In cities that do not sleep, plants do not sleep either. This is what you reveal study A new scientific published on June 16 in the “Nature Citizen” magazine, where a team of researchers monitored a remarkable change in the behavior of plants within the major cities, caused by artificial light and the growing heat of urbanization.
The study concluded that the growth season in urban areas has become about 3 weeks longer compared to rural areas, a major time difference that carries environmental and economic connotations that are not underestimated.
The study, which covered 428 cities in the northern hemisphere, from New York to Beijing, and from Paris to Tehran, relied on satellite images analysis and accurate data about temperatures near the surface of the earth and the severity of night lighting, as well as plant growth indicators during the period between 2014 and 2020.
When lamps become a compass for growth
The main researcher in the study “Lin Ming” – Professor of Earth Sciences and Environment at the American University of Vanderlt – says that the results of the team showed that “industrial night lighting is not just an aesthetic or security issue in cities, but rather has become an environmental factor that changes the rhythm of plant life.”
The researcher explains in statements to “Al -Jazeera.net” that the plants in cities start the growth season 12.6 days earlier on average, and end it 11.2 days later compared to the countryside, which actually means that urban plants are active about 3 additional weeks annually.
According to Ming, the clear effect of light was not only in accelerating growth, but also delaying it to stop. “What surprised us is that the end of the season in the cities is noticeably delayed, which prolongs the period in which the leaves grow and continue optical representation, and this has cumulative effects on the environment.”
The study was not satisfied with monitoring the temporal impact, but rather measured the strength of industrial lighting and its geographical distribution, and found that the intensity of the lighting increases as we approach the city centers, which gradually enhances its impact on the plant.
Although American cities were the most brighter, the beginning of the growth season was earlier in European cities, followed by Asian, then American. The study indicates that the climate type plays a role in these differences, as the impact of industrial light in accelerating growth was evident in areas with dry summer or cold winter without drought periods.
New questions about “Luminous Night”
These results open the door to questions that were not previously asked when designing cities infrastructure. Can night lighting overlap with the environmental system of plants? Should we rethink the way to light our streets and public gardens? According to the main author of the study.
“Ming” believes that the answer is yes, and she adds: “We should not lose sight that the new lighting systems – especially LED lights that have become a global standard – send light spectra closer to the spectrum that plants feel, which makes their biological effect stronger than we thought.”
The study recommends that cities plan to take into account the environmental effects of lighting, whether in terms of their intensity or type, so that more “vegetable” techniques are developed a balance between human safety and the integrity of the urban environment. Not only does it depend on the gardens. The long growth name may also mean changes in human allergies, and the extension of the spread of some insects, and perhaps even changes in air quality.
Although the study focused on the northern hemisphere, its results are gaining global importance, especially with the continued urban expansion in the global south, where the density of cities is increasing and industrial light spreads at a rapid pace. In the absence of accurate environmental planning, the effects of the “luminous night” that were monitored in Paris and Beijing may be repeated in cities such as Lagos, Cairo and New Delhi.