Highlights from the October 2022 Chapter Meeting
The Announcements
It’s National Hispanic Heritage Month! We are honoring our members with Hispanic/Latin American heritage. Please open this presentation to learn more by clicking here. Note that announcements begin immediately after the Hispanic Heritage slides. Further activities are listed on the chapter calendar. Opportunities and contacts, websites, and other details are available in the announcements.
Highlights of the Meeting
Recognition – Congratulations to Master Naturalists achieving major milestones in the third quarter of 2022.
250 Hours – Adrienne Cortez, Mark Jones, Nicole Jones, Margaret Marshall, Kim Sanders George, Shelby Smith
500 Hours – Sierra Carter, Doug Guiling, Julia Koch
1000 Hours – Cecilie Wallace
And Wow! 2500 Hours – Bruce Leiding
Well done, each of you!
Protecting Dark Skies for Humans & Wildlife
A huge thank you to Dr. Karen McGraw for such an excellent presentation on light pollution, its effects, and how to protect dark skies. Karen is the North Texas Outreach Coordinator for the International Dark-Skies Association (IDA), Texas Chapter.
Karen began by helping us recall our own experiences under a truly dark sky and how healthful that can feel. She then reviewed the extent of global light pollution and the alarming rate at which it is increasing, twice the rate of population growth. A nighttime satellite view illustrated the extent of light pollution and its impacts on key bird migration routes.
To frame her discussion, Karen defined light pollution as excessive or inappropriate uses of artificial light. She categorized light pollution as glare, skyglow, light trespass, or clutter and gave examples of each.
Karen reviewed the effects of excessive artificial light, especially blue light, on human health – how it can disrupt our natural rhythms. Even dim light suppresses our melatonin production, impacting our immune systems. Recent studies suggest links between blue light exposure and heart disease, obesity, and cancer. Her demonstration using diffraction grating glasses showed how much blue light we’re exposed to from phones, computers and various home light sources. Thus, she recommends lowering home lighting levels an hour or two before going to bed.
Of course, artificial light also affects wildlife. When exposed to night lighting, birds’ metabolism does not slow down adequately, preventing needed rest. Light pollution affects navigation, especially during migration, contributing to the hundreds of millions of fatal bird-building collisions.
Night lighting also disrupts turtle navigation, particularly with newly hatched turtles trying to make their way to the sea. Further, it affects amphibian behavior. For example, frogs reduce or stop calling and have less success finding mates. They are less able to find cover and avoid predation.
Artificial lighting affects insect communication, foraging, reproduction and pollinating. Quoting one researcher, “We strongly believe artificial light at night – in combination with habitat loss, chemical pollution, invasive species and climate change – is driving insect declines. We posit that artificial light at night is another important – but often overlooked – bringer of the insect apocalypse.”
Karen outlined three key outdoor lighting challenges: glare and safety, light trespass, and wasted energy costs. She showed how high levels of outside lighting often create so much glare that they are neither safe nor effective.
Light trespass from unshielded fixtures creates about 75% of artificial sky brightness, with the rest coming from street lights. Unshielded lighting wastes energy and money by lighting areas (and sky) that we don’t want or need to.
IDA has developed five principles to remedy these problems:
- All lighting should have a specific purpose – it should be useful
- Light should be directed where it’s needed – it should be targeted
- Use light no brighter than needed to do the job – levels should be kept low
- Control light with timers and sensors – it should be on only when it’s needed
- Use warmer light colors when you do use light at night – reduce blue light
Following these guidelines significantly increases safety, reduces glare and trespass, and saves energy. Most of all, they promote a darker sky.
In closing Karen encouraged us to take action by
- Analyzing your residential lighting practices
- Retrofitting lighting that is contributing to light pollution – use shields, timers or sensors to reduce lighting use
- Contributing to research as a citizen scientist – Globe at Night
- Joining IDA (automatically makes you a member of the Texas IDA Chapter) and advocating for dark skies – the “Be A Star” award program shows commitment to reducing light pollution
- Supporting IDA Certified Dark Sky Parks – many parks in Texas are already engaged in this process
Going Deeper:
Karen provided these additional resources:
- Texas Chapter, International Dark-Sky Association website
- International Dark-Sky Association website
- Lights Out Texas project at Texan by Nature
- BirdCast Alerts – forecast on bird migration activity and special needs for reduced lighting
- Fabio Falchi (2016), The World Atlas of Light Pollution, the first book showing in detail the spread of light pollution on our planet
- How to Find Dark Sky Friendly Lighting – IDA’s resource on fixtures with links to “Lighting Basics” and “Dark Sky Retailers”
The recording of this meeting is available here.
Thanks to our guests and members for participating in this month’s meeting. I hope all feel welcome at NTMN.
Take care,
Scott Hudson
President
North Texas Master Naturalist