Towards eco-efficient and enjoyable lighting

Light pollution is a novel environmental issue widely affecting ecosystems, human cultures, societies, and health and well-being of individuals. Rapidly increasing use of new lighting technologies – in particular Light Emitting Diodes (LEDs) – may either increase or reduce disturbing and ecologically harmful outdoor night-time light pollution. Public attention and policy measures aimed to reduce light pollution helps to avoid energy wastage and to create efficiently illuminated and enjoyable outdoor spaces.

Read the full brief below and share your comments:

2 thoughts on “Towards eco-efficient and enjoyable lighting

  1. John Barentine

    The following are the comments I sent to the author via email, posted here at his request.

    Overall, I really like what you have done with this, and it touches on all of the aspects of the issue that are of highest priority to our organization. In particular:

    (1) It doesn’t shy away from the things we don’t know. (“Rapidly increasing use of new lighting technologies — in particular Light Emitting Diodes (LEDs) — may either increase or reduce disturbing and ecologically harmful outdoor night-time light pollution.”) As an example, the apparent reduction in brightness in some developed parts of the world which, with the suggested explanation given, shouldn’t lull us into the naive belief that the problem is being solved by improved technology alone without reductions in the total amount of light we use.
    (2) At the same time, it asserts that what we don’t know could be harmful, and that demands caution in proceeding. (“These technologies are often uncritically welcomed…”)
    (3) It’s sufficiently forceful based on what we DO know. (“More research is needed but the existing knowledge base is already sufficient to justify actions aimed at reducing light pollution.”) In this sense the issue is much like climate change, and the fact that we don’t have definitive answers to all possible questions about the issue doesn’t mean we shouldn’t take action on issues in which we are confident of our knowledge.

    Some suggestions, by section:

    “Introduction: Too much of a good thing”

    In the first paragraph, the first instance of light pollution should be in quotes to indicate it is a proper term (so: “Light pollution” has been coined as a concept…)

    The definition of light pollution given in the first paragraph: a number of different definitions have been proposed, so it may be worth noting that this isn’t the only one. Also, as it stands, you might want to add something about wasted resources/costs to society. e.g., “Light pollution can be defined as artificial night-time lighting causing adverse aesthetic, health or ecological effects that represents a waste of natural resources and GDP.” I would say we’re trying in part to get across the idea that light pollution is ultimately a drag on a nation’s potential.

    2nd paragraph, 2nd sentence I would slightly reword: “Global emission of light energy into the nighttime environment have increased rapidly since the advent of electric light.”

    Later in that paragraph, you cite statistics from Cinzano et al. (2001) about the fraction of people living in light-polluted areas and those who can’t see the Milky Way anymore. We’re increasingly hesitant to attach numbers to questions about light pollution and visibility due to concerns over the reliability of data from which the estimates were derived. As an example, Kyba et al.’s recent (2015) paper in Nature Scientific Reports asserts that “Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%” which casts some of the World Atlas conclusions in doubt. We’re now simply saying that “billions of people around the world” live in light-polluted conditions and leaving it at that.

    “Attention to wise use of lighting technologies is needed”

    I think the sentiment of the first paragraph is almost understated, in particular because the ascendancy of white LED in outdoor lighting, with the attendant short-wavelength emission, is one of the biggest challenges we currently face. Efficiencies of white LED systems with progressively lower color temperatures are improving, but municipalities looking to simply lower their electric bills are choosing high CCT white LED systems with little consideration given to any environmental drawbacks. This is particularly important right now in parts of the world where white light is the dominant cultural preference, such as Asia. So this paragraph may be the most important one in the document, from our perspective.

    2nd paragraph: you cite our Model Lighting Ordinance as “(IDA & IES 2014)”. This is a minor detail, but the latest revision of that document is 2012.

    Later in that paragraph (and again in the 4th paragraph) you pick up on a very important theme in the realm of light pollution and public policy, which is enforcement. While it’s technically “implementation”, it’s also “efficiency” because a functionally unenforced/unenforceable policy has zero efficiency in achieving its intended goal. Passing a law isn’t a victory, as much as politicians would have us believe. The hard work is in enforcement, and we find that many jurisdictions have neither the budgets nor the zeal for proper enforcement. It may be worth mentioning this, and pointing out that the metric is actual gains achieved, not merely the fact that a law exists on the books. (The downside is that I’m not aware of much in the way of research on this, so as to be able to cite the relevant literature.)

    The bullet points from Falchi+ in the 3rd paragraph are excellent, and pretty much exactly the advice we give policymakers and the public.

    5th paragraph: you point out, rightly, that determining what kind of light is “best” is “a value-based question that cannot be solved by scientific facts alone”. However, research can determine those preferences and, I think, the preferences are subject to being shaped by public awareness campaigns, policies, etc. Failing to take this into account can be costly; what immediately comes to mind is the recent situation in Davis, California, where the municipal government installed a white LED system for its street lighting. The city did not take public sentiment into account, and found that the fixtures chosen for the project were roundly rejected by the public. As a result, the city is now eating the cost of replacing those fixtures; fortunately, they put up some demonstration projects the second time around to get public input in the selection of new fixtures. So while admitting that acceptable lighting is driven in part by aesthetics, jurisdictions need to consider both the scientific facts AND public sentiment (revealed through, e.g., survey data) before making lighting choices.

    Lastly, in the final paragraph, I might suggest changing the wording of the final sentence (“The key part of such awareness-raising is the prevention and reduction of unnecessary and harmful light pollution.”) While I sense the underlying message regarding IYL, I think the sentence is a little unclear. Maybe something like to the effect the following: Light is not a panacea for the world’s problems; while it can solve some, it creates others. (That, I think, underscores the notion that while IYL is a good thing, we can’t let the dominant message be that light is always good for us.)

  2. James Hale

    This brief is very timely given the current step-change in lighting around the world as a result of LED lamps, due to the largely unrecognised impact of artificial lighting on human and ecological health (from a policy perspective) and due to the recent increase in related research. There is also likely to be greater interest in this issue from the broader public given that 2015 is the UN international year of Light and Light-Based Technologies.


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