Posts Tagged ENSO

Still warming after all these years (again) Gareth Renowden Jan 10

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Spread this excellent new video from the talented team at Skeptical Science far and wide. It explains why the latest denialist trope — no warming for 16 years — is rubbish. Take out the impact of the three biggest factors driving natural variations in the global average temperature — volcanoes, the El Niño Southern Oscillation and the solar cycle — and what’s left is the underlying upwards trend being driven by our CO2 emissions. The world’s warming, Australia’s burning, ice is melting and we did it. No room left for wishful thinking or complacency.

2011: a hot cold year Gareth Renowden Jan 22

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The NASA numbers are in, and 2011 was the ninth warmest year since 1880 — 0.51ºC above the 1951-80 global mean. Nine of the ten warmest years in the long term record have occurred in this century. According to the analysis released by James Hansen and his team at GISS, a combination of low solar activity and the continuing cool phase (La Niña) of the El Niño Southern Oscillation kept global temperatures down — but as this map from the Earth Observatory shows, many parts of the world still managed to experience a very warm year, especially over the Arctic and Russia:


NOAA’s overview of last year puts 2011 in eleventh place in their long term series, and confirms that the USA experienced a record 14 extreme weather events that caused more than $1 billion in damage — up two from their previous estimate.

At the end of last year I considered the prospects for a new global temperature record in 2012, but the GISS team’s analysis provides a much more detailed look at the factors influencing global temperature. The NASA news release quotes James Hansen:

Hansen said he expects record-breaking global average temperature in the next two to three years because solar activity is on the upswing and the next El Niño will increase tropical Pacific temperatures. The warmest years on record were 2005 and 2010, in a virtual tie.

“It’s always dangerous to make predictions about El Niño, but it’s safe to say we’ll see one in the next three years,” Hansen said. “It won’t take a very strong El Niño to push temperatures above 2010.”

Thermal lags in the system – the delayed effects of a switch from La Niña to El Niño (discussed in the analysis), and the similar but slightly longer delay in the solar radiation upturn — means that 2012 is unlikely to be a record-breaker. Meanwhile, ENSO watchers expect the current La Niña to continue into the northern hemisphere spring, and then fade towards neutral conditions (NOAA ENSO advisories here).

McLean’s folly 2: the reckoning Gareth Renowden Jan 12

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Ten months ago, Aussie “sceptic” John McLean predicted that 2011 would be “the coolest year since 1956″. I pointed out at the time that this was nonsense, and so it has proven to be. I’ve taken the GISS global temperature figure for Jan – Nov 2011 (+0.51ºC compared to the 1951-80 average) and added it to the graph I created to illustrate the full extent of McLean’s folly:


Last year was warmer than 1956 by a whopping 0.68ºC — about three standard deviations, in statistical terms — making McLean’s forecast an abysmal failure. Yes, 2011 was cooler than 2010 or 2009, but still one of the top ten warm years.

ENSO does have an effect on global temperature — that’s been understood since the 1970s, if not earlier. La Niña years tend to be cooler than the years around them, as this WMO graph illustrates.


It’s clear that even cool La Niña years have been warming, with 2011 being the warmest such year in the instrumental record.

The reason McLean’s forecast failed is quite simple. He failed to take into account the warming trend that’s incredibly obvious when you look at the GISS and WMO data. Why would he do that? Well, he was lead author on a paper that “established” a link between ENSO and global temperature, but did that by filtering the global mean temp to remove any long term trend and to emphasise the ENSO time scale. Voila! The Southern Oscillation Index (SOI) suddenly accounted for most of the variability in the (filtered and detrended) global mean temperature. As pointed out in the rebuttal to McLean et al, just about any time series would be “explained” by the SOI after passing through their filter.

In order to make his unphysical forecast, McLean must have forgotten what he had done in the paper he was so keen to promote. I could perhaps be forgiven for suspecting that he didn’t know what he was doing in the first place — but then that just makes his co-authors, Chris de Freitas and Bob Carter look equally daft. They certainly didn’t rush to correct McLean’s folly. As ever, in the land of the Climate Cluelessâ„¢, anything goes.

See also: McLean, de Freitas and Carter win the Friends of Gin and Tonic’s inaugural Climate Idiots of the Year award. Richly deserved.

[A glimpse of stocking.]

Shapes of things (2012 and all that) Gareth Renowden Dec 29

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‘Tis the silly season, time for journalists with little real news to report to reflect on the year past and make predictions for the year to come. I don’t normally play that game because there are too many interesting things to write about on the climate beat, but this year I’m going to make an exception. Glenn “Climate Show” Williams persuaded me to have a chat with him on his summer Radio Live show — and yes, we did cover the last year, and the prospects for 2012. The audio’s available to stream for the next week from the Radio Live site (select Dec 28th, then the 1-15pm segment — my bit starts after about 5 minutes). You may regard this post as an expanded version of my comments there (and a bit of recap on the last Climate Show of the year).

So: 2011 was the year of extremes, beyond any shadow of doubt. Wherever you looked around the world, there were record-breaking floods, heatwaves and hugely damaging extreme weather events. The USA alone had 14 separate extreme weather events with billion dollar plus damage bills (NOAA puts it at 12 with 2 more to finalise, the World Meteorological Organisation plumps for 14). The year broke no records for global average temperature — 2011 will probably end up as the 10th or 11th warmest year in the long term record — but it will be the warmest ever La Niña year. Here’s a WMO graph to illustrate the point:


The prospects for 2012 depend in large part on what happens to the El Niño Southern Oscillation this year. Will the current La Niña hang around for another year, decay to neutral conditions, or swing round to an El Niño? The odds, according to NOAA’s Klaus Wolters (on Dec 7th) are interesting:

Based on current atmosphere-ocean conditions, I believe the odds for this La Niña event to continue right through early spring (March-April 2012) are higher than 50%. Beyond that, it is worth noting that of the ten two-year La Niña events between 1900 and 2009, four ended up as a three-year event, so I would put the odds for this to occur in 2012-13 at 40% right now. Interestingly, the other six all switched to El Niño, leaving no ENSO-neutral case. Will be interesting to see how 2012 evolves.

It will indeed. A return to El Niño conditions in the first half of 2012 would boost global average temperatures, and that, coupled with the currently active phase of the 11 year solar cycle, might be enough to push 2012 above 2010 and 2005 for a new record. But more importantly, a return to El Niño would also change the patterns of weather around the world, and with them change the places that experience record extremes. Exactly how this will play out is impossible to predict, because the timing of a move out of La Niña conditions is difficult to forecast, and because the nature of El Niño’s impacts on weather patterns around there planet depend on the season (see Wikipedia, NOAA and NIWA for more).

So what do am I looking out for in 2012?

  • More extreme weather events, with a pattern shift if ENSO changes phase.
  • Possible new global temperature record, if El Niño arrives early enough in the year.
  • Continued Arctic sea ice melt (in both volume and area), with a possibility1 of a new record minimum in September.
  • Lots of fine words at the Rio +20 conference in June, but little concrete action. Ditto for COP 18 in Qatar in December.
  • At least one nasty surprise emerging from current research. I hope it isn’t East Siberian seabed methane, but we’ll know more when the papers describing the 2011 Arctic research season are published.

And a very happy new year for all Hot Topic readers…

[Update 31/12: Jeff Masters' end of year review counts "32 weather disasters costing at least $1 billion worldwide. Five nations experienced their most expensive weather-related natural disasters on record during 2011--Thailand, Australia, Colombia, Sri Lanka, and Cambodia." The year of extremes, indeed...]

  1. No I’m not betting, but greater than 50% chance, I’d say, because at some point volume reductions have to show up in extent/area numbers.

Wake of the flood (first reprise) Gareth Renowden Oct 26

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Thailand is experiencing its worst monsoon flooding for at least 50 years. The NASA Earth Observatory image above shows the waters piling up to the North of the capital Bangkok, which is already beginning to experience flooding (visit the EO page to see a comparison with earlier floods, and The Guardian for a striking set of flood pictures). The Thai government yesterday declared a five day weekend to allow the city’s inhabitants to make preparations. The intense monsoon season has also brought extensive flooding to Cambodia and northeastern India over the last couple of months, and destroyed a significant part of SE Asia’s rice crop. On the other side of the planet, heavy rain and flooding has been affecting Mexico, El Salvador, Costa Rica, Honduras, Guatemala, and Nicaragua. Jeff Masters reported that in the ten days up to October 20th, Huizucar in El Salvador received an astonishing 1.513 metres of rain.

At first glance, it looks like a continuation of the remarkable series of extreme weather events — especially heavy rainfall and flooding — that we’ve seen over the last few years. But apart from the human suffering and economic dislocation being experienced around the world, it appears there’s another interesting consequence of all this precipitation — it’s causing global sea level to fall.

I stumbled across this idea in a NASA news item released back in August, and referred to it in the last edition of The Climate Show, but I think it’s worth developing the idea a little further. Here’s what NASA had to say:

[Josh] Willis said that while 2010 began with a sizable El Niño, by year’s end, it was replaced by one of the strongest La Niñas in recent memory. This sudden shift in the Pacific changed rainfall patterns all across the globe, bringing massive floods to places like Australia and the Amazon basin, and drought to the southern United States.

Data from the NASA/German Aerospace Center’s twin Gravity Recovery and Climate Experiment (Grace) spacecraft provide a clear picture of how this extra rain piled onto the continents in the early parts of 2011. “By detecting where water is on the continents, Grace shows us how water moves around the planet,” says Steve Nerem, a sea level scientist at the University of Colorado in Boulder.

So where does all that extra water in Brazil and Australia come from? You guessed it–the ocean. Each year, huge amounts of water are evaporated from the ocean. While most of it falls right back into the ocean as rain, some of it falls over land. “This year, the continents got an extra dose of rain, so much so that global sea levels actually fell over most of the last year,” says Carmen Boening, a JPL oceanographer and climate scientist. Boening and colleagues presented these results recently at the annual Grace Science Team Meeting in Austin, Texas.

The story included a couple of graphs to illustrate the point. Here’s the drop in sea level, as recorded by satellite:


And here’s where the GRACE satellites showed it ended up.


When I first read the NASA article, I was amazed. Perhaps I shouldn’t have been. After all, lots of things can cause sea level to rise and fall — thermal expansion, ice melt (or freeze), and so on. During ice ages lots of ocean ends up on land in the form of the great ice sheets that are built by accumulating snowfall. But this is, to coin a phrase, a really neat demonstration of an interesting effect — one that we can only begin to appreciate because of the application of truly remarkable technology.

So what’s happening now? Here’s the latest sea level chart from the University of Colorado (data to Sept 19th):


There’s been a slight upwards tick over the last few months, but no dramatic surge back towards to the trend line. That suggests to me that the processes that caused the drop in the first place are still operating. The population of Thailand might agree…

Eventually, as Josh Willis says at the conclusion of the NASA article, the floodwaters will run off the land and return to the ocean, La Niña will swing back to El Niño, and sea level rise will resume its upwards trajectory. With La Niña likely to stay in place through the southern summer, it will be some time before El Niño returns and imposes its own pattern on the world’s weather. But when it does we could be in for a wild ride as sea level surges and global temperatures reach new peaks. We live in interesting times.

[Update 27/10] Flash flooding has ripped through Liguria and Tuscany in Italy. Both the Guardian and BBC videos open with water roaring down the streets of (I think) Monterosso — a place I visited in September. Dublin has also experienced torrential rain and flash flooding in the last few days: video here. Intensification of the hydrological cycle anyone?

[Grateful Dead]

The Climate Show #20: the boys are back (on Tuvalu) Gareth Renowden Oct 20

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Battling against rural broadband that resembled digital molasses (or the bunker oil being pumped out of the Rena), Gareth returns to NZ and joins Glenn Williams and John Cook to discuss drought in Tuvalu, the El Niño Southern Oscillation (ENSO), floods and sea level falls, ocean cooling (that isn’t), solar towers of power and much, much more…

Watch The Climate Show on our Youtube channel, subscribe to the podcast via iTunes, listen to us via Stitcher on your smartphone or listen direct/download from the link below the fold…

Follow The Climate Show at The Climate Show web site, and on Facebook and Twitter.

The Climate Show

News & commentary: [0:05:54]

Tuvalu, La Nina/ENSO and water

Tuvalu drought could be dry run for dealing with climate change ’I believe the odds for a La Niña winter have indeed risen to near 100%, with the ‘fall window’ of disrupting this evolution closing rapidly. However, it does not appear likely that we will see as strong an event as in 2010-11.’

The research team, which was led by Samantha Stevenson (University of Colorado Boulder) and includes NCAR scientists Markus Jochum, Richard Neale, Clara Deser, and Gerald Meehl, used the NCAR-based Community Climate System Model (CCSM) to simulate the effects of climate change on ENSO over the 21st century. They found no significant changes in its extent or frequency.

However, the warmer and moister atmosphere of the future could make ENSO events more extreme. For example, the model predicts the blocking high pressure south of Alaska that often occurs during La Niña winters to strengthen under future atmospheric conditions, meaning that intrusions of Arctic air into North America typical of La Niña winters could be stronger in the future.

And while we’re talking about ENSO…

The strong La Nina caused intense rainfall in Australia and Brazil – enough to cause a downward blip in sea level rise… confirmed by GRACE satellite measurements.

Meanwhile, on sea level:

’For the two more realistic scenarios, calculated based on the emissions and pollution stabilizing, the results show that there will be a sea level rise of about 75 cm by the year 2100 and that by the year 2500 the sea will have risen by 2 meters.’

Worst case: ’sea levels will rise 1.1 meters by the year 2100 and will have risen 5.5 meters by the year 2500.’

Starbucks concerned world coffee supply is threatened by climate change.

New climate science roundup

NIWA’s new Climate Change Atlas:

Debunking the skeptic, John Cook from [0:35:50]

Ocean Cooling? (No it’s not).

Model-based evidence of deep-ocean heat uptake during surface-temperature hiatus periods (Meehl et al 2011)

Solutions [00:45:45]

Solar Decathlon results:

NZ team finished third:,

The Kiwi bach of tomorrow:

Sky-scraping Tower Will Power 100,000 Homes with Hot Air

A 2,600-foot tower planned for the Arizona desert will be the world’s second tallest structure and will be able to power 100,000 homes through hot air alone.

NASA issues award in green aviation competition

On Monday, the space agency issued the award to team of State College, Pa., as part of the Comparative Aircraft Flight Efficiency, or CAFE, Green Flight Challenge.

The competition, sponsored by Google, was created to inspire the development of more fuel-efficient aircraft and spark the start of a new electric airplane industry, NASA said. The winning aircraft had to fly 200 miles in less than two hours and use less than one gallon of fuel per occupant, or the equivalent in electricity.

Electric car infrastructure begins to roll out across the UK

Thanks to our media partners: Idealog Sustain, SciblogsScoop and KiwiFM.

Theme music: A Drop In The Ocean by The Bads.

Catch a fire (worst year since 1816) Gareth Renowden Jun 26

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The extraordinary sequence of extreme weather events during the last 18 months is probably the worst run of natural disasters since 1816, when a huge volcanic eruption at Mt Tambora cooled the earth enough to cause the famous “year without a summer“, according to a powerful blog post by Weather Underground founder Jeff Masters. He runs through the list, giving details of each:

  • Earth’s hottest year on record
  • Most extreme winter Arctic atmospheric circulation on record
  • Arctic sea ice: lowest volume on record, 3rd lowest extent
  • Record melting in Greenland, and a massive calving event
  • Second most extreme shift from El Niño to La Niña
  • Second worst coral bleaching year
  • Wettest year over land
  • Amazon rainforest experiences its 2nd 100-year drought in 5 years
  • Global tropical cyclone activity lowest on record
  • A hyperactive Atlantic hurricane season: 3rd busiest on record
  • A rare tropical storm in the South Atlantic
  • Strongest storm in Southwestern U.S. history
  • Strongest non-coastal storm in U.S. history
  • Weakest and latest-ending East Asian monsoon on record
  • No monsoon depressions in India’s Southwest Monsoon for 2nd time in 134 years
  • The Pakistani flood: most expensive natural disaster in Pakistan’s history
  • The Russian heat wave and drought: deadliest heat wave in human history
  • Record rains trigger Australia’s most expensive natural disaster in history
  • Heaviest rains on record trigger Colombia’s worst flooding disaster in history
  • Tennessee’s 1-in-1000 year flood kills 30, does $2.4 billion in damage

Masters argument is straightforward:

…it is highly improbable that the remarkable extreme weather events of 2010 and 2011 could have all happened in such a short period of time without some powerful climate-altering force at work. The best science we have right now maintains that human-caused emissions of heat-trapping gases like CO2 are the most likely cause of such a climate-altering force.

There’s more heat accumulating in the system, and more water vapour in the atmosphere to drive weather events.

A naturally extreme year, when embedded in such a changed atmosphere, is capable of causing dramatic, unprecedented extremes like we observed during 2010 and 2011. That’s the best theory I have to explain the extreme weather events of 2010 and 2011–natural extremes of El Niño, La Niña and other natural weather patterns combined with significant shifts in atmospheric circulation and the extra heat and atmospheric moisture due to human-caused climate change to create an extraordinary period of extreme weather.

However Masters doesn’t think that this sort of weather is the new normal — at least not yet — but it does suggest where we may be heading in 20-30 years time:

…the ever-increasing amounts of heat-trapping gases humans are emitting into the air puts tremendous pressure on the climate system to shift to a new, radically different, warmer state, and the extreme weather of 2010 – 2011 suggests that the transition is already well underway.

You don’t have to be an alarmist to find that alarming.

[Update: 30/6: The Guardian turns Masters' list into a slideshow of compelling images.]

[Bob Marley]

Predicting the bleeding obvious (and getting it wrong) Gareth Renowden May 31

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A couple of days ago one of the leading figures in the New Zealand climate crank pantheon, the Climate “Science” Coalition’s very own Bryan Leyland, popped in to Hot Topic and left a comment drawing attention to his new favourite game — “predicting” global temperatures by projecting the southern oscillation index forward seven months. He bases this on the “work” of John McLean, last mentioned here a couple of months ago when I looked at his prediction (happily promoted by the NZ C”S”C) that 2011 will be the ’coolest year globally since 1956 or even earlier’. Suffice to say, it won’t be.

Leyland first notes the infamous McLean, De Freitas and Carter paper of 2009, then his own “prediction” that this year’s La Niña would bring a cooling in global temperatures, and then says:

What is remarkable about this is that a retired engineer with access to the Internet has been able to make accurate predictions of future climate. Yet, to my knowledge, no computer-based climate model nor any mainstream ’climate scientist’ predicted this cooling. To me, this is truly remarkable.

What’s really remarkable is that Leyland is actually only showing his ignorance of some pretty basic climate relationships.

As I commented when McLean et al was published (back in 2009), we’ve understood that the state of the El Niño Southern Oscillation (ENSO) has an impact on global temperatures for a very long time indeed. The Climatic Research Unit’s Phil Jones showed this in a paper in 19891, and the Swedish meteorologist Hildebrandsson may have written about the idea in the 1890s2. Even more obvious perhaps, for a retired engineer with an internet connection, you can trawl back through the Goddard Institute for Space Studies GISTEMP web site, and find comments about ENSO’s effect on global temperatures. This is what they said a decade ago:

The global warmth in 2001 is particularly meaningful, because it occurs at a phase of the Southern Oscillation in which the tropical Pacific Ocean is cool. The record warmth of 1998, in contrast, was bolstered by a strong El Niño that raised global temperature 0.2°C above the trend line.

Not only that, but GISS has been producing and updating this figure (source) since it was first published in 1999:

GISTEMPFig E201104

The influence of ENSO on global temperatures amounts to common knowledge amongst those who study climate. When a La Niña follows an El Niño, you get a cooling. That’s not news. And when the current La Niña ends 3 temperatures will pick up again, and we’ll be heading back into record territory. That’s because the underlying planetary energy imbalance isn’t going away, and the main driver of that imbalance — the amount of CO2 in the atmosphere — is increasing every year. Take a look at another GISTEMP graph (source):

DTs 60+132mons201104

This shows the global average temperature smoothed over 60 months (to minimise ENSO impact) and over 132 months (to reduce the effect of the 11 year solar cycle). There’s only one way that line is heading (barring a volcano or two) and that’s up.

Leyland finishes his soothsaying with a chilling warning:

Records from all over the world show that a long sunspot cycle is followed by cooling in the next cycle and a short sunspot cycle indicates warming. The last sunspot cycle was 12.5 years and the previous one was 9.5 years. The evidence tells us that a 3 year increase in cycle length will result in cooling of at least 1°C. As the total amount of warming that has occurred since the early 1900s is 0.7°C, this is potentially very serious. We could be returning to the conditions in the little ice age.

The only reference Leyland gave me for this assertion was a pdf of one his talks, which contains a few unreferenced slides (it’s turtles all the way down). However, the solar cycle length effect is one of the oldest and most effectively debunked theories offered by sceptics, as this page at Skeptical Science points out. On that flimsy basis, Leyland goes one better than his pal McLean, who you will recall predicted that this year could be as cool as 1956 (not looking good, that one) and warns that over the next decade we might see a return to global temperatures last seen a century ago4. Let’s see what that might look like:


McLean’s 1956 prediction was stupidly implausible. Leyland at least ensures that his year to year fall (at about -0.1ºC per year) is within the range of physical possibility, but requires every year for a decade to be cooler than the last if he’s to reach his goal — wiping out 150 years of global warming. Unfortunately, that’s just as implausible because it completely ignores the growing energy imbalance I noted above. That’s not going to change any time soon.

So, in the real world, where might temperatures be heading? Arthur Smith at Not Spaghetti took a look at this a couple of months ago, using statistical models (based on a post by tamino at Open Mind) that account for all the major climate drivers. His “model 1″, with ENSO set to neutral, is plotted in red above. As you can see, after a pause this year caused by the current La Niña, we get back into record territory in 2012. With the current solar cycle ramping up (which increases the amount of energy reaching the earth from the sun), and La Niña ending, temperatures move on up. Barring volcanoes, this where I expect global temperatures to go in the near term.

The lesson here is pretty simple. Leyland is pleased to trumpet his ability to make a trivial prediction because he appears to lack the sort of straightforward understanding of the climate system that would be available to anyone willing to read an introductory textbook. That lack of understanding leaves him prey to any old tosh — which is abundantly available around the crank web. When you rely on the Climate Cluelessâ„¢ for your science education, you end up looking foolish.

PS: Leyland also reminded me that I had offered to bet against his proposition that world would soon enter a cooling phase. If Leyland is willing to stick with his prediction as graphed above, then I will happily bet $1,000 that the world will not cool by 1ºC over the next 10 years. We might also be able to frame a shorter term bet. Over to you, Bryan.

  1. Jones, P.D. (1989). The influence of ENSO on global temperatures. Climate Monitor 17: 80-89
  2. Salinger, J. pers comm
  3. This year or next, take your pick — Klaus Wolter (MEI) gives a 50% chance of the current event extending into 2012.
  4. I assume that’s what he means — one degC cooling over the next solar cycle.

McLean’s folly and the climate clueless Gareth Renowden Mar 13

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In an astonishing press release issued last week, the New Zealand Climate “Science” Coalition predicts that 2011 will be the “coolest year globally since 1956 or even earlier”. The C”S”C bases its prediction on the work of Australian “computer consultant and occasional travel photographer” John McLean. Hot Topic readers will remember McLean as the lead author of a rapidly rebutted 2009 paper (written with Chris de Freitas and Bob Carter) which claimed that El Niño/Southern Oscillation (ENSO) events were a driver of global temperature increases. I covered the full story at the time: see Mother Nature’s Sons and subsequent posts.

One unoriginal finding of the McLean paper was that global temperatures were affected by ENSO events — warming after El Niños and cooling after La Niñas. Last year NZ C”S”C member Bryan Leyland used this to “predict” a coming cooling, which was lapped up by the usual suspects. In January this year, Leyland predicted cooling would continue until at least June. Now McLean has taken this a step further by predicting that temperatures will plunge to that of a cool year 50 years ago. There’s no justification for this prediction in the press release, beyond McLean pretending that his 2009 paper showed that CO2 was a minor player in global temperature change.

Unfortunately for the credibility of all involved, McLean’s prediction is utter unphysical nonsense. Here’s why…

I wanted to find out how McLean’s prediction looked in the context of the long term temperature record, so I downloaded the NASA GISS series data (available here), and plotted it on a graph:


I’ve shown the 1956 temperature (-0.17ºC referenced to the 1951-80 average) as a blue line. The red cross on the end is where the 2011 temperature would plot if McLean’s prediction were to come true. I also looked through the data series for the biggest single year cooling event. That was a fall of 0.29ºC from 1963 to 1964, helped along by the explosive eruption of Mt Agung in Bali. The higher red cross labelled “1963 cooling” is where 2011 would plot with the same temperature fall. By way of contrast, the largest recent cooling not benefitting from volcanic help was 1998 – 1999, and “only” 0.24ºC.

McLean wants us to believe that global temperatures will fall by 0.8ºC in a single year. There is no precedent for such a large drop in the last 130 years — the variation between years is much smaller, not often exceeding 0.2ºC. The reason for that is easy enough to understand: there’s a lot of thermal “inertia” in the climate system, provided by the oceans that cover 70% of the planet’s surface. The only way global temperatures could fall by 0.8ºC in a single year would be for the amount of solar energy reaching the earth’s surface to be hugely reduced — and the only natural mechanism that could do that would be a volcanic eruption (or series of eruptions) of truly vast size. It won’t happen because of a single La Niña event, however strong and long one might be.

Here’s my prediction. Barring the volcanic equivalent of a nuclear winter, 2011 will probably turn out to be slightly cooler overall than 2010, because of the current La Niña (which may or may not fade away later this year). Given a really steep fall like the one from 1963 to 64, we might have the coolest year since… 2000. That’s what 50 years of heat accumulating the system means. And the underlying warming trend will continue.

You might think that the “scientists” and “experts” at the NZ Climate “Science” Coalition would have noticed that McLean’s temperature forecast is rubbish. After all, they have noted scientists like Bob Carter and Chris de Freitas as members and advisers. Unfortunately Chris and Bob appear to have a bit of a blind spot when it comes to criticising their erstwhile co-author. Meanwhile, the Climate “Science” Coalition, and everyone involved in promoting this sorry little weather forecast are shown, yet again, to be the Climate Cluelessâ„¢.

[PS: I haven't got round to formulating a bet with Bryan Leyland on "warming" v "cooling" (yet), but if he's willing to bet that McLean's right, I'll very happily take the other side.]

[Robert Palmer]

Lessons from a drowning continent: no time like the present to invest in our future Gareth Renowden Feb 15

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Jim Salinger’s spending the summer at the University of Tasmania in Hobart. This reflection on the lessons of Australia’s recent floods first ran in the Waikato Times at the beginning of the month, but I felt it deserved a wider audience and so with Jim’s permission reproduce it here.

As I watch from my summer roaring forties perch in Hobart, Tasmania the somewhat unprecedented rains that are deluging parts of Australia raise some pertinent lessons on climate and risk management for New Zealand. Firstly let’s look at some figures and ask the question of what are the climate mechanisms behind the deluges.

For December 2010 the Bureau of Meteorology figures show that eastern Australia (the states of Queensland, New South Wales, Victoria and Tasmania) had its wettest December on record, with an average area total of 167 mm (132% above normal). What caused Brisbane to flood were the heavy falls to the north and west between 10-12 January with totals for the three days exceeding 200 mm. In Toowoomba over 100 mm fell in less than an hour.

Further south in Victoria heavy rainfall and flash flooding occurred between 10 to 15 January, with more than 100 mm of rain across two thirds of the state. Bureau of Meteorology figures show many weather stations in Victoria have now broken their all-time January records in over 100 years of observationd: 259 mm fell on Dunolly (the previous record was 123 mm), and the 282 mm of rain that fell in 1 day at Faimouth in the north east of Tasmania – the highest 1-day total for any gauge on record for the state.

The extremely wet December had eastern Australia primed for the record floods that were to follow in January. The soil could not take any more moisture and the heavy rains turned into runoff, with record floods in some parts.

The causes of these floods have been laid at the feet of the La Niña climate pattern — the sister of El Niño. La Niña brings strengthened moisture-laden easterly winds on to the Australian continent. This year the La Niña event is strong, with it being amongst the top three in magnitude, ranking with the 1918/19 and 1973/74 events. However there is one distinct difference this season: temperatures in Australia this past decade have been 0.5 deg C warmer than in the 1970s, and 0.9 deg C warmer than in the 1910s, all as a result of global warming. And during the 2010/11 season, La Niña seas off eastern Australia have been much warmer than average, being 1 to 2 deg C above the 1985-1998 average.

It is a simple law of physics that a warmer atmosphere holds more moisture. With the long term heating of the oceans more moisture has been measured in the atmosphere during the last decade. The consequence is that global warming leads to an increase in the magnitude and incidence of heavy rainfall, and the resultant floods.

Global warming has arrived, and the climate has warmed. Global warming is no longer a theory…

The first lesson from the Australian flooding events is that global warming has arrived, and the climate has warmed. Global warming is no longer a theory based on abstract calculations of what the climate is very likely to do in future decades. In 2007 the Intergovernmental Panel on Climate Change (IPCC) concluded that ’It is very likely that hot extremes, heat waves and heavy precipitation events will continue to become more frequent.’

The second lesson — the canary in the coal mine — is that because of global warming the frequency of these extreme weather events is only going to increase. Thus the one in 100 year high rainfall event will become far more common, with highest-ever totals being exceeded more and more often in the future.

The third lesson is that there needs to be better preparation for these events by civil society. The responsibility in New Zealand falls on local bodies through the Civil Defence and Emergency Management Act (CDEM). It’s local government that is responsible for district plans and granting developers the permission to build. Firstly should major towns be located on river floodplains? This is where there is pressure from developers. A solution is to build higher and higher flood levees but should the cost be borne by the community? Perhaps the full costs should be placed on the developer. Another option is to ban development in flood-prone areas.

However New Zealand is the lucky country in regard to the fourth lesson. We have an Earthquake Commission that covers citizens for flood damage, which Australia does not have. But insurance should be compulsory for all dwellings, to share the cost of these disasters between all citizens.

Global warming is here, now — and not a phenomenon for future generations to deal with. Thus we must embark on a course of emissions reductions targets as soon as possible, to claw back rapidly rising greenhouse gas levels in the atmosphere. If we do not act now the severity of such floods, and the subsequent loss of life and property — let alone the effect on the economy — will increase dramatically. There is no time like the present to invest in our future wellbeing.

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