More damn lies and statistics

One of the difficult things for us non-expert lay observers of the ongoing global warming debate is that the zealots on both sides seem to have little hesitation in misusing climate statistics to “prove” their case. The website of global warming sceptic John Daly currently contains a particularly egregious example, and it highlights my hometown Darwin. Daly says:

Darwin, the capital city of the Northern Territory and deep in the tropics, normally has daytime temperatures around 32 to 33 °C all year round, with overnight temperatures typically in the low to mid 20s celsius.

But not this August or September. There were some of the coldest temperatures in decades during August and finally on 5th September, Darwin recorded the lowest September temperature since records began, 15.1 °C., a real cold snap for a tropical location like Darwin. The previous lowest temperature was 16.7 °C on the 9th of September 1963.

The local media was informed of the new record and it will be available here. The records are also published in the NT Monthly Weather Review. However, had Darwin recorded a hot temperature record, it would have been proclaimed loudly from the rooftops of all the major media, announcing the coming of the greenhouse Armageddon.

But for a cold record? Only the local media takes interest or needs to know.

However, the facts bear very little relationship to Daly’s claims.

It’s certainly true that 5 September (last Friday) was the coldest September night on record at 15.1 °C, and the couple of nights before that were fairly cool too. However, it’s been warmer and steamier ever since, and has actually rained most days, hinting at a possible early beginning to the build-up. I even got soaked by a tropical downpour early this morning while on my daily bike ride along Casuarina Beach. Moreover, and directly contrary to Daly’s claim, the month of August wasn’t especially cool. In fact this map from Darwin Bureau of Meterology for the month of August shows that temperatures were slightly above the long-term average throughout most of the NT including Darwin itself. As any Darwinian will tell you, the dry season just ending has been a fairly disappointing one: neither as cool nor as dry as one might have hoped (although quite pleasant nonetheless). Maybe we’ve just been spoiled by the superb dry season Darwin experienced last year, which actually was the coolest on record.

Incidentally, Daly’s claim that “overnight temperatures [are] typically in the low to mid 20s celsius” in Darwin is also misleading. It’s certainly true for the year as a whole, but dry season night-time minimum temperatures are typically between 18 and 22 °C, so while 15.1 °C is certainly cool it isn’t as great a contrast as Daly’s treatment suggests.

Finally, it’s worth noting that isolated temperature minima or maxima (or even a run of high or low temperatures) prove nothing at all about global climate change. Local weather patterns are highly variable, and only long-term changes in averages have any significance. This is even more true for somewhere like Darwin, where temperatures and rainfall are heavily affected by extremely variable large-scale weather events, namely the incidence and tracks of tropical cyclones and the arrival date and intensity of the north-west monsoon each year. Moreover, most of the computer climate models on which the global warming advocates rely project very little long-term warming in the tropics. They actually show most of the warming taking place in higher latitudes, mostly in winter and mostly at night. Thus you wouldn’t really expect to see a place like Darwin becoming measurably hotter (or colder) even if the alarmists’ worst-case warming scenarios turn out to be true. So Daly’s story is a classic beatup of the worst sort.

On the other side of the global warming debate, the blogosphere’s own John Quiggin has also been enthusiastically misusing statistics in the opposite direction to Daly. Professor Q says:

Anyway, I was particularly interested in Australian contrarian John Daly because, earlier this year, he took the unusual step of making a testable prediction. In this entry he predicted that, with the sunspot cycle turning down and El Nino ending, the climatic extremes of 1998-2002 would be a thing of the past.

Finally, last year in 2002, even before the solar cycle had started its usual decline towards the cooler Solar Minimum, we saw the development of another El Ni±o on top of an already stretched out solar maximum. A Solar Maximum happening concurrently with an El Ni±o, with no cooling volcanic action for the last 10 years, is a potent combination climatically. And the weather has been very active as a direct result of this combination.

But it will pass. These things always do. The solar cycle is now heading down towards its expected solar minimum around 2006, while the current El Ni±o is expected to wane in the next few months, possibly being replaced by its cooling counterpart, La Ni±a.

The greenhouse industry has thrived off Nature’s climatic drama of the last 4 years, using a combination of public hysteria and bent statistics, but the pickings will be leaner in the months and years ahead – until we reach the next El Ni±o or the next solar maximum expected around 2012 (the same year the Kyoto Protocol expires) .

How has this prediction stood up so far? As Daly’s own site shows, the solar cycle has indeed turned down, and the El Nino has passed, (though without a return to La Nina). But, in case you haven’t been reading the news, the weather hasn’t got any cooler.

Professor Q then claims that Daly has been proven wrong but is refusing to admit it. To make good his claim, Professor Q links to this page at the NOAA/National Climatic Data Center graphing global surface temperatures for the month of July 2003. The accompanying commentary observes that “For July 2003, the global average land and ocean surface temperature was 0.53 °C (0.95 °F) above the 1880-2002 average, ranking as the second warmest July in the period of record” and “For January-July 2003, the global average land and ocean surface temperature was 0.54 °C (0.97 °F) above the long term mean, third warmest”. From these graphs and comments Professor Q purports to conclude that “the weather hasn’t got any cooler”. But the NOAA figures don’t support that claim at all, nor do those of the Goddard International Space Center (on which I suspect the NOAA figures are based). GISS statistics in fact show that the global average temperature for the period December 2002-May 2003 was 0.15 °C cooler than the corresponding period the previous year, the temperature for June 2003 was 0.05 °C lower than June 2002 and that for July 2003 was 0.09 °C lower than July last year. Thus the weather has got cooler since last year, albeit only slightly so far. But that’s pretty much what you’d expect (whether or not Daly is correct). The recent El Ni±o only started to taper off around February, so you’d expect that temperatures would so far only have fallen slightly. It’s simply too early to tell at present, and Professor Q does his credibility no good at all by leaping on the July figures (which were significantly affected by a 2 week heatwave across most of Europe during late July and early August) and claiming for them a significance they simply don’t have. The proof of Daly’s pudding will lie in what happens between now and 2006. If the global average temperature falls back to well below the long-term average by 2006 that would suggest Daly may be correct. On the other hand, if it continues to fall but remains above the long-term average, that will clearly demonstrate the imprint of man-made global warming.

About Ken Parish

Ken Parish is a legal academic, with research areas in public law (constitutional and administrative law), civil procedure and teaching & learning theory and practice. He has been a legal academic for almost 20 years. Before that he ran a legal practice in Darwin for 15 years and was a Member of the NT Legislative Assembly for almost 4 years in the early 1990s.
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slatts
slatts
2022 years ago

Seems there’s a whole lot of forces at play and bugger all has been proven. More snow forecast this weekend in the Vic alps. Most unusual. If there is a point, it is this: In 1987, “experts” predicted man-made global warming would have world temperatures up to 5 degrees warmer by 2005 with sea levels rising and disaster all round. Hasn’t happened. So why Kyoto? Redistribution of global resources. Fair enough, would happen anyway. Why bother with the big lie? Only get caught out in the end.

Jim
Jim
2022 years ago

Ken,
“On the other hand, if it continues to fall but remains above the long-term average, that will clearly demonstrate the imprint of man-made global warming.”
If the temperature remains above the long term average,it can obviously be concluded that warming is ocurring or has occurred. Why is it obvious that it is man made?
I don’t know if artificial warming is a real phenomenon or not – there seem to be experts arguing both ways – but following your post,I am interested in your conclusion.

Ken Parish
Ken Parish
2022 years ago

Jim,

I don’t profess to fully understand the stuff about cosmic rays emitted by supernovae discussed in posts a month or so ago. However, leaving that aside, it seems to me that the combination of a solar minimum and La Nina conditions SHOULD result in at least a couple of years of global temperatures below the long-term average. If it doesn’t, it seems to me that would fairly clearly show the imprint of human-induced warming. What other significant (non-human) warming factors that would explain a failure to return to below the long-term mean in those circumstances?

mark
2022 years ago

slatts is right. This is a clear example of the majority of scientists — or, as they are more accurately known, clown-jockeys — getting together for a good nut, and deciding over a cup of Earl Grey that, dash it all, now would be a good time to invent some lie with which to fool the Earth’s population.

Look at those PC Black Armband Thugs! Look at the Gun-Grabbing Soccer Marms! Look at the Global Warming Brigade! In each and every case the clown-jockeys trying to interfere with us decent, right-wing folk have lied hysterically, again and again, and again and again, despite gaining nothing from the exercise^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H to further some dark librool purpose so evil we dare not speak its name, for fear that it shall rise up from the depths and attack with such ferosity that not even Cthulu, our greatest ally, can save us.

Jim
Jim
2022 years ago

Ken,
As I understand it your assunption then is similar at least to the IPCC’s – in the absence of any other explanation it must be man made?

Alene Berk
Alene Berk
2022 years ago

For a knowledgable and unimpassioned consideration of the science, there’s a rather long but worthwhile entry on crumb trail blog. It concludes that we don’t even begin to know the variables. One might conclude that Kyoto is a result of hubris.
http://back40.blogspot.com/2003_09_07_back40_archive.html#106313242242091540

Mark Bahner
2022 years ago

“For a knowledgable and unimpassioned consideration of the science,…”

…there’s always *my* website:

http://pages.prodigy.net/mark.bahner

:-)

P.S. Truth-in-posting comment: I guess my website isn’t “unimpassioned”. I get a tad impassioned about the lack of good science that went into producing the temperature predictions in the Ingovernmental Panel on Climate Change’s (IPCC’s) Third Assessment Report (TAR).

Dave Ricardo
Dave Ricardo
2022 years ago

Ken
Quiggin’s response on his website has skewered your criticism completely, IMO.

I must say, Ken, you took a big risk in taking him on a statistical question. You are a lawyer and he is a mathematical economist. On this occasion, he is playing at home, and you are playing away.

Ken Parish
Ken Parish
2022 years ago

Dave,

With respect, you don’t know what you’re talking about. Read my above post and my comment on JQ’s blog. I explicitly acknowledged that the temperature drops so far were tiny. JQ, on the other hand, seized on anomalous results for July alone in his enthusiasm to claim that Daly had been proven wrong. I suggest any objective observer won’t have too much difficulty working out who’s stretching the facts here.

Dave Ricardo
Dave Ricardo
2022 years ago

Ken

Since ASIO/CIA/Mossad is blocking my access to Quiggin’s blog, I can’t see what you wrote there, so could you reproduce it here?

BTW, “With respect”, is an interesting phrase, since those who use it invariably mean “without respect”.

Ken Parish
Ken Parish
2022 years ago

Dave,

I mean it in its grammatical sense i.e. I DO respect you, but on this occasion you’re talking through your arse. I’ll copy the relevant comments from JQ’s blog and post them here in a few minutes.

Ken Parish
Ken Parish
2022 years ago

Dave,

I posted the following comment to JQ’s response to my post:

John,

My post was hardly a nitpick, nor does it merit your “lesson” on statistics. My post made precisely the point you’ve just repeated about the recent temperature drop being statistically insignificant:

Thus the weather has got cooler since last year, albeit only slightly so far. But that’s pretty much what you’d expect (whether or not Daly is correct). The recent El Ni

John Quiggin
John Quiggin
2022 years ago

I tried to post this earlier, but it doesn’t seem to have worked. Apologies if it is double-posted.

I just wanted to point out that, contrary to Ken’s claims I didn’t ” seized on anomalous results for July alone “. I didn’t even mention July in my post and the data I linked to was for the entire period (Jan-July 2003) since Daly’s prediction. Since July is the most recent month, the link included specific data for that month, but July wasn’t much different from the rest of 2003.

trackback
2022 years ago

A lesson in statistics

Ken Parish supply the expected quibbles for my post on global warming. He illustrates some important statistical fallacies in the process. To support my case that the weather has got no cooler relative to the “the climatic extremes of 1998-2002”,…