New Extreme Weather Claims Based On Flawed Data

By Paul Homewood

 

Latest junk science  from the “Bad weather is due to climate change” Dept:

 image

Global floods and extreme rainfall events have surged by more than 50% this decade, and are now occurring at a rate four times higher than in 1980, according to a new report.

Other extreme climatological events such as storms, droughts and heatwaves have increased by more than a third this decade and are being recorded twice as frequently as in 1980, the paper by the European Academies’ Science Advisory Council (Easac) says.

The paper, based partly on figures compiled by the German insurance company Munich Re, also shows that climate-related loss and damage events have risen by 92% since 2010.

Prof Michael Norton, Easac’s environmental programme director, said that greenhouse gas emissions were “fundamentally responsible for driving these changes”.

“Trends towards extremes are continuing,” he said. “People have experienced extreme weather already – big switches [between] warm and cold winters – but the frequency of these shifts may be changing.”

“Some of the underlying drivers of extreme weather which were speculative four years ago are now looking less speculative and [more like] credible hypotheses. That is the weakening of the Gulf Stream and the meandering behaviour of the jet stream.”

The Easac study, Extreme weather events in Europe: Preparing for climate change adaptation, looked at new data and models focused on a potential slowdown of the Atlantic Gulf Stream, due to an influx of freshwater from melted ice sheets in Greenland.

It was compiled by experts from 27 national science academies in the EU, Norway and Switzerland, although the data was not peer-reviewed.

The UN’s Intergovernmental Panel on Climate Change (IPCC) has assessed the probability of a slowdown before 2100 at more than 90% – or “very likely”. However, a complete “switch off of the gulf stream – or Atlantic Meridional Overturning Circulation (AMOC) – is increasingly thought possible by some scientists.

Some studies say this could lower land temperatures in the UK, Greenland, Iceland and Scandinavia by up to 9C.

UK arrays positioned in the north Atlantic measured a 30% drop in AMOC strength between 2009-10, the Easac study says. And while uncertainties persist about the pace and scale of possible future changes, the decline in Gulf Stream strength itself has now been “confirmed”.

Citing “gathering evidence of an emerging negative phase” in Atlantic temperature swings driven by a weakening Gulf Stream, the study calls for research to be stepped up.

“With potentially substantial implications for the climate of north-west Europe, it is clearly desirable to quantify this risk further,” it says.

https://www.theguardian.com/environment/2018/mar/21/flooding-and-heavy-rains-rise-50-worldwide-in-a-decade-figures-show

 

The report by the EASAC is centred around the MunichRe database of natural catastrophes:

image

https://easac.eu/publications/details/extreme-weather-events-in-europe/

 

Yet, as the EASAC’s previous report in 2013, which presented a similar graph, spelt out:

Extreme weather-related events may have great humanitarian impacts entailing loss of lives, in addition to the economic and partly insured losses. Data collected since 1980 by the insurance industry provide one indicator of trends in extreme events. Although these are not direct measures of extreme weather events per se and may not have recorded all perils in the earlier record, they show weather-related catastrophes recorded worldwide to have increased from an annual average of 335 events from 1980 to 1989, to 545 events in the 1990s and to 716 events for 2002–2011

In other words, the data is worthless, and cannot be used to prove trends in weather events. This alone wrecks the central plank of the report’s claims, that extreme weather events are increasing. (It is also relevant to point out that the report itself states that the MunichRe data has not been peer reviewed).

The report then goes on to look at two specific areas, where more comprehensive data is available – thunderstorms in the US, and floods in Europe:

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It gives us this explanation of how the numbers are arrived at:

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This process of normalisation is in itself highly subjective, and should not be accepted in any way as “factual”.

But one wonders why they did not use the official NOAA tornado data, if they wanted to assess storm trends. (Most of the thunderstorm damage would, presumably come from tornadoes, as the 2011 spike indicates).

EF3-EF5-t

https://www.ncdc.noaa.gov/climate-information/extreme-events/us-tornado-climatology/trends

We can see that the number of violent tornadoes has clearly been declining since 1954. There is simply no need to use insurance data, with all of its inherent bias, when we already have the accurate climate data anyway.

According to the MunichRe data for Europe floods, there does not appear to be much going on, other than a big spike in 2002, the year of the big Central European floods.

image

However, we also know that in the UK the 1970s and 80s were a “flood dry” period. This coincided with the cold phase of the AMO, which tends to result in lower rainfall over N Europe (see NOAA here).

We would therefore actually need to go back much further to identify meaningful long term trends.

The IPCC’s AR5 did just that, and concluded that there was no evidence of any trend in either magnitude or frequency in floods, either in Europe or globally:

image

https://ipcc.ch/report/ar5/wg1/

Attempts to link the increasing economic losses from weather disasters with climate change are bedevilled with unknowable variables and bias. What we do know though is that they are reducing as a proportion of GDP:

image_thumb19

https://notalotofpeopleknowthat.wordpress.com/2018/01/05/weather-disasters-as-proportion-of-global-gdp-1990-2017/

 

Gulf Stream

There is a strange section in the report about the weakening of the AMOC (Atlantic meridional overturning circulation). It even discusses the possibility that it could switch off entirely “with substantial implications for Northwest Europe’s climate”.

And there is the usual nonsense about “melting Greenland icecap”, which is going to be responsible, which the Guardian hypes up to maximum alarm.

In fact, what the report reveals is something much more banal. There are signs that the Atlantic Multidecadal Oscillation (AMO) is about to enter its negative phase, which will bring lower temperatures to much of the NH for the next thirty years.

There is no secret about this, as the AMO works on a 50 to 60 year cycle, and it has been positive since the mid 1990s.

Neither does it have anything to do with global warming, as it is a perfectly natural process which has been around for at least the last millennium, and probably much longer.

As the report identifies, freshwater plays a key role in the process. During the warm phase, higher temperatures across the Arctic lead to increased rainfall. This finds its way back to the Arctic Ocean, particularly from rivers in Siberia.

This freshwater freezes more easily than saltwater, thus beginning the process of increasing sea ice extent, just as it did in the late 1960s, a period known as the Great Salinity Anomaly between 1968 and 1982, marking the bottom of the AMO:

https://www.esrl.noaa.gov/psd/cgi-bin/gcos_wgsp/tsanalysis.pl?tstype1=91&tstype2=0&year1=1895&year2=&itypea=0&axistype=0&anom=0&plotstyle=0&climo1=&climo2=&y1=&y2=&y21=&y22=&length=&lag=&iall=0&iseas=1&mon1=0&mon2=11&Submit=Calculate+Results

 

Hot/Cold Winters

The Guardian also mentions:

Prof Michael Norton, Easac’s environmental programme director, said that greenhouse gas emissions were “fundamentally responsible for driving these changes”.

“Trends towards extremes are continuing,” he said. “People have experienced extreme weather already – big switches [between] warm and cold winters – but the frequency of these shifts may be changing.”

It is not clear where he gets this ridiculous nonsense from. As far as the UK is concerned, at least, these big switches from warm to cold have always been commonplace.

UK Mean temperature - Winter

https://www.metoffice.gov.uk/pub/data/weather/uk/climate/actualmonthly/16/Tmean/UK.gif

 

The MWP & LIA

Claims that a warmer climate is leading to more extreme weather contradicts what we know about climate history, in Europe at least.

Brian Fagan wrote about the Middle Ages, in his book “The Little Ice Age”:

For five centuries, Europe basked in warm, settled weather, with only the occasional bitter winters, cool summers and memorable storms. Summer after summer passed with long, dreamy days, golden sunlight and bountiful harvests. Compared with what was to follow, these centuries were a climatic golden age.

Fagan goes on:

throughout Europe, the years 1560-1600 were cooler and stormier, with late wine harvests and considerably stronger winds than those of the 20th Century. Storm activity increased by 85% in the second half of the 16th Century and the incidence of severe storms rose by 400%.

HH Lamb came to similar conclusions, “there was a greater intensity, and a greater frequency, of intense storm development during the Little Ice Age”, in his book “Historic Storms of the North Sea, British Isles and Northwest Europe”.

Lamb believed that “it is likely that the increased intensity of storms in the Little Ice Age had to do with the source of potential energy in the, at that time, enhanced thermal gradient between the colder ocean surface in the seas about Iceland and the ocean south of 50-55N and the Bay of Biscay”

Many other studies come to similar conclusions, see here.

And if you need more convincing just how extreme Europe’s weather became during the 17th and 18thC, just read historian Geoffrey Parker’s account of storms, floods, cold and drought in his masterpiece on the Little Ice Age, “Global Crisis

In short, a warmer climate is a less extreme one.

via NOT A LOT OF PEOPLE KNOW THAT

https://ift.tt/2G13OyJ

March 24, 2018 at 03:03PM

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