I have just received an environmental report for a property I am hoping to buy, which flagged up increased risk of subsidence. This is due to clay in the soil - which expands/contracts depending on temperature and water content.
This is very common in south of the UK, and usually doesn't have too much risk involved (especially if the foundations were built under soil considerations) but I wonder what impact this might have in the close future, with temperatures soaring and so many old buildings/homes over 100 years old.
Climate change will impact on things that don’t even cross our minds.
It may very well happen that the same thing happens now with the top soil as with groundwater - once the water is gone and the ground is dry, the weight of everything above it will settle down and compress the lowest parts of the ground - rinse and repeat and you suddenly have soil which is not capable of storing or even buffering water, which means a massive risk increase for flash floods at one side and a lack of drinking water on the other side.
Well the strict mathematical term doesn't even make sense because a scalar can't be perpendicular. Unless you're claiming the moisture is imaginary, I guess...
This is not consistent with the data presented in the article, which shows that the "percent of Europe's area that is dryer than normal" is historically between 5% and 25%.
An anomaly in this case is defined as outside one standard deviation[1], so in a perfectly normal year you would expect ~15.9% of soil to be dryer than normal.
You're the one who's defining normal badly. If you are told someone, or even all the people in a country, is/are "taller than normal", would you think they were all above 1.853 meters or whatever, or that they were all outside the range of normal heights? Because that's what anyone else would assume.
The Dutch, as a country, are "taller than normal", and this is a fairly common point to make about them. I've always taken it to mean that their population average is somewhere above 1.852 meters or whatever, not that they are alarmingly, abnormally tall (which they are not).
So I think this example fails, at least. The original article is trying to make the point that Europe's soil is alarmingly, abnormally dry.
Dryer than the 'average' dryness of all the soil, perhaps, but if normal is an expected range of values - the soil in this place is typically somewhere from here to here in dryness - then it's not that case.
Even if we are looking at the mean average, it's still not necessarily the case that half the soil will be on one side of the mean average; long tails tugs that mean average above and below the median.
But if what's meant here is the median, then yes, half will always be below.
Excuse me now while I go and beat myself up in the car park for being that person on HN.
You mean mean, not average. Mean, median and mode are all averages. Only median splits into equal groups.
The point I was trying to make though is that "normal" is not in any way equivalent to any kind of average. It always refers to a range or distribution, even if that range is very small (eg if there is only one normal value, the normal range is the margin of error). 5'8" and 5'10" are both normal heights; you would not say they are taller or shorter than normal. They're shorter/taller than average.
Yao Ming is taller than normal. Dwarfism is by definition abnormally small size. Normal can't be the average, because there wouldn't be anything to describe the range of heights between abnormally short and normal height. Also, normally short and normally tall would be the same thing. Makes no sense.
The normal distribution does not define a mathematical meaning of the term "normal". Any distribution can define a normal range relative to that distribution.
Given an expected normal distribution of soil dryness you can compare a given year's distribution.
> Any distribution can define a normal range relative to that distribution.
Any particular sample will always have a corresponding probability in a normal distribution. So what you're saying is kind of right- values always fall within the range of a normal dostribution. That's not what it means to be outside the normal distribution, though. If you have another year that only partly overlaps with the expected distribution, you'll have an area that does not overlap despite being within the same range. That area is the fraction of values outside the normal range.
Log-normal is extremely common in hydrology. Turns out an anomaly in this case is defined as outside one standard deviation[1], so in a perfectly normal year you would expect ~15.9% of soil to be dryer than normal.
The term "normal" has to refer to a range - not a point - exactly for the reasons you gave. Then it does make sense to make a statement like 90% of some population is normal.
Both in mathematics as well as in colloquial language a term's definition must be such that it is useful. The term "normal" is grammatically an attribute (something is normal or is not normal). If "normal" is defined such that no object can be called "normal" - then the the term "normal" is useless.
This way of thinking about language is not just logical and economical but also conforming with a friendly approach on communication. Of course, this is something unattractive to many people who celebrate their incredible and superior intelligence for the purpose of grandstanding. And I fear this attitude is relatively more normal on HN.
It's not "dryer than normal". It's "dry like the new normal". Also "lower end of dryness of tomorrows normal".
Climate change is happening. It's a bad take to make it sound like something's going back to a "normal" that will probably never happen again. What is "normal" is changing and we need to think how to deal with this, not consider it an anomaly.
I think the headline is just trying to be objective and let the readers come to their own conclusions.
Climate change has always been happening. What is "normal" has always been changing. The Azolla event led to the decrease of atmospheric CO2 from 3500ppm to 650ppm over the period of 800k years. Humanity has (so far) increased atmospheric CO2 from 280ppm to 400ppm. Yes, we're faster than Azolla. But we'll probably stop or be stopped before we reach 3500ppm.
> So, this is all a part of natural cycle. Humans are part of life on Earth. Some life on Earth captures CO2, and the other emits CO2, until it runs into some consequences; then the cycle repeats.
I see that Greece's soil is wetter than normal, that must be because we've been getting atypical rains, almost tropical (including an unprecedented hurricane!).
At least we haven't been getting heat waves, I guess.
Well, I dont know why, call it a gut feeling or whatever. But I suspect that germany and maybe even whole Europe gets weather like Texas (dry rainy, hot)
If you would like additional context, here’s the U.S. drought monitor which shows very little drought currently in the United States. https://droughtmonitor.unl.edu/
Draught is an extremely noisy measurement. Because California got some unexpected but not unprecedented rain, draught on average is way down. However many parts of the US are also extremely abnormally dry- even if they aren't pushed into full on draught: https://www.wbur.org/news/2016/09/01/driest-boston-summer
It doesn't even matter if the dryness has no negative effect whatsoever (which it certainly does), because it's a measurement of a trend and it WILL eventually cause issues.
For me no data analysis is necessary to come to a similar conclusion. My parents have a farm in the Netherlands and they are reminded of the lack of rain daily. The most clear example is of the channel ('gracht' in Dutch) around the house. The channel is almost drying up this year. This has never occurred before while my parents or my grandparents occupied the farm.
It was also clear on a recent visit to family in Poland. The corn, potatoes and beets looked yellow and awful for all fields except the parts where somehow there was some water (for example, valleys).
• Low confidence in an observed global-scale trend in drought or dryness (lack of rainfall) since the 1950s, due to lack of direct observations, methodological uncertainties and choice and geographical inconsistencies in the trends;
• High confidence that the frequency and intensity of drought since 1950 have likely increased in the Mediterranean and West Africa (although 1970s Sahel drought dominates the trend) and likely decreased in central North America and northwest Australia;
• Low confidence in attributing changes in drought over global land areas since the mid-20th century to human influence owing to observational uncertainties and difficulties in distinguishing decadal-scale variability in drought from long-term trends;
• High confidence for droughts during the last millennium of greater magnitude and longer duration than those observed since the beginning of the 20th century in many regions.
Surprised to see that there are places in Cyprus where the soil is wetter than normal. I thought i live in a semi-desert. In addition, the climate is wetter in the southwest areas here (near Paphos) and dryer northeast, map shows it other way around. For example, bananas are commericaly grown around Paphos but won't be a viable cash crop east of Limassol.
Most of these dry areas on the map are pretty mountainous/significantly higher elevation. Have no idea how that makes things different, but it still strikes me as a significant point to consider when interpreting the data.
It does not coincide with elevation (see an elevation map of Europe: https://www.eea.europa.eu/data-and-maps/figures/elevation-ma...). Finland, the Baltics, Netherlands, Denmark, England, South of Sweden, North of France and Germany are pretty low. Italy, Greece and Turkey are all higher elevated and they are wetter than normal.
Personally, I've reached a point where I think changes are irreversible - there is no point trying to persuade the world to down tools, because the developing world is not going to listen (understandably so) and it's probably too late anyway (changes originally predicted by models to happen around 2070 are already here). From now on, we just have to put our collective minds to preparedness and countering: we will have to manage the excess water and heat as best as we can, and accept populations will be displaced.
Unlike with medieval plagues, we understand this problem and most of its effects. We can deal with it, as long as we don't deny it nor use it to push unrealistic beliefs.
Sorry to be so blunt but fatalism is a pretty convenient thing. It dispenses one from having to put up a fight and saves one from any efforts that this might entail. I don't like this attitude as it only gets in the way of others who do not give up easily.
This is very common in south of the UK, and usually doesn't have too much risk involved (especially if the foundations were built under soil considerations) but I wonder what impact this might have in the close future, with temperatures soaring and so many old buildings/homes over 100 years old.
Climate change will impact on things that don’t even cross our minds.