If, like me, you’re a stargazer in an urban area then you will already know exactly what this article is about. Light pollution and its trademark “skyglow” is getting worse. Much worse. It’s getting so serious that stars, beautiful open clusters and even distant galaxies in the night sky there were visible just a decade ago are now impossible to see.
All urban stargazers know this and have done since the switch from orange sodium vapor lamps to white LEDs, which emit much more blue light. Now we have a mass of observational evidence.
Published today in the journal Science, a new paper analysed 51,351 naked-eye observations by citizen scientists in 19,262 locations (including 3,699 in Europe and 9,488 in North America) from 2011 to 2022 as part of the “Globe at Night” Citizen Science Project from the National Science Foundation’s NOIRLab. Each stargazer looked at their night sky on cloud- and moon-free nights and reported which of a set of eight star charts (each showing the sky under different levels of light pollution) best matches what they see.
The main finding over the 12 years is incredibly depressing—the sky brightness increased by seven to 10% per year (and 9.6% on average).
In Europe, they found a 6.5 per cent increase in brightness per year matched the data; in North America, it’s 10.4 per cent.
The culprit, of course, is rapidly growing light pollution despite policies to prevent it.
“The rate at which stars are becoming invisible to people in urban environments is dramatic,” said Christopher Kyba, lead author and researchers at the GFZ German Research Centre for Geosciences and the Ruhr-Universität Bochum, Germany. “If the development were to continue at that rate, a child born in a place where 250 stars are visible will only be able to see 100 stars there on his 18th birthday.”
Astronaut photographs of parts of Calgary (Canada) show examples of how lighting changed from … [+] 2010-2021: New lighting has been installed and many streetlights have been converted from orange high pressure sodium to white LED. (Note: The photos are not taken with the same settings, and have different spatial resolution. Thus, the 2010 photo appears somewhat brighter.
Images courtesy of the Earth Science and Remote Sensing Unit, NASA Johnson Space Center, georeferencing by GFZ Potsdam
Light pollution is not just a threat to stargazing.“Skyglow affects both diurnal and nocturnal animals and also destroys an important part of our cultural heritage,” said Constance Walker, co-author of the study and head of the Globe at Night project of NSF’s NOIRLab since its inception.
Over a large part of the Earth’s land surface, the sky continues to glow with an artificial twilight long after sunset. This “skyglow” is a form of light pollution that has serious effects on the environment and should therefore be the focus of research, as Constance Walker, co-author of the study and head of the Globe at Night project. In August 2021 a study in Science Advances demonstrated the detrimental impacts of street lighting on local insect populations and in September 2022 another study highlighted the harmful effects of nighttime lighting to ecosystems across Europe.
Worryingly, the rate of change is much faster than satellite measurements of artificial light emissions on Earth suggest, the authors report. Satellite data for the locations of the observers in the study record that artificial brightness had slightly decreased—by 0.3 percent per year in Europe and by 0.8 percent in North America—over the same time-frame.
One reason for the discrepancy is likely changes in lighting practices. “Satellites are most sensitive to light that is directed upwards towards the sky,” said Kyba, who thinks that it is horizontally-emitted light that accounts for most of the skyglow. “If advertisements and facade lighting become more frequent, bigger or brighter, they could have a big impact on skyglow without making much of a difference on satellite imagery,” he said.
Light Pollution Impact 2 – From excellent dark sky (left) to inner city sky (right)
NOIRLab/NSF/AURA, P. Marenfeld
Another reason is the swap over the last decade from warm orange sodium vapor lamps to blue light-emitting white LEDs, which have been adopted en masse in street lighting, car headlights and security lighting at night. The problem LED lighting is that they emit light in the blue spectrum. “Our eyes are more sensitive to blue light at night, and blue light is more likely to be scattered in the atmosphere, so contributes more to skyglow,” said Kyba. “But the only satellites that can image the whole Earth at night are not sensitive in the wavelength range of blue light.”
It’s the main reason why the study used individual people working together as if they were a global sensor network, said Kyba.
“Perhaps the most important message that the scientific community should glean from the Kyba et al. study is that light pollution is increasing, notwithstanding the countermeasures purportedly put into operation to limit it,” writes Fabio Falchi and Salvador Bará in a related Perspective in Science. “Light pollution is an environmental problem and as such should be confronted and solved … awareness must greatly increase for artificial light at night to be perceived not as an always-positive thing, but as the pollutant it really is.”
The project is ongoing (anyone can contribute a report) and researchers want to identify trends for other continents, individual states and cities.
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
