Lights off please, let them work !

Time to time NASA releases images of Earth at night. These are  night maps of human activity.  In these snapshots  Mother Earth seems  like a diamond studded field.  Eastern US , Western Europe and Japan are the most glittering areas in the map with Africa remaining true to its name:  Dark Continent-  leading to   rather confusing trend  of equating a nation's development index to its energy consumption.  NASA's  nighttime images have multiple objectives- to collect  climatic & meteorological  data, to spot oceanic activities such as  unregulated fishing  and  of course they could serve as surveillance maps- monitor ing clandestine activities in war zones.  

Earth at Night  Courtesy NASA

But there are others who strongly believe that  such images  can be used as powerful tools to monitor Light Pollution and take necessary steps to protect  endangered and fragile ecosystems.  Light Pollution? Are we waking up to a new threat?   Not exactly. We have been unconsciously aware of this issue for quite some time now but didn't take it seriously. For example when did we last spot  the glow of fireflies in our garden?  Scientists have attempted to quantify the danger of depleting nocturnal visitors.  In a research  article published in the 10th August issue of Nature,  Eva Knop and coworkers alert us to the dangers of  ALAN (Artificial Light At Night).     Knop et al provide data on how ALAN  adversely affects the habitats of nocturnal species consequently how  their population has registered  a global decline. Nocturnal pollinators (insects and animals) are essential for sustaining Nature's biodiversity.   The research team is  apprehensive that dwindling   nocturnal pollinator population will eventually affect   the well-being of  diurnal pollinators too because  decreased pollen transport means reduced food availability. In their detailed study, which covered  14 wild meadows ( 7 test fields, and 7 controls), the team  monitored  interactions between flowers(plants)  and their nocturnal visitors. They recorded  that in illuminated fields,  nocturnal visitors  flocked towards the light source,  totally  neglecting the flowers with the result that  pollinator -flower contacts were  reduced by 62%.  

Several earlier studies highlight the issue and provide detailed  cost-benefit analyses of artificial nighttime  lighting on the environment. Perhaps for our part we could switch off our porch  and garden lights and thus encourage   fireflies to visit us.  But there a lurking dangers-  a house wrapped in darkness might attract burglers and thieves too. 

Tailpiece:

Day and Night is a 6 minute animated film (2010) in which an exuberant guy  Day, encounters  Night who is forever a gloomy.  The initial  intense dislike between them soon turns into a unique friendship when each realises that  that they are just two sides of the same coin. 

REFERENCES:

1. Artificial light at night as a new threat to pollination.Knop et al, Nature 548 p.206-9 2017

2. The dark side of street lighting : impacts on moths and  evidence for the disruption of 
    nocturnal pollen transport  Macgregor et al  Glob.Change Biol. 23, 697-707 2017

3. Ecological consequences of Artificial Night Lighting: edited by Catherine Rich and 
     Travis Longcore, Island Press 2013