Lights, lights everywhere, but what about the risks of light pollution? The world has experienced an unprecedented environmental change during the past century as the electric light has permeated our nights. In the near future, this change may accelerate because of increasing use of new illumination technologies such as LED lights.

In most parts of urbanized world the disappearance of natural darkness is easy to observe even with bare eyes. Night-time satellite pictures give a wider view on the extent of the glow of city lights and other sources of artificial light. Economic progress is accompanied by increasing emissions of light energy into the environment. However, the question is not only about the waste of energy.

Ecological and health risks related to this global environmental change have been nearly absent from public debate, apart from occasional news reporting on light pollution potentially causing breast cancer, for instance.

Not surprisingly, there are various risks related to light pollution. Ecosystems and organisms have evolved through millions of years under natural cycles of dark and light periods. Disappearance of natural night is therefore a radical change. During the recent years, a variety of harmful effects of artificial outdoor illumination have been described, in addition to well-known problems such as the inability of sea turtle hatchlings to find their way to sea or collisions of migratory birds to illuminated structures. Some of these lesser-known problems include the disturbance caused to underwater biota by lights from land and ships or the disruption of night time pollination of plants by nocturnal insects. What remains in the dark – figuratively speaking – are the long-term effects cascading through ecosystems.

Risks related to light pollution pose various challenges to science communication. One problem is the genuine lack of knowledge. It’s reasonable to assume that we don’t know what we don’t know about the long-term effects of light pollution. This kind of unintentional unawareness creates space both for unjustified scares and unfounded negligence. Unintentional unawareness cannot be entirely eradicated but as our knowledge accumulates it can be partly turned to deliberate unawareness.

Another challenge is that the notion of light pollution challenges deeply rooted cultural assumptions and values emphasizing light as a symbol of safety and security, progress, wealth, and virtue. A prime example is the commonly held belief that street lighting automatically reduces crime rates or improves safety. Such positive connotations may lead to deliberate inattention regarding potential negative effects of artificial light. In fact, dimming overly-bright lights in most cases actually improves security, as sparingly used but carefully directed light means less glare and better visibility. This is especially true during bad weather conditions. Side-benefits include decreased energy consumption and less pollution from energy production. In many cases it is also possible to improve the aesthetic quality of the built environment by avoiding light clutter.

Communicating about emerging environmental issues such as light pollution is not easy. To be successful, risk communication must be able to tackle different forms and causes of absent information, compare different types of costs and benefits, and communicate the information in a right moment to the right audience. New knowledge unavoidably creates new types of uncertainties and introduces new areas of absent information. Increasing public awareness of such unknown unknowns is perhaps the greatest challenge of risk communication.

Featured image credit: San Francisco Cityscape by 12019. CC0 public domain via Pixabay.