Quantcast

Ozone Layer Recovery Falters Unexpectedly

Science
NASA / International Space Station

By Alex Kirby

The Earth's protective ozone layer is not recovering uniformly from the damage caused to it by industry and other human activities. And scientists are not sure why it isn't.

An international research team says the ozone, which protects humans and other species from harmful ultraviolet radiation, is continuing to recover at the poles. But recovery at lower latitudes, where far more people live, is not.


The layer has been declining since the 1970s because of the effect of man-made chemicals, chiefly chlorofluorocarbons (CFCs) and similar gases, used mainly in refrigerants and aerosols.

There is a link between the CFCs and global warming, though they are different and neither is the main cause of the other. Some suggested CFC replacements themselves proved to be powerful greenhouse gases.

CFCs and the other gases were banned under an international agreement, the Montreal Protocol, and since then parts of the layer have been recovering, particularly at the poles.

But the latest research, published in the journal Atmospheric Chemistry and Physics, finds that the bottom part of the ozone layer at more populated latitudes is not recovering, for reasons so far unidentified.

Radiation Blocker

Ozone forms in the stratosphere, between about 10 and 50 km above the Earth and above the troposphere where terrestrial species live. Much of it is in the lower part of the stratosphere, where it absorbs UV radiation from the Sun which can damage DNA in plants, animals and humans if it reaches the Earth's surface.

So the discovery in the 1970s that CFCs were destroying the ozone and causing the Antarctic ozone "hole" sparked rare international co-operation to solve the problem.

The outcome was the 1987 Montreal Protocol, the phase-out of CFCs and, recently, the first signs of recovery in the Antarctic. The upper stratosphere at lower latitudes is also showing clear signs of recovery.

But scientists have now found that stratospheric ozone is probably not recovering at lower latitudes, between 60⁰N and 60⁰S (London lies at 51⁰N), because of unexpected decreases in ozone in the lower part of the stratosphere.

Jonathan Shanklin, one of the British Antarctic Survey (BAS) scientists who discovered the ozone hole in 1985, told the Climate News Network from the BAS Halley research station where he is working now:

" … This new research is interesting and provides a novel perspective on changes in the ozone layer. It shows that even in an area of science that is fairly well understood there are still surprises in the fine detail.

It is clear from Antarctic data that the ozone layer is beginning to recover where it was worst affected, though it will take many more decades before it is back to its condition of the 1970s.

Although significant ozone depletion mostly affects the Antarctic, conditions in the ozone layer over the Arctic are sometimes sufficient to create substantial depletion. That is the case this year and at the moment there is significant ozone depletion over northern Ireland and Scotland. The problem and consequences of ozone depletion are not yet over."

"We do not yet understand what's causing the decline," said Dr. Anna Jones, senior tropospheric chemist at BAS. "To enable predictions of future ozone amounts, and to identify whether (and what) action might be needed to prevent further decreases, it is extremely important to understand what is causing the observed downward trend."

Prof. Joanna Haigh, co-director of the Grantham Institute for Climate Change and the Environment at Imperial College London, is co-author of the study. She said ozone had been declining seriously since the 1980s, but while the banning of CFCs was leading to a recovery at the poles, this did not appear to be true for the lower latitudes.

Greater Risk

"The potential for harm in lower latitudes may actually be worse than at the poles," she said. "The decreases in ozone are less than we saw at the poles before the Montreal Protocol was enacted, but UV radiation is more intense in these regions and more people live there."

Although they're not certain what's causing this decline, the authors suggest two possibilities. One is that climate change is altering the pattern of atmospheric circulation, causing more ozone to be carried away from the tropics.

The other is that very short-lived substances (VSLSs), which contain chlorine and bromine, could be destroying ozone in the lower stratosphere. VSLSs include chemicals used as solvents, paint strippers and as degreasing agents. One is even used in the production of an ozone-friendly replacement for CFCs.

Scientists had thought that VSLSs would not persist long enough in the atmosphere to reach the stratosphere and affect ozone. But Dr. William Ball from ETH Zurich, who led the analysis, said: "The finding of declining low-latitude ozone is surprising, since our current best atmospheric circulation models do not predict this effect. Very short-lived substances could be the missing factor in these models."

The study was the work of researchers from Switzerland, the UK, the U.S., Sweden, Canada and Finland, and included data from satellite missions, including by NASA.

Reposted with permission from our media associate Climate News Network.

EcoWatch Daily Newsletter

Environmental Investigation Agency

By Genevieve Belmaker

Last week, the Peruvian Palm Oil Producers' Association (JUNPALMA) promised to enter into an agreement for sustainable and deforestation-free palm oil production. The promise was secured by the U.S. based National Wildlife Federation (NWF) in collaboration with the local government, growers and the independent conservation organization Sociedad Peruana de Ecodesarrollo.

Read More Show Less
Jessica Kourkounis / Stringer

The rallying cry to build it again and to build it better than before is inspiring after a natural disaster, but it may not be the best course of action, according to new research published in the journal Science.

"Faced with global warming, rising sea levels, and the climate-related extremes they intensify, the question is no longer whether some communities will retreat—moving people and assets out of harm's way—but why, where, when, and how they will retreat," the study begins.

The researchers suggest that it is time to rethink retreat, which is often seen as a last resort and a sign of weakness. Instead, it should be seen as the smart option and an opportunity to build new communities.

"We propose a reconceptualization of retreat as a suite of adaptation options that are both strategic and managed," the paper states. "Strategy integrates retreat into long-term development goals and identifies why retreat should occur and, in doing so, influences where and when."

The billions of dollars spent to rebuild the Jersey Shore and to create dunes to protect from future storms after Superstorm Sandy in 2012 may be a waste if sea level rise inundates the entire coastline.

"There's a definite rhetoric of, 'We're going to build it back better. We're going to win. We're going to beat this. Something technological is going to come and it's going to save us,'" said A.R. Siders, an assistant professor with the disaster research center at the University of Delaware and lead author of the paper, to the New York Times. "It's like, let's step back and think for a minute. You're in a fight with the ocean. You're fighting to hold the ocean in place. Maybe that's not the battle we want to pick."

Rethinking retreat could make it a strategic, efficient, and equitable way to adapt to the climate crisis, the study says.

Dr. Siders pointed out that it has happened before. She noted that in the 1970s, the small town of Soldiers Grove, Wisconsin moved itself out of the flood plain after one too many floods. The community found and reoriented the business district to take advantage of highway traffic and powered it entirely with solar energy, as the New York Times reported.

That's an important lesson now that rising sea levels pose a catastrophic risk around the world. Nearly 75 percent of the world's cities are along shorelines. In the U.S. alone coastline communities make up nearly 40 percent of the population— more than 123 million people, which is why Siders and her research team are so forthright about the urgency and the complexities of their findings, according to Harvard Magazine.

Some of those complexities include, coordinating moves across city, state or even international lines; cultural and social considerations like the importance of burial grounds or ancestral lands; reparations for losses or damage to historic practices; long-term social and psychological consequences; financial incentives that often contradict environmental imperatives; and the critical importance of managing retreat in a way that protects vulnerable and poor populations and that doesn't exacerbate past injustices, as Harvard Magazine reported.

If communities could practice strategic retreats, the study says, doing so would not only reduce the need for people to choose among bad options, but also improve their circumstances.

"It's a lot to think about," said Siders to Harvard Magazine. "And there are going to be hard choices. It will hurt—I mean, we have to get from here to some new future state, and that transition is going to be hard.…But the longer we put off making these decisions, the worse it will get, and the harder the decisions will become."

To help the transition, the paper recommends improved access to climate-hazard maps so communities can make informed choices about risk. And, the maps need to be improved and updated regularly, the paper said as the New York Times reported.


"It's not that everywhere should retreat," said Dr. Siders to the New York Times. "It's that retreat should be an option. It should be a real viable option on the table that some places will need to use."

Sponsored
Pixabay

By Manuella Libardi

Leaked documents show that Jair Bolsonaro's government intends to use the Brazilian president's hate speech to isolate minorities living in the Amazon region. The PowerPoint slides, which democraciaAbierta has seen, also reveal plans to implement predatory projects that could have a devastating environmental impact.

Read More Show Less
XL CATLIN SEAVIEW SURVEY / THE OCEAN AGENCY

Hope may be on the horizon for the world's depleted coral reefs thanks to scientists who successfully reproduced endangered corals in a laboratory setting for the first time, according to Reuters.

Read More Show Less

Last week we received positive news on the border wall's imminent construction in an Arizona wildlife refuge. The Trump administration delayed construction of the wall through about 60 miles of federal wildlife preserves.

Read More Show Less
Sponsored
PhotoAlto / Frederic Cirou / Getty Images

Drinking water treated with fluoride during pregnancy may lead to lower IQs in children, a controversial new study has found.

Read More Show Less
National Institude of Allergy and Infectious Disease

The Centers for Disease Control and Prevention (CDC) warned Thursday of a drug-resistant strain of salmonella newport linked to the overuse of antibiotics in cattle farming.

Read More Show Less
A Greenpeace rally calls for a presidential campaign climate debate on June 12 in Washington, DC. Sarah Silbiger / Getty Images

The Democratic National Committee (DNC) voted down a resolution calling for an official, party-sanctioned debate on the climate crisis, ABC News reported Thursday.

Read More Show Less