Why do Climate Scientists keep hiding their data?

Dr. Michael Mann - the most famous climate scientist in the world - has lost a lawsuit.  He sued another climate scientist (Tim Ball) for libel:

Dr. Ball was sued because he said, of Dr. Mann's seminal "hockey stick" work, "he belongs in the state pen, not Penn State." While others came to the same conclusion about the hockey stick, Mann sued Ball for libel. After eight years, Mann refused to provide a single document under the court-ordered discovery.

Dr. Mann has been in the news for a long time.  He was the lead author on a paper that turned climatology on its head.  In the 1990s the consensus view was that climate changed over time, that the Medieval period was as warm or warmer than today and that it was followed by the Little Ice Age that was so cold that millions died.  The Little Ice Age was followed by today's warming that dates back to around 1860 or so.  The UN IPCC wrote this up as the best scientific understanding of climate in the first Assessment Report.

But Mann's paper said this wasn't so - that climate was stable for a thousand years before suddenly spiking upwards in the 20th Century:

1998 saw the publication of a blockbuster scientific paper, one that showed that a climate that had been stable for a thousand years had suddenly begun to overheat.  Dr. Mann was the lead author, and this is the famous image from the article: 

 

This picture was not only used in Al Gore's movie "An Inconvenient Truth", it was sent to every household in Canada by the Canadian Government. 

As my post from 2008 says, it was a fraud, and Mann knew it was a fraud.  But he's done it twice more since then.  I'd like to explain how so you see just how deep the rot goes.

Click through to get the background of Dr. Mann's repeated scientific shenanigans.

But that's not the end of the list of dodgy science for Dr. Mann, oh no.  Remember the ClimateGate emails?  One in particular became moderately famous because it has a memorable phrase ("hide the decline"):

I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) amd from 1961 for Keith’s to hide the decline.

The email is from the head of the University department that suffered the Climategate data disclosures.  "Mike" refers to Dr. Mann.  "Nature" refers to Nature magazine, one of the 2 or 3 most prestigious scientific journals in the world.  Specifically, this refers to a paper by Dr. Mann that was published there.

So what was Mike's "trick"?  He was studying long term (1000+ year) climate, and so relied on non-thermometer data (we call these "proxies" because they are closely related to temperature but are not specific temperature measures;  tree rings, ice cores from glaciers, etc).  Dr. Mann removed the proxy temperature data after 1960 and replaced it with thermometer readings.  It's not because he didn't have proxy data up to the present day - he had complete proxy data).  So why replace some of it?

Hide the decline.

This is a short (the first 3 minutes from where this begins playing) and very accessible explanation of what the Climategate crowd did with Mike's trick.  The speaker is Dr. Robert Mueller, a climate scientist and head of the Berkeley climate science team.  Dr. Mueller is not one of those beastly Deniers like me, but he is really shocked at all this manipulation.



This is also a pretty interesting example of how Big Tech is trying to sweep this under the carpet.  There used to be a short clip of just this segment from Mueller's talk, but Youtube has dissappeared it.  So there's the whole hour (which gives a lot of background on climate science shenanigans) but we start at the Climategate bit.

So that's Dr. Mann - the only thing left to add is that he is notoriously thin skinned (he sued Dr. Ball, after all) and also a hypocrite - he sued Judy Curry, then a climatologist heading the Georgia Tech school of earth sciences.

But pride goeth before a fall.  Dr. Mann lost his court case because he refused to release his data to the court.  Even now he's hiding the decline, or whatever it is.  He will be paying some of Dr. Ball's costs.

So what is it with climate scientists and this refusal to release data?  I posted about this ten years ago on this day, but will hide all that below the jump.  The thing to keep in mind is that things have not gotten better in a decade.  Climate science is still diseased in how it is performed, by the lead scientists in the field.

Climate Change Data suspect

Sometimes when you try to turn an Apple into an Orange, you get a Lemon. We hear that the "Science is settled" about Climate Change, and it's All Our Fault. The proof, we're told, includes the "inconvenient fact" that 1998 was the warmest year in a thousand years.

Interesting. How exactly do we know? After all, the Thermometer was only invented in the early 17th Century. There's a chance - albeit a slender one - that the measurements show that 1998 was the warmest year in 350 years. How do they know what the temperature was before that?

Easy, say the Climate Warming Crowd. There are lots of "proxies" - other measurements that map pretty well to temperature. Tree rings will vary - growth will typically be faster in warm years, slower in cold ones. Ice cores, pollen counts from cores drilled into prehistoric bogs, even harvest records from medieval monasteries or Imperial Chinese court documents. These are reasonable proxies - everyone agrees on this.

So we have direct temperature readings for 100 or 200 years (the data is surprisingly weak when you go back more than 60 or 70 years). There are tree rings that go back maybe a thousand years. Ice cores will take you back tens or hundreds of thousands of years.

Ah, but these are different types of data. How do you put them together?  Splicing:

Splicing data sets is a virtual necessity in climate research. Let’s think about how I might get a 500,000 year temperature record. For the first 499,000 years I probably would use a proxy such as ice core data to infer a temperature record. From 150-1000 years ago I might switch to tree ring data as a proxy. From 30-150 years ago I probably would use the surface temperature record. And over the last 30 years I might switch to the satellite temperature measurement record. That’s four data sets, with three splices.

What's tricky is how you join them. You don't want big discontinuities in the record occurring where the data sets are spliced. Data sets are calibrated, or zeroed to try to make sure that the record stays smooth. This can be tricky, and can lead to False Positive results - reporting that something is happening, when in reality it's just an artifact of the data instrumentation:

But there is, obviously, a danger in splices. It is sometimes hard to ensure that the zero values are calibrated between two records (typically we look at some overlap time period to do this). One record may have a bias the other does not have. One record may suppress or cap extreme measurements in some way (example - there is some biological limit to tree ring growth, no matter how warm or cold or wet or dry it is). We may think one proxy record is linear when in fact it may not be linear, or may be linear over only a narrow range.

So back to the "Warmest year in 1000 years" headline. Remember Mann's "Hockey Stick" graph, the one from Al Gore's movie An Inconvenient Truth? The temperature was pretty stable until 150 years ago, and then it spiked, remember? What happened 150 years ago?

Well, say the Climate Change Crowd, the Industrial Revolution started cranking out, well, industrial quantities of Carbon Dioxide into the atmosphere. All that CO2 is what's to blame, and they have computer models to show it. Fair enough. Ignore the many problems with with models. The Industrial Revolution was built on steam power, which was driven by Coal. And it did hit its stride around 150 years ago.

But is there anything else that happened around 150 years ago? Why, yes. The temperature data sets changed from proxies to actual thermometer readings. The sudden upswing in average global temperature is entirely from a different set of measurements than the earlier data sets.  Entirely.

So, could this be a False Positive, an artifact of splicing two different data sets together. Y es it could be. In fact, it's likely that this is the case, and that's why you don't hear the Climate Change Crowd talk about Hockey Sticks and "Global Warming" anymore. Want proof? What if we ignore the thermometer readings, and just look at the proxy temperatures? We have tree ring data that goes right up to the present - why stop 150 years ago?  What does it tell us about recent climate?

You can see that almost all of the proxy data we have in the 20th century is actually undershooting gauge temperature measurements. Scientists call this problem divergence, but even this is self-serving. It implies that the proxies have accurately tracked temperatures but are suddenly diverting for some reason this century. What is in fact happening are two effects:

1. Gauge temperature measurements are probably reading a bit high, due to a number of effects including urban biases
2. Temperature proxies, even considering point 1, are very likely under-reporting historic variation. This means that the picture they are painting of past temperature stability is probably a false one.

All of this just confirms that we cannot trust any conclusions we draw from grafting these two data sets together.

So, the proxy data is not accurate enough to get reported by the Climate Change Crowd, but it's plenty accurate enough to show that 800 years ago was cooler? Selection Bias, anyone?

And if you think I'm harsh accusing the scientific community of selection bias, how about this little tidbit about one of the proxy-based data sets:

For some reason, the study’s author cut the data off around 1950. Is that where his proxy ended? No, in fact he had decades of proxy data left. However, his proxy data turned sharply downwards in 1950. Since this did not tell the story he wanted to tell, he hid the offending data by cutting off the line, choosing to conceal the problem rather than have an open scientific discussion about it.
The study’s author? Keith Briffa, who the IPCC named to lead this section of their Fourth Assessment.

When you combine this with repeated errors in the reported data - and with total refusals to release the data for scrutiny - you should be very skeptical of any claims about climate change. Any.

There is a massive, ugly problem with data integrity concerning climate change. Rather than being a done deal, things are getting curiouser and curiouser. Settled? You must be kidding. The science is getting very interesting indeed.

UPDATE 26 November 2009 19:01: More about Dr. Biffra here.