And you thought we only had to worry about CFCs (chlorofluorocarbons) destroying the ozone layer in the upper atmosphere (e.g., the Arctic and Antarctic ozone “holes”) that protects all life on the planet from dangerous ultraviolet light emissions. Guess again. For the first time, a study by Harvard scientists has linked deadly extreme storms, such as the derechos the US has been experiencing this year, to destruction of the ozone layer over the continental United States..
A team of Harvard scientists led by Weld professor of atmospheric chemistry James G. Anderson announced today the discovery of serious and wholly unexpected ozone loss over the United States in summer. […]
Anderson’s team has discovered that during intense summer storms over the United States, water vapor is thrust by convection far higher into the lower stratosphere than previously thought possible, altering atmospheric conditions in a way that leads to substantial, widespread ozone loss throughout the ensuing week. The paper links the loss of ozone over populated mid-latitude regions in summer to the frequency and intensity of these big storms, which could increase with climate change resulting from rising levels of carbon dioxide and methane in the atmosphere.
… Anderson and his team realized the significance of the finding because higher water- vapor concentrations in the cold reaches of the lower stratosphere change the threshold temperature at which chlorine is converted to a free radical state: in the presence of water vapor, direct catalytic removal of ozone takes place at warmer temperatures.
In continuing studies the team used isotopic signatures to demonstrate that the water vapor had been carried directly to the stratosphere as a result of convective injection. And in the region of convectively injected water vapor, the researchers found that the catalytic loss of ozone increased by a hundredfold. As a result, rates of ozone loss could exceed the natural rates of ozone regeneration (and replacement through transport from other regions) by two orders of magnitude. These data come from experimental evidence gathered over the United States, but the researchers note that similar conditions may exist elsewhere. […]
These findings have a public-health impact because they indicate that significant amounts of ozone can be destroyed in only a few days within regions of high water-vapor concentration—and skin-cancer incidence is associated with ultraviolet (UV) dosage levels, which in turn depend on ozone concentrations.
Ozone loss has been linked to increased incidence of skin cancer and other health effects in humans and other species. From the EPA website:
Laboratory and epidemiological studies demonstrate that UVB causes nonmelanoma skin cancer and plays a major role in malignant melanoma development. In addition, UVB has been linked to cataracts — a clouding of the eye’s lens. All sunlight contains some UVB, even with normal stratospheric ozone levels. It is always important to protect your skin and eyes from the sun. Ozone layer depletion increases the amount of UVB and the risk of health effects. […]
Physiological and developmental processes of plants are affected by UVB radiation, even by the amount of UVB in present-day sunlight. Despite mechanisms to reduce or repair these effects and a limited ability to adapt to increased levels of UVB, plant growth can be directly affected by UVB radiation.
Indirect changes caused by UVB (such as changes in plant form, how nutrients are distributed within the plant, timing of developmental phases and secondary metabolism) may be equally, or sometimes more, important than damaging effects of UVB. These changes can have important implications for plant competitive balance, herbivory, plant diseases, and biogeochemical cycles. […]
Solar UVB radiation has been found to cause damage to early developmental stages of fish, shrimp, crab, amphibians and other animals. The most severe effects are decreased reproductive capacity and impaired larval development. Even at current levels, solar UVB radiation is a limiting factor, and small increases in UVB exposure could result in significant reduction in the size of the population of animals that eat these smaller creatures.
Extreme storms have been previously linked to anthropogenic climate change by numerous scientific studies, including these two mentioned in this 2011 report by the Boston.com in 2011:
WASHINGTON — Extreme rainstorms and snowfalls have grown substantially stronger, two studies suggest, with scientists for the first time finding the telltale fingerprints of man-made global warming on downpours that often cause deadly flooding.
Two studies in yesterday’s issue of the journal Nature link heavy rains to increases in greenhouse gases more than ever before.
The Harvard study on Ozone loss, “UV Dosage Levels in Summer: Increased Risk of Ozone Loss from Convectively Injected Water Vapor due to extreme weather,” was published in advance at the online website of Science, a publication of the American Association for the Advancement of Science. Here’s the text of the abstract from the article:
The observed presence of water vapor convectively injected deep into the stratosphere over the United States fundamentally changes the catalytic chlorine/bromine free radical chemistry of the lower stratosphere by shifting total available inorganic chlorine into the catalytically active free-radical form, ClO. This chemical shift markedly affects total ozone loss rates and makes the catalytic system extraordinarily sensitive to convective injection into the mid-latitude lower stratosphere in summer. Were the intensity and frequency of convective injection to increase as a result of climate forcing by the continued addition of CO2 and CH4 to the atmosphere, increased risk of ozone loss and associated increases in UV dosage would follow.
It just keeps getting worse, yet many of the world’s governments, hostage to the whims of the fossil fuel industry or their own desire to profit from continued use of fossil fuels (OPEC, Russia, etc.) continue to do nothing to resolve this ongoing environmental catastrophe. Indeed, how much the issue will be a campaign issue this election season remains to be seen, but the odds of the candidates and the media raising the concerns related to climate change such as the elevated risk of loss of our protective ozone layer appears slim at best.
