Records show Dunedin floods not caused by climate change

A crowd-sourced rebuttal to the empty-headed Greens

Dunedin flood 2015

April 1923 – Flooding on Anzac Avenue, looking towards Harrow Street (DCC archives). Click to enlarge.

God bless our readers!

These two comments appeared under yesterday’s midnight post Greens blame “climate change” for Dunedin floods and provide all the proof we need that the Green Party is entirely wrong to blame the June 3 Dunedin flooding on climate change. Why? Because they show that the severe flooding two days ago is not new. Unusual, but not unique. A combination of rainfall data and photographs makes these comments as convincing as they were prompt.

First, from Ron

Hmm. A quick search came up with this fascinating site of extreme NZ rainfall data. It does make the obligatory incantation in the introduction (“As global warming brings more extreme and more frequent floods…”) but states:

22 Apr 1923 Dunedin 230mm in 24 hours
19-20 Mar 1929 Ross Creek (Dunedin outskirts) 279mm in 24 hours
[June 3] was 175mm in 24 hours

The Otago Daily Times said it was double the previous record for a full day since records began in 2006. [But 2006 was only the start of recording rainfall in the city centre rather than Musselburgh, 3 km away.]

Second, from Peter Yates

There are photos of the 1923 and 1927 floods here:
April 1923, Anzac Avenue, Central/North Dunedin.

13 May 1923, Leith over-flowing at HarbourTerrace, North Dunedin.

1927, South Dunedin.

In 1927 South Dunedin was mostly farmland. This is what the recent flooding would look like without the roads, buildings, and storm water pumps. I guess being in the 1920’s they were not caused by climate change, or global warming for that matter! 😉

Thanks for your excellent contributions, Ron and Peter. Looks like you were having a late night, too!

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Ian CooperRichard C (NZ)Richard TreadgoldAndy Recent comment authors
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Andy
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Andy

The flooding in Dunedin on Wednesday was not caused by climate change, a University of Otago climatologist says.

”I think this is just a weather event,” Dr Nicolas Cullen, of the department of geography, said.

http://www.odt.co.nz/news/dunedin/344762/dont-blame-climate-change-city-deluge-weather-experts-say

Andy
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Andy

O/T but from the “weather is not climate dept”, in Norway
http://www.newsinenglish.no/2015/06/02/january-in-june-strands-drivers/

( I was in this area late April and it was very snowy then. I thought it would be gone now)

Richard C (NZ)
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Richard C (NZ)

After reading Muller et al (2013) in regard to surface solar radiation over time e.g. 10, 20, and 30 yrs (see link previous post thread), I went looking for the NZ equivalent. Didn’t find any at NIWA, any such information is on a commercial basis (user pays). Anyway, came across this: genesis ENERGY schoolgen GRAPHING REAL WORLD SOLAR ENERGY DATA WITH EXCEL Facilitator/Student Resource This resource guides students to download, process and present real-world numerical data from the Schoolgen online database of solar energy generation. Students will learn important cross-disciplinary skills in Microsoft Excel 2010 as well as emphasising the links between science and maths, and the usefulness of maths as a tool in science. Page 4, – STUDENT INSTRUCTIONS – HOW TO DOWNLOAD DATA FROM THE SCHOOLGEN WEBSITE 1.Go to the schoolgen website: http://www.schoolgen.co.nz 2.Click on the NZ map to select your region/school: 3.What is the Output Power of your schools PV panels right now? http://www.schoolgen.co.nz/pdf/SE_L3-4_FS_Graphing.solar.data.pdf Searching the website returns Participating Schools http://www.schoolgen.co.nz/Default.aspx?SiteSearchID=1944&ID=/community/school-search For example, one I attended a long, long, time ago: Maeroa Intermediate School – Hamilton City 2 kw http://www.schoolgen.co.nz/schoolgen-schools/maeroa-intermediate-school-hamilton-city#! Last 12 Months graph (that’s all unfortunately, no annual time… Read more »

Richard C (NZ)
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Richard C (NZ)

I suppose rather than be bothered with NIWA’s MJ/m2 units I can be content with the Hamilton NZ Weather data in W/m².

Currently (at 4:30 PM) Solar Radiation: 30W/m²

http://www.hamiltonweather.co.nz/

Richard C (NZ)
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Richard C (NZ)

Solar “Station Records” at Hamilton NZ Weather above (SSR).

June to date: 650 wm2, 12:20 03 Jun 2015

Year to date: 1429 wm2, 12:35 02 Feb 2015

All time: 1750 wm2, 12:52 21 April 2007

The 2007 record was 321 W.m2 higher than 2015 (conversely 2015 was 321 W.m2 less than 2007). This is a big number (think miniscule CO2 change), a time series would be instructive. The station was moved from Hamilton East to Horsham Downs on the Northeastern outskirts’ of Hamilton in mid-November 2008.

Still, might be worth contacting these guys, Willoughby and Jaime, in the hope of getting a SSR time series of some sort for Hamilton: About/Contact http://www.hamiltonweather.co.nz/

Richard C (NZ)
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Richard C (NZ)

NIWA has been very quiet about this: ‘Global dimming and brightening in New Zealand’ Ben Liley, 2014 https://www.niwa.co.nz/sites/niwa.co.nz/files/Liley_UV%20Workshop_2014_Global_DB_0.pdf See references, Liley (2009) is cited by the IPCC. Table 1, page 2. Auckland Airport (W.m2 per decade) -11.8, 1970 – 1990 +3.7, 1990 – 2013 Table 2, page 2. New Zealand (W.m2 per decade) -2.4, 1950 – 1990 (4 decade total -9.6) +4.85, 1991 – 2013 (2.2 decade total +10.67) In only 2.2 decades 1991 – 2013, SSR increased +10.67 W.m2. This is radiative energy that does work (a surface heating agent). For comparison, OLR – DLR (net longwave, Rnl) is a cooling effect at the surface (does no heating work). Nevertheless, Berkeley Lab found DLR and CO2 radiative change 2000 – 2010 for 2 sites in Alaska and Oklahoma: “Both series showed the same trend: atmospheric CO2 emitted an increasing amount of infrared energy, to the tune of 0.2 Watts per square meter per decade. This increase is about ten percent of the trend from all sources of infrared energy such as clouds and water vapor.” http://newscenter.lbl.gov/2015/02/25/co2-greenhouse-effect-increase/ Whoop-de-doo. CO2 change +0.4 W.m2 for 2 decades (NZ SSR change +9.7, 24.25 times greater) But… Read more »

Richard C (NZ)
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Richard C (NZ)

>”OLR – DLR (net longwave, Rnl) is a cooling effect at the surface (does no heating work).”

Repeating from previous post thread:

Surface solar radiation (SSR) – heating effect.

Net longwave radiation (OLR – DLR = Rnl) – cooling effect

Global Energy Flows:
http://www.aps.org/units/fps/newsletters/200904/images/trenberth-fig1.gif

396 – 333 = 63 W.m-2 cooling of the earth’s surface (DLR includes CO2 component about 6 W.m-2).

On a clear cool night enough cooling to freeze water:

‘Nocturnal ice making’

In India before the invention of artificial refrigeration technology, ice making by nocturnal cooling was common. The apparatus consisted of a shallow ceramic tray with a thin layer of water, placed outdoors with a clear exposure to the night sky. The bottom and sides were insulated with a thick layer of hay. On a clear night the water would lose heat by radiation upwards. Provided the air was calm and not too far above freezing, heat gain from the surrounding air by convection would be low enough to allow the water to freeze by dawn.[1]

From Radiative cooling http://en.wikipedia.org/wiki/Radiative_cooling

Ian Cooper
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Ian Cooper

Thanks to Ron for that excellent web site about extreme rainfall events in New Zealand’s past. When you have lived through a few of them this info is very relevant. The background research into the Multi-river floods that hit the lower North Island mid February 2004 is very interesting.

Richard C (NZ)
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Richard C (NZ)

New term (to me anyway): “Dramagreens”

Credit, Bitter&Twisted in this comment thread:

http://www.bishop-hill.net/blog/2015/6/4/carbon-brief-on-the-sahel.html

Richard C (NZ)
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Richard C (NZ)

NZ should expect more droughts – climate change issues minister

Groser – “…The science is very clear on this. The prevalence of these droughts will increase,”

http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11465003

“Very clear” on what basis for knowing the future (crystal ball?), and Is that before or after the floods?

Or are these droughtfloods?

Richard C (NZ)
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Richard C (NZ)

‘Extreme weather linked to climate change’ [Re Northland and Dunedin floods] Dr Dean said New Zealand was exposed to conveyor belts, or atmospheric rivers, which brought moist air from the tropics. “Most of our extreme rainfall events are caused by subtropical air coming out of the tropics, very wet, and as climate change warms the tropics it causes more moisture to be held in that air. So as it comes down to New Zealand those air flows do carry more moisture. They can also actually potentially speed up, so it’s both the rate at which that moisture comes down as well as the [increased] moisture content that’s in the air.” http://www.radionz.co.nz/national/programmes/ourchangingworld/audio/201757686/extreme-weather-and-climate-change OK, so what then is Groser on about with “The prevalence of these droughts will increase”? What is it: more rainfall (floods), or less rainfall (droughts)? An internally consistent and plausible message please. Except Dr Dean is telling porkies (either that or he doesn’t know what he’s talking about): ‘Precipitable Water in the Tropics’ Precipitable Water (PW) data is available from the NOAA Earth System Research Laboratory from 1949 to 2014. The data is world-wide at 2.5 degree increments of latitude and… Read more »

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