In our world today, a majority of our light shines back at us. This is a scientific fact, as increasing light pollution has made it so more than 1/3 of the planet's population can no longer visibly see the Milky Way galaxy in our night-time skies [Note 1]. By letting our excess of artificial light cloud our skies, we have, in effect, created our own little bubble in which our human-centered world is the only world and nothing else matters.

Except, here is the problem; everything else matters.

Lord Martin Rees, astronomer royal, said that “The night sky is the most universally-shared part of our environment.” Plants, animals, humans, even other stars and galaxies. We all share and rely on the night-time sky. Yet, through increased use of artificial light, we break those ties.

What is light pollution?

Light pollution comes in two different forms. Astronomical light pollution occurs when our ability to view the night sky is diminished due to atmospheric scattering of artificial lights. Ecological light pollution occurs when the alteration of light patterns has a detrimental effect on flora, fauna, and human health [Note 3]. The effects can be seen across the board. It has been estimated that 60% of Europeans and 80% of North Americans no longer can view the Milky Way due to light pollution, whereas places like Singapore and Kuwait have 100% diminished viewing capabilities [Note 4].

Other detrimental effects include changes in the circadian rhythms in healthy adults. The human body relies on changes in light to help calibrate its internal 'clock.' The increased brightness has also affected many insects, who rely on light for mating purposes, as well as prey species that use darkness as cover. Whether we choose to see it or not, everything is slowly changing due to the increases in light pollution.

For a recent example light pollution caused changes, take a look at a study, published on June 29th, 2016, on light pollution and its effects on several species of deciduous trees around the UK. Scientists conducted research over a 13 year period, from 1999 to 2011, looking specifically for effects of photoperiod on four types of deciduous trees: European sycamore, European beech, Pendinculate oak and European ash. Using night satellite images to quantify the amount of artificial light, the study looked at the change in bud bursts for each of the trees. Three of the four species had negative effects due to light pollution. The most dramatically affected was the European ash, a typically late blooming tree, for which the difference between bud bursts of trees in the darkest rural areas and the brightest urban areas was 7 days [Note 5]. The artificial light had caused the ash tree to bloom a full week early.

In the report, the researchers claim; “the results highlight, for the first time, to our knowledge, at a national scale, a relationship between the amount of artificial night-time light and date of budburst in deciduous trees.” They have also hypothesized that smaller plants growing below the level of the street lights are more likely to be affected.

So, what can we do to stop this rapid change?

There is no denying the benefits of artificial lighting, such as illuminating hazardous areas or making it safer to drive during night-time hours [Note 6]. The key is marrying the benefits with less polluting strategies. For example, a large amount of light pollution arises due to streetlamp illumination. Most street lights now operate with a Cobrahead model which emits 6% of its light upwards. By transitioning to a Helios model, a cut-off street light which emits only 1% of its light upwards, we could foreseeably cut artificial light emissions in certain regions where implemented [Note 7]

Another way to help stop light pollution is to protect areas where dark skies remain unpolluted. An excellent example of this is the Ballycroy National Park and Wild Nephin which is also known as the Mayo International Dark Sky Park. The Mayo International Dark Sky Park has achieved the incredible gold-tier classification, which is only awarded to the most exceptional dark skies and stunning nightscapes. The defensibility of this nightscape is enhanced by its proximity to the Atlantic coast, which allows for more limited influences of light. The area, which spans 15,000 hectares, or 110 sqaure kilometers, is especially important because it contains one of the largest remaining blanket bog habitat in Western Europe [Note 8].

The application for dark sky status was project managed by Georgia MacMillan, resident in Newport Co. Mayo.

MacMillan has her honours degree in Outdoor Education from Galway-Mayo Institute of Technology, and given her interest in the ceiling of starry skies visible in the west of Ireland, she started researching the impact of light pollution when preparing her dissertation for her degree. As part of her dissertation, she put together a case study of a potential dark sky in County Mayo, and the rest, as they say, is history.

The Success of the Mayo International Dark Sky Park

When asked about how the steering group was able to get Dark Sky recognition for the Ballycroy National Park and Wild Nephin, she will tell you that it started from small beginnings. She will tell you about the arduous submission process for getting approval as a Dark Sky park, for which the application is 150 pages long. She will tell you about the letters of support the park received upon its application to be considered a Dark Sky Park, which An Taisce, along with other organizations, contributed to. And she will tell you it wouldn't have come together without the support of the local community and the national park.

And it is truly impressive how much the local community has embraced the new Dark Sky status. The community has since come together to create a citizen scientist project, as well as to send letters of support of Dark Sky initiatives to council members. Two local astronomy groups have also been formed since the designation of the park, one located in Ballycroy and one in Newport. The national park has also agreed to help foster the program and keep the area protected from future risks of light pollution.

All of this development really excites MacMillan. “Light pollution is a pollution that people aren't really aware of,” she states. Her hope is that through community involvement, more people will gain an awareness of light pollution and its detrimental effects.

For example, when speaking of educating the public, MacMillan talks of helping raise communities' awareness of their individual contributions to light pollution along with community wide contributions such as street lights. One of the ways she suggests people cut back on their light pollution is through reconsidering how security lighting is used.

“People have a tendency to over-light their homes, causing glare and often hiding what they intend to reveal,” she says. Strategies such as thinking critically on what in your home needs to be lit versus what you want to be lit as well as changing lightbulbs in favour of those with lower wattages are only some of the suggestions she makes for those hoping to help lower their light pollution.

As for the Mayo International Dark Sky Park, it is revelling in its precious darkness. In order for the park to have Dark Sky status, the park is required to have at least 4 educational outreach events per year. MacMillan happily reports that the Mayo International Dark Sky Park will have at least 10 outreach events this year thanks to events put on by both the community and events hosted by the national park.

Along with outreach programmes, the park has also seen an influx of astro-photographers, many of whom are based in Mayo. The park hopes to increase its astro-tourism in the future. There are plans in place for a Dark Sky festival to be hosted at the Mayo International Dark Sky Park this coming October.

The Mayo International Dark Sky Park is incredible for a plethora of reasons, but perhaps the most important is the fact that it helps marry land and night heritage together in one of the most spectacular of settings. With the newly designated Mayo International Dark Sky Park, it seems we might finally be heading in the right direction when tackling light pollution.


Note 1: Davis, Nicola. "Milky Way No Longer Visible to One Third of Humanity, Light Pollution Atlas Shows." The Guardian. Guardian News and Media, 10 June 2016. Web. 29 June 2016. 2. Katz, Yali, and Noam Levin. "Quantifying Urban Light Pollution — A Comparison between Field
Measurements and EROS-B Imagery." Remote Sensing of Environment 177 (2016): 65-77. Web. 3. Davis, Nicola. “Milkey Way No Longer Visable to One Third of Humanity, Light Pollution Atlas Shows.” 4. Richard H. ffrench-Constant,Robin Somers-Yeates,Jonathan Bennie,Theodoros Economou, David Hodgson, Adrian Spalding, Peter K. McGregor. Proc. R. Soc. B 2016 283 20160813; DOI: 10.1098/rspb.2016.0813. Published 29 June 2016. Web. 5. Bradley, Tomas. “Protecting the Night Sky on the Urban Fringe of Dublin.” 6. Aubé, Martin, and Johanne Roby. "Sky Brightness Levels before and After the Creation of the FirstInternational Dark Sky Reserve, Mont-Mégantic Observatory, Québec, Canada."Journal of Quantitative Spectroscopy and Radiative Transfer139 (2014): 52-63. Web. 7. “First International Dark Sky Park in Ireland Recieves Accreditation” Web.