Regular readers of the blog know that light pollution is a growing problem around the world. Each year, nights get brighter as humans deploy ever more outdoor lighting. This makes it harder to see the stars at night. It can also harm wildlife, threaten human health, and diminish the natural nighttime environment.

We know that much of this problem comes from wasted light. Lights are often too bright, shine where they are not needed, or stay on when they are not useful to users of outdoor spaces. Of course, this does not mean all outdoor lighting is bad. Lighting is important for safety, work, and amenity in public spaces. The challenge is using the right amount of light in the right places and at the right times.

Public policies can help reduce light pollution, but only if people support them. Many people want darker skies, but they also want safe streets, active businesses, and control over their own property. Any workable solution must balance these needs.

​One possible solution is the use of Lighting Zones. Lighting Zones guide limits on outdoor lighting based on the type of activity on a property and expectations for the availability of light at night. Different places have different lighting needs, and Lighting Zones try to match lighting levels to those needs. This month, we explore how Lighting Zones came to be, what their benefits and drawbacks are, and what new developments in this area mean for urban planning.

Lighting Zones emerged from ideas long used in city planning. Cities often divide land into zones, such as residential, commercial, or industrial areas. An overlay zone adds extra rules to these areas without changing the original zoning. The intent of land-use planning is to promote desirable development outcomes as well as more efficient uses of resources.

The idea is to match allowable activities on land parcels to their geographic situation. Compatible uses tend to cluster together. Zoning tends to isolate and restrict activities the public finds objectionable. In short, planners believe that zoning influences patterns of human behavior. Furthermore, the resulting changes are beneficial to society.

As applied to outdoor lighting, each Lighting Zone has its own rules for new buildings and outdoor spaces. City planners can then check if a new project follows the rules for its zone. This approach allows cities to focus on lighting without rewriting their planning laws.

But zoning rules can be hard to design and use correctly. Also, many urban planners don't learn about outdoor lighting in their formal education. They often know little about lighting technical information. As a result, outdoor lighting policies like ordinances and bylaws can be ineffective.

​The creation of Lighting Zones intended to make lighting rules easier to understand and apply. The idea originated from international standards promoted by the International Commission on Illumination, known by the French abbreviation "CIE". The Environmental Zones first appeared in a 2003 CIE publication intended to reduce obtrusive light at night. In 2011, these ideas were later expanded in the Model Lighting Ordinance (MLO). The result offered local governments a clear way to regulate outdoor lighting.

Lighting Zones are divided into five levels, from Zone 0 to Zone 4. These cover a wide variety of situations from areas with little or no outdoor lighting to very bright places, such as busy city centers or entertainment areas like the Las Vegas Strip. The table below shows the definitions of the Lighting Zones and how they relate to the CIE Environmental Zones.

Lighting allowances tend to scale up as the Lighting Zone number increases. The goal is simple: allow more light where people expect it, and less light where darkness is important. This system helps planners and decision makers set clear limits. Instead of arguing about every new light proposed, they can use the zone rules to guide their choices.

Lighting Zones have several benefits. They are flexible, easy to explain and match well with existing land-use zones. In some cases, local governments map them to their existing zoning systems. Lighting Zones help communities set clear lighting expectations for different areas. They can mediate dispute resolution as land uses change over time. And they are a tool local governments can use to push back against requests for exceptions or adjustments to development rules.

But there are also some drawbacks. Some places do not fit neatly into one zone. If zones are applied carelessly, areas may be given higher lighting limits than they really need. Over time, this can lead to brighter nights instead of darker ones. Some people also worry that Lighting Zones are too simple and do not capture real-world needs. Others may resist them because they do not want new rules or limits on outdoor lighting.

Many communities do not make use of Lighting Zones in their planning systems. At some level this is because of a lack of awareness that they exist. But even when planners know about Lighting Zones, they may hesitate to embrace them. They may find the distinctions between Lighting Zones unclear. In turn, they find it difficult to know when and where to apply them. Elected officials sometimes turn away from adopting policies they don't completely understand. They may also sense a lack of public support for this kind of zoning. 

The Illuminating Engineering Society, a U.S.-based professional organization of lighting engineers, promotes various lighting recommendations. Among its 'recommended practices' is RP-43 ("Lighting Exterior Applications"). 2026 will see a major update to this document. It's relevant to this discussion because RP-43 maintains the Lighting Zone definitions that first appeared in the MLO.

While the new recommendations are not yet published, they are public by way of the American National Standards Institute (ANSI) review process. We know that they contain a few amendments to the Lighting Zones. One major change is the addition of a Natural Conditions Zone. At last, this recognizes that the goal in some places should be to keep them naturally dark. These are places where the human presence at night is small or nonexistent. As a result, there is no expectation of permanently installed outdoor lighting. Where lighting deemed necessary, it should take the form of flashlights/torches and similar portable lighting.

​This is a turning point for the lighting engineering and design community. Before this update, the zone with the most restrictions was Lighting Zone 0. The definition of that zone calls for "little or no lighting" but does not exclude lighting altogether. Establishing the Natural Conditions Zone acknowledges that some situations call for a total prohibition of permanent outdoor lighting installations. As a result, the new RP-43 brings clarity to the Lighting Zone 0 definition. While Lighting Zone 0 still allows the installation of permanent lighting, its use is minimized by design. These updates help protect places where darkness is especially important, while still allowing bright lighting where it is legitimately needed.

Lighting Zones are a useful tool for managing outdoor lighting. When used carefully, they help protect dark skies while keeping places safe and usable at night. But for Lighting Zones to work well, they must be applied thoughtfully and supported by the public. As lighting technology and community needs change, the zones and their rules will also need to change. Right now, the biggest challenges are that many people do not know about Lighting Zones, and some resist new regulations. Better education and clear communication can help show that smart lighting benefits everyone.

"Water is life." Anyone who lives in an arid climate has heard this phrase. As the global climate crisis intensifies, more people are hearing it. It signals the value of a crucial natural resource threatened by overconsumption and pollution. Many years of water conservation efforts have shown the need for a unified approach. And careful collective management of water resources is a proven way of sustaining access to clean water supplies.

​What lessons can we learn from this kind of resource management that we may apply to conserving nighttime darkness? In this post, we dig into the idea of light pollution reduction through the management of "lightsheds". This approach has great untapped potential to surpass current shortcomings in the way we protect the night around the world.

We have previous written here about aspects of outdoor lighting pollution. In "Good/Better/Best Outdoor Lighting Policies" we examined the main elements of such policies. And in "Toward a 'Clean Night Skies Act': a roadmap for a U.S. national light pollution policy​" we presented a vision of a national outdoor lighting management strategy.

We find there are two main regulatory approaches: "supply side" and "demand side". Supply side limits the kinds of lighting that can be sold, installed, and/or operated in a jurisdiction. (Make bad lighting difficult to get and people mostly won't use it.) The demand side aims to change behavior by incentivizing the use of some kinds of lighting  through, e.g., more allowances. (Encourage the development of a market for better lighting products catering to consumer preferences.) Some policy approaches are a combination of these two that apply in "carrot-and-stick" fashion. A hybrid policy might restrict some popular kinds of lighting applications to reduce light pollution while permitting others. 

Another dichotomy in lighting policy involves when enforcement happens: "before the fact" and "after the fact". The former takes place before operation of the lighting. Examples include planning permission, comparison with standards, obtaining building permits, and post-construction inspection. Policies are enforced after the fact through citations issued to property owners whose lighting does not follow the law. 

Most lighting policies thus tend to prescriptive and/or proscriptive: they say what is and isn't allowed, and if lighting is allowed, how it is to be designed, installed and operated. But in many countries, as a practical matter, this is all still matter of local enforcement. Local authorities make decisions about how to interpret lighting policies and how (or even whether) to enforce the law. 

But often that doesn't happen. The public doesn't like being told what to do. It also dislikes state regulation of individual behaviors. The result is that property owners may simply disregard the law. Jurisdictions with laws on the books may be loathe to enforce the law, citing factors like inadequate staffing.

From time to time, other ideas about how to regulate outdoor lighting are tried. Some countries have very strong top-down policies: national legislation decrees artificial light at night (ALAN) to be environmental pollution subject to regulation and tasking lower jurisdictions with enforcement. 

An example of this is Mexico, which recently amended its General Law of Ecological Balance and Environmental Protection of 1988, also known as LGEEPA. The move attached light pollution to the existing LGEEPA, which makes its control obligatory to municipalities.

Where there is strong public support, this method can work well. But it is difficult to enact this kind of legislation in contentious political environments. And implementing jurisdictions may well ignore the central government's mandate. As a result, these efforts often produce only symbolic outcomes. 
Another idea stems from the fact that light pollution isn't restricted to any particular jurisdiction. It does not respect boundaries between municipalities, regions or nations. As a global problem, it might benefit from a global solution. This could involve a new international treaty that binds signatories to meet pollution reduction targets. 

Such was the goal of the spectacularly successful Montreal Protocol on Substances that Deplete the Ozone Layer (1987). 198 countries that ratified it agreed to phase out the production of industrial chemicals that historically caused a 'hole' in the Earth's ozone layer. Since it took legal effect, compliance with the Montreal Protocol has been high, and the ozone layer is repairing itself. 

This example proves that treaties can achieve important and meaningful results. But such solutions need buy-in from many countries. Developing economies may balk, making it difficult to achieve consensus. And the process of drafting and bringing a new treaty into force is often painfully slow.
These challenges prompt some to ask: what if we tried something new and thus far untested? One such new way of looking at outdoor lighting regulation turns many of the existing ideas on their heads. 

A lightshed is the territory around a given point containing all the sources that send light at night to that place. Some of that light is directly emitted from sources on the ground near the point, while other sources contribute indirect light scattered in the atmosphere.  Managing a lightshed to reduce light pollution in that place targets the source of the pollution in an outcome-based fashion.

Lightsheds are analogous to watersheds. The U.S. National Oceanic and Atmospheric Administration (NOAA) defines a watershed as "a land area that channels rainfall and snowmelt to creeks, streams, and rivers, and eventually to outflow points such as reservoirs, bays, and the ocean". It's built on the water cycle that carries water through the terrestrial environment from and back to large accumulation basins through an interface with the land. 

The management of watersheds identifies water as a shared resource that all entities and jurisdictions in the watershed must protect in order that they themselves — as well as others — can continue to enjoy it. The intent is to make the resource indefinitely renewable by ensuring that the "cash flow" in the system is always greater than zero. It attempts to avoid a so-called "tragedy of the commons" in which groups within the watershed consume all of the resource.

The analogy between water and light isn't perfect, of course. There are plenty of sources of light in the nighttime environment but also plenty of sinks. There isn't a "light cycle" that works like the more or less closed loop of the water cycle. And while there are both natural and artificial sources of LAN, but there's nothing like "artificial water". (An imperfect comparison is how humans draw water out of the watershed, depleting it.) In a watershed the conservation object is the resource (water). But in a lightshed the object is natural nighttime darkness. 

Lightshed management focuses on places where nighttime darkness still exists (at least to begin with). Managers determine the sources of ALAN arriving at a given location through computer simulations that use satellite data as model inputs. Associations of governments at different jurisdictional levels pledge to protect darkness in the target location through policy changes. The policies aim to limit and ultimately reduce light emissions in their territories. This could involve a strategy like "cap-and-trade": the influence of newly installed lighting is offset by the removal of unnecessary lighting elsewhere. Over time, the rate at which ALAN reaches the target area slows to zero and then turns negative.  

Another way to look at this concept is to think of light pollution is the byproduct of consumption of light at night for useful purposes. Dividing the light emissions in a region by its population yields a metric like "lumens per capita". The number in a certain area depends on many social variables. But in that area it provides a point of comparison as time passes under a lightshed management plan. 

​By reducing waste and improving outdoor lighting, an area's lumens per capita consumption can drop. Even as its population grows, light pollution can continue decreasing. Acting on the entire system rather than its components, as lighting policy typically does now, might turn out to be the winning strategy. Instead of blanket regulations and ill-defined targets, lightshed management targets the underlying sources of the problem for remediation. 

To be clear, there are many ways that lightshed management may fail. No one has (yet) tried lightshed management as a policy lever on the problem of light pollution, at least not at any meaningful scale. As with new international treaties, it may be very difficult to sign up all the actors in a lightshed to take part in the project. And if even one major light polluter doesn't sign up, the integrity of the project may be compromised. 

Still, conditions are ripe for a small-scale experiment. We have glimpses of what this could look like already. Large parks and protected areas participating in the International Dark Sky Places Program are trying something a lot like lightshed management. Large and complex land arrangements accredited by the program must devise Lighting Management Plans. This often involves obtaining participation from many stakeholders. When it works, we see real reductions in light pollution; for examples, see here and here.

The next big test is to identify a lightshed and set a quantitative goal for light pollution reduction. For the test to be realistic, it should encompass a large landscape with diverse land uses, including urban centers. Both public and private landowners should be involved in the experiment. 

If it is successful, the same stakeholders should take part in planning for how to maintain the improved conditions. They have a strong interest in doing do, whether for conserving local nocturnal wildlife, furthering astrotourism development, or for many other reasons.

Big, challenging problems call for bold new solutions. Light pollution is readily reversible, and when steps are taken to reduce it we see clear social and economic benefits. Now is the time for society to take a more measured and deliberate approach to preserving nighttime darkness. Lightshed management may be the solution that brings the meaningful global change that the problem deserves.

Public policy is an important tool in creating lasting social change that may decrease light pollution over time. We have written here before about policy matters here, considering the motivations ("Why pursue an outdoor lighting policy in your town or city?") and important elements ("Good/Better/Best Outdoor Lighting Policies"). But how do technical concepts and policy proposals on the use of outdoor lighting become law? In short, they must withstand scrutiny by, and gain the support of, elected officials. In some democracies the legislative process may seem to outsiders like a daunting prospect. Yet in most cases it starts with simple conversations that develop into relationships.

In this post we will look at ways to influence that process by communicating with elected leaders. It starts by understanding how the relevant level of government works. Understanding how policy agendas are set is important. But most significant is learning a new language of politics and procedure. Catering to these issues is the key to becoming an insider. Here we'll look at each of these ideas in turn.

In most Western countries, policies that affect the use of outdoor lighting are made at the national level. These policies filter down to the level of individual cities and towns, which must follow them. An example is France, which sets legal standards across its territory that all jurisdictions must observe.

Some countries with federal systems devolve the authority to set these policies onto lower levels of government. This is true in the United States and Canada, where lighting policies originate at the state/province of municipal level. In still other countries, like Mexico, the central government sets very high-level standards and leaves lower governments to decide how to implement them.

This may be confusing to people who have no prior experience in dealing with government other than voting. It may require a consultation with an attorney to figure out which jurisdiction governs lighting. But it’s important to figure out early in the process in which jurisdiction your lighting problems exist. This ensures that efforts to address those problems target the proper level of government. Doing so also means time is not wasted asking for solutions that a given level of government isn’t empowered to address.
​
One more point of significance here is what kind of law is best to pursue. Statutory laws are familiar to most people. These are proposals written by legislative bodies that endure the political process before becoming laws. Many Western countries also have some form of common law, which is a series of mostly unwritten precepts derived from history and tradition. Certain legal notions like nuisance derive from the common law. And third, most governments have some sort of administrative or regulatory procedures that function like laws. Sometimes the change one wants to bring about don't demand new laws at all. A changing interpretation of an existing law can yield the same result.

It's not enough to know to which level of government one should present a policy idea. Governments everywhere face many concerns vying for their attention. Representative democracies are in part designed to address this situation. Constituents vote not only for candidates but for the ideals and priorities they espouse. Competition among policy proposals places them on a policy agenda for legislative bodies to consider.

In a recent post we described the "issue attention cycle". This is a model for the process by which policy ideas are generated, considered, implemented and revised. In brief, the cycle works like this. In the first phase, a social problem of some kind emerges as the result of different influences. Public awareness of the problem grows during the second phase. Some people who become aware of the problem realize the cost of inattention to the problem and begin to demand solutions in the third phase. The cycle reaches its peak at the start of the fourth phase in which a policy solution is devised and implemented. As the problem targeted by the policy change diminishes in significance, public attention begins to ebb. In the fifth and final phase, the policy implementation is mature. But new problems may pop up despite the policy change or even because of it. These new problems may then start attention cycles of their own.

The extent to which lawmakers are thinking about any given problem depends very much on the phase of the cycle. The days of 'early adopters' may see no interest at all from elected officials. Often it is only when a problem becomes acute (and even severe) do officerholders begin to pay attention.

But elected representatives are always mindful of their terms of office. They know that, on a reliable schedule, voters will hold them to account for their time in office. This often makes officials very sensitive to public perceptions of issues. If they hear from enough of their constituents to the effect that an issue is important to them, they are more likely to take steps to address it. The timing of issue advocacy is thus crucial to the success of efforts to bring about change.

Successful advocates for change study trends in political discourse very carefully to choose the best time to make policy proposals. The foundational work needed to bring society up the "hill of awareness" may be long, lasting sometimes even decades. Deploying a proposal too soon usually leads to elected officials ignoring it. Waiting too long invites complacency and a sense that adverse outcomes are inevitable. Careful stewarding of proposals through the attention cycle seems to yield the best results. 

Policy ideas become law through a complex process of influence that caters to the needs of the people whose input is necessary at different steps along the way. Sometimes that’s a policymaker; other times it’s staff, and at certain points it’s definitely the public. All these groups must be carefully managed to anticipate obstacles and figure out ways over or around them. This goes beyond being polite to people. It involved getting to know them at some level and thinking of them as colleagues rather than mere gatekeepers. And despite these relationships, one still might not get the desired outcome in the end.

Legislative staff often hold outsized power in setting the detailed policy agenda. They also occupy key positions of influence over the legislative bodies they serve. Staff can bring attention to your proposal to get it on the agenda of the legislature and keep the process moving at the proper pace. They act as the first screen or filer through which policy ideas pass during the enactment process. Furthermore, given the electoral cycle, elected representatives have short time horizons. As professional employees, staffers often last much longer in their positions. They are the repository of information transmitted from one generation of lawmakers to the next. 

Next comes the policy idea itself. This is the core of every change movement. Don't just complain that you don't like the status quo as it affects the issue at hand. Instead, show why the status quo is inadequate and come prepared to discuss specifics. Bring evidence to the discussion where you can get it.  And communicate in a convincing way what it is you want the elected officials to do. 

Successful policy changes begin as well-constructed, logical arguments. They appeal in equal measure to reason (the mind), emotion (the heart), and feasibility (the gut). Ask yourself: what is the solution, and why is it the right one? Consider alternative policies and explain why they won't work as well (or at all). Expect objections to the solution and game out strategies for responding to them.

Elected officials, and their staffers, expect advocates to come to them with an "ask". That is, they presuppose that the purpose of a phone call or a meeting to discuss an issue is to convince the legislator to support some specific action. Advocates should lead these discussions with the ask and provide context establishing a need for the action. They should conclude by making clear that the ask is the right and best way to address the problem. They should also suggest the consequences of inattention to the issue or inaction in response to the ask.

Of course, this element should not dramatize the problem beyond what the facts prove. But the argument should convey a sense of urgency that the advocate wants the official to sense and confront. "Success" in this context is turning a skeptic into a supporter. With deepening relationships come trust, and with trust often comes endorsement.

Enactment of a new or amended outdoor lighting policy isn't the end of a process but the start of a different one. Once governments decide to improve their lighting policies, often they want help with, e.g., evaluating permit applications and deciding how to enforce rules. They can also use information about lighting and light pollution to educate the public in hopes of increasing support for change. And for this leadership they look to policy advocates as the experts.

Relative to those who write or implement laws, individuals and groups that advocate for those laws are uniquely positioned. Their knowledge of problems and solutions runs deep. Officials may enlist their help during implementation to understand the fine points of a law's requirements. This is a separate matter from legal interpretation, which is for courts to decide. Rather, governments may ask advocates to take part in implementation to ensure it proceeds correctly. The relationships forged during enactment of policy often survive the end of the formal process. Better outcomes seem to result when advocates remain engaged.

This may all seem discouraging to the uninitiated. But each advocate starts out new to an issue like everyone else. Like the issues themselves, effective advocacy is something to learn. And experience proves the view expressed by the American cultural anthropologist Margaret Mead, who once famously advised: "Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has."

If you found this post inspiring but don't know how to get started, we can help. Advocacy for policy change, and supporting successful lighting policy proposals, is at the heart of what we do. Contact us today to find out how we can devise, launch and support policy initiatives in your community.