JoNova

A science presenter, writer, speaker & former TV host; author of The Skeptic's Handbook (over 200,000 copies distributed & available in 15 languages).


Handbooks

The Skeptics Handbook

Think it has been debunked? See here.

The Skeptics Handbook II

Climate Money Paper


Advertising

micropace


GoldNerds

The nerds have the numbers on precious metals investments on the ASX



Archives

Books

Eucalyptus trees cope fine with extreme heatwaves, defy climate models, survive 50C temps

What happens to a poor tree when you withhold rain for a whole month, then hit it with four days in a row of 43C temperatures? It was so hot, some of the leaves on these trees got close to 49-50 °C.

In at least one gum species in Australia, the answer is “not much”. They suck up lots of water from their deep roots and sweat it out til the heatwave passes. The trees become evaporative coolers “siphoning up” water. They cope so well, that not only did the trees not die, but their trunk and height growth were unaffected. Indeed, only about 1% of the leaf area even exhibited browning.

Whole tree chambers in Richmond, New South Wales, Australia. Twelve 9-m-tall chambers in a field setting (a) enclose the canopies of individual Eucalyptus parramattensis trees rooted in soil (b). Two heatwave chambers can be seen on the left of the infrared image, along with several control chambers (c; temperature in °C).

But with global warming running at a heady 0.13C per decade, you might wonder how many years will it take for the trees to adapt?

From the paper — “one day”:

The gums rapidly [...]

Health Warnings issued for Tasmanians facing six days over 25 degrees (77F +) !

Hobartians face a record heatwave for November

Things are so serious they may find Echidnas in their dog’s water bowl.

Wildlife struggling to find water during the hot weather are likely to seek relief in your backyard. Photo: Emma C

Spend billions. Stop climate change. We simply can’t allow this kind of disaster:

Heatwave health alert issued for southern Tasmania as 130yo record set to fall

The weather bureau’s Tim Bolden said it was shaping up to be the first time Hobart has recorded six consecutive days on or above 25 degrees Celsius in November in nearly 130 years.

“[We'll break the record] if we make it to the six days that we’re currently forecasting over 25 degrees — since last Saturday up until Thursday — and it’s certainly looking very likely,” Mr Bolden said.

“[We are] currently forecasting 28 for Tuesday, 29 for Wednesday and 29 for Thursday, having reached 30 last Saturday, 27 on Sunday and 27 on Monday.

“If we make it to that stretch of six days above 25 degrees, that would be a record heat spell for November, and equal to the maximum heat spell for [...]

Climate numerology! Man-made CO2 caused heatwaves in 1930s,’40s, ’80s and ’90s

How convenient?! A new study shows that human influence on the climate started just before the major (and unerasable) heatwaves of the late 1930s, thus wrapping those awkward years under the banner of Man Made Climate. This study provides the handy peer reviewed link-bomb “answer” to that.

The inexplicable heat of the 1930s and 40s has been a constant source of pain  for Global Worriers. Skeptics can point out that the decadal rate of warming was pretty much the same back then, even though CO2 was at the ideal, clima-perfecto level, of 310ppm. How could it be that massive 400ppm of CO2 was barely able to break the heat records set when CO2 was almost 25% lower?

Well, finally, mystery solved. A new Australian study compares models that don’t-explain-the-climate with CO2, to ones that-don’t-explain-the-climate without CO2. These models assume CO2 causes warming, so when they take out the CO2 factor that was added in to produce “the climate”, the models prove, ipso gloriousi, that CO2 causes warming. Indeed their method is so good, it can’t fail. As Anthony Watts says “it seems clear to me that the conclusion existed before the paper was written.”  Quite.

Say hello to Climate Numerology [...]

BOM method finds more heatwaves in Antarctica than Marble Bar

The danger is in the definition

Ken Stewart has been diligent at trying to understand the Bureau of Meteorology (BOM) method for finding heatwaves. He’d heard BOM head, Rob Vertessy speak on ABC radio, declaring that heatwaves were the “number one cause of death” from natural disaster in Australia. Ken wrote to Vertessy repeatedly  but for some reason, despite the deadly risk to Australians, Vertessy was unable to answer the question of how to define and estimate heatwaves. (Perhaps if the BOM had The Internet, he could have sent Ken Stewart this link, which Stewart has now found himself four months later.)

The Excess Heat Factor: A Metric for Heatwave Intensity and Its Use in Classifying Heatwave Severity, John R. Nairn and Robert J. B. Fawcett (2015) [1]

With these instructions Ken has now replicated the BOM results for the 2014 heatwave in Melbourne. He has also used the same technique on Marble Bar, Western Australia, and Mawson, Antarctica and found that potentially heatwaves are a killer danger to our Antarctic researchers, and if heatwaves kill, they’d be much safer in Marble Bar. For the record, Marble Bar is the place that had 160 days in a row [...]

Fewer heatwaves for 9 million Australians in Sydney, Darwin, Hobart, Melbourne –”thank CO2″!

Let’s play the Heatwaves PR game. If CO2 had an effect we’d see a significant increase in the rate of global warming over the decades since WWII, the models would work, and climate scientists would be able to predict our climate. Since none of that is true, those with a political agenda have to clutch at noisy but marketable extremes instead. Apparently even a half-true, noisy, non-causal link is good enough for post-modern scientists.

Heatwaves are perfect for generating scientific sounding fear, but not so useful for generating actual scientific knowledge. There are an infinity of ways to measure them. They can last 3 days – 160 days, and be cut off at any number from 35  – 40C, or at some percentile outlier. They can be measured one town at a time, or on a regional or state-wide level. The permutations are rich with headline scoring possibilities. And in the end, on a long warming trend that started 300 years ago, it is obvious, inevitable, and predictable that we should score more now. What’s surprising is how often we don’t.

On ABC radio before Easter, Dr Vertessy, Director and CEO of the Bureau of Meteorology, claimed that we are seeing [...]

Heatwaves in Australia: in many ways they are not hotter, longer or more common. Why won’t BOM and ABC say that too?

Heatwaves are a wonderful headline generator. That’s because the term sounds scary, yet the “wave” itself is undefined. A hundred different types of heatwave are theoretically possible, but they all sound the same in a headline. It means an activist team could pick and choose the particular one that scores a “record”. Heatwaves can be 3, 4, 5, 7 or 10 days. They can be measured by town, city, state or national data and they are can be above 35, 37, 40 degrees or… pick a number. A heatwave can be measured as days above some percentile of average. That means a few warm days in a cold town can be defined as a heatwave.

Geoff Sherrington, drawing no dollars from the taxpayer, takes a simple and obvious approach, and looks at 5 capital cities with the BOM raw and adjusted ACORN data. He considered 4, 5, and 6 day heatwaves to see if there was a trend. With 5 cites, 2 data types, 3 lengths of heatwave, Sherrington created 30 graphs. After testing all those different combinations of heatwaves, there were only three graphs out of 30 that showed an increasing trend. Over half of the heatwave graphs showed [...]

Be afraid! Trapped atmospheric waves on the rise. Extreme heatwaves to come.

There are waves piling on waves in the weather.

A new press release tells us that there have been an “exceptional” number of weather extremes in summer.

Weather extremes in the summer — such as the record heat wave in the United States that hit corn farmers and worsened wildfires in 2012 — have reached an exceptional number in the last ten years. Human-made global warming can explain a gradual increase in periods of severe heat, but the observed change in the magnitude and duration of some events is not so easily explained.

Heatwaves lend themselves to headlines. Not only are they scary, but for climate researchers at a loose end, there are 1,000 flavors of wave to comb through. Is that a 3 day, 4 day or 7 day wave you are interested in? Is the cut-off 40C, 38C, 35C or a flexible percentile anomaly above the monthly average? Is it a statewide average, a national record, or a hot week in Houston? Shall we analyze that in seasons, by months, years, or part thereof? The combinations and permutations can keep a supercomputer up late at night. There’s a whole field of cherry trees ripe for the plucking.

It [...]

What the CSIRO State of the Climate report forgot to tell you

The CSIRO decided to leave out some information about the state of our climate in their  State of the Climate Report CSIRO.

CSIRO published these “Fast Facts” in bold. I’m publishing the things they didn’t say, but could have, in points in between.

UPDATE: The CSIRO budget is $1.2 billion a year and the BOM’s is $300 m. Why is it left to unfunded volunteers to provide the full story?

Fast Facts from the CSIRO and BOM “Australia’s climate has warmed by 0.9°C since 1910, and the frequency of extreme weather has changed, with more extreme heat and fewer cool extremes.” The CSIRO-BOM team could have said: Scientifically, extreme weather measures are lousy indicators. They’re noisy and not very meaningful. They are however useful for getting newspaper headlines. It depends on what your aim is… Australia’s had extreme hot days for as long as we’ve been measuring the temperature. Charles Sturt recorded 53C in 1828 which seems fairly extreme. Thomas Mitchell did it too in 1845 and are many others (see the map below, check Trove, ask the BOM — no don’t ask the BOM). The records prior to 1910 seem to have gone down the memory hole, [...]

Get Headlines! How to find a heatwave in five easy steps

Heatwaves have become a publicity tool. Far from there being a clear trend in Australian heatwaves, Geoff Sherrington shows that it’s also legitimate to claim heatwaves were worse 80 – 100 years ago in Adelaide and Melbourne and things are getting better. Those officials who cherrypick their claims might be technically correct, but it’s outrageously deceitful and unscientific at the same time.

Just how hard is it to get a record heatwave? It’s so easy that if it’s summer in Australia, it’s hard not to set a record. That’s because heatwaves come in so many flavors  –  there are seven capital cities which can all have 3 day, 4 day, 5 day or 6 day heatwaves. Then there are the heatwaves over 40C, or over 38 C, or over 35C… already that makes 84 flavours of wave. If a hot spell doesn’t break one type of wave, it could easily break another. Then there is the pre-heatwave, and there would be another 84 types of heatwaves that we haven’t had, but might get, you never know. You might think I’m kidding, but pre-heatwaves get headlines already:

“More Canberra heatwaves forecast”

“A heatwave could return to Canberra next month, [...]

Mystery black-box method used to make *all new* Australian “hottest” ever records

There were not many long term sites (in black dots) in the centre of Australia in 1930.

This summer the Bureau of Meteorology (BOM) invented a whole new metric to measure average national heat, which might be all very well except no-one (other than the BOM) seems to know what it is.

On January 7th the BOM claimed Australia set a new “average maximum daily temperature record”. Now the headlines are about the “hottest” Australian summer.

With both records, no one outside the BOM team has access to the methods or data. This post is about the new “daily” temperature of Australia used to declare Jan 7th was a record, but the same point applies to the “hottest summer” records, even though they may be a different data set. Where is the data? Where are the methods?

Is the BOM a science agency or a PR bureau?

The January 7th heatwave supposedly broke all previous “daily” records in this category — a dubious honor since no-one can remember any records like it.

It’s a bit like winning the Side-Jump. It’s not an event anyone knew was on until the medal ceremony. Worse, no one knows how the [...]