Tag Archives: ozone

2012 Antarctic Ozone Hole Update

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NASA and NOAA announced today that the hole in the ozone layer over Antarctica reached its annual maximum size on Sept. 22. Highlights include:

  • The Antarctic ozone hole reached its annual maximum size on Sept. 22, covering 8.2 million square miles — the area of the United States, Canada and Mexico combined.
  • That’s smaller than the record maximum of 11.5 million square miles reached on Sept. 6, 2000, and also smaller than last year’s maximum size of 10.1 million square miles.
  • Scientists attribute the smaller ozone hole in 2012 to warmer temperatures in the Antarctic lower stratosphere.

“The ozone hole mainly is caused by chlorine from human-produced chemicals, and these chlorine levels are still sizable in the Antarctic stratosphere,” said NASA atmospheric scientist Paul Newman of NASA’s Goddard Space Flight Center in Greenbelt, Md. “Natural fluctuations in weather patterns resulted in warmer stratospheric temperatures this year. These temperatures led to a smaller ozone hole.”

Read the full story here. Also read about the history of the ozone hole and its path toward recovery, and then check out the satellite-based image that in 1985 revealed for the first time the size and magnitude of the ozone hole. Finally, visit NASA’s Ozone Hole Watch to follow the state of the Antarctic ozone hole throughout the year.

Smog Blog Outtakes

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On Earth Day, we published an interview about the “smog blog” created by Ray Hoff of the University of Maryland – Baltimore County. Today, we follow up by sharing this video, which has some striking shots of laser pulses from the instrument that Hoff’s atmospheric LIDAR group uses to take air quality measurements near Baltimore.


Plus, here are some outtakes from Hoff that did not fit into the original interview:

On the importance of satellites…
“We spend quite a bit of time trying to use satellite measurements as a surrogate for what we see on the ground because the Environmental Protection Agency can’t be everywhere. EPA has a thousand monitors in the United States, but those monitors are largely in urban areas, and they can be spaced quite far apart. There are, for example, no EPA samplers in Wyoming. NASA satellites can look everywhere.”

On why satellite measurements of aerosols are less accurate in the western U.S…
“In the West, the correlation between what happens on the ground is worse for two reasons. The land surface out in the western United States does not have as much vegetation, so it’s brighter and more difficult for NASA satellites to see the aerosols from space. The other thing is that there are a lot of fires in the West, which make it challenging to distinguish between aerosol types.”

On the challenges facing air quality researchers…
“One of the things they’d really like to have is better measurements of ozone at the ground level. Much of the ozone we have on the planet is in the stratosphere, about 20 kilometers or 15 miles up, and it’s hard to see through the ozone layer, since it’s so thick. We have to combine models with measurements from the ground and NASA airborne platforms, but the difficulty of seeing through this layer to surface ozone is kind of the holy grail of tropospheric air quality research right now.”

On geoengineering the climate with sulfate aerosols…
“A Nobel Prize winner has suggested putting more pollutants in the atmosphere in order to keep the planet cool. I actually think that’s a rather poor experiment for us to be trying with so little knowledge of how the atmosphere works. Humans have a pretty bad record of trying to “fix the planet.”

–Adam Voiland, NASA’s Earth Science News Team

Same Words But Different Meanings

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Earth scientists milling around the lobby during coffee breaks at this year’s AGU had something unusual to mull over this year.  A phalanx of colorful posters, created by a visual communicator who describes herself as a note taker on steroids, adorned the lobby of the Moscone Center. Snippets from the illustrated notes offer a fascinating look into some of the brainstorming sessions that have taken place about communicating climate science. AGU intstalled the posters at a fitting time: it’s been a disorienting month for climate scientists who have watched seemingly specious charges of scientific malpractice become a major news item.

One of the posters — called Communicating with Congress (and Everybody Else) — brainstorms some of the pitfalls that make communicating climate science such a challenge. High on the list: jargon. Scientists use such a specialized language that it can be difficult for non-scientists — even for those of us who cover the topic regularly — to distill the meaning from certain scientific presentations or articles. Complicating matters more, there are some words that have distinctly different meanings to scientists and the public. The poster highlighted a handful of them. I’ve taken the liberty of elaborating upon and defining a few of them below. 

Did you know the difference?  Have any good examples to add to the list?

The Public: Spray cans that dispense a liquid mist, many of which damage Earth’s ozone layer.

Scientists: A suspension of any solid or liquid droplet in the atmosphere. Includes dust, soot, pollen, sea salt, sulfates and more. More details about aerosols. 

The Public: Harmful material that leaks from nuclear material and is used to battle cancer.
Scientists: Energy that comes from a source and travels through some material or space. Includes electromagnetic radiation such as radio waves, infrared light, visible light, ultraviolet light, and X-rays.  More details about
electromagnetic radiation.

The Public: Something over Antarctica that protects against cancer-causing light waves. 
Scientists: A molecule containing three oxygen atoms that functions as a harmful air pollutant near the surface, a greenhouse gas in the upper troposphere, and a buffer against ultraviolet radiation in the stratosphere. 
More details about ozone.

The Public: Willful manipulation of facts to suit political ideology.
Scientists: A term used to describe a statistical sample in which members of the sample are not equally likely to be chosen. Also a term used to describe the difference between an
estimator’s expectation and the true value of the parameter being estimated. For some scientific analyses, a certain degree of bias can actually be beneficial.

–Adam Voiland, NASA’s Earth Science News Team

Science Advice for an Evolving Ozone Layer Agreement

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NASA scientist Paul Newman briefly stopped in Cairo, Egypt, on his way to the
Montreal Protocol meeting in Port Ghalib. Credit: Paul Newman

The view of the Red Sea was spectacular, but it was all work and no play for NASA atmospheric scientist Paul Newman during a recent trip to Port Ghalib, Egypt. That’s where scientists, policymakers, and representatives of the United Nations Environment Programme, convened Nov. 4-8 for an annual meeting to discuss and amend the Montreal Protocol — the international agreement that regulates ozone-depleting substances. Newman attended as co-chair of the Scientific Assessment Panel and gave us an inside look.

Q: Scientists use satellites and computer models to better understand the recovery of the ozone layer. How does this kind of science contribute to the policy decisions?
A: The Montreal Protocol regulates gases that destroy ozone, also known as ozone depleting substances (ODSs). The most famous of these are the chlorofluorocarbons (CFCs) that were used in spray cans and as refrigerants. Science provides that foundation for the Protocol. We used (and still use) models to predict the evolution of ozone in our atmosphere in response to the regulations made by the signatory countries. Satellite, aircraft, balloon, and ground observations provide a check on our model estimates. If you can’t simulate the past, it’s hard to claim that you can predict the future.

Q: What is involved in a typical day as “co-chair of the scientific assessment panel”?
A: We’re commonly referred to as the SAP. Not a great acronym for the scientists! In any case, we are the “on-the-spot” science advisors on all policy questions. 

In a typical day, there is a lot of discussion amongst the delegates about technical issues. Delegates actively discuss “critical use exemptions.” For example, methyl bromide is used as a fumigant. Plants, flowers, vegetables are all fumigated to help preserve them or to stop the spread of invasive species such as fruit flies. Without some sort of fumigation, entire farming industries might be destroyed. However, methyl bromide is also an ozone depleting substance. The SAP provides information on methyl bromide as an ozone depleting substance. For example, if we stop all methyl bromide usage, how much will this help the ozone layer?

Q: Why is there the need to revisit the Montreal Protocol with regular meetings?
A: The Protocol was designed to be an evolving agreement. Originally, the production of ODSs was limited, not stopped. Over the years, policymakers strengthened the original agreement such that all CFC production is now stopped. However, there is still some usage in developing countries, and there are stocks of ODSs that could potentially be destroyed. The nations get together twice per year to talk over the needs for evolving or strengthening the agreement.

Q: What are hydrofluorocarbons (HFC’s), and why do you think a proposal to include HFCs in the protocol was unsuccessful this year?
A: Hydrofluorocarbons, or HFCs, are used as refrigerants, and they don’t destroy ozone. However, HFCs are powerful greenhouse gases.

When CFCs were banned, alternative refrigerants were developed to take their place. The initial alternatives were hydrochlorofluorocarbons (HCFCs). HCFCs were still ozone depleting substances, but they had much shorter lifetimes than CFCs, and hence, were less ozone dangerous than CFCs. In 2007, the HCFCs were banned under the Montreal Protocol and are now being phased out.

HCFCs are now being replaced by HFCs. The Montreal Protocol shifted from the ozone dangerous CFCs to the less dangerous HCFCs, and now to the ozone safe HFCs. By banning CFCs, the Montreal Protocol had a double benefit: less ozone depletion and less greenhouse gas warming (CFCs are powerful greenhouse gases).

However, by banning CFCs, the Montreal Protocol created a demand for the ozone-safe HFCs (people still want air conditioners). All of the climate benefit gained by banning CFCs might be lost as HFCs increase in our atmosphere. Hence, some people are calling for the banning of HFCs under the Montreal Protocol, in spite of the fact that HFCs don’t destroy ozone. By banning HFCs, the Montreal Protocol would become both an ozone treaty and a climate treaty.

The HFC amendment did not go through for a number of reasons. The primary reason is that many countries believe that HFCs are climate related and should therefore be regulated under the Kyoto Agreement.

Q: What current research do you think could impact future meetings?
A: The Montreal Protocol is evolving into both an ozone and climate agreement. It is still necessary for scientists to investigate the impact of human-produced chemicals on both ozone and climate. Every day new chemicals are being proposed for various uses, and the scientists need to assess the environmental impact to select those chemicals that are non-toxic and environmentally safe.

–Kathryn Hansen, NASA’s Earth Science News Team