Understanding Climate Data made easy

As a full service climate skeptic blog, I chew on a lot of the science so I can present what's going on in an easy to digest manner.  This leads me into the actual temperature data sets pretty regularly which quite frankly is where the action is.  When you actually look at the data it becomes immediately clear that the science is anything but settled.  The planet may be warming, but if so there are some very unexpected things that remain unexplained.  To me, this is the biggest source of skepticism, and it's a skepticism that's entirely justified.

As a starting point, here's a good discussion about temperature measurements.  It's a bit thick going if you're not a science nerd like I am, but let me boil this down for you.  The weather stations that feed data into the climate databases.  For the USA - and actually most of the world, really - this is the Global Climate Historical Network, or GHCN.  You can get you a copy here.

The weather stations daily record two items of primary interest to us:

• TMax, the highest temperature recorded on each day, and
• TMin, the lowest temperature recorded on each day.

This actually makes a lot of sense, and there's a ton of analysis of this data which gives us daily average temperature and the like.  So far, so good.

The biggest fly in the ointment (as I've repeatedly complained about) are the adjustments made to the data after it was recorded.  This is done for many reasons: a change in equipment to a model that reads a slightly different temperature, a station movement to a hotter or cooler location, a change in the time of day when the readings were taken, and a bunch of others.  If you're talking about satellite data one of the adjustments is for orbital decay and another is for relativistic effects which is pretty cool.

I won't talk about adjustments here because I've beaten that horse to death.  If you're interested, a starting point is my Layman's Guide to the science of global warming on the right hand sidebar of this blog.  For now we'll just leave it as my opinion is that the most or all of the warming we've seen in the last 100 years are do to adjustments (i.e. it's not in the actual data as recorded from the weather stations) and a bunch of these adjustments are very poorly justified.

So let's talk about data that are not adjusted, namely temperature records.  These by definition are unadjusted TMax and TMin readings.  I'm interested in these because if you're suspicious of the adjustments, you can avoid them entirely by just looking at records.  Wikipedia has an interesting page of record high and low temperatures for each of the 50 US States here.

Now it's Wikipedia, and we've seen over and over again.  But facts are stubborn things, and record high or low temperatures are stubborn facts.  So let's take a look at them, as shown on the Wikipedia page and use this to figure out what we think may be going on regarding global warming.  After all, we're continually told that the world is rapidly warming and that things are a crisis.  You'd expect to see this in new temperature records being set.

Actually, we're not.

In the last 50 years (since 1968), only nine states have set high temperature records.  41 states set high temperature records in the years before that (the records date back to 1888, when Colorado had a record hot day).  The highest recorded temperature in any of the 50 states was set in 1913 in California.

The sneaky thing that Wikipedia does on this page is that if a state tied a record, the latest date is shown.  This adds another 3 states to the last 50 years, but I am not including them in the 9.  The reason is that the proposition that we're testing is that the climate is warming - getting warmer over time.  If it is as warm as it had been then that's not evidence for warming.  Wikipedia is sneaky here, not showing the original  date that the record was set (and I'm too lazy to dig this up) so for our analysis today we are going to ignore these three data points.

So we see 9 states (18% of the total) setting high records in the last 50 years. 41 states (82% of the total) haven't seen record high temperatures in the period we've been told is an accelerating and hotter climate.  You would expect to see a lot more states - another 15 or so setting recent high temperature records.  Weird, huh?  It's almost like if you remove the adjustments to the temperature data, you don't see accelerating warming.

In fact, we may be seeing the opposite.  If you look at record low temperatures you see a lot going on in the most recent years.  15 states have set record low temperatures in the last 50 years (once again ignoring dates listed with an asterisk which tells us the year that the previous low record was tied).  This is only 30% of the total, but that's basically twice as many as set record high temperatures.

So the unadjusted data tell a different story than the adjusted data.  While inconclusive, there's actually more data showing cooling than show warming.  At the very least, the proposition that the climate is unusually warm and getting warmer is not supported.

Now the establishment science story is that average TMin has been increasing over time, while average TMax has not been increasing much (looking at adjusted data).  Left unexplained is how increasing carbon dioxide in the atmosphere increases average low temperatures while not increasing average high temperatures.  Also left unexplained is how increasing average low temperatures (without increasing average high temperatures) will lead to ecological disaster.  Maybe it could, but it's not at all obvious how this would happen.

It's also not explained why Urban Heat Island (UHI) doesn't explain the higher average low temperatures (TMin).  UHI is where a weather station that used to be in a nice grassy field is now in the middle of an airport, surrounded by tarmac and blasted with jetwash.  It's surprising just how many weather stations are not sited to accurate data collection norms - only 8% of GCHN stations are accurate withing 1°C.

You'd think that if the science were as settled as everyone tells us that evidence supporting global warming would be falling off the trees and piled on every street corner.  Instead, we see evidence against is kind of everywhere.  Hmmmm.