FGS Sarsain

For years, the standard estimate said a warming climate would slightly help European growth, adding about 0.18 percentage points a year. A new study finds the opposite: warming costs Europe about 0.19 points a year. Same continent, same question, opposite sign. Nothing about Europe's economy changed. What changed was the size of the map the researchers used. The big, influential climate-economics studies compare whole countries: one temperature and one growth rate per country per year. Fit a curve through that and it says heat hurts hot places and helps cool ones. Europe is mostly cool, so on that logic Europe comes out ahead as the planet warms. A great deal of climate damage modelling and policy leans on exactly that result. A new study, in Nature Communications, zooms in from countries to individual districts. The researchers pulled together economic-output and growth figures for districts right across Europe and asked how growth responds to temperature at three levels at once: the country, the district, and the specific industry. That last bit is pretty important. A region's mix of industries decides what heat does to it, and lumping farming districts together with finance-heavy cities averages the damage out of view in both. What emerges is a different kind of shape. Warmer-than-usual years drag down growth in cool districts, the ones averaging 0 to 14°C, and lift it in genuinely warm ones above 14°C. Push to the extremes, below freezing or past 20°C, and it turns harmful again at both ends. These are same-year effects, growth responding to this year's temperature, which is the same setup the country-level studies used, so the comparison is clean. Add it all up properly across the continent and warming costs Europe roughly 0.19 points of annual growth instead of handing it 0.18. Under a moderate emissions path, the projected hit runs from 0.20 to 1.24 points off annual growth by the end of the century, and that's before extreme events become more frequent. The sign flipped for one reason alone: the analysis moved from comparing countries to comparing districts within them, where the differences between places and industries are visible instead of blurred together. The authors are blunt about what this means. A national average can mislead both how hard we cut emissions and how we prepare, because the places and industries that lose are precisely the ones the average hides. For anyone who works with spatial or economic data, this is a familiar monster in new clothes. It's the old problem that the answer you get can depend on how big you draw the units you measure, applied here to one of the largest policy questions there is. The link between night-time lights and GDP behaves the same way, holding up across countries and breaking down when you zoom into districts, and the lesson carries to most fitted relationships between the environment and the economy. link to full article: nature.com/articles/s41467-0…

NASA found something pretty strange in nightlights images. The planet is getting brighter, but some of the richest places are going dark. NASA analysed Black Marble satellite data from 2014 to 2022, covering the main inhabited landmasses of Earth. The dataset tracks artificial light at night after correcting for moonlight, clouds, snow, terrain, atmosphere, and viewing angle. The old story was pretty straightforward that the world is getting brighter and the richest places stay bright. But the new picture is more interesting. Some places are lighting up fast. Some are dimming. Many are switching direction again and again. Globally, brightening added the equivalent of 34% of the 2014 baseline level of night-time radiance. Dimming offset 18%. The net result was a planet about 16% brighter. But it seems like night lights are becoming more unstable. Locations that changed didn’t usually move in a neat straight line. On average, they went through 6.6 separate shifts over nine years, brightening, dimming, brightening again, then dimming again. China and India showed major brightening, linked to urban growth, industrial activity, rural electrification, and street lighting programmes. Parts of Sub-Saharan Africa also brightened as electricity access expanded in places that had previously been much darker. Europe moved in the other direction. France dimmed by 33%. The UK dimmed by 22%. The Netherlands dimmed by 21%. Of course, that doesn’t mean this is evidence of Europoorness. Anyway, much of the dimming probably reflects LEDs, energy efficiency, light pollution controls, and conservation measures. So a dimmer night can be a sign of decline. It can also be a sign of better technology... Dimming in France can reflect policy. Dimming in Venezuela can reflect economic collapse and failing infrastructure. Brightening in northern India can reflect electrification. Brightening in gas fields can reflect more flaring. For years, night-time lights were treated as a proxy for economic activity. Not to beat a dead horse, but this is yet more evidence that this view is too simplistic... Link to NASA article: science.nasa.gov/earth/earth…