸线会与现在非常不同。

大海升高半米，天，恁多海景房不都全泡水里了么。。。
要去马代旅游的赶紧啦。。。

作者: 李根 时间: 2013-10-3 05:17

潜客发表于 2013-10-2 15:05 , ?9 _' _4 p( I3 [8 H" u
南极冰盖面积在增加，但是北冰洋冰盖是在减小

你是对的，南极冰盖在增加，北极冰盖今年只是恢复性增长，尚未回到常年水平

作者: 雪个 时间: 2013-10-3 07:57

橡树村发表于 2013-10-2 11:56 1 W9 i8 ^) L4 a( U0 R# O/ K U
气候的年计变化非常大，高于平均变化，所以气候变化要看至少十年的平均，看的是大趋势，而不是某年的变化 ...

嗯，也不能拿一个地方的数据来说明问题。老有人跟我说“明明比以前冷，偏要说全球变暖！”

作者: 潜客 时间: 2013-10-3 10:57

李根发表于 2013-10-2 16:17 , U0 V) L$ W, @' ^$ S
你是对的，南极冰盖在增加，北极冰盖今年只是恢复性增长，尚未回到常年水平
$ `' \ A6 x$ e* P* T( H ...

2012年夏天北极海冰的面积是近五年来的最小值，今年属于“触底反弹”，但是依然明显低于2000年以来的平均值。

作者: 橡树村 时间: 2013-10-3 12:20

李根发表于 2013-10-3 05:17 0 N% @9 U2 r( w# e
你是对的，南极冰盖在增加，北极冰盖今年只是恢复性增长，尚未回到常年水平
2 u4 e/ O/ H5 O+ J9 E0 M- @ ...

1979年以来南极海冰面积平均以每十年1.2-1.8%的速度在增加，对应的面积是每十年增加13-20万平方公里。原因被归结于局域性的气候变化，一些区域的海冰面积在扩大，一些地方在缩小。

不过海冰不是冰盖，冰盖这个词说的是陆地上的那层冰壳，一般专指格陵兰和南极大陆。

这次评估成功检测到了冰盖质量的变化，观察到了两个冰盖质量的损失。

作者: 山远空寒 时间: 2013-10-3 17:44
感觉海洋可以调节气候，虽然冰川融化，气候变暖，但由于海平面升高，海洋面积增大，海洋相应的蒸发量也会增加，对某些原来干旱地区的降水量会增加，比如新疆的北疆，记忆中，南疆和北疆的年均降水都在增加，其中南疆增加的幅度要大于北疆。北疆的准格尔沙漠已经变成戈壁滩，黄羊越来越多，狼也多起来。这主要归功于来自大西洋的水汽增加——这是新疆降水的主要水汽来源（主要有四种，都来自海洋好像）。

所以呢，中国西北大片土地的降水会增加，打听过，目前的水利主要是政府修建的水利工程，将山区的水通过渠道或管道引到干旱的戈壁。（因为新疆降水的87%都集中在山区）

从这个角度看，气候变暖对西部的好处多一些。

作者: 橡树村 时间: 2013-10-3 17:52

山远空寒发表于 2013-10-3 17:44
' m9 H4 I; a4 m$ Z5 l- M T感觉海洋可以调节气候，虽然冰川融化，气候变暖，但由于海平面升高，海洋面积增大，海洋相应的蒸发量也会增 ...

目前程度的温升对国内整体特别是西部地区基础设施很少的地方是利大于弊的，继续增加一度温升对西部大约也还是好的，东部的洪涝灾害会增多，可能就不这么好了，不过综合权衡如何还不好说。

升高幅度继续增加就不好说了。新疆的径流主要依靠的是冰川融水，目前是冰川消融加快阶段，供水量增加。等到冰川消融完了，新疆的供水就会出大麻烦，那个时候就是弊大于利了。

作者: 山远空寒 时间: 2013-10-3 18:00
本帖最后由山远空寒于 2013-10-3 18:12 编辑

橡树村发表于 2013-10-3 17:52 : l! ~1 X/ h6 {' t9 _3 `7 U( Z( D
目前程度的温升对国内整体特别是西部地区基础设施很少的地方是利大于弊的，继续增加一度温升对西部大约也 ...

哈哈，村长，说起新疆的水，在爱坛我可算是内行呀！

新疆的农业用水主要还是来自山区降水——渠道引水，冰川融水占比例比较少，忘记了，但估计10%左右吧（150亿立方，每年？）。

虽然有过旱季炸冰川取水的事情，但是后来被专家阻止了，以后就没干过。

而且，塔里木盆地底下长年累月积累了8-10万亿立方苦咸水（含氟，有毒），平铺在塔里木盆地有15米深。这个资源不好好利用一下怎么对得起自己。

气象专家们争论的主要是塔里木盆地以自循环为主，还是外来水汽为主。现在比较一致的意见和证据表明，，主要是外来水汽从罗布泊灌入影响了塔里木盆地的降水。

作者: 橡树村 时间: 2013-10-3 18:11

山远空寒发表于 2013-10-3 18:00
' O s" ~0 z# b @. E5 D! Z& ?哈哈，村长，说起新疆的水，我可算是内行呀！
5 E, A/ b! A' J1 V6 b0 i1 b. a$ [" i3 b3 z/ e/ _/ J$ x, m
新疆的农业用水主要还是来自山区降水——渠道引水，冰川融 ...

这里有文章，

http://link.springer.com/article/10.1007%2Fs11434-011-4720-8

冰川融水贡献比你说的大不少。

作者: 山远空寒 时间: 2013-10-3 18:21

橡树村发表于 2013-10-3 18:11
# q b3 i- Q7 z, W这里有文章，
+ Y0 D6 A* ~( G0 n7 J, k7 r8 E3 k. @( g4 }/ h2 ]" l
http://link.springer.com/article/10.1007%2Fs11434-011-4720-8

和我说的不矛盾啊！我记得新疆的冰川总量占全国的一半稍多好像，大约2万亿立方，他说某个冰川减少了五分一在48年间，平均一下差不多。

具体我需要翻以前的资料，都是10年的记忆，非常不准。

不过大体上，国家对冰川总量，新疆的总降水量，和每年的补充量还是非常重视，新疆每年的总降水量大致在2400亿立方，南北各一半。

如果您需要，我就去翻以前的资料，如果不需要，我们就当闲聊，大伙儿图个乐子！行不！

作者: 奉孝 时间: 2013-10-3 19:10
从个人的感觉是气候变化更为极端，夏天更热更长，冬天更冷更长。

作者: 橡树村 时间: 2013-10-3 20:50

山远空寒发表于 2013-10-3 18:21
7 f! \! a$ N7 t6 I. H6 P和我说的不矛盾啊！我记得新疆的冰川总量占全国的一半稍多好像，大约2万亿立方，他说某个冰川减少了五分 ...

闲聊么。

我只能看文献，其他知道的很少。

最近几年去了几次克拉玛依，那里很显然降雨增多，我去年七八月份起竟然最高气温只有28度，赶上下小雨。再加上前几年那个人工河工程，那里受益不浅。

不过也不是完全没有问题，比如克拉玛依城市根本没有排水，于是就涝了，所以市政就需要考虑街道排水问题。好在西部基础设施普遍少，比起所带来的好处，就绝对可以接受了。

长期的影响如何要复杂很多。气候变化不仅仅是简单的升温问题，要这么简单很多危害也就没了。温度升高后大气的环流情况有可能会变化，比如刚过去的这个冬天欧洲的奇怪气候，就是大气环流受到了影响。达到人类从来没有见过的温升幅度以后，大气环流究竟会是什么样子，还是一个研究并不很清楚的地方，所以仍然很难保证目前的好处肯定会持续。

可靠的历史上中国这块地方大气环流就有过改变的，对降雨模式的影响非常大。

作者: 山远空寒 时间: 2013-10-3 21:14
本帖最后由山远空寒于 2013-10-3 21:20 编辑

橡树村发表于 2013-10-3 20:50
# r$ i8 L3 a2 u) {$ n; O# W% C( K4 r闲聊么。
9 B. V+ g( h) S X$ p* M" q) n; Q, U1 `5 t
我只能看文献，其他知道的很少。

没错，我看到的文献记载，2000多年前的汉朝，南疆盆地周边一圈儿小国，都是靠河水灌溉发展农业。当然，那会儿整个中国北方降水都多，偏暖湿。现在新疆北部的水我们尽量用，沿途看过去都有牧民在戈壁滩放牧骆驼。以前可是一眼望不到边儿的沙漠。现在都是戈壁滩，北疆的戈壁滩，只要引渠灌溉，第一年固沙，第二年种西瓜，第三年种土豆，大家都非常高兴。不过引水成本非常高，这个成本都是国家来负担。因为修水库，搞水利工程历来都是花钱多。

我看到的资料是这二十年左右，新疆的年均降水逐年增加，比例不小。南疆增加量还要大过北疆。似乎总体比二十年前南疆增加17%左右（记忆），北疆增加百分之13%（记忆）。这也是我说全球气候变暖可能对新疆等西部地区带来好处。另外，新疆严令不许砍树，西部的退耕还林还草，都对大气中的水汽含量增加有帮助，应该是综合各种因素增加的降水。

但是新疆相对还是干燥，新疆的东部整体更干燥些。

我记得以前有篇雅思文章，说的是几百年前英国遭遇了一次特大寒流，非常非常冷。大概就是比正常低了二三十度吧。冻死好多人似乎。

另外，也是雅思文章上说的，好像是洋流的变化影响着地球的气候？？？这个就更早啦，实在想不起。反正原文大致是风暴，台风等大气现象无法改变洋流。而洋流可能改变它们？？
（佩服一下自己的记忆力，做模拟题的时候做过一遍，竟然记了这么多，这么久。）

所以我在想，村长也关注一下洋流变化，因为融化的冰多了，会导致洋流变化，而洋流变化会影响气候变化。当然，我是瞎说的，毕竟是外行。

希望地球有一定的自我调节能力！

作者: 橡树村 时间: 2013-10-3 21:36
本帖最后由橡树村于 2013-10-3 21:40 编辑

山远空寒发表于 2013-10-3 21:14
% ~, Q! U2 c+ ]1 \! A没错，我看到的文献记载，2000多年前的汉朝，南疆盆地周边一圈儿小国，都是靠河水灌溉发展农业。当然，那 ...

洋流变化最大的危险在欧洲。

有一种可能，就是格陵兰的冰盖溶化后，淡水大量注入北大西洋，北大西洋径流有可能被切断，北大西洋暖流改变方向，欧洲立刻进入冰期。这也就是那几个气候变化题材的电影所讲述的那种情况。类似的事情的确发生过，后果很严重，所以欧洲人很关注这个问题。目前的研究结论是还没有观测到任何向这个方向发展的倾向。

地球自然是有调节能力的。只不过这个调节能力不一定走向人类最希望的方向而已。

作者: 山远空寒 时间: 2013-10-3 21:48

橡树村发表于 2013-10-3 21:36
' u( l" t8 W7 d0 F4 b+ H3 a" H% c洋流变化最大的危险在欧洲。
: P: G( C- S3 V# [0 f* R6 i8 s2 S/ @, l3 f7 r' c& v& F
有一种可能，就是格陵兰的冰盖溶化后，淡水大量注入北大西洋，北大西洋径流 ...

哇！专家就是厉害！佩服！

原来洋流会如此严重的影响欧洲！那几百年前英国那次突然变冷也是洋流干的啦？冷了一年，好像很快就好了。

如果和几百年前那次类似或者接近，欧洲现在的能力应该不怕，当然，粮食问题解决的情况下。

如果华北减产，东南沿海绝收，中国说不定还能撑一下，毕竟国家大。就怕那会儿全世界各主产区全部都减产来个三五年，那就吓人啦。

不过，要说不过，西伯利亚有好多冻土，原先无法种粮食，现在可以种，这是另一个好处吧。

作者: 橡树村 时间: 2013-10-3 22:24

山远空寒发表于 2013-10-3 21:48 - h, m, V8 P4 ~+ k+ d; T) f
哇！专家就是厉害！佩服！2 f5 I/ q2 Z9 d! W" t
' `( v% O: r f
原来洋流会如此严重的影响欧洲！那几百年前英国那次突然变冷也是洋流干的啦？ ...

我说的事件恢复起来可不会这么快。8200年前发生过一次大规模淡水进入北冰洋的事件，导致的气候变化花费了两百年的时间恢复。

俄罗斯原来对于气候变暖是持无所谓态度的，一个原因就是气候变暖后西伯利亚会出现大量农业区，俄罗斯是受益者，而且俄罗斯因为经济崩溃，本身已经提前实现了大规模碳减排。不过近些年越来越多的森林火灾也能算到全球变暖头上的，所以俄罗斯最近又开始积极了一些。而且西伯利亚冻土有大面积解冻现象，那么建设在冻土上的建筑物几乎都要重新考虑地基问题，这也是一个相当大的投资。

大规模的地貌变化，无论最终结果是好是坏，变化过程中的代价都是很大的，不这么好玩。

作者: 木不铎 时间: 2013-10-3 23:53
标题: 你为嘛不加大时间尺度呢？
下图为俄罗斯的沃斯托克站根据所采集的南极冰核所得到的地球大气以及温度变化图，跨越年代为42万年（自上而下第二条红线为温度变化图）

实际现在，地球是处于一个“小冰期”

作者: 橡树村 时间: 2013-10-4 00:09
本帖最后由橡树村于 2013-10-4 00:24 编辑

木不铎发表于 2013-10-3 23:53 2 x, n8 [! W1 I: Y. C/ ~1 t* E, {. V
下图为俄罗斯的沃斯托克站根据所采集的南极冰核所得到的地球大气以及温度变化图，跨越年代为42万年（自上而 ...

现在处于间冰期。小冰期的说法一直有，说得是如果没有人类活动影响，那么现在应该比几百年前平均气温低。

详细报告里面何止有四十万年前去年的气温复原，几百万年来的气温复原都有。

作者: 冰蚁 时间: 2013-10-4 00:19

木不铎发表于 2013-10-3 10:53 : H* n9 ~/ H/ T9 e0 ~# T
下图为俄罗斯的沃斯托克站根据所采集的南极冰核所得到的地球大气以及温度变化图，跨越年代为42万年（自上而 ...

你这个图不正好支持报告所说的么。

图中从左到右，时间从现在往前推到42万年。可见最近1万来年，气温处于自然周期高点。在高点的基础上，目前观测结果是人类活动使得温度继续在升高，超过了自然波动。

作者: tanis 时间: 2013-10-4 02:02
二氧化碳浓度变化曲线为什么是那么均匀的锯齿？是测量手段的缘故么？

作者: 橡树村 时间: 2013-10-4 02:18

tanis 发表于 2013-10-4 02:02
2 `4 P! N8 \* R4 @1 y8 c二氧化碳浓度变化曲线为什么是那么均匀的锯齿？是测量手段的缘故么？

那个是季节波动。春天夏天植物生长旺盛的时候二氧化碳浓度会降低，秋冬二氧化碳浓度会增高。

北半球因为陆地面积远大于南半球，所以波动非常明显。

作者: 晨枫 时间: 2013-10-4 02:51

橡树村发表于 2013-10-3 12:18
2 w, q( t' M0 a那个是季节波动。春天夏天植物生长旺盛的时候二氧化碳浓度会降低，秋冬二氧化碳浓度会增高。
! q7 s- S8 X* s8 M
) b9 U" K- \( }' ~北半球因为 ...

季节是每年都有的，这个图上的波动周期怎么也得有个几十年、上百年吧？

作者: 橡树村 时间: 2013-10-4 03:05
本帖最后由橡树村于 2013-10-4 03:06 编辑

晨枫发表于 2013-10-4 02:51
0 ?2 i/ Q3 @" e/ _' [6 R; Y季节是每年都有的，这个图上的波动周期怎么也得有个几十年、上百年吧？ ...

二氧化碳浓度的准确测量才六十年的历史。

一个周期是一年。

作者: 洗心 时间: 2013-10-4 18:13
村长好文，转发一篇在现场的NGO同事的報道

IPCC: How the Key Issues Were Resolved
The Stockholm meeting that adopted the IPCC’s report on Climate Science saw governments and scientists debating several key issues before coming to a conclusion. Meena Raman who was at the meeting provides an account of the discussion on some key issues and how they were finally resolved.
By Meena Raman

Prior to the approval by governments of the Intergovernmental Panel on Climate Change (IPCC)'s ‘Summary for Policymakers' of Working Group I on the ‘Physical Science Basis', intense debates took place on several key issues.

Among the issues which were deliberated during the meeting of Working Group 1 (WG1), which began on 23 September in Stockholm, Sweden, included: the "pause" in the warming trend for the 15-year period from 1998 to 2012; the lack of temperature data for the pre-industrial period from 1750; the evaluation of climate models and their reliability in reproducing observations; the emission cuts needed by 2050 relative to 1990; and the carbon budget remaining in relation to temperature limits.

Also addressed was the issue of ‘geo-engineering'.

Concerns raised by governments were in some cases referred to contact groups or informal consultations for resolution. The Summary for Policy Makers (SPM) was approved by governments on 27 September.

Below are highlights from some of the discussions.

‘PAUSE' IN WARMING

When the initial draft of the SPM (dated 7 June 2013) was made available to governments, a key issue of concern was reference to "the global mean surface temperature trends, where the rate of warming over the past 15 years (1998-2012) was smaller than the trend since 1951". (This has been referred to in the media as a ‘pause' in the warming).

"The mean rate of warming for the 15 years was 0.05 degree C compared to the mean rate per decade (1951-2012) of 0.12 degree C," according to the SPM.

According to Thomas Stocker (Switzerland), who is the co-chair of WG1, concerns were raised by some governments regarding the scientific basis of looking at short term periods. He said that an equal number of governments felt that this (15 years) is an important period of time on which the IPCC has to make a statement on a scientific basis.

During the meeting, several governments including Germany, Switzerland and the United States said that it is important to discuss the 15 years as this is now in the public domain and explanation is needed.

Germany stressed that showing trends alone is misleading and there is need to also show the context. It said that the impression given is that warming is going to slow down or is halted. It wanted reflection of the trends for the following 15 years.

This was however not agreed to.

The US emphasised the need to address inter-annual variability. It also wanted the mention of 1998 being an El Nino event. The US said that the rate of warming since the late 1990s is very sensitive to choice of start dates.

(An El Nino event is a temporary change in the climate of the Pacific Ocean, in the region around the equator where effects are seen in both the ocean and atmosphere, generally in the Northern Hemisphere winter. Typically, the ocean surface warms up by a few degrees Celsius).

China said that it is important to reflect the temperature changes which are a fact and to also reflect the short term uncertainty.

Saudi Arabia stressed the need to state the internal climate variability.

The final paragraph agreed to is as follows: "In addition to robust multi-decadal warming, global mean surface temperature exhibits substantial decadal and inter-annual variability. Due to natural variability, trends based on short records are very sensitive to the beginning and end dates and do not in general reflect long-term climate trends. As one example, the rate of warming over the past 15 years (1998-2012; 0.05 [-0.05 to +0.15] degrees C per decade), which begins with a strong El Nino, is smaller than the rate calculated since 1951 (1951-2012; 0.12 [0.08 to 0.14] degrees C per decade)."

A footnote was added that reads: "Trends for 15-year periods starting in 1995, 1996, and 1997 are 0.13 [0.02 to 0.24], 0.14 [0.03 to 0.24], 0.07 [-0.02 to 0.18] degrees C per decade, respectively."

LACK OF TEMPERATURE DATA FOR PRE-INDUSTRIAL PERIOD

During the discussion on ‘observed changes to the climate system' relating to the atmosphere, an issue which arose was the reference year used.

In the initial draft circulated to the governments in June, the paragraph of concern read as follows: "The globally averaged combined land and ocean surface temperature data show an increase of 0.89 [0.69 to 1.08] degrees C over the period 1901-2012. Over this period, almost the entire globe has experienced surface warming."

The Netherlands said that the SPM did not make clear why 1901 was chosen, and asked why different sections used different reference years. It referred to negotiations under the United Nations Framework Convention on Climate Change (UNFCCC), where the reference year is 1990 and there is agreement to hold the increase in global average temperature to below 2 degrees C above pre-industrial levels. It suggested the use of the period 1850-2012.

This was supported by Norway, which added that it is important to peg the reference year to the pre-industrial level of 1850.

St. Lucia also agreed with the Netherlands that it is important to have a consistent reference period from 1850 for policymakers.

In response, the authors (who are scientists) said there are several reasons for choosing 1901 to 2012, as they wanted to highlight the long-term change and that before 1901, data coverage and quality was sparse, hence the focus on 1901. The other reason is that comparison with previous SPMs (of previous IPCC assessments) is now possible because they also start in 1901.

Stocker said that 1901 is a conscious choice because of the availability of the datasets.

The Netherlands insisted that for policymakers, 1850 is the relevant period for the 2 degree C. Germany also said that the temperature estimate between 1850 to 1901 is important.

Stocker, in response, said the temperature figure for the period 1880-2012 could be given as this is the result from three datasets.

The United Kingdom also wanted a reference to the pre-industrial period as this is what is referred to in the Convention.

Germany referred to the IPCC's 4th Assessment Report (AR4) where the total temperature increase was from 1850-1999 and from 2001-2005. It wanted the authors to provide figures that allow for direct comparability.

India said that it would be appropriate to give the same period and give direct comparison with AR4 time periods. If there are data limitations, qualifying statements about the limitations of that figure should be provided.

Stocker also clarified that on the use of the term ‘pre-industrial', that term is used to refer to the period that goes back to 1750. So, the period from 1850 is what we would call as early instrumental period, and then from 1900, is the period with instrumental observations.

The authors reiterated that the datasets on global scale go back only to 1850; there are sparse observations that go back to 1750 on a global scale.

The UK said that there must be some way of addressing the issue of the ‘pre-industrial' period. Germany said that there could be text to say "pre-industrial, approximated by 1850-1900".

Brazil said that the pre-industrial period refers back to 1750, and it did not think one can use 1850 as an approximation for that as there is a difference of 100 years.

Given the lack of consensus in this regard, an informal consultation group was formed to discuss the issue.

Following the informal consultation, what was finally agreed to is as follows: "The globally averaged combined land and ocean surface temperature data as calculated by a linear trend, show a warming of 0.85 [0.65 to 1.06] degrees C, over the period 1880-2012, when multiple independently produced datasets exist. The total increase between the average of the 1850-1900 period and the 2003-2012 period is 0.78 [0.72 to 0.85] degrees C, based on the single longest dataset available."

A footnote was added at the end of the paragraph which reads: "Both methods presented in this bullet were also used in AR4. The first calculates the difference using a best fit linear trend of all points between 1880 and 2012. The second calculates the difference between averages for the two periods 1850 to 1900 and 2003 to 2012. Therefore, the resulting values and their 90% uncertainty intervals are not directly comparable."

EVALUATION OF CLIMATE MODELS

The SPM which was approved states that "understanding recent changes in the climate system results from combining observations, studies of feedback processes, and model simulations. Evaluation of the ability of climate models to simulate recent changes requires consideration of the state of all modelled climate system components at the start of the simulation and the natural and anthropogenic forcing used to drive the models. Compared to AR4, more detailed and longer observations and improved climate models now enable the attribution of a human contribution to detected changes in more climate system components".

In the SPM, under the section on ‘understanding recent changes in the climate system', one aspect relates to the ‘evaluation of climate models'.

In this regard, in the June version of the draft of the SPM, there was a statement that "there is very high confidence that models reproduce the more rapid warming in the second half of the 20th century and cooling immediately following large volcanic eruptions. Models do not generally reproduce the observed reduction in surface warming trend over the last 10-15 years. There is medium confidence that this difference between models and observations is to a substantial degree caused by unpredictable climate variability, with possible contributions from inadequacies in the solar, volcanic, and aerosol forcings used by the models and, in some models, from too strong a response to increasing green-house gas forcing."

Following comments by various governments prior to the meeting in Stockholm, the authors amended the above paragraph to read as follows: "The long-term climate model simulations show a trend in global-mean surface temperature from 1951- 2012 that agrees with the observed trend, despite differences between simulated and observed trends over the past 10-15 years (very high confidence)."

"The observed reduction in surface warming trend over the period 1998-2012 as compared to the period 1951-2012, is due in roughly equal measure to a reduced trend in radiative forcing and a cooling contribution from internal variability, which includes a possible redistribution of heat within the ocean (medium confidence). The reduced trend in radiative forcing is primarily due to volcanic eruptions and the timing of the downward phase of the 11-year solar cycle. However, there is low confidence in quantifying the role of changes in radiative forcing in causing the reduced warming trend. There is medium confidence that internal decadal variability causes to a substantial degree the difference between observations and the simulations; the latter are not expected to reproduce the timing of internal variability."

(Levels of confidence is the IPCC indicator for the robustness of conclusions drawn from the data and literature that is assessed.)

Venezuela sought clarification over the ‘very high confidence' judgement by the authors while China said that the paragraphs above were new and are supposed to be an evaluation of the climate models. It wanted to know the advantages and disadvantages of the models and said the June version of the SPM draft had this.

Similar sentiments were expressed by Saudi Arabia.

The United States said the paragraphs did relate to the evaluation of the models and it is about observations in a broader context and not just 10 to15 years. Switzerland said that one could not test models in 15 years.

Saudi Arabia, referring to the Technical Summary of WG1, wanted the following sentence added: "Most, though not all, models overestimate the observed warming trend in the tropical troposphere over the last 30 years, and tend to underestimate the long-term lower-stratospheric cooling trend."

(The Technical Summary is drawn from the full report of the Working Group.)

Following consultations with the authors, the following compromise was reached at around 2 am on Thursday, 26 September: "The long-term climate model simulations show a trend in global-mean surface temperature from 1951 to 2012 that agrees with the observed trend (very high confidence). There are, however, differences between simulated and observed trends over periods as short as 10 to 15 years (e.g., 1998 to 2012)."

"The observed reduction in surface warming trend over the period 1998-2012 as compared to the period 1951-2012, is due in roughly equal measure to a reduced trend in radiative forcing and a cooling contribution from internal variability, which includes a possible redistribution of heat within the ocean (medium confidence). The reduced trend in radiative forcing is primarily due to volcanic eruptions and the timing of the downward phase of the 11-year solar cycle. However, there is low confidence in quantifying the role of changes in radiative forcing in causing the reduced warming trend. There is medium confidence that internal decadal variability causes to a substantial degree the difference between observations and the simulations; the latter are not expected to reproduce the timing of internal variability. There may also be a contribution from forcing inadequacies and, in some models, an overestimate of the response to increasing greenhouse gas and other anthropogenic forcing (dominated by the effects of aerosols.)"

When the meeting resumed on the final day at around 8 am, Germany requested a reconsideration of the last sentence in the paragraph above as it had concerns.

Since agreement on the above paragraph had been gavelled, Stocker did not want a re-opening of the agreed text.

EMISSION REDUCTIONS REQUIRED BY 2050

Under the discussion on ‘Future global and regional climate change', the SPM which was approved states that: "Projections of changes in the climate system are made using a hierarchy of climate models... These models simulate changes based on a set of scenarios of anthropogenic forcings. A new set of scenarios, the Representative Concentration Pathways (RCPs), was used for the new climate model simulations... In all RCPs, atmospheric CO2 concentrations are higher in 2100 relative to present day as a result of a further increase of cumulative emissions of CO2 to the atmosphere during the 21st century."

(The four RCPs used are RCP2.6, RCP4.5, RCP6, and RCP8.5, and named after a possible range of radiative forcing values in the year 2100).

One aspect that was discussed in this regard related to ‘carbon and other biogeochemical cycles'.

Member States were asked to consider the following statement: "Based on Earth System Models, following RCP2.6 requires by 2050 an average emission reduction of 50% (range 14% to 96%) relative to 1990 emissions, and requires, about as likely as not, sustained net removal of CO2 from the atmosphere by the end of the 21st century."

Germany wanted additional information on the emissions pathway beyond 2050 and asked for a figure for emissions reduction in 2080.

China expressed concerns as to how one single figure is obtained and asked how the 50% figure was obtained when this is not what the ranges indicate. It also said that no information has been provided from other scenarios and that only one scenario in RCP2.6 is considered.

Saudi Arabia said that members are talking about projections that would resonate with policymakers. It can be misleading to talk about a range from 14% to 96%. It wanted the entire paragraph deleted. Russia also had similar concerns.

A contact group was formed to address this issue. Following the discussions, the following paragraph was agreed to: "By 2050, annual CO2 emissions derived from Earth System Models following RCP2.6 are smaller than 1990 emissions (by 14% to 96%)... By the end of the 21st century, about half of the models infer emissions slightly above zero, while the other half infers a net removal of CO2 from the atmosphere."

CARBON BUDGET

In the discussion on ‘climate stabilisation', Member States were asked to consider the following paragraph: "Limiting the warming caused by anthropogenic CO2 emissions alone to likely less than 2 degrees C relative to pre-industrial, will require cumulative CO2 emissions from all anthropogenic sources to stay below about 1000 GtC since the beginning of the industrial era. This amount is reduced to about 800 GtC when accounting for non-CO2 forcings as in RCP2.6. An amount of 545 [460 to 630] GtC, was already emitted by 2011."

China raised concerns that the cumulative reductions required to stay below 2 degrees C are not consistent with the figures in the underlying assessment report of WG1 which reflect that emission reductions should be in the range of 800-2500 GtC between 1750 to 2100.

The US said that the IPCC is supposed to be policy neutral and the information needs to be presented in a neutral way.

Informal consultations were held in this regard and the text which was agreed is as follows: "Limiting the warming caused by anthropogenic CO2 emissions alone with a probability of >33%, >50%, and >66% to less than 2 degrees C since the period 1861-1880, will require cumulative CO2 emissions from all anthropogenic sources to stay between 0 and about 1560 GtC, 0 and about 1210 GtC, and 0 and about 1000 GtC since that period respectively. These upper amounts are reduced to about 880 GtC, 840 GtC, and 800 GtC respectively, when accounting for non-CO2 forcings as in RCP2.6. An amount of 531 [446 to 616] GtC, was already emitted by 2011."

GEO-ENGINEERING

Another issue in the SPM concerns ‘geo-engineering'

Member States were asked to consider the following statement: "Methods that aim to deliberately alter the climate system to counter climate change, termed geo-engineering, have been proposed. Limited evidence precludes a comprehensive quantitative assessment of both Solar Radiation Management (SRM) and Carbon Dioxide Removal (CDR) and their impact on the climate system. CDR methods have biogeochemical and technological limitations to their potential on a global scale. There is insufficient knowledge to quantify how much CO2 emissions could be partially offset by CDR on a century timescale. Modelling indicates that SRM methods, if realizable, have the potential to substantially offset a global temperature rise, but they would also modify the global water cycle, and would not reduce ocean acidification. If SRM were terminated for any reason, there is high confidence that global surface temperatures would rise very rapidly to values consistent with the greenhouse gas forcing. CDR and SRM methods carry unintended side effects and long-term consequences on a global scale."

The US raised concerns over the last sentence, as it felt that it overstated the state of science in that the side effects are known and that they were unintended. It wanted reflection of the uncertainties in understanding.

The authors responded that there is evidence of the side effects but were prepared to delete the word ‘unintended' from the last sentence. This led to agreement of the text.

Author: Meena Raman is legal advisor of Third World Network.

作者: 山远空寒 时间: 2013-10-4 21:35
本帖最后由山远空寒于 2013-10-5 10:10 编辑

橡树村发表于 2013-10-3 22:24
# a) J5 }9 q& n我说的事件恢复起来可不会这么快。8200年前发生过一次大规模淡水进入北冰洋的事件，导致的气候变化花费了 ...

之前我觉得对新疆、对西部好，现在完全同意村长的意见，气候变化如果太快，我们人类可能受不了。

最好减缓这种变化，有个几百年慢慢的过度，至少我们能在太空种出粮食，就不怕了。

作者: 小木 时间: 2013-10-6 04:39

雪个发表于 2013-10-2 17:57 ' C# q# a. }0 x3 i
嗯，也不能拿一个地方的数据来说明问题。老有人跟我说“明明比以前冷，偏要说全球变暖！” ...

主流难道不是每年冬天都在高喊全球变暖是扯淡，每年夏天都在高喊全球变暖果然是大问题哎么。。。。

作者: heinsect 时间: 2013-11-17 12:24
本帖最后由 heinsect 于 2013-11-17 12:37 编辑

有人反对IPCC的数据，说这也是个利益集团。IPCC的很多人是曾在GreenPeace、WWF任职，很多人出身于大化工企业。IPCC报告的数据来源、方法都有很多问题，不是严格的科学成果。很多报告作者的资质也有问题，比如其中一个只是硕士研究生。

来源：
Donna Laframboise is a Canadian journalist and writer, whose latest book is Into the Dustbin: Rajendra Pachauri, the Climate Report & the Nobel Peace Prize.

wiki:
In 2010, Laframboise organized a citizen audit of the IPCC AR4 report, to determine how many of the report's sources were peer-reviewed. The audit found that 21 of the report's 44 chapters used less than 60% peer-reviewed sources.[4][5] She maintains noconsensus.org, a website that argues that there is no scientific consensus on global warming.[4][6]

这是她的博客：
http://nofrakkingconsensus.com/

作者: 橡树村 时间: 2013-11-17 13:04

heinsect 发表于 2013-11-17 12:24 , ^/ ~; ^. C; `& _' C u' a4 i
有人反对IPCC的数据，说这也是个利益集团。IPCC的很多人是曾在GreenPeace、WWF任职，很多人出身于大化工企 ...

没有科学意义的指责而已。

现在还对全球变暖本身持怀疑态度的不是智商有问题就是拿黑心钱的了。

反IPCC方的多数都不待见这种人了。

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