#ALAN2023 talks are about to start! I'm sitting next to a biologist who studies the effects of light pollution on sea turtles in Australia, and another who studies the effects on mammals in the western US. This is so cool!
N. Schulte-Romer: a lot of urban lighting motivated by fear - humans are scared of the dark! There's also an element of control: lighting allows surveillance
She encourages everyone to ask who needs lighting and why? Think beyond your own cultural group beyond your own species.
Her guidelines:
-slow down
-accept 'uncommons': 'safe' isn't the same for everyone
-ask 'who will be safe?' think beyond humans
LED replacements offer window of opportunity for change
Lan Yu: New York City put a bunch of money into replacing streetlights with LEDs with the goal of reducing energy usage. Used special ground-based cameras+machine learning to measure where LEDs have been added and how that has changed NYC's spectrum - it's now dominated by LEDs rather than high-pressure sodium lights
@sundogplanets@jgkoomey AIUI the actual LEDs are narrow, but many LED bulbs have a coating similar to fluorescents that expand that to a similarly broad spectrum
K. Walczak: Adler planetarium doing lots of light pollution work now. Project: using all-sky images to try to identify sources of light pollution in an "urban dark sky" area near Chicago
"In Calgary, you have 16 hours of darkness in the winter. In Chicago, we have zero"
Set up 10 moveable all-sky cameras for triangulation - able to confirm this for a rural site. Comparing urban site with satellite data is surprising to see what is bright and what's not - good targets for outreach
B. Portnov: hormone-dependent cancers and obesity on the rise worldwide. Is it related to light pollution? (Or something else, like vitamin D?) Tries to take out food consumption, sun exposure, other factors across many countries [sounds hard!]
Melatonin production and estrogen production are linked, so light pollution affects both.
Finds artificial light exposure is significant contributor to some cancers and obesity (though not as significant as some other factors), w/ caveats
@skyglowberlin is presenting on imaging from an airplane with a big camera of Cologne to measure light pollution in green, red, near-IR, and UV
Brightest things: sawmill, transportation, restaurants. Pinpoints a few UV bright metal halide lamps (some on cathedral). Stadium is super bright NIR source - growing grass! Hotels are very bright in NIR and UV: advertising?
N. Gabinet: Our sleep environment has changed dramatically in last couple hundred years: noise, air pollution, artificial light.
Study of people sleeping looked at noise and light exposure and how that affects sleep, using simple smartphone apps
Artificial light exposure before bed reduces sleep by 10%, exposure to light while asleep made no difference (but noise while asleep reduced sleep by 15%)
M. Okuliarova: there are a lot of metabolic processes in us that are synchronized by exposure to light-dark cycle. Used rats, gave them just dim artifical light with no changes. Biggest change: higher cholesterol [lots of small changes in biological abbreviations with alphas in them... not sure what those are] Some stuff about liver function changing and more sugar consumption? [This is very much a talk for biologists...]
E. Schernhammer: A previous study of women nurses showed artificial light exposure caused significantly (14%) higher rates of breast cancer - this is related to melatonin and estrogen.
Artificial light is now considered a "probable carcinogen" [whoa I did not know that]
Previous studies have also shown night shifts increase cancer risk - this is probably artificial light causing something called "oxidative stress". Found prostate cancer risk in men, not just women have this risk
This latest study uses the "Finnish twin cohort" - longest running twin cohort study. Thousands of women were part of this cohort and answered questionnaire.
Study analysed connection between night shift work and breast cancer. Women who worked nights had a 58% higher breast cancer rate.
@sundogplanets thanks! Small numbers, definitely needs lots more similar work. Interesting (and wouldn't surprise me if the hypothesis holds, we know night shifts are bad news for health in various ways) but the numbers probably shouldn't be too much cause for alarm
@noodlemaz I mean, I think everyone knows that night shifts are not great for your health. It's pretty interesting to see such a specific result of that (I'm not a biologist, just interested)
@sundogplanets yep, just saying it's important not to over-egg the results - there are so many factors to cancer, and the shift work patterns are unlikely to be the only things differing there - plus the small numbers. Larger studies might show an even smaller or insignificant effect. One to keep an eye on!
C. Vilbrandt: Helped organize "Gather around the light" events to raise awareness of light pollution, particularly aimed at Berlin's lighting designer community (apparently a lot of lighting designers are based in Berlin). Points out that most lighting around the world (95%) is not put together by lighting experts, need to think about life cycle of lighting products.
A. Jechow: Light pollution has a huge impact on whole ecosystems and on individual animals. Animals are out in all seasons, all weather - how do clouds affect/amplify artificial light (can be 1000x brighter). But how much do clouds darken a natural sky?
Using hemispherical cameras to measure sky in dark and polluted places. Dark site in Namibia went from 21.6 mag/arcsec^2 to 24.9 with clouds (beautiful sky movie!)
Modelling tall buildings is a lot harder - angles and windows are really important! Has a working light pollution model pretty well working now, can be used as input for radiative transfer models
Saw an increase in light in majority of places, but saw some decreases (I guess overall there are no decreases, only increases in Texas, so the dark sky status is definitely helping)
I have noticed a shift in our small city (Palmerston North, New Zealand) we mostly have LED street lights so it appears that there are no lights until you are almost directly under one. Not sure if that is what they are meant to do?
Fascinating topic and I can tell you are fascinated with it 🙂
S. Morrell: How do you find out how animals respond to different lighting environment? First need to measure or model - does looootttsss of careful modelling, based on real city data. Now can change the lightning in the model to see what happens.
Next try to "walk" through simulations, where can animals go without getting into super bright parts. Sodium is better than LED for leaving dark paths, but overall worse for light pollution. Adding a dark corridor doesn't help that much.
Emphasize that you need to look at whole light environment, can't just take out one lamp and think it's ok.
Next steps, measure bats and hedgehogs(!!! I want to measure hedgehogs!!!) and how they respond to these real lighting environments. Also improving model to include foliage and scale it up.
@sundogplanets@salvabara I remember when I lived in Greater London, after snowfall, it was amazingly bright, with the streetlights being reflected between the low stratus clouds and the snow.
@sundogplanets I still can't work out why all street lights have to be on all night. After about midnight in most areas the only people walking are up to no good, and those driving have lights. So switching them off after 12:30 would save electricity and costs...
@sundogplanets Did you know that East and West Berlin were distinctly different in light colour, even visible from space? East yellow, West whitish. It Fades, because of LEDs.
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