Image from NASA
updated: As many noted, I (idiotically) cited the Montreal Protocol's success here, which has nothing to do with reducing tropospheric ozone -- rather, it has to do with fixing the ozone layer. Thank you commenters, and my apologies for the gross mistake
Despite significant international progress made in reducing global ozone levels, they are still too high, exposing the environment and humans to their dangerous effects, and could worsen because of climate change, a new Royal Society report finds. Background concentrations of ozone have surged by 6 percent, or 2 parts per billion (ppb) in the atmosphere, per decade since the 1980s in several parts of the world, including many regions of the Northern Hemisphere.
According to the report, even background ozone levels, roughly 35 - 40 ppb, are now believed to have impacts on human health, environment and food crops (by reducing their yield and nutritional quality) in most developed nations. In some cases, when ozone levels reach a peak in these regions during hot, sunny weather conditions, they can exceed 100 ppb. Ozone: A dangerous "global traveler"
One of the major problems associated with ozone pollution, like other air pollutants, is that it is a "global traveler," as David Fowler, the chair of the Royal Society's ground level ozone working group, put it. The United Kingdom, for example, gets most of its ozone from outside of Europe; that is because weather systems and jet streams help move it around -- often far from their point of origin.
A growing source of these pollutants is the international shipping sector, which, along with forest fires and vehicle exhaust, now constitutes the bulk of ozone emissions. Because of their global nature, Fowler cautions that national or even regional-level controls won't be enough to protect human health or the environment. Only a globally coordinated program can address a problem of such magnitude, he says.
Climate change and ozone: A match made in hell
To make matters worse, climate change, by increasing production in polluted areas of the world, will likely make slashing ozone levels even more difficult. The scientists also predict that climate change will aggravate the existing feedback loop in which rising ozone levels worsen climate change. This seems to go along with the results of another study published earlier this year in Science, which suggested that fixing the ozone layer could help mitigate climate change.
Studies published in 2000 estimated that crop yield losses for India were around 13 percent for wheat, 6 percent for rice and 19 percent for soya bean -- figures that, at the time, were already underestimates and that will only get worse.
The full report isn't yet available, but it will appear on the Royal Society website tomorrow.
More about ozone
::Climate Change? This Looks Like a Job for Captain Ozone, Environmental Hero
::Could Fixing the Ozone Layer's Hole Make Global Warming Worse?
::Ozone Hinders Plants' Ability to Absorb Carbon Dioxide
Ozone Pollution to Worsen Under Climate Change