Looking out of the window I see a Paris bathed in sunshine on this warm winter Sunday. But the headlines talk of bathing in blood. This blog post will be about art school, climate science, statistics and the politics of terror. Each of us must struggle to find balance in life.
We decided yesterday to not cave in to terrorism and give them an attention they covet but to “live normally”. So we set off to indulge our hobby and went to croquis, which is drawing rapid poses of a live model, in a historic painting school next to the Jardin de Luxembourg. It has been a long time since I did croquis and I worried if I would still be able. No problem really, on second thoughts I was never any good and always get the proportions wrong – but that is why the exercise is such good training for the eye. I was asked to donate a painting for Handel’s auction to the benefit of the refugees. I wonder if these drawings would do.. (feels pretentious but - it is for such a good cause). It was wonderful to spend the afternoon drawing but not a total escape. The model told us she was almost a victim. The evening before she was at a bar just opposite the Bataclan and saw people shot and running. In the night she was crying and could not stop hearing the sound of machine guns in her head. The art school had offered her to stay home but she said it was worse being alone. Makes you realize that there are so many more “victims” of terror than just the killed and wounded. We must think also of all those who are traumatized.
Let me switch to some very powerful and relevant mathematical prose. Please read it even if you think it is nerdy, we must find a way to talk about climate causality: “It is a generic property of a time series consisting of a natural oscillatory part and a downward trend that the minimum is most likely to occur toward the end of the time period when the negative influence of the trend is greatest and when the oscillation is also at a minimum. The century-long trends in precipitation and temperature, here implicated as evidence of anthropogenic influence, point toward them being key contributors to the recent severe drought.”
I am reading an article that just appeared in one of the world’s most prestigious journals, the PNAS, that tries to establish a link between climate change and the civil war in Syria.. So back to the citation above. It says that if there is a trend going down then you will get lower and lower values over time. If you walk downhill you eventually get to a lower point. This applies even if there are ups and downs on the way just that the connection becomes a little harder to prove and show mathematically. (Another illustration: think of a bell-shaped normal distribution curve shifting to the right… those unusual outlier values become much more frequent – yet we cannot definitively prove the shift caused a particular value). The article shows that in Syria the average temperature has a trend that has gone up by about a degree over the last century. This does not prove that a heatwave on any particular day or year is just “due” to climate change but of course hot days become much more frequent as average temperature rises. Similarly rainfall has a downward trend implying a fall of about 5 mm/month (or 10%) over the last century. That is climate change. Does it “explain” the latest drought when rainfall was a third less than usual? Well there have been (3 year) droughts regularly before this was the worst on record and with a downward trend that is just what you would expect.
Looking at the data, any sensible person would agree climate change is a main contributing factor to the severity of the drought. Does this mean climate change “causes” civil war in Syria? That would be a far leap, there are so many factors. But the drought 2007-2010 did mean that Syria which was self-sufficient had to start importing food. It did mean food prices and feed prices for livestock fodder, escalated severely, more than a million small farmers lost harvests and herds and had to leave their homes and lands and became internal migrants moving towards the cities. Again other factors are maybe even more important. The Syrian population has surged from 5 to 22 million in the last half century. The invasion of Iraq added a million and a half refugees from that country. Add the complexities and autocratic rule of the Assad family and the regional tensions in the Middle East. Of course it would be simplistic to say that climate change “caused” the civil war in Syria. But it would be equally or more blind not to see any connection at all. And what an irony if terror were to weaken our resolve, or further hamper our ability, to do something constructive in Paris to stop climate change.
References
Kelley et al “Climate change in the Fertile Crescent and implications of the recent Syrian drought”, PNAS vol. 112 no. 11
3241–3246, doi: 10.1073/pnas.1421533112
http://www.pnas.org/content/112/11/3241.full#
New York times comment