Ozone on EARTH Magazine

Reconstructing ancient oxidant levels and their climatic effects

Tue, 15 Aug 2017 14:23:14 -0400

Credit: Sara E. Pratt.

Oxidants in the troposphere, such as ozone and hydroxyl radicals, influence the life spans of other atmospheric components, including pollutants and greenhouse gases like carbon monoxide and methane. But how the abundance of tropospheric oxidants varies as climate changes is poorly understood. Part of the challenge is that these oxidants are too reactive to be preserved in paleo-records, such as ice cores.

"Blob"-related warming contributed to Pacific Northwest ozone spike

Mon, 15 May 2017 15:00:06 -0400

In June 2015, tropospheric ozone levels measured at the observatory on Oregon's Mount Bachelor were more than 20 percent above the decadal average. Credit: Pao Baylon.

In June 2015, instruments on Oregon’s Mount Bachelor recorded mean ozone for the month at 56 parts per billion, more than 20 percent higher than the average level for the 11 years prior. Other stations around the West noted similarly high readings, puzzling scientists over the cause of the rise. In a new study in Geophysical Research Letters, researchers describe a confluence of meteorological conditions that appear to have driven the phenomenon.

Red Planet Roundup: February 2017

Wed, 25 Jan 2017 14:11:41 -0500

The bright spots in this ultraviolet view of Mars, assembled from images collected by the MAVEN orbiter in July, are clouds that rapidly formed over Mars' largest volcanic peaks. Credit: NASA/MAVEN/University of Colorado.

With two rovers patrolling the surface of Mars, six spacecraft orbiting above it, and scientists here on Earth studying the Red Planet from afar, new findings are announced often. Here are a few of the latest updates.

Benchmarks: September 16, 1987: Montreal Protocol Signed

Tue, 01 Sep 2015 10:26:04 -0400

Stratospheric clouds facilitate ozone depletion. The ice in these clouds provides a surface on which ozone-destroying chemical reactions occur. Credit: Photograph by Lamont Poole, NASA Langley Research Center.

Each year in late September to early October, atmospheric scientists watch with anticipation as ozone concentrations over Antarctica drop, opening a window in Earth’s defenses against harmful ultraviolet radiation. This ozone “hole” grew steadily in the 1990s and set a record for its size in 2006: At its peak, the hole covered an average area of 27 million square kilometers, approximately the size of North America. But scientists think that the overall ozone layer is on the slow road to recovery, thanks to the Montreal Protocol — one of the most successful international environmental agreements in history.

Hydrogen chloride on the rise in Northern Hemisphere skies

Mon, 08 Jun 2015 12:44:20 -0400

Concentrations of hydrochloric acid measured over the South Pole on Aug. 13, 2004 (warm colors indicate higher concentrations). Credit: NASA/Goddard Space Flight Center.

Levels of the atmospheric pollutant hydrogen chloride have increased substantially in the lower stratosphere over the Northern Hemisphere since 2007, according to a new study. The increase, however, is not due to an influx of chlorine, but rather to a side effect of the recent slowing of stratospheric circulation that was first reported in 2005.

Carbon tet still offensive to ozone layer

Tue, 04 Nov 2014 11:13:38 -0500

The ozone hole (purple and blue) over Antarctica, visualized from satellite data, reached its greatest extent in 2006. Levels of ozone-depleting chemicals in the atmosphere have been declining overall in the last 10 to 15 years, although carbon tetrachloride has not dropped off as rapidly as expected. Credit: NASA.

Earth’s ultraviolet light-shielding ozone layer is recovering, according to a report released in September by the World Meteorological Organization and the United Nations Environment Programme. The findings, authored by more than 250 scientists and presented as part of the latest Scientific Assessment of Ozone Depletion (SAOD), suggest the ongoing success of the 1987 Montreal Protocol and its amendments in cutting atmospheric levels of chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODS’s), which have fallen by about 10 to 15 percent overall since peaking in the late 1990s.

Montreal Protocol affects more than just ozone

Thu, 05 Jan 2012 06:41:58 -0500

The Antarctic Peninsula is warming - but the warming might have been faster if the Montreal Protocol hadn't slowed the growth of the ozone hole. Michael Collier, ESW Image Bank

In 1987, nearly 200 nations signed the Montreal Protocol to restrict the use of ozone-depleting chemicals. The international treaty helped keep the ozone hole over Antarctica from growing further, preventing an increase in harmful radiation reaching Earth’s surface. Twenty years later, new research suggests that the treaty helped the planet dodge more than one bullet: The Montreal Protocol also prevented significant regional climate change.