No significant trends in rainfall extremes

In January 2013, in the wake of some heavy rainfall, the Met Office published a non-peer-reviewed briefing paper that found that extreme rainfall might have increased. This was reported by Roger Harrabin here, with readers informed that "Professor Julia Slingo, chief scientist at the Met Office, said the preliminary analysis needed further research but was potentially significant."

Today, the International Journal of Climatology has published just what Prof Slingo was a looking for. However, the paper concerned has a more mixed message than I think she might have wanted:

The England and Wales precipitation (EWP) dataset is a homogeneous time series of daily accumulations from 1931 to 2014, composed from rain gauge observations spanning the region. The daily regional-average precipitation statistics are shown to be well described by a Weibull distribution, which is used to define extremes in terms of percentiles. Computed trends in annual and seasonal precipitation are sensitive to the period chosen, due to large variability on interannual and decadal timescales. Atmospheric circulation patterns associated with seasonal precipitation variability are identified. These patterns project onto known leading modes of variability, all of which involve displacements of the jet stream and storm-track over the eastern Atlantic. The intensity of daily precipitation for each calendar season is investigated by partitioning all observations into eight intensity categories contributing equally to the total precipitation in the dataset. Contrary to previous results based on shorter periods, no significant trends of the most intense categories are found between 1931 and 2014. The regional-average precipitation is found to share statistical properties common to the majority of individual stations across England and Wales used in previous studies. Statistics of the EWP data are examined for multi-day accumulations up to 10 days, which are more relevant for river flooding. Four recent years (2000, 2007, 2008 and 2012) have a greater number of extreme events in the 3- and 5-day accumulations than any previous year in the record. It is the duration of precipitation events in these years that is remarkable, rather than the magnitude of the daily accumulations.

I haven't read the paper, and so I wonder what other multi-day accumulations they tested and whether they assessed the possibility that these results might have happened by chance. I'm not sure I'm alarmed by any of this.

Malaria maths

Bjorn Lomborg's article in the New York post riffs on his traditional theme of prioritising spending on areas where the greatest benefits can be gained. It's not rocket science of course, although perhaps on the tricky side for your typical environmentalist.

As ever, Lomborg is fully accepting of mainstream climate science, as well as some of the wilder claims that are made about the impacts. Take malaria, for example. Lomborg accepts claims that malaria will be a bigger problem in a warming world, but does not accept that this is an argument for spending money on climate mitigation:

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Joe Biden, ambulance chaser

Despite the fact that the Sahel has experienced relatively benign weather conditions for many years now and despite the fact that there has been a striking and well-documented greening of the region, attempts to link the wars and strife that still bedevil the region to the climate are still being made.

And the people spinning these yarns are often those who should know better. Last weekend US vice-president Joe Biden claimed that the Darfur conflict, which started more than ten years ago, is "all about" climate.

You think there’s a migration problem in Syria? Watch what happens when hundreds of millions of people in the south, south Asia are displaced trying to find new territory to live. Look what’s happened with Darfur. Darfur is all about climate change. It’s about arable land being evaporating, figuratively and literally, and warring over land.”

Unfortunately for Mr Biden's hypothesis, this review of Sahelian climate by UEA's Nick Brooks takes a different view:

• 20th century changes in climate probably not unusual...
• Darfur conflict from 2003 at time of climatic improvement
• Earlier droughts may have helped set stage, but no climate change “trigger”

I think we can conclude that Mr Biden is engaging in a bit of ambulance chasing. How low the office of VPOTUS has fallen!

Sahel greening confirmed

Another paper has confirmed that the Sahel is greening. A team from South Dakota State University led by Armel Kaptué have looked again and confirmed earlier reports:

The predominance of increasing rain-use efficiency in our data supports earlier reports of a “greening” trend across the Sahel. However, there are strong regional differences in the extent and direction of change, and in the apparent role of changing woody and herbaceous components in driving those temporal trends.

That's (yet another) one in the eye for Desmog's (alleged) debunking.

Autocorrelation in the Sahel

Sahelian forest in Mali, courtesy Wikimedia

This is a guest post by Doug Keenan.

In August, the journal Nature Climate Change published a piece by a researcher at the Earth Institute of Columbia University. The researcher, Alessandra Giannini, is an expert on precipitation in the Sahel, and her piece was on that topic.

Giannini’s piece notes that Sahel precipitation has been slightly increasing during the past few decades, but then warns as follows.

… a gap in research: a complete understanding of the influence of [greenhouse gases], direct and indirect, on the climate of the Sahel. This is needed more urgently…. While precipitation may have recovered in the seasonal total amount, it has done so through more intense, but less frequent precipitation events. This state of affairs requires more attention be paid to the climate of the Sahel, to ensure that negotiations around adaptation, such as those taking place in the run-up to the Conference of the Parties of the UN Framework Convention on Climate Change that will be held in Paris at the end of this year, are based on the best science available….

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Minor drying in Iran causes farmers to flee Syria

The origin of the claim that the Syrian refugee crisis is partly caused by climate is a paper by Kelley et al in PNAS. This has picked up quite a lot of media attention, yesterday's Independent  article being just the latest.

Kelley et al is a bit odd though. Consider at what they found. In the top panel of the following figure, they claim to have found a significant drying trend. They are using a significance level of P <0.05. (Questions, questions: why do they calculate trends since 1931 when they have data going back to 1900?)

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More Syria shamefulness

The ambulance chasers are still, rather disreputably, hovering around the fringes of the migrant crisis. Today I came across a cartoon that again seeks to link the 2007 Syrian drought to climate change. Entitled Syria's Climate Conflict, it opens with the 2007 drought and then moves on to the displacement of people thereafter, before moving on to the uprising itself, describing its beginnings in the southern city of Daraa and the spread to Damascus before asking whether maybe climate change had something to do with it. A scientivist type is on hand to insinuate that it did.

If you take a look at the cartoon though, you will notice something odd: there is not even a vague insinuation that the climate in Syria has changed. There has been a drought of course, but Syria is nothing if not a country prone to drought. So where is the climate change? It is so transparently an attempt to use a weather event to advance a climate argument that it is hard to avoid the conclusion that the authors are not just playing fast and loose with the facts.

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On Syria and climate change

Never a man to let a good crisis go to waste, Barry Gardiner MP is trying to use the deaths of Syrian migrants to advance his climate change agenda. If we want to understand the crisis, he says, we must look beyond Assad and ISIL to the weather and the "ruined farmers" - hundreds of thousands of them apparently - who left Syria's wheat belt for the cities. We learn, moreover, that 2010 was during the longest drought in Syria's records.

Now take a look at a graph of Syrian wheat production (data from here).

Tells a rather different story doesn't it? You can see that the drought wasn't actually in 2010 at all, but rather in 2007/8 and, although rainfall remained sub-par thereafter, by 2009 wheat production had recovered to near normal levels and remained there for several years.

Perhaps there is more to this than meets Mr Gardiner's eye.

Gauges versus satellites

There is a fascinating post at No Tricks Zone on sea level rise, focusing particularly in the difference between the (heavily adjusted, short-term) satellite record and the (relatively pristine, long-term) tide-gauge data. The former is over 3mm per year, while the latter is much lower.

Author Dave Burton has been trying to reconcile the two numbers and has drawn a blank:

It is not possible to torture the tide-gauge data into yielding a globally averaged rate of relative sea-level rise anywhere near 3.3 mm/yr.

The upshot is that the satellite record might be as much as double the correct figure, or at least the relevant figure for coastal planning purposes. I wonder what figure is used for assessing the economic impacts of climate change?

Polar bears walk on water?

Polar bears are remarkable creatures, but I bet you don't know just how remarkable they are. Scientists tracking some of these majestic beasts in the Southern Beaufort sea using radio-collars have determined that some of them spent the whole of the month of August in an area in which there was almost no sea ice!

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Duelling models

Climate models eh? If nothing else, they are at least the cause of some wonderfully convoluted arguments among climate scientists as they pore over the outputs like psychics gazing at the tea leaves in a saucer.

Recall, if you will, the story over the Sahel. GWPF put out a briefing pointing out that earlier claims that global warming was going to lead to perennial drought there were nullified by a long period of greening. This led to a cod debunking from Desmog, but later to a paper by Dong and Sutton, which claimed, on the basis of a GCM study, that the greening was in fact caused by greenhouse gases (background here).

The latest development is a new paper (£) by Alessandra Giannini of the Earth Institute at Columbia, which critiques Dong and Sutton. Her case is that there is a well-established link between sea-surface temperatures and Sahelian drought:

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The World Bank's sexed-up climate claims

The World Bank's climate change unit put out a tweet about climate threats to Eastern Europe yesterday that caught my eye. This one:

#ClimateChange & rising temps increase #health #risks in several ways: http://t.co/k83V1EJCHU #climateaction pic.twitter.com/MOzNKxzGmS

— World Bank Climate (@wbclimatechange) August 23, 2015

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The wit and wisdom of Dr Glikson

A few days ago, there was a rather good article in the Conversation about fossil fuels and development. Written by Jonathan Symons, it covered themes that are favourites at BH, most notably that there is a trade-off between expanding access to electricity in the developing world and emissions targets:

...if the US Overseas Private Investment Corporation were allowed to invest in natural gas projects (not just renewables) it could roughly triple the number of people who gained electricity access from a US$10 billion investment. Whereas a renewables-only portfolio could supply 30 million people, natural gas could reach 90 million and generate around ten times as much electricity.

The comments thread featured a series of critical responses from Andrew Glikson, an Australian geologist who has caught the eye before, most notably when he protested the willingness of an Australian theatre to put on a performance of Richard Bean's The Heretic. This earlier thread also bears looking at. The thrust of his comments can be summarised as "But climate", but they are worth looking at in more detail because Dr Glikson has some truly astonishing views:

A very large part of the poor populations referred to in the article live in low river valleys and delta prone to flooding extreme rainfall, torrents originating from mountain regions and sea level rise, as is the case of mega-floods in Pakistan, Bangladesh and low-lying islands, associated with climate change. The “option” of developing higher standards of living based on fossil fuels is therefore short sighted and no more than a Faustian bargain....

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Gary Yohe's fictional citation

Updated on Aug 14, 2015 by Bishop Hill

It is...irresponsible to ignore the preponderance of evidence on floods, extreme precipitation events (and if it is winter, these are snow storms), wildfires, etc. These were anticipated to occur as the climate changes. They have occurred around the world (U.S., Russia, Indonesia, Japan, Argentina, etc..), and they are getting worse and more frequent^[2].

The quote is from famous environmental economist Gary Yohe, writing at Climate Feedback, a site where climate scientists rate media articles on their scientific content. Yohe was writing about a Bjorn Lomborg piece.

Yohe's citation is to the detection and attribution chapter of AR5, which is, on the face of it, a bizarre thing given that there are whole chapters in the IPCC about observations of the climate. Intrigued, I looked at the chapter cited.

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The FCO misleads

Sir David King, the Foreign Office's adviser on climate change, has commissioned a report into the effects of climate change on food security. There's a monster team of authors featuring among others Tim Benton, a population ecologist and the "UK Champion for Global Food Security", and Rob Bailey, a former executive at Oxfam who now works at Chatham House.

The underlying study is a mega-hypothesis of course - it's computer models all the way down, you might say - so it's of no practical use, but with the project led by someone like Sir David, one can be reasonably sure that it will at least provide some entertainment.

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