by Bruce Torrie
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As a lawyer and policy analyst studying global systems and government policy, I believe it is now time to face the prospect of a full systems collapse of Earth's environment. There is now a clear possibility of a runaway greenhouse effect - caused by deforestation and the collapse of the Earth's protective ozone layer.
The normal context for policy and planning is to frame out best and worse case scenarios, and evaluate where the future will lie between these possibilities. Unfortunately, the global warming modelers are still in their infancy, only now adding the role of oceans and clouds to their calculations. A more serious criticism of the existing models is that they only evaluate the effect of additional CO2 and other greenhouse gasses being added to the Earth's atmosphere. They ignore the significance of "carbon sinks" - the oceanic plankton and the forests - in removing CO2 from the systems.
Accordingly, the current models and timetables are seriously flawed. We are, in fact, in a profound crisis with enhanced ultra violet radiation - caused by a depleted ozone shield - threatening the viability of plankton and forests - the world's carbon sinks. There are a number of positive feedback systems now being discussed by scientists which are poorly understood. I will attempt in this article to outline these scenarios, evaluate their importance and effects, and offer some recommendations for government policy response.
Understanding Ultraviolet Radiation
Ultraviolet radiation (UVR) is very damaging to life forms on Earth. Before the ozone layer developed, life existed only deep in the ocean, where it was protected from UVR by the water column. Bacteria deep in the ocean gave off oxygen as a waste product. Over millenia, the oxygen accumulated in the atmosphere and when it had sufficiently concentrated in the stratosphere the ozone layer began to form. With the ozone layer blocking the damaging UVR, life was able to develop in the shallow seas and from there it moved onto land. Our world is dependant on a stable stratospheric ozone shield.
Ozone Layer Dynamics
The world community, in what has been described as the most rapid response to an international threat ever, approved the Montreal Protocol for the phasing out of ozone depleting substances in 1987. In that year scientists predicted the northern hemisphere could face ozone depletion of 5-10% by 2000-2005. In March of 1988 the Ozone Trends Panel announced it could confirm ozone losses of 1.7% - 3% over the northern hemisphere. The profound concern of the world community over these minor impairments of the ozone layer led quickly to further strengthening of the Montreal Protocol in 1989. By spring of 1992 when the world was congratulating itself on having moved so quickly to eliminate the threat of ozone depletion - NASA announced that because of polar ice cloud dynamics the northern hemisphere could face spring ozone depletion of 25%-40% in years in which the north polar region remained cold in the spring when the sun first hits the northern polar stratospheric clouds. In the spring of 1993 the polar region remained cold enough for the formation of polar stratospheric ice clouds and many areas of the northern hemisphere encountered peak spring ozone depletion of 15- 25%. NASA continues to forecast potentially huge ozone depletion in years in which the polar stratosphere remains cold (-80C) as spring begins.
Stratospheric ice clouds require moisture to form. The two major sources of moisture reaching the stratosphere are water vapour trails emitted by high flying jets and the gas methane (natural gas) which degrades and produces H2O when it is bombarded by UVR in the stratosphere.
There is now a proposal to limit jet travel to lower altitude flight paths to reduce the H2O delivered to the stratosphere. This is a very important initiative and should be supported. The emissions of natural gas are of much greater concern, as they will dramatically increase in response to global warming. In particular, vast deposits of fossil methane lie frozen in the arctic tundra. With dramatic warming of northern regions , vast quantities of fossil methane will be released into the atmosphere. When the gas reaches the stratosphere, it will release H2O, which will serve as feedstock for future stratospheric ice clouds which will, under proper conditions, massively deplete the northern hemisisphere's ozone shield.
Global Warming's Impact on Stratospheric Temperatures
The prospect for disaster was intensified when John Austin et al published a cover story in Nature on 19 Nov. 1992 (vol 360 p.221) which predicted that as the global surface warmed with global warming, the stratosphere would cool, enhancing the prospect of polar stratospheric clouds forming. The abstract reads:
"Increased atmospheric CO2 concentrations are expected
to cause cooling of the lower stratosphere. This could
enhance the formation of polar stratospheric clouds
which convert potential ozone depleting species to their
active forms... doubling the CO2 leads to the formation
of an arctic ozone hole comparable to that observed over
Antarctica with nearly 100% local depletion of lower
The lower stratospheric ozone is about 35% of the ozone column, so as the surface warms the stratosphere cools and when circumstances are right the stage is set for massive depletion of ozone producing a northern hemispheric arctic ozone hole.
Stratospheric temperature is also affected by the destruction of ozone - as it is the ozone blocking UVR that transfers heat to the stratosphere. As more ozone is destroyed, the stratosphere cools, which sets the stage for more ozone depletion and more cooling, which destroys more ozone resulting in more cooling and so on. This is called a "positive feedback" and is only one of several positive feedback mechanisms affecting ozone dynamics.
Ozone Depletion, Ultraviolet Radiation and Climate Change
Prior to 1992, most of the scientists writing about climate change and global warming were uninformed about the effect of elevated ultraviolet radiation on forests and oceanic plankton. This led to their models not incorporating ozone depletion as a driver of global warming because of UVR impacts on carbon sinks. As new research is released, concern is mounting about potential catastrophic acceleration of the global warming process because of damage to carbon sinks.
The world's plankton is the primary carbon sink, feeding on CO2, releasing O2 and sinking carbon deep into the ocean when the plankton dies. This is the "oceanic carbon sink". Most of the world's plankton lies in the sub polar oceans. It is 1,000 to 10,000 times as abundant in the subpolar ocean as it is in the tropics or temperate oceans. The bulk of the plankton is in the south because the north is mostly continents and ice. Therefore most of the world's plankton lies exposed to an ever expanding southern ozone hole. The last three years have seen a dramatic expansion of the southern ozone hole. In 1991 the hole was as big as the continental USA and was 50% depleted of ozone. In 1992 the hole was 60% depleted over an area as large as North America. In 1993 the hole was 75% depleted of ozone over an area quite a bit larger than North America.
This puts the world's major carbon sink in jeopardy as research shows that many of the varieties of plankton are negatively affected by UVR which can penetrate as deep as 60 metres (180 feet) into the water column.
Research is showing that the world's forests are in jeopardy because of multiple environmental stresses. Massive clear-cuts are decimating the world's forests. As the forests are cut, erosion causes soil loss and desertification. As the forests disappear, runoff increases leading to further drying. It is also becoming apparent that tree plantations may not be viable because of heat and drying stress, frost and ultraviolet radiation.
Little seedlings naturally regenerate in the shade and protection of the forest canopy where the climate is moderated by shade and moisture and nutrients are provided by the forest and decomposer species. Modern clear-cut forestry completely destroys the natural regenerative processes of reforestation. Plantations are often monocultures, vulnerable to disease, pests and fire, and lacking the essential biodiversity of our native forests.
As a further stress, the tender seedlings now face enhanced UV radiation and global warming. Evidence is accumulating that plantations are failing, especially on low and high elevation south facing slopes where radiation is the most intense. Yet we continue to cut our resilient mature forests and rest our future on the dubious prospect of vigorous re-growth. Many of the plantations around the world are displaying distorted growth, disease and pest infestations which are an indication that these new forests are not resilient or healthy. Over the last 2,000 years humans have destroyed 1|3 to 1|2 of the world's forests. The destruction is now proceeding much faster than ever before. Research sponsored by the Government of Canada indicates the boreal forest in Canada
will largely by destroyed by die-off and out of control wildfires as climate change proceeds. As the forest burns, more CO2 is added to the atmosphere and less trees are available to remove it, setting in motion another positive feedback system.
We are now realizing that there may be many wildcards yet unplayed in the game. A tiny marine plankton: coccolythophore, which is abundant in the temperate latitudes, is a very effective carbon sink because it's body is composed of calcium carbonate scales. When the plankton dies the scales fall to the ocean floor, substantially contributing to the oceanic carbon sink. These cells also produce an organic sulphur compound dimethyl sulphoxide (DMS) and when the plankton dies, or is eaten, the DMS rises into the atmosphere, where the tiny particles of DMS act as "seeds" for clouds.
Unfortunately, this organism is vulnerable as it is unable to tolerate enhanced UVR. A possible scenario of enhanced UVR would see die off of the coccolythophore and a dramatic reduction in cloud formation. The absence of clouds, which reflect radiation back into space, would further contribute to both accelerated global warming and enhanced UVR further damaging the plankton, and so on. The reduction in clouds will also reduce rainfall to the forests, further accelerating global warming and stratospheric cooling, resulting in more ozone loss and elevated UVR, and so on.
In June,1994, a senior Environment Canada scientist, Dr. Max Bothwell of Saskatoon announced that his research at the Thompson River indicated that midge larvae, the prime food supply for bottom feeders in shallow water systems were very susceptible to elevated UVR. This may jeopardize many important fish species.(See article in June 1994 Science)
In late June, Environment Canada announced that cod stocks are now greatly depleted from 1989 levels - even though fishing has largely stopped. I predict that scientists will soon announce the cod fisheries' collapse is due in large part to the effect of increased UVR on cod eggs and the eggs of species upon which the cod feeds.
Perhaps the biggest wildcard is the emerging Abrupt Climate Change Theory postulated by Dr. Wally Broeker of Columbia University. Based on Greenland ice core samples and Atlantic Ocean Sediment cores, Dr. Broeker postulates that climate can jump between two states. We are currently in a warm period. As global warming intensifies it may cause a part of Antarctica, the Pine Island Glacier, to sluff off into the ocean, destabilizing the West Antarctic Ice Sheet and raising global sea levels 6 - 10 metres (20 - 30 feet), inundating coastal areas and causing an immediate shift to a glacial period. Dr. Broeker makes a compelling case that this has occurred regularly in geological history.
Dr. Broeker also states that major volcanoes could trigger rainfall events which could turn off the Transoceanic Conveyor oceanic conductor. Major volcanoes can also substantially damage the ozone layer; yet another wild card. Recent geological activity has been very intense, and predictions are being made that a catastrophic eruption of Mount Pinatubo or Mount Mayon in the Philippines will shortly occur.
What is a Person to Do?
In these times it is important to consider how our lifestyles affect our planet . Where do products come from? At what cost are they created or extracted from the earth? What is the long term effect on our atmosphere, drinking water and soil? Our current ozone depletion problem was caused by the short sightedness of companies who produced products without examining what their long term effects might be.
The problem of ozone depletion is not going away. It will be with us long into the future, and our children's future. We must deal with the expected long term effects of increased ultraviolet radiation. Protective clothing and avoidance of the sun are ways we can protect ourselves, but protecting crops, forests, oceans and animal species is an overwhelming dilemma. We need our old growth forests, not for commercial value, but as shading to protect new seedlings and other creatures of the forest from UVR, and as carbon sinks to trap CO2 from the Atmosphere. We should plant trees which will survive and thrive in a rapidly changing climate, and find alternatives to timber products, such as hemp, recycled plastics and paper.
We should work on co-operative local food production without methyl bromide and other damaging pesticides and fertilizers. We must improve global top soil and humus or we will surely perish.
We must learn to walk softly on the earth. We must eliminate the production and release of ozone depleting substances, and eliminate or reduce emissions of CO2 and methane into the atmosphere. Jets should be re-routed to lower flight paths. Walk, bike or use public transport to work. If you must drive, own a fuel efficient car. Do you really need air conditioning?
Be responsible when buying new fridges, air conditioners and cars. New products are on the market which are less damaging to ozone but a grassroots push for totally safe products must come about immediately. Don't buy products from companies like Du Pont, the worlds largest CFC producer, or Seagrams, their largest shareholder. Whirlpool, and other companies in North America, have refused to produce the new Greenfridge, which is CFC free. These companies have misled the public and wasted valuable time, instead of looking for alternatives.
See that old CFCs are recycled safely. Plant trees and tend a vegetable garden. Keep a stock of non-perishable foods on hand. Eat more locally grown food, organic when possible. Take steps to boost your immune system, as UVR is very detrimental to immune functions. Think magic thoughts for the health and safety of your community, and design mechanisms to bring about the changes that are needed if we and our planet are to survive.
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