Written evidence submitted by Isabelle Ficker (INS0039)

I write to give evidence on the impact of artificial light at night (ALAN) on insect decline.  Given the scientific evidence1;2, it is surprising that ALAN is not mentioned in the Call for Evidence.  While perhaps understandable as LEDs are relatively new, it does testify to a lack of awareness on the part of the House.  This clearly needs to be rectified and action taken.  The harm to the biosphere has been exacerbated by the introduction of blue-rich (ie 2700K and over) LEDs. 

Biodiversity Intactness Index3

• Britain has just 53% of its biodiversity left;
• this is lower than: Western Europe; all G7 nations; many other nations such as China. 
• 90% biodiversity needs to be maintained in every country worldwide to maintain ecological processes such as pollination and nutrient cycling, and so avoid starvation. 

Contributors to Insect Decline are:

• habitat loss
• chronic exposure to mixtures of pesticides
• water and air pollution
• plastics
• intensive farming
• soil degradation
• climate change

ALAN has emerged as an equally important contributor4.  If insect declines are not halted, terrestrial and freshwater ecosystems will collapse, with profound consequences for human well-being and global food supplies5. 

A review of 150 insect studies concluded that ALAN is a significant cause of insect loss2. ALAN is an additional, but avoidable stressor, on already stressed bio-systems.  It should properly identified as a form of pollution but one that, fortunately, it is easy to address.

ALAN and the Biosphere

ALAN only serves Man and has brought with it unintended consequences. 

All living organisms, including plants, have inherent biorhythms.  These organisms (ranging from the smallest plankton through to Man) have evolved over hundreds of millions of years to adapt to the natural rhythm of light and dark.  Night and daylight act to fine-tune these biorhythms which govern essential health maintenance systems.

Many vertebrates and invertebrates, including vital pollinating insects, are nocturnal.  They rely on circadian, lunar, stellar and seasonal rhythms of light for orientation, migration, foraging, pairing, reproduction, and evading predation. ALAN blurs the distinction between night and day, “disturb(ing) this natural behaviour and ha(ving) a negative impact on their chances of survival”6 Blue-rich light (i.e. 2700K and over) is particularly disruptive7.  Its effects cascade through the eco-system, affecting day-time organisms and their ecological function as well8;9;10;11;12 

ALAN and its associated skyglow affect :

Insects

• 90% of all known living organisms are insects13;14
• 60% of insects are nocturnal: moths are amongst our most vital pollinators15
• Fruit flies (Drosophila) are indicators of insect vulnerability. Their mitochondria (energy cells) are vulnerable to 420nm (blue band) light which undermines their function and is associated with reduced fly mobility16
• Moths account for 95% of all Lepidoptera. They undertake 15% of all pollination15;17
• Blue-rich light affects moth reproduction by reducing the quality and quantity of the pheromone in females17;18
• Moth pollination is reduced in the presence of street lights19;20
• Moths die of exhaustion, predation or trapped in fittings21;22
• Moths’ natural camouflage does not protect them from predation in lit areas22 They also fail to perform bat-evading manoeuvres around light sources22

Moths are attracted to light Photo S. De Peak

• Moths migrate long distances at night.  Lights on their flight path exert a ‘crash barrier’ effect, preventing migration22
• ALAN disrupts moths life-cycles that are carefully synchronised with those of their food-plants.  Caterpillars are timed to hatch when food is plentiful. Predators, such as birds, rely on caterpillars for their young and time breeding to coincide with moths’ life-cycles. Climate change and ALAN disrupt these delicate relationships: breeding cycles may no longer match food supplies. This could be disastrous for some species23
• Street lighting negatively impacts local insect populations22
• pollination decreases 62% in the presence of ALAN20
• Insect populations decline under long time exposure to ALAN24
• Crickets exposed to constant light have lower melatonin levels and impaired immune function compared with those exposed to only 12 hours of light per day25
• the bioluminescence of female glow-worms decreases in the presence of street lighting26
• UV and blue-rich light triggers ‘flight-to-light’ behaviour27;22;28;29 drawing insects from their natural environment and behaviour30, affecting pollination, reproductive opportunity, feeding22 and survival31;22;21.  Numbers and distribution are consequently affected.
• Mayflies emerge looking for polarized light.  This is compromised by blue-rich light. Asphalt  and other surfaces resemble water; however, eggs laid on asphalt die, thus reducing the mayfly population32.

Dead mayflies around a security light (Photo: P. de Vries)

• Insect larvae drift is impaired in illuminated flowing waters33;34
• Loss of insects35;36;27;37 impacts insectivorous creatures, its effects cascading through the eco-system, potentially restructuring ecological communities by modifying the interactions between species38
• The carcasses of dead insects attract an increase in phytosanitary pests (slugs, snails, spiders and rats etc)39 to 42
• insects are a vital food source for many organisms; bats, which in natural conditions rather catch beetles, will consume more moths43, leading to decreased nocturnal pollination and moth populations.

Plants

Plants and insects are interdependent, providing each other with nutrition and pollination. 

ALAN affects plants’ perception of seasonal changes and their associated physiological responses (bud break; leaf fall; seed production and maturation; starch production to sustain metabolism and growth; stimulation of immune defences) affecting food supply and making plants more vulnerable to disease44 to 54.

Immature soy bean growth can be seen behind each HPS roadway lighting fixture. Virginia Tech Transportation Institute

Bats

Bats perform vital pollination and insect control services and are protected and priority species.  They are nocturnal and light-averse, some highly so.  They are highly effective at controlling agricultural pests, leading to economic benefits for farmers.  It follows that they require insects to survive and to provide alternatives to pesticides55 to 62.

Birds

Insects are an important food source for birds that contribute to seed dispersal.  ALAN affects inter alia pairing, reproduction, feeding (including of young), and migration63 to 80

Non-flying mammals

Rodents are indicator species.  ALAN induces circadian disruption with intendent physiological consequences81:

Loss of mammals can lead to loss of eco-system connectivity and ecological ‘blind spots’82.

Geographical and Territorial Impacts

ALAN can impact environments (and their eco-systems) hundreds of kilometres from emission points and distract animals and insects (ie migratory birds, bats and moths).  Since the introduction of LEDs, ALAN has been increasing globally at a cumulative rate of 2.2% per annum - the so-called ‘rebound effect’:  LEDs are cheap and energy-efficient, and people are lighting more83:

Many of these lights are ‘blue-rich’ (in the ‘Neutral’ to ‘Cool’ and ‘Very Cool’ range)84. 

Linear structures (i.e. highways) fragment ecosystems so luminaire height, lighting duration and use of dimming and tuneable fixtures are relevant to minimising light spill. The nocturnal environment can only be ameliorated by modifying the source. Even when lighting is carefully installed (downward facing, shielded, with appropriate colour temperature) light can be reflected and scattered by the atmosphereAppendix 1

Shorter wavelengths (electromagnetic radiation 350-500 nanometres) scatter 6 times more than red wavelengths and are thereby responsible for the substantial increase in sky glow since the introduction of blue-rich LED lighting.   Even small amounts of blue have a noticeable effect on the night sky and environment.  The commissioning of lighting installations is therefore critical and its impact on the biosphere should be carefully considered. 

A Healthy Biosphere: ‘Red’ v ‘Blue’ Light

Blue wavelengths are highly effective at suppressing melatonin which, in turn, affects healthy biological functions. Life on Earth has evolved over millions of years to cope with large amounts of short blue wavelengths during the day (the reason the sky is blue) but not at night:

Spectral irradiation graphs of Moonlight (left) and a 4000K LED used in many streetlights (right)

(Interestingly, although Moonlight and a 4000K LED share the same colour temperature, they do not share the same spectral distribution.  The latter’s spike of short-wave blue has important implications for well-being.)

The widespread spectral shift, across Europe and the UK, to broad white, blue-rich LEDs is increasing the risk of harmful effects to ecosystems85

Lighting has changed from:

• spectrally balanced daylight to….                                    (beneficially) red-dominated early incandescent bulbs  

• to red-poor fluorescent lighting                                        to ‘neutral’ and ‘cool white’ blue-dominated LEDs

Spectral Irradiation Graphs courtesy of Professor Robert Fosbury, UCL Institute of Opthalmology

• Blue wavelengths emit in the reactive oxygen-producing band.
• Environmental stressors (pesticides etc) and developmental transitions (such as seed formation and maturation) involve the formation of oxidative stress (free radicals) in both animals (including insects) and plants. 
• Many signalling pathways are involved in oxidative stress triggering responses in insect cells which could be physiological, pathological, and adaptive. Drosophila melanogaster (fruit flies) is a well-studied organism in the field of oxidative stress86
• Combatting oxidative stress is melatonin dependent.  Without melatonin, immunity to damage is depressed87
• Short LED wavelengths provide the mechanism for damage. (In humans, blue light plays an essential role in the pathogenesis of chronic diseases such as cancer and diabetes). 

The mitochondria of Drosophila are vulnerable to 420nm (blue) light which undermines their function and is associated with reduced mobility16.  This has implications for other species and can also be applied to human health.

• At the other end of the spectrum, is the beneficial, near infra-red region where infra-red light is readily absorbed by living tissue (human, insect, plant etc). It is obtained in abundance from sunlight but virtually not from the current white LEDs. Infra-red absorption is very important: it is associated with the production of protective subcellular melatonin.

Spectral diagram courtesy of Professor Robert Fosbury, UCL Institute of Opthalmology

• Experiments on insects help to elucidate impacts of ALAN on humans88:
• Bees, starved overnight and given a glucose load in the morning, showed a 50% reduction in glucose levels when exposed to 650nm light and a 50% increase when exposed to 420nm light89.  This has implications for diabetes in humans and suggests that inter alia insects, birds and bats have circulatory melatonin.
• Body irradiation with red light improved sleep quality in elite athletes, offering a nonpharmacologic and non-invasive therapy to prevent sleep disorders post-training90

• The organism’s natural antioxidant system relies on melatonin.  Subcellular melatonin is stimulated within cells through exposure to the infra-red wavelengths of sunlight91;92. The release of circulatory melatonin is triggered by the fading light of day.  Melatonin is a powerful anti-oxidant that protects against diseases characterized by mitochondrial dysfunction, including reduced survival and fecundity (see Insects)93. 

Melatonin production and suppression is explained below using a human model:

• Intrinsically Photo-sensitive Ganglion Cells (ipRGCs) in the eye gauge overall light intensity and turn light energy into electrical signals. ipRGCs have a direct link to the brain and are the pathway to Melatonin release (at nightfall) and suppression (at daybreak). ipRGCs have a peak sensitivity in the blue part of the spectrum which is particularly effective at shutting down Melatonin production. 

• Although humans have a sophisticated system, it reveals the existence of systems which, though simpler, exist across the ecosystem.

From Light as Medicine, Dr. Roger Seheult, University of California Riverside School of Medicine (LM)94

• The Master Clock maintains the organism’s Circadian Rhythm which in turn regulates physiological functions. 

                                                                                                                                                                                                                LM

• Even low intensities of lighting suppress Melatonin92 Melatonin suppression interrupts the repair and maintenance that normally takes place at night for both non-human and human organisms95.  Exposure to light should therefore be limited as much as possible after sunset.

• Blue-rich, high CCT lighting should therefore come with a health warning to humans, wildlife and plants – in short, to all living organisms.

Unnecessary ‘blue’

• The human eye uses just a fraction of the blue light emitted by high CCT LEDs;
• Ergo, lighting of 2700K and over (which is being installed country-wide) is emitting vast quantities of unnecessary blue light to the detriment of the biosphere and should be banned.

Spectral Graphs courtesy of Professor Travis Longcore, UCLA

Further interdisciplinary research

• is urgently needed between lighting, medical and environmental research communities to ensure that future developments in LED technology minimize their potential ecological effects96
• further research needed is identified by the UN OOSA report1 pages. 36-37, N5.11;96
• research needs to be made more of a priority area, and funding unlocked.

Public Policy and Regulatory Framework

1. Statutory nuisance laws :
• are reactionary
• do not require installations to prevent pollution as a matter of design
• are not effective due to the difficulty of proof by the victim.
• focus on people and light spill, not on the wider metrics of light pollution, landscapes, wildlife and dark skies. 
• Include unnecessary exemptions97.  Safety, security, and environmentally-responsible lighting are not mutually exclusive.

The APPG Ten Dark Sky Policies for the Government summarise the current problemspage 12, 98

Street lighting inhabits a ‘grey’ area, being neither specifically included under Statutory Exemptions, nor specifically excluded.  It should be included.

2. Regulatory Regime

Light pollution is very easy to tackle; however, it requires adequate legislation.

Current legislation:

• is inadequate and governed by a plethora of different regimes, frameworks and regulations; 
• has significant gaps;
• is often reactive, loosely applied, inconsistent and out-dated against emerging evidence on the impact of light pollution. 

There is insufficient expertise within government agencies, departments and local authorities. 

3. Planning System

• is slightly more proactive but lacks strength and consistency.
• the only reference to light pollution in NPPF19 is in paragraph 180 section c which states: “limit the impact of light pollution from artificial light on local amenity, intrinsically dark landscapes and nature conservation”.

A key failing of the existing legal regime is that development proposals are rarely assessed against such policies at all. Again, the APPG’s Ten Policies summarises the problempage 10, 98

• Temporary events are given licences without regard to Planning Policy. This enables events such as the First Breath light installation in Manchester to take place99

Such installations are emulated and lead to an increase in similar events and domestic/residential interpretations.  They encourage bolder and more daring designs: the proposed dome for Stratford, London refers to a concept ‘like a sun on earth’. Some level of principle is needed to stop this competitive tendency.

Stratford, East London could be the site for a new MSG sphere

The UK needs a single instrument for regulating light pollution so that agencies, departments, and local authorities are required to apply and monitor light pollution according to specific laws rather than interpreting guidelines as at present.

• New legislation is required to protect the darkness of the night sky, including the creation of a Statutory Commission for Dark Skies to “punish non-compliance” and empower Local Authorities to enforce regulation.  There needs to be standardisation of brightness, and colour temperature, including legal limits on the amount of blue light.  There is also a need for Dark Sky Hours requiring dimming or switch-off of lights.

Urgent Government action is needed including:

1. an immediate moratorium on further blue-rich LED installations;
2. suspension of the sale of blue-rich lights for outdoor use;
3. sponsorship of urgent scientific research and environmental impact assessments on blue-rich LEDs;
4. introduction of new technical regulations aimed at addressing ALL the environmental harms produced by artificial, particularly blue-rich, lighting.

In the meantime, ALL Local Authorities should follow best practice as set out in:

1. Towards a Dark Sky Standard100
2. Southdowns Dark Skies Technical Advice Notes and Appendix101

And adopt the recommendations of:

1. the APPG’s Ten Dark Sky policies98;
2. UNOOSA Report recommendationsSection N.5 pp. 32–37 1

This will fix the shortcomings in the current system and be based on the existing successes of the UK Dark Sky Places family.

• Existing Legislation in other countries 

Growing awareness of the impact of ALAN is resulting in legislation and initiatives :

1. European Union: Brno appeal to reduce light pollution in Europe102 was launched under the Presidency of the Czech Republic in 2022.  To support the proposal, the International Dark Sky Association (IDA) has developed a European Policy Brief and Recommended Actions document103

2. Legislation in other countries:

Croatia104;105

France106;107

Mexico108;109

Slovenia: effective of the legislation has been compromised by the introduction of LEDs110

Regions of other EU countries inter alia

Lombardy, Italy111

Andalucia (Spain)112

Austria, Ireland and Liechtenstein: non-binding guidelines only.

Conclusion

Life on Earth depends on a complex ecological web. The natural alternation of night and day, light and dark are essential to many life forms. It is imperative to restore more natural levels of lighting at night.   We depend on a healthy ecosystem for our well-being and survival, so we need to make intelligent use of the available spectrum of CCTs and redirect our choice towards, ideally, 2200K for the sake of the biosphere and the well-being of future generations.  While there may be more research to be done on the impact of ALAN, there is sufficient evidence of its detrimental impact for proper legislation, as outlined above, to be enacted.

Appendix 1: 

              Night Blight : Light Pollution in Britain

Interactive CPRE Night Blight Map of Britain (2015)113

Facilities exempt from Statutory Nuisance Legislation97 are significant contributors to light pollution in Britain; however, safety, security and environmentally-responsible lighting are not mutually exclusive

a) Sports lighting :