变化的科学政治的气候

Richard A. Muller在《未来总统的物理课》中费了很多篇幅讨论气候变暖问题，还批评了戈尔副总统的作秀。最近，气候变化又成了“未来总统”的问题。新候选人Ted Cruz在“Late Night with Seth Meyers”（一个深夜秀节目）中“挑战了现代科学”，说最近17年的卫星数据表明气候没变暖，一点儿也没有（Nonewhatsoever）：

Debates on this should follow science and should follow data. And many of the alarmistson global warming, they’ve got a problem cause the science doesn’t back them up. And in particular, satellite data demonstrate for the last 17 years, there’s been zero warming. None whatsoever. It’s why — you remember how it used to be called ‘global warming’ and then magically the theory changed to ‘climate change’? The reason is it wasn’t warming, but the computer models still say it is, except the satellites show it’s not.

Ted是有名的climate denier，而令空间科学家们难过的是，他还是参议院Space, Science and Competitiveness委员会的主席：一直想着从NASA减钱的人却来管NASA了！他早就挖苦过气候变暖的“科学”：

You always have to be worried about something that is considered a so-called scientific theory that fits every scenario. Climate change, as they have defined it, can neverbe disproved, because whether it gets hotter or whether it gets colder,whatever happens, they'll say, well, it's changing, so it proves our theory.

这话当然（永远）是对的——很多经验科学都是如此；不过，他自以为有数据支撑的“科学论断”也有大大的问题：

数据问题：不用陆地和海洋的，却单用卫星的；即使从卫星数据说，他也误读了。

时间问题：1998年是一个极端年，不能作为趋势分析的标准。

序列问题：17年的数据序列太短，不能代表几十年尺度的变化趋势。

报道见http://www.washingtonpost.com/news/energy-environment/wp/2015/03/24/ted-cruz-says-satellite-data-show-the-globe-isnt-warming-this-satellite-scientist-feels-otherwise/  文章最后总结说

So in sum: In claiming the globe hasn’t warmed in 17years, Cruz selectively highlighted satellite temperature data, rather than other data (which NASA and NOAA recently used to call 2014 the hottest year on record). He also selectively focused on one year (1998), rather than examining the aggregate temperatures of many years or decades. And finally, a key scientist who studies this type of satellite data, and whose work was cited by Cruz’s spokesman (as backup), criticizes Cruz’s approach and conclusions.

Speaking of conclusions — at this point, feelfree to draw your own.

最后一句话很有意思——至于结论，随你。

不管怎么说，这个故事提醒我们在用数据和选数据的时候，要考虑得周详一些。这才是我对它感兴趣的地方。