Friday, October 14, 2016
Book Review: Trees Are the Answer – by Patrick Moore (PhD Ecology) (Beatty Street Publishing, 2000, Anniversary Edition 2010)
This is a very thoughtful and highly informative book by one of the founding members of Greenpeace who later “dropped out” of Greenpeace and became critical of their radicalism. The book is basically about forestry and particularly about sustainable forestry and what are the best practices and policies going forward. Moore comes from a family of loggers in the Canadian Pacific Northwest coast and seems to have quite detailed knowledge of forest environments. He deals with forestry from several different perspectives: environmental, economic, and comparison to other sources of building materials and energy. Moore is often criticized by Greenpeace because he does consulting work for industries and governments but he has contributed to sustainable certification efforts and is eminently qualified to do just that. It is a nicely done book with many color pictures. This is a much-revised 10th anniversary edition of the original book.
In the forward to the new edition Moore points out new developments: more focus on climate change, expanded anti-forestry activism around the world, and sustainable certification becoming more common and widespread. He thinks that forest management can offer important overall means for emissions reductions. He disagrees with the European Emissions Trading System (ETS) in dropping forest-based carbon credits. However, they did so after fraudulent and other questionable activities. Moore seems to think cellulosic biofuels will be viable soon but thus far these 2nd-generation biofuels have yet to become so and others doubt they will be that important.
He begins with environmentalist efforts to preserve forests, particularly what they deemed “high conservation value forests” (HCVF). He acknowledges that these efforts have led to more awareness of forest preservation issues and the development of better management practices. He also notes that they have spread some misinformation and confusion.
Moore touts himself as a lifelong environmentalist but believes that the common environmentalist views of forestry in general, and clearcutting in particular, are simply wrong and must be contextualized to each area and ecosystem. Of course, he acknowledges that past practices such as clearcutting vast swathes of forest have negatively affected fish-bearing streams and other wildlife habitat. Current clearcutting practices are much different, he notes, with some trees left standing to provide habitat, avoiding sections along streams, and smaller contiguous cuts to minimize forest fragmentation.
He calls out those who argue that humans are “unnatural” as propagators of a false dualism:
“The central teaching of ecology is that we are part of nature and interrelated with it. All our acts are “natural” in this sense.”
Moore spent his early life on remote northwest Vancouver Island in the Pacific rainforest where his father worked as a logger in the “float camps” in the 1950’s. He has lived much of his adult life as well near these forests and knows first-hand how they regenerate after clearcutting.
He attended the University of British Columbia and had a turning point when hearing a lecture by Czech immigrant ecologist Vladimir Krajina. Krajina spoke out against the practice of ‘slash burning’ which was widespread in the Pacific Northwest at the time. That lecture, he says, awakened the power of ecological thinking for him. Moore’s own PhD thesis about the effects of dumping copper mine waste into the waters of Rupert Inlet, led to criticism by professors and his own birth as a radical environmentalist – entirely through the academic process, he notes. He was one of the original founders of Greenpeace in Vancouver in 1971 and worked with them as they grew to be the largest group of environmental activists in the world, protesting whaling, baby seal killing, nuclear power plants, supertanker traffic, logging, and many other environmental issues. He left Greenpeace 1986 having served for a some years in the past as its leader. He needed a break from it but he also saw its missions as having been largely accomplished – to bring awareness to environmental problems. Fixing such problems would require the combined efforts of governments, industries, and organizations. He is critical of extremist environmentalists that began, he says, in the 1980’s when environmentalism became more mainstream and as government and business began partnering with environmental organizations. Some were not willing to work with a perceived “enemy” and instead became more radicalized. Greenpeace and other radical orgs began moving toward more extreme positions as a result, he charges. It was the beginning of a split that leaves environmentalism divided, polarized between those who are willing to cooperate and compromise and those who are not. He also suggests that after the fall of the Berlin Wall and the Soviet breakup many of the Marxist peace radicals moved into environmentalism, taking their Eco-Marxist approach with them. He sees “deep ecology” in this manner as well, as imbued with extremism and intolerance. Greenpeace even called in 1990 for a “grassroots revolution against pragmatism and compromise.” Many in Greenpeace view Moore as a traitor simply due to him working as a consultant for government and business and for taking a more center political stance. He says they now propagate much misinformation about forestry and its effects and he points this out in more detail throughout the book.
Moore devotes a chapter to aesthetics and how it is not a good measure of forestry practices or ecological health. Clearcut forests may be ugly for a while then regenerate to various healthy and beautiful states. Settlers cleared land for farming and put a high value on cleared land. Clearcuts are seen as destructive but so too are volcanoes, fires, windstorms, landslides, pests, and diseases. Many of the lands we see as grasslands, grazing and farmlands, and other open lands were once forests. Clearcuts are typically planted back with trees while agricultural land remains deforested. And yet, hayfields are farmlands are often seen as aesthetic while clearcuts are seen as ugly. Some have suggested that humans have an aesthetic preference for open lands due to our history of evolving in open savannas. Moore presents a well-designed clearcut as a temporary meadow. After logging or another disturbance the process of renewal and re-colonization is known as “ecological succession.” This is because some species appear first on cleared land then others take over, then others – all in a typical succession for the area and forest type. Natural meadows are typically areas that are too wet, too dry, or too cold for trees. Many shrubs and species like fireweed in the West will thrive in new clearcuts. The left over wood after logging may be ugly but it also provides habitat and soil nutrients.
Moore is very critical of a 1993 Sierra Club book: Clearcut: The Tragedy of Industrial Forestry, which depicts many pictures of fresh clearcuts intended to equate them with ugliness and destruction of nature. He notes simply that beauty and morality are not equivalent nor are beauty and health. He also notes that aesthetics differ in some places. In Scandinavia some prefer the heathlands over forests and may protest turning an open heather land to a spruce forest.
Moore also mentions applying a principle of relativity to environmental issues:
“There is no perfect ecosystem for any given landscape.”
It is not easy to determine, he says, what is ideal for a given ecosystem and many situations may be acceptable. Nature is always changing. It is always finding balance then losing balance then finding it in a cycle where impermanence is the only certainty. The relationship of humans to the environment is also one that seeks balance – between the needs of humans and the needs of nature, between ecology and economy, and even the balance of reason and emotion. “There are no easy answers, only intelligent choices.”
Biological diversity is the next topic. He divides this into genetic diversity, species diversity, and landscape diversity. Genetic diversity refers to the degree of genetic variation of individuals within a species. Many different factors affect genetic diversity and it is often not something that can be seen directly. Species diversity is what most people assume to be equivalent to bio-diversity. Species diversity can be directly measured in most ecosystems although it is difficult to measure diversity of microbes. Landscape diversity, also called ecosystem diversity, “refers to the variety of distinct ecosystems within a given landscape or geographic area.” A more diverse landscape usually coincides with more species diversity as well. More species diversity means that attacks by pests and drought will likely be less catastrophic. He argues that logging “old growth” forests will typically not cause the “irreparable” loss of biological diversity that is depicted by the radical environmentalists.
Moore argues that logging does not affect net genetic diversity. Nearby unlogged trees will drop seeds into logged areas. Other species will thrive in the clearings. If trees are replaced by nursery-grown seedlings that does not negatively affect net genetic diversity but just the opposite since those individual seedlings have their own genetic diversity. In fact, he notes, nursery-grown seedling selected for good qualities will likely add to the genetic diversity and reduce inbreeding. He also addresses cloning (which is simply growing trees from cuttings), selective breeding, somatic embryogenesis – which is simply cloning that is able to produce an unlimited number of plants from a single source, and genetic engineering – all of which are used to increase genetic diversity and protect against problems. Thus far, China is the only country to commercialize GMO trees with a GMO poplar tree developed to be able to resist caterpillar infestations. China is significantly deforested and reforestation efforts are needed there.
Major disturbances like fire and logging can drastically reduce species diversity in a given area. However, that is only true where the disturbance occurred and species diversity generally returns through time. Species diversity may even be increased in the early years of recovery due to the invasion of light-loving flowering and fruiting plants. I have tried (and failed for the most part) to grow several of these awesome understory plants from the Pacific Northwest here in the Midwest – but I think the droughts and the winters are just too severe here for them. He notes that there in the Pacific Northwest the renewal of forests happens often with no input but sometimes with herbicides and mechanical weeding to reduce competition but even that is less needed or not needed when regenerating with larger tree seedlings. Due to the value of Pacific wood and the amount of protected public-owned land there is more original forest there compared to other lands where deforestation to make grazing land for sheep, goats, and cattle is perfectly acceptable. Europe suffers from many centuries of overexploitation of their forests. There are less commercially valuable tree species there too. The viability of forest renewal in Europe is questionable. Spruce is grown in Germany but not widely liked even though it is an indigenous species. Lodgepole pine from British Columbia is extensively grown in Sweden due to its faster growth rate than Scots pine but some don’t like it and consider it an ‘exotic’ species. The Pacific Northwest has an abundance of commercially valuable conifers and hardwoods as does much of North America to a lesser extent. Importation of other species is not required since the native species are quite adequate. For comparison, in New Zealand there are no native commercial wood species so Radiata pine from California is now extensively grown there as a commercial crop.
Forest management can increase species diversity by increasing landscape diversity. Landscape diversity, or ecosystem diversity, he says, is a general term, an indicator of overall bio-diversity. Diversity can also be seen as diversity of ages of trees of a species. He mentions areas where fire spread through valleys and lodgepole pine all the same age becomes the new pioneer species forest so that there is little species and age diversity. He mentions that “progressive clearcutting,” where continuous strips up to 2500 acres of valley forests were cleared, has been discontinued from the late 1980’s onward so the positive effects of better management of clearcutting are just now (2000-2010) beginning to be seen – increases in bio-diversity. Selective habitat preservation is another forest management technique that can be strategically implemented and documented. He mentions the need to protect certain low elevation forests as winter ranges for deer and elk. If you notice – the green grass and other greens grows well and quickly in wet lowland and streamside areas. The flowing water can temper and melt the snow. Forage in clearcuts can also help deer and elk populations. Leaving some standing dead trees and completely avoiding areas along salmon streams are other positive practices. Forest fragmentation is another very important consideration and should be minimized. However, he thinks that some environmentalists have taken the idea too far comparing the fragments to islands separated by oceans – since islands are known to have fewer species. He confirms that fragmented forests are magnitudes less separated from each other than islands by seas and that most isolation of species can recover quickly, especially with keen management.
Moore also strongly disputes assertions by the World Wildlife Federation (WWF) that logging has caused species extinctions and massive deforestation in industrialized countries. He called them out on this and they did lessen their rhetoric but he still says their reports regarding logging impacts are not credible nor are those of Greenpeace. He goes into some detail about this and explains that attempts to link forestry and species extinction are simply not credible but are merely hypothetical. He does acknowledge and discuss the factors of human-caused species extinction in the past: introduced predators and diseases (islands are most vulnerable), over-hunting and eradication, and vast clearance of forests for agriculture which causes loss of habitat. He notes that these issues are not currently common in the Pacific Northwest so there is no valid reason to assume species extinction is happening there due to logging which typically causes temporary loss of habitat. He refutes that we are currently experiencing a “mass extinction” noting that most human-caused extinctions were caused by initial introductions of predators and disease and new land clearing of virgin forest areas. He notes that 75% of extinctions have occurred on islands, which are more susceptible to extinctions. He also refutes that logging necessarily threatens the spotted owl in the Pacific Northwest. He notes the 30,000 loggers lost their jobs due to the perceived threat. This led to more research on the owls which revealed that the owls are quite capable of surviving and thriving in second-growth forests and don’t require old growth forests as was assumed, at least in the southern range of the species. More owls have been found than were predicted as the maximum number of owls that a certain amount of forest could sustain – in some places more than twice as many owls were found than the land was thought capable of supporting. The Endangered Species Act has shut down much forestry in the Western U.S., much due to perceived threats to the spotted owl. He gives “A Tale of Two Woodpeckers” from the U.S. southeast showing that the ivory-billed woodpecker went extinct due to land-clearing for agriculture beginning in 1948. Its cousin, the red cockaded woodpecker, has survived among patches of longleaf pines and this has been helped by conservation efforts among both landowners and forestry companies who developed conservation plans.
Next he explores “monoculture,” what it means and common misunderstandings. The term as applied to forests is generally different than applied to agriculture. While there are tree monoculture crops such as palms, bananas, oranges, some pulp paper crops, eucalyptus, and hybrid poplars, other forests which have been dubbed monocultures have merely a dominant species combined with other trees, shrubs, and plants, rather than the single species tracts typical of agricultural monoculture. Agricultural crops are typically annual crops too. Some monocultural forests appear naturally as pioneer species like lodgepole pine, predominate after fires, and are much more biodiverse than annual agricultural croplands. Replanting single desired species such as Douglas fir after clearcutting have also been called monoculture but there is typically quite a bit of diversity. Moore even emphasizes a study that showed that post logging diversity was greater than pre-logging diversity in the Pacific Northwest, though not in other parts of the world. Two reasons for this are forest management and pioneer hardwood species that often fill cleared areas first along with the conifers.
Exotic and invasive species are explored. Many plants imported for ornamental value have become invasive but others have become important. Many or most of our main food crops would also be considered exotic non-natives. He gives the example of California where 50% of U.S. fresh produce is grown – of 375 species grown none are native! Of course, some invasive species have been catastrophic so each needs to be evaluated separately along with the environment in which it is introduced. In many places in the world, non-native tree species are planted for their positive qualities: ornament, commercial crop, and habitat. Species are quite variable in their needs so perhaps forest management should also be variable to accommodate more species rather than ‘blanket’ prescriptions. Measures to increase biodiversity can be implemented at different levels: at the level of a “stand” of trees any herbicide applied to reduce competition from shrubs during initial growth can be avoided in certain areas of the stand so that the shrubs can grow to provide habitat. Mini-reserves can be established, especially around streams and wetlands. Retaining some hardwoods on a pine plantation and similar-type measures can increase diversity. Individual dead and dying trees can be retained for the same purpose. Piled woody debris can provide bird habitat. At the landscape level the technique of streamside reserve management or riparian reserve zone can be established since that is an area typically rich in species diversity and habitat. Permanent wildlife reserves can be established especially where exotic non-native tree plantations are grown. Another strategy is providing corridors that connect streamside reserve zones so that fragmentation and islanding are minimized. One goal of sustainable forest management is to minimize loss of biodiversity since some will inevitably occur.
Moore thinks it is important that we appreciate forest health and forest limits at different time scales and recognize their climatic and geographical variation. He uses an interesting example of the Aleutian Islands where trees do not grow naturally even though it usually doesn’t freeze and is quite wet. The problem there is that it doesn’t get warm enough in summer for the trees to make seed. Planted trees can do quite well there. He also mentions that many trees like the giant sequoia can actually grow quite far from their natural climatic ranges with assistance since they often won’t seed beyond those ranges.
He makes the significant point that the Amazon Rain Forest which many have called the “lungs of the earth” for its ability to take up carbon, was mostly savanna 9000 years ago. Forest, floral and faunal species migrated south during the Ice Ages and back north in the interglacials. Canada and Russia currently make up 30% of the world’s forests. During the Ice Ages (near 90% of the past 400,000 years) much of those areas were entirely covered in ice. He compares post-ice-age migrations of forests in Europe and North America and notes that these migrations left North America with greater diversity since the mountain ranges and subsequent valleys run north and south rather than east-west as in Europe. As a result some areas of Scandinavia have only two species of conifer. This has all happened by chance with climate and geography being major influences. Thus Moore concludes that:
“There is no ideal forest composition for any given climate or region.”
Thus re-introduction of lost species and introduction of comparable species should not be seen as “unnatural” but as a way to enhance diversity.
Moore describes the process of ecological succession from minerals, microbes, and fungi, to mosses, lichen, ferns, to the later development of trees. Different regions have their own typical succession patterns but they can vary according to circumstances. He gives examples of this variability through different successions from disturbances by landslide and fire and by competition between species from light such as Douglas-fir and Pacific alder.
Old growth forests are typically defined as forests that are 150-250 years and older depending on type and region. Some types are longer-lived and some regions experience less natural disturbance. Typically the understory is also mature and highly diverse. There are also many high nesting sites for birds. One question is how much of it should be protected. Moore says it will grow back faster than radical environmentalists would have us believe. He mentions the term “ancient forest” as being deceptively defined by Greenpeace and others which often also includes forests with very young trees. All old growth forests may not be healthy. He gives the example of some Pacific Coast Rainforest areas that are so wet and protected that they have thrived for thousands of years but some are now so full of rot, choked with mistletoe and pests, and have no commercial value so that they are considered to be in decline. Adjacent younger forests have less disease problems and rot and grow at a much faster rate. These are areas that suffer periodic disturbance suggesting that it can be healthy for forests.
The effects of forest fires are a matter of deep study for foresters. A balance of letting nature take its course and human safety needs to be established. There are arguments about whether letting fires burn, controlled burning of some areas, or prevention are the best policy in each forest area. Fires are started by lightning, careless humans, and as controlled burns. In Canada, he says, half are lightning and half human-caused. Some areas in Alaska and the Northwest Territories of Canada have big lightning fires every year. Some fires may burn so hot that they sterilize soils so the seeds can’t grow. Different trees have different susceptibilities to burn. In some areas ground fires may reduce the risk for tree fires by reducing the availability of dry fuel. Controlled burns can be dangerous and unpredictable. Each situation is different so not likely amenable to a single rule. Forest management can be complex, involves judgement, cost/benefit analyses, and location-specific requirements.
He gives some case histories of fire effects, recovery times, and strategies in Yellowstone Park and he chronicles the effects of the Mount St. Helens volcanic eruption and forest recovery efforts there. There he shows with pictures that human intervention by forestry companies can drastically improve the look, function, and diversity of the landscape – and do it while developing a commercial product. The recovery time has dropped by years and perhaps decades. Slow recovering areas at Mount St. Helens also provide grazing habitat for elk and deer – as do clearings made by clearcutting or fire. One might say that the disturbances often cause an increase in landscape diversity. Beneficial forestry can and must happen. I think that precise, detailed, and well-monitored resource management will be a requirement from here forward. Resource management needs to be optimized. Windstorms and landslides are common in the otherwise stable Pacific coastal rainforests. They also regenerate areas of forest. Regeneration by disturbance means that that will be more variability of maturity levels and succession levels in given areas. Landslides can reset succession levels to the beginning where removed soil reveals bare rock. Over-mature and infested old growth areas have very slow growth rates compared to young forests.
Foresters are also concerned with controlling tree pests and diseases. Very young, very old, and tress stressed by drought or injury are most susceptible. While some may see pest and disease as natural as they are, we also want to improve the health of the trees so we seek to limit pests and disease as some can be quite devastating. Parasitic bark beetles have damaged forests in the Pacific Northwest, particularly the pine bark beetle on lodgepole pine. Control of wildfires can let the trees grow older and more susceptible to bark beetles. After the trees die the dry dead trees are more susceptible to fire. Some claim that the trees should be left alone and fires should not be controlled but fire damage and/or beetle damage are generally not welcomed by forest managers and commercial foresters. Typically, loggers will “follow” bark beetle infestations (mainly pine and spruce), harvesting the dying trees soon after they succumb. He notes that one of the largest clearcuts in Canada followed a vast bark beetle infestation in this manner but was inaccurately portrayed by the Sierra Club and others as a routine commercial clearcut. Another infestation is by parasitic mistletoe on the Pacific coast, particularly on older Western Hemlock. Younger forests are not affected so logging can change an unhealthy old forest to a healthy young one in time. Selection logging, where some trees are left, may also be employed where applicable.
Discussing soil degradation and erosion he notes that although it does occur it can be minimized and is not as bad as often depicted by anti-loggers. Many of the problems have been caused by improper road building. Better road construction practices and increased cable and helicopter logging have reduced soil problems in recent years. Landslides can also damage soil, obviously. He give the examples of Germany and Australia, both which have poor, sandy soils and which had thorough scavenging of timber leftovers for firewood. This tended to decrease soil fertility. He notes that the nutrient-rich parts of trees are often in the roots, leaves, and needles rather than in the wood. Much of the wood is carbon with hydrogen and oxygen (as water). So logging itself tends not to remove many nutrients compared to agricultural crops where the nutrients are often in the parts used for food. Some have criticized the loggers for leaving tree tops behind (an eyesore) so they are blamed for both taking too much and leaving too much. This “waste” can be very valuable as habitat and some nutrient source.
He notes that while people often associate logging with deforestation, really deforestation is a two-stage process: after removal there is land use that assures that the forest cannot grow back. The three main causes of deforestation are agriculture & grazing, urbanization, and industrialization. Sheep, goats, and cattle prevent forest regeneration on vast amounts of land. Demand for wood is high and expected to remain high so proper management and regeneration of supply is vital. The need to decrease overall deforestation is also being pursued to help sequester carbon and keep habitat. With more efficient agriculture and grazing management, and less overall urbanization and industrialization deforestation can be minimized while other areas can be reforested. He notes that 55% of wood demand is for fuel for cooking and heating, particularly in tropical developing areas. Many of those areas are suffering deforestation. Poor forest management contributes to the problem. 15% of wood is used for solid lumber products, mainly for construction and furniture. The remaining 30% is used for pulp and paper products like packaging. About half of these pulp and paper products come from sawmill waste fibers with most of the rest from tree plantations. Very little comes from natural forests.
In Southeast Asia, particularly Indonesia, deforestation by burning and logging, in order to develop palm oil plantations has devastated large areas, created long-burning uncontrolled wildfires that contribute significantly to atmospheric CO2 and pollution, and destroyed habitat. Forests and species in these areas need better management. Overall, forest area has increased in Asia, mainly due to reforestation efforts in China. Sweden, South Africa, New Zealand, and Asian countries are also seeing reforestation. Tropical and subtropical areas in Africa, the Caribbean, Latin America, and the Near East are seeing the highest levels of deforestation. While logging may be associated with deforestation in those areas, forestry, or forest management, is not. Forestry often requires 100% reforestation of logged areas. Projected future population increases will likely require more land clearing for agriculture and urbanization so that is the main driver of deforestation by far. Population management, more intensive agriculture, and urban densification will help decrease future deforestation.
The relationship between forests and climate change can be complex and sometimes misleading, he notes. It is desirable to conserve forests thereby increasing carbon uptake. Controlling fire may help as well. Carbon is also conserved in durable wood products, he notes. Thus effective forest management can really help mitigate climate change – by growing more trees and by using more wood. Moore believes that using more wood is a sensible and beneficial way toward sustainability. Anti-logging activists, however, would disagree. There is disagreement about cutting old growth forest areas – whether it releases too much carbon. Foresters counter that new growth after logging is often much faster and takes up carbon much faster than older forests. He explains the carbon cycle of sources and sinks with atmospheric carbon as CO2 and fixed carbon in plants. While old forests indeed do contain more carbon than new ones they take up less carbon than new ones since they are in a mature state and new growth is slow. 10% of atmospheric CO2 is derived from deforestation, primarily from tropical forests. The use of wood (from sustainably grown forests) as durable and enduring products such as furniture and in houses and buildings actually sequesters a significant amount of carbon and should be well-considered in carbon budgeting equations related to forests. On the other hand, burning wood for heat and cooking results in the carbon being released to the atmosphere much faster than through natural decay as well as putting toxins in the atmosphere. Moore notes that nearly every material – plastic, steel, and concrete require far more energy to produce than wood so wood is a good sustainable choice as a material.
He mentions the decision of the European Emissions Trading System (ETS) to discontinue the trading of forest-based carbon credits (presumably due to fraud and difficulties in measuring and verifying). He also mentions that environmental organizations are split on the value of wood and sustainable forestry with more moderate groups like World Growth, Nature Conservancy, World Resources Institute, and Environmental Defense acknowledging the value of forest products in offsetting carbon while the more radical groups like Greenpeace, World Wildlife Fund, and Friends of the Earth have refused to concede the positive role of forestry in offsetting carbon.
New understandings in science and ecology have led to recognizing the value of forests in providing habitat, biodiversity, and in sequestering carbon. Old-style destructive logging practices have, as a result, been largely abandoned, except in some areas such as the tropics and in developing countries. Moore gives a good overview of the idea of sustainability:
“On one level, sustainability is an ideal state in which the actions of today’s generation have no adverse impact on the opportunities of future generations. On another level, it is a pragmatic, rational approach to changing our behavior in order to conserve rather than squander our natural resources so future generations have more choices. There is no perfect state of sustainability. It is a relative concept that requires a high level of strategic planning and consideration of details.”
Key to sustainability is considering the future. With trees as a renewable commercial product, such planning can be reasonably precise. Land use conflicts can be complex and ecological considerations are very important. Sustainable forestry principles are now becoming well established and mainstream with many regulations and guidelines on local, state, regional, and national levels. Soil conservation, protection of watershed integrity, habitat protection, representation of variable successional stages to promote biodiversity, rapid reforestation of harvested land, and smart wildfire control, can all promote sustainable forestry. Government and industry must provide accurate inventories of forest resources, develop best practices for minimizing problems, minimize economic waste while also leaving sufficient woody debris for habitat and nutrients, utilize smart brushing and thinning, minimize the use of herbicides and pesticides, and burn carefully. Tourism, grazing, hunting, fishing, trapping, honey production, and foraging are other considerations. Local effects, visual impacts, and recreational uses also need to be considered. Forest research should also be promoted and done.
Clearcutting has been the focus of environmental opposition to logging. Swedish foresters simply avoid using the term and call virtually the same thing – select area felling, or (SAFE). In the U.S. Southeast pine forests the term “regeneration harvest” is employed to denote rapid reforestation after clearcutting. Another term is “variable retention harvest” which focuses on the trees left in the landscape. The negative connotations of clearcutting are a remnant from past logging practices with few rules or consideration for damages to soil, habitat, streams, and diversity. Much of the past practices involved clearing vast tracts of land for agriculture and grazing. Groups like Greenpeace have called for global bans on clearcutting invoking these past practices as proof of the damage inflicted. Slightly more moderate groups like World Wildlife Fund have stopped short of calling for a ban, saying some clearcutting is OK.
What defines a clearcut is not exactly clear. The effects of the surrounding trees on the cleared land depend on several factors: the trees’ height, the latitude (since the cleared land will be more shaded by surrounding trees in higher latitudes), the type of forest, species present, and the slope of the land. Many radicals advocate for single-tree selection logging which would be prohibitively time-consuming and expensive for loggers and could result in building roads to access and haul very small numbers of trees which would be very inefficient.
Moore defines some logging terms: “selective cutting” means taking only trees of certain species and of a certain size. This has also been called “high-grading.” Thus loggers take only the most valuable species. Eventually this could lead to a lack of those species in the landscape relative to other species and plots that have less commercial value. Clearcut forests typically grow back with similar species ratios to the original forest. Thus, he notes, selective cutting can degrade a forest more than clearcutting. Similar-sounding term “selection logging” means “carefully selecting the trees that are cut on the basis of the ecology of the forest.” He notes that some forests are especially amenable to this technique such as the hardwood forests of the U.S. Northeast and Eastern Canada. Dry Western conifer forests in high elevations are also amenable. Clearcutting in these areas would result in slow regrowth of the new forest due to the dryness so the retained shade holds in moisture. In high elevation areas the trees also shelter the seedlings from frost at night. These areas have been defined and mapped such as the dry-belt Douglas-fir areas. Clearcuts have gotten smaller due to the need for forestry management and now are typically less than 100 acres in size. Clearcutting actually mimics some natural forest degradation such as from fire, windstorms, and volcanoes. Clearcuts can be designed with aesthetics in mind utilizing the natural land contours. Loggers prefer clearcutting because it is safer and more economic than cutting single trees among other trees. Shade tolerance is a factor in the environmental advantages of clearcutting. Pioneer species like lodgepole pine won’t grow in shade, even their own shade. Often they will fill clearings and become a monoculture forest area of same-age trees after disturbance. Swedish forests were degraded by selective cutting the pine and spruce until the forests were no longer commercially valuable. By not removing other species new pine and spruce trees were not regenerated due to being shaded out by the other species. A law was actually passed in Sweden requiring clearcutting but was recently relaxed to allow some selection cutting. Clearcutting is still by far the dominant method of logging in Scandinavia.
Clearcutting can also be beneficial when pests and diseases are a problem to keep them from spreading. Clearcutting was banned in the Alps due to poor past practices related to unregulated clearcut logging to obtain wood fuel for industry which left the land scarred. Selection logging can damage trees left standing making them more vulnerable to pests and diseases. Well-managed forests are the easiest to log. Old growth forests may have high wood value but are not easy to log. While Greenpeace claims that even-age stands of trees are rare in nature Moore notes that this is simply false – the boreal forests of Canada and the dry interior forests of Western North America have widespread naturally-occurring even-age tree stands. He makes the point that the anti-forestry activists are not properly educated on these facts. Many, he notes, are not only even-age but also dominated by a single species as naturally-occurring monocultures. The Society of American Foresters has concluded that clearcutting can have a positive role in forest management, particularly for regenerating shade intolerant species of trees, although it needs to be done properly. The technique of ‘variable retention harvesting’ seeks to preserve overall biodiversity by employing different techniques in an area such as selection logging, selective logging, and clearcutting.
He goes through a history of the development of forestry certification standards. The need for third party certification is acknowledged by all parties, but there are disagreements about what the standards should include. During the early 1990’s environmental groups Greenpeace and World Wildlife Fund collaborated on forestry standards to deal mainly with problems in tropical countries such as illegal logging. The forestry industry was excluded from this system so that the Forest Stewardship Council (FSC) certification system was developed entirely by the environmental movement. During the same time period the forestry industry was developing sustainable practices and developing guidelines for best practices. British Columbia’s Forest Practices Code was an early effort along these lines. The forestry industry argued that the certification system developed entirely by environmentalists who are hostile to industry was also developed by people with little to no training in forest management and its complexities. There was also industry bias against environmentalists.
Moore gives three elements of the certification systems: the standard itself and its governing body, independent certification of compliance with the standard, and “chain of custody certification” which traces the certification from source to final product. In 1994 the Forest Products Association of Canada with the Canadian Standards Association developed a standard (CSA standard) and in the same year the American Forest and paper Association began what was to become the Sustainable Forestry Initiative (SFI). In 1998 Western Europe and Scandinavia adopted a similar standard. Both the American and European standards included individual forest landowners. He compares these three standards. The Forest Stewardship Council (FSC) was the first standard and has been adopted by small forest landowners, some major forest companies mostly in Sweden and Canada, and some publically-owned state forests in the U.S. FSC has a more complicated structure, more stringent requirements, and is still largely hostile towards the logging industry. For these reasons it has far less areas certified than the others. CAS and SFI utilize similar structures and requirements. Moore accuses the FSC of picking winners and losers, thus overarching its power. The SFI system is now the main system used in North America. In 2001 the SFI separated itself from the American Forest and Paper Association as a non-profit so that it could be seen as an independent third party certifier. Greenpeace and other radicals, in support of FSC over SFI, have waged a conflict, but SFI competes with it well through good marketing practices with buyers and certifies much more forest than FSC. The CSA standard is considered the most technically rigid but has not been marketed well so is less used. Globally the Program for the Endorsement of Forest Certification (PEFC) recognizes various certification schemes into an umbrella standard. Since PEFC endorsed SFI and CSA there are now two main standards: PEFC and FSC. PEFC certifies twice as much forest as does FSC. He notes that at press time about 8.3% of global commercial forest is certified as well-managed. Certification was developed in regards to tropical forests but has instead developed mainly in temperate forests. Only 0.5% of African and Asian forests and only 1.6% of Latin American forests have been certified. Cost of compliance has been one main reason these tropical forests have not been certified. Moore thinks the antagonistic stance of the FSC and their rigid requirements are another important factor.
Green building certification is another issue with forest products. He mentions the benefits and the flaws of the main U.S. system, the Green Building Council’s LEED certification system. He compares LEED to FSC in discriminating – indeed LEED specifically requires FSC certified wood which ends up discouraging the use of wood due to cost, since FSC-certified wood is rarer than wood otherwise certified. Like FSC, LEED often reflects standards favored by activists which can be punitive. He thinks they have an anti-wood bias reflective of the anti-forestry bias of activists. He also thinks LEED does not adequately consider full life-cycle analyses in determining the sustainability of production processes. He does mention that LEED is reviewing its requirements and may drop some its bias as a result. It is not clear if this has happened yet. He thinks they may lower their bias against wood and perhaps vinyl as well – a durable and recyclable product for siding, flooring, pipe, and other uses. He also promotes geothermal energy from heat pumps and would prefer to give it more value in certification than is current. He promotes a wood-vinyl-geothermal home as a potentially inexpensive green option.
Next is considered the place-value, the so-called sacredness of forests. Indeed indigenous peoples have long built their lives around the perceived power of places. Leaving land undisturbed is the goal of conservation. Moore compares a giant forest to a giant cathedral. Here he invokes Thoreau and the beginnings of the conservation movement. He tells of some of his own favorite forests such as Pacific Spirit Park in Vancouver, an area of nearly 2000 acres that was clearcut early in the 20th century but the regrowth, now mature, was exempted from further logging. It is now often mistaken for an old growth forest. For him it is proof that clearcutting is not deforestation.
The world has recognized that three of the biggest issues are climate change, biodiversity, and forests. Growing more trees and using more wood can benefit all three of these issues compared to alternatives, he says. Greenpeace has done the opposite in promoting reduced use of wood in favor of more environmentally appropriate alternatives. The Sierra Club’s “zero cut” policy wants to ban logging on all Federal land. Moore debunks the notion put forth by Paul Ehrlich and others that per capita consumption of resources like wood correlates directly to environmental impact. He notes that it is obvious that poverty can relate to environmental impact as well in ways like lack of proper sewage treatment and complete stripping of local trees and woody debris for cooking and heating fuel. More wealth recently in India and China has led to successful reforestation efforts there. Moore seems pretty certain that trees will remain massively important in the post-fossil fuel era ahead. He thinks the global demand for wood will continue to increase so more forests need to be managed well.
Moore sees calls by Greenpeace and NRDC to boycott forest paper products from “virgin fiber” as nonsense. He notes that paper and toilet paper are typically made from waste sawdust and chips from sawmills used to make boards for building. Although there is a small amount of plantation forest that is grown and used for paper, particularly from South America, it is not significant, he says. Apparently recycled wood made into toilet paper, as advocated by environmentalists, tends to be rough rather than soft. Environmentalists tend to advocate annual crops like hemp and kenaf to make “tree-free” paper. But Moore notes that trees provide many further benefits than these exotic annual crops and to grow trees instead in these areas offers vastly more benefits. He notes that in growing crops to make paper, trees are simply the best choice, for the additional benefits they provide.
Looking to the future he sees possibilities for cellulosic biofuels, although that has yet to happen. He notes that in many tropical areas with few native commercial tree species it makes sense to grow non-natives on plantations for this purpose, particularly on previously cleared agricultural land. Deforestation for mere subsistence farming is widespread in the developing world and needs to be addressed by governments in those countries. Illegal logging is a big problem throughout the developing world. He also calls for more international funding for forest management in these areas. He says those in tropical areas have no incentives to develop certifiable wood products through proper forest management – that certification is prohibitively expensive for them unlike in wealthy countries where forests have been managed and kept reforested for many decades. He suggests that anti-forestry groups become less confrontational but he also suggests that the forestry industry become less self-promoting and more socially engaged so they can further their “social license to operate” rather than automatically dismissing their detractors. Environmentalists promoted a FSC-only policy for certification while dismissing the standards developed with foresters. Home Depot adopted an FSC-only policy in 2001 which gave those FSC producers a monopoly there, effectively excluding 99% of British Columbia timber. Moore’s consultancy worked to convince Home Depot to adopt a more inclusive policy than the exclusive FSC-only one. As a result, Home Depot did re-evaluate its buying policy to be more inclusive. Moore advocates sensible collaborative approaches to forest management issues and certification.
This is a very important and detailed book about forestry and all the issues surrounding it. Essential reading on this subject.
Saturday, September 24, 2016
Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future
Book Review: Under A Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future – by Peter Ward, Ph.D. (Harper Collins Publishers, 2007)
This is a fun foray into the scientific worlds of paleontology, paleoclimatology, geology, and mass extinctions. The book reads like an adventure story, or rather a detective story – trying to piece together geologic clues from the past to determine what caused the mass extinctions of the past and what processes were involved in the preceding and subsequent years and how they compare to today’s global warming challenges. The author and his colleagues visit outcrops and sedimentary sequences all over the world, sometimes in isolated places and harsh environments.
The first place worked is the Muller Canyon area of Nevada where rocks at the end of the Triassic period are exposed. I have done some rock-hounding and geologic mapping in central Nevada in the much older rocks of the Valley and Ridge in the sagebrush desert areas. It’s a great place to look at rocks. At the time geologists were looking for evidence of asteroid impact at the end of the Triassic as evidence was found at the end of the Cretaceous in the mass extinction that wiped out the dinosaurs. No convincing evidence has been found for impact at the end of the Triassic there, only a loss of many fossil species and a thick siltstone nearly bereft of fossils. If it wasn’t asteroid impact was it climate change, he considers. Eventually he builds up a model, a case, that it was indeed fast climate change, with rapid global warming and strong positive feedbacks that led to massive amounts of CO2, methane, and eventually other toxic gases like H2S bubbling out of the ocean and accumulating in the atmosphere, raising temperatures and making it hard to exist for many species. About 60% of all species on earth were lost in the mass extinction event at the end of the Triassic.
Next he ends up in the summer of 1982 in the Basque region, in the Pyrenees Mountains between France and Spain. Here he meets up with another geologist, Jost Wiedmann, a biostratigrapher cataloging, correlating, and dating fossil assemblages throughout the world. He noted that the extinction of ammonites in the fossil record near the K-T (Cretaceous-Tertiary) boundary was gradual, lasting about 20 million years, rather than immediate. Ward, with a fresh Ph.D., was interested in why the ammonite cephalopods went extinct at the K-T event after a 360 million year biological success and their cousins, the chambered nautilus, survived. He also studied wild nautilus by diving in the Pacific off the coasts of New Caledonia and Fiji.
A paper came out in 1980 by Luis and Walter Alvarez, a father and son team from the University of California, Berkeley that strongly advocated that the K-T extinction event was the result of an asteroid impact. Catastrophic environmental changes, particularly a long lasting “blackout” from massive amounts of particulate matter in the air, they proposed, were the mechanism of the mass extinction. Ward and Wiedmann found no ammonites within 15 meters of the proposed impact layer.
Mass extinctions were recognized in the fossil record in the 19th century but were attributed to “catastrophism,” typically worldwide floods like the biblical flood. Such ideas were tossed as the science of paleontology developed further. The two largest mass extinctions divide the stratigraphic record into three main eras: the Paleozoic, the Mesozoic, and the Cenozoic. There are five main mass extinction events noted in the geologic record - from oldest to youngest: 1) Ordovican, 2) Devonian, end of Permian (Permian-Triassic), end of Triassic (Triassic-Jurassic), and end of Cretaceous (Cretaceous-Tertiary, or K-T).
Ward talks about a split among vertebrate and invertebrate paleontologists in the 1970’s where views on mass extinction was a factor: the vertebrate paleontologists did not think the mass extinctions occurred, only that the fossil record was missing. Evidence is now much stronger that the mass extinction indeed did occur and there is little dissent from that view. Two types of mass extinction were proposed: slow and gradual ones due to climate change, changing sea levels, disease, and predation; and rapid catastrophic ones characterized by the sudden disappearance of a large number of fossil biota in the record. The slow extinctions could not really be tested, only theorized. When asteroid impact became seen as a plausible mechanism for extinction there was at least something to look for – iridium and altered quartz that is associated with impacts.
The Alvarez’s paper began a new paradigm, or revolution, in thinking about mass extinctions, that they weren’t slow and gradual and due to climate change but fast and due to asteroid impact and its after-effects which include climate change. He puts this in the contexts of Thomas Kuhn’s “structure of scientific revolutions.” Much evidence for a K-T boundary impact was accumulated: iridium, “shocked quartz,” spherules, and carbon isotope ratio changes which indicated a rapid loss of plant life presumably due to fire. However, some other geologists had another explanation: volcanism involving “flood basalts” and associated ash and lava flows. The impact vs. volcanism battle went on for over a decade. Flood basalts strongly correlated to all mass extinctions and even minor extinctions. Iridium, shocked quartz and spherules could also be associated with volcanism. Ward suggests that the geochemical evidence for impact was strong because they found what they were looking for in the impact layer but the fossil evidence required looking before and after in different places where the intervals were preserved.
He tells of an odd experience stalking the Cretaceous-Tertiary boundary in France at a beachside outcrop where there was a large group of tanned naked frolicking gay men while he hammered rocks in geologist garb! Here he finds 12 species of ammonites in abundance near the boundary where in other places they seemingly died off gradually – here they did not until the actual boundary layer, which is further evidence of the asteroid impact. Ward proves that impact cannot kill off just what would become microfossils but macrofossils as well. He presents his findings at a conference where Jost Wiedmann was in attendance, after Wiedmann asserted that impact was not the cause and that the extinction of the ammonites came slowly. Wiedmann listened to his talk then left and never spoke to Ward again – dying a few years later, as Ward explains, his life’s work disproved by an apprentice. Science can indeed be a sad world. By the end of the 1980’s the evidence for impact as the cause of the K-T extinction was very strong. The 120-mile wide impact crater was found (in the Yucatan peninsula of Mexico) and both the geochemical and paleontological evidence supported a very rapid mass extinction. The problem, notes Ward, is that now all the other mass extinctions were assumed to have been caused by impact, as the new “paradigm” took hold.
Ward’s further studies in the French Pyrenees examined the quick (geologically speaking) recovery of life in the Late Paleocene of the Tertiary Period the first 5 million years after the K-T extinction event. The new fossils are of species still around today and indicate the area was warmer as they were tropical species. Oxygen isotope ratios found in shell material provide a very good record of temperatures when they were made. Analysis of oxygen isotope ratios from bottom-dwelling (benthic) organisms from the Antarctic a few million years after the K-T boundary showed that the basal ocean water there had anomalously warmed over a short period of time. The warmer water in the polar high latitudes (both Arctic and Antarctic) was also found to be more depleted of oxygen which caused an extinction of benthic organisms here at the Paleocene-Eocene boundary a few million years after the K-T asteroid impact boundary. The benthic organisms were not affected directly by the impact. The suggestion was that the oceanic conveyor belt which transfers heat to and from depth in the ocean was somehow shut down – presumably by the warm surface temperatures. This became known as the Paleocene thermal event. The event was confirmed to have occurred on land also by compared patterns of carbon and oxygen isotope ratios in well-measured fossil assemblage sections in Wyoming. Here many exotic forms of mammals were found, many now extinct. The Paleocene thermal event is considered a minor extinction event. More evidence was searched for in Aeolian (wind) deposits – basically dust that made it to the ocean floor. The amount was reduced and extremely reduced at the point of the event suggesting low wind conditions – typically as a result of prolonged arid weather. Also found was volcanic ash and indeed a great uptick in volcanic activity 58-56 million years ago. Estimates of seawater temperature differences from equator to poles (now 45 deg C) then shifted from 17 deg C to a mere 6 deg C, suggesting a quite unusual homogeneous ocean temperature. The basic mechanism of the Paleocene thermal event is thought to have been volcanoes spewing carbon dioxide with the CO2 heating up the surface of the planet and later the ocean, shutting down the deep-water circulation conveyor belt. The event ended after the volcanism subsided and later when the CO2 levels finally dropped. By 2000, other minor extinctions began to show similarities to the Paleocene event.
He ends up in the Southern Tunisian Desert in 2000 at one of the best exposures of the K-T boundary. This time they took small cores with the goal of discovering the magnetic stratigraphy as Alvarez and colleagues did in other sections. Here there is a six-foot layer of black rock in an otherwise 100ft thick cliff of white limestone. This black layer can also be found in Italy, England, Wyoming, Colorado, California, offshore British Columbia, and Alaska. This represents an abrupt change to anoxic (oxygen depleted) water. This extinction and others were now firmly linked to warming oceans.
Next he explores the Permian mass extinction, the “mother of all extinctions” and the Great Dying, along the Caledon River in South Africa. After ten years of studying the K-T boundary, Ward was now fossil hunting near the Permian-Triassic boundary for land animals, terrestrial fossils. The P-T mass extinction resulted in the loss of up to 90% of species on earth. He found one of the best outcrop sections of the transition and noted the difference between the K-T and P-T boundaries’ fossil losses – The P-T losses were more gradual and seemed to be the result of many small events and one big one, rather than one abrupt big one as in the K-T asteroid impact. No asteroid impact was implicated here even though at the time he was looking for one. The P-T boundary was associated with global warming, an anoxic ocean, and volcanic activity via flood basalts from the massive Siberian Traps – a source of CO2 to heat everything up. However, the impact advocators also found what they thought was evidence – so-called “bucky balls” or “fullerenes,” geodesic-dome shaped carbon molecules named after Buckminster Fuller, that were thought to be of extra-terrestrial origin – thus suggesting impact. However, no iridium was found. NASA scientists reported that they may have found an impact crater that caused the P-T extinction in 2003. In 2006, scientists at Ohio State University reported a large impact crater deep in Antarctic ice detected with gravity anomaly measurements but it could not be seen or dated. Ideas of a comet impact also came about with that impact initiating volcanism but these ideas were all vague and difficult to confirm. Eminent paleontologists and geochemists got together to discuss the ideas and re-examine the evidence. They later found that the bucky balls did not come from the Permian but from much younger rocks in the Triassic and so did not correlate to the loss of species.
Another aspect of P-T boundary time was increased atmospheric methane, a greenhouse gas which would have heated things up. Extinction of many plant species occurred and subsequent increases in sedimentation rates. Tropical species appeared where there were previously temperate species. Increased volcanism, repeated changes in oceanic circulation, and presumed methane hydrate melting impulses are also in evidence. Impact as a possible cause for the Permian extinction has been rejected by the majority of scientists.
A group led by Harvard paleobotanist Andrew Knoll beginning in 1996 proposed that the Permian extinction was similar to the Precambrian extinction of 600 million years ago. Similarities were a stratified ocean with oxygen near the surface but depleted at depth and large amounts of organic material as bottom sediments. When this changed, possibly due to plate tectonics, the deep ocean carbon began to be liberated to surface water and then to the atmosphere through large bubbles. The P-T boundary isotope changes showed a series of perturbations rather than a single one as the K-T had shown. This suggested multiple events over several million years.
In 2001 Ward ends up in the Queen Charlotte Islands off of the coast of British Columbia to study well-exposed sections of the Triassic-Jurassic boundary, the T-J extinction being responsible for the loss of about half of earth’s species. They wanted to get auger cores stratigraphically through the boundary to compare isotope signatures to the other extinctions. They did so in 1996 and found a main single event but did not get very far into the Jurassic section where they now hoped to see if there were multiple perturbations as there had been in the Permian. That is indeed what they found. However, iridium was recently found in several localities in some of the best T-J boundary exposures in the Newark Basin and Connecticut River valley areas of New Jersey, which suggested impact. However, the amount of iridium was quite small compared to the K-T iridium. The proposed impact crater in Quebec was later dated to be about 15 million years too soon to have caused the event. The impact from that massive crater apparently did not cause any significant extinctions – which suggests that the effects of asteroid impact may have been overestimated.
In 2004 he returns to the Queen Charlotte Islands to look at older rocks on the distant islands to see if extinction was single or multiple, gradual or abrupt. He digs ammonites beginning about 12 million years before the extinction and notes a classic slow gradual decrease in species of them and other fossils. He notes that while his early career was involved in showing what was once thought to be a gradual extinction at the K-T boundary was actually abrupt, now he was showing what was presumed by many to be a sudden extinction at the T-J boundary was actually a slow gradual one. The progression seemed to be that ammonites first reduced their variety as some species died out then a new species of clam, Monotis, appeared in abundance, only to be reduced as the extinction got worse. Monotis might possibly have been adapted to lower oxygen sea bottoms. Better dating techniques by finding a volcanic ash bed to date revealed that the Rhaetian stage of the late Triassic, with low oxygen seas largely devoid of life lasted up to 11 million years. After the Rhaetian stage came the Norian stage when the rest of the bivalves and ammonites died out so Ward sees this as two extinctions, one quite gradual and culminating at the end of the Rhaetian and one more abrupt but still gradual ending at the end of the Norian stage. Subsequent fossil work in other places showed extinction pulses occurring into the Jurassic as well. To sum up it was now thought that most extinctions were gradual and only one, the K-T, was definitively associated with impact, the others being logically ruled out. Thus the ‘extinctions were caused by asteroids’ paradigm was given up except for K-T.
The next chapter finds Ward diving in a pristine coral reef near Palau in tropical Pacific Micronesia. This was back in 1983. Ward was a long-experienced diver. He lost a fellow diver in the past who had passed out during a deep dive and Ward got a serious case of the bends attempting to save his live by bringing him up fast. His friend died but Ward suffered chronic bodily pains and a permanent limp from his own injuries. Here they were studying the nautiluses, along with the ammonites, another cephalopod. The ammonites survived many extinctions but were wiped out at the K-T boundary in the Cretaceous. They tagged the nautiloids and found that they dived deep during the day and came closer to surface at night. That may have been why they survived the K-T and the ammonites who stayed in shallow water did not. It seems that while the Permian, Paleocene, and Tertiary extinctions wiped out bottom dwellers the K-T extinction wiped out the surface dwellers.
It was still unclear exactly how a slow gradual change of climate could have killed so many species several times in the past. New ideas were forming. Microbiologists studying anoxic lakes found some new fossils, chemical fossils, known as biomarkers. They did not leave behind skeletal remains but chemical remains in the lake sediment. Toxic hydrogen sulfide gas (H2S) was one chemical marker and calculations by one author, Kump, suggested that the amount of H2S was significant in the Permian – 2000 times that produced by volcanoes. The Kump Hypothesis also noted that the H2S would have destroyed the ozone layer and evidence from Greenland of fossils damaged by ultraviolet light suggests this may have occurred. Destruction of the ozone layer would mean a decrease in phytoplankton, the base of the food chain. Another hypothesis suggests the ozone layer could have been destroyed by particles from a supernova. With increased CO2 and methane bubbling up from the sea in a hot Permian the H2S would have been more toxic as it is in a warmer environment. Evidence was found of H2S –producing microbes in the Permian throughout the world. Since sea level was low at the time they also looked for evidence of eroding phosphorous which would have been a nutrient for microbes to accelerate their growth.
Next he ends up near his hometown, Seattle, looking at fossils in non-bedded limestones deposited in a “mixed” ocean of little oxygen variation with cold areas at the poles and warm ones at the tropics, as now, or since the Oligocene, about 30 million years ago. Older rocks show black bedded rocks deposited in an anoxic ocean bottom. Pyrite is common in these rocks. Anoxic bottoms are filled with black shales, around since 3.5 billion years ago and sometimes with very-well preserved fossils of life forms that fell into the sediment with their forms preserved. The famous Burgess Shale is one example. There are two types of stratified oceans, he notes: one with low-oxygen bottoms which supports some life, mostly microbial; and one entirely devoid of oxygen which supports only microbes that utilize sulfur for food and give off H2S as a waste product. The latter is known as a Canfield ocean. Canfield oceans were toxic to life. They are thought to have been around in the Precambrian inhibiting the development of life. The eukaryotes require microbes to fix nitrogen, a needed nutrient, for them. The sulfur-imbibing microbes do not fix nitrogen, instead inhibiting it. Chemical biomarkers also suggest that the T-J extinction is associated with pulses of short-lived Canfield ocean conditions. The oceanic circulation, the conveyor belt, may be the key to the changing ocean states. There is strong evidence that the conveyor belt shut down (or shifted) in the Paleocene and now it appears that this happened in the Permian as well. Of course, the continents were in different places in these past times due to plate tectonics so the actual circulation patterns were different than today but a similar mechanism is still likely to have been in play. The shift in ocean circulation in the Permian was thought to have brought anoxic water to the deep ocean which allowed the H2S-producing microbes to thrive and upwelling of poisonous bottom-waters. If the Paleocene had H2S-producing microbes they were at far lower concentrations than in the Permian. He compares extinctions from Anthony Hallam’s and Paul Wignall’s 1997 book, Mass Extinctions and Their Aftermath, which was written when impact was still thought to be associated with most or all extinctions. Even so, their data revealed that of the 14 mass extinctions that were catalogued, 12 were associated with poorly oxygenated oceans as a major cause. The three “kill mechanisms” are now thought to be heat, low oxygen, and perhaps H2S.
Next he ends up in Namibia in Southern Africa where the scorching hot Kalahari Desert is flanked by a foggy Atlantic Ocean that is very cold. Models of atmospheric CO2 and O2 concentrations of the past can be made using changes in sedimentation burial rates. One of the main modeling setups for paleoclimatological studies is GEOCARB for CO2 and GEOCARBSULF for oxygen. Modeling indicates that CO2 levels were very high from the Precambrian to the lower Permian – from about 5000 then down to about 300 PPM, rising back up to 3000 near the Permian extinction. Modeling also indicates that all of the mass extinctions of the past with the exception of the K-T impact-caused extinction, are associated with maximum or ‘rising toward maximum’ atmospheric CO2 concentrations. Thus rapid rises in CO2 correlate strongly to mass extinctions. This implicates our anthropogenic CO2 increase as a potential cause as well – if it were to rise ever higher – though likely far beyond current projections. Another way to estimate past CO2 concentrations is through fossil plant leaves. These readings on leaf stomata confirmed the CO2 estimates modeled.
Ward summarizes the sequences of events that are thought to have taken place in these mass extinctions: 1) world warms due to increase in greenhouse gases, initially from volcanoes; 2) The ocean circulation system is disrupted or shut down; 3) the deep ocean becomes de-oxygenated then shallow water suffers the same fate; 4) deoxygenated shallow water bottoms with some light penetration allow green sulfur bacteria to grow and produce H2S which rises in the atmosphere and breaks down the ozone layer with the UV light killing off phytoplankton. – The high heat and H2S also cause mass extinction on land. He notes significant variability in each extinction and calls the model the ‘conveyor disruption hypothesis.’ He envisions seas full of gelatinous bacterial mats, stromatolites which would later become food for terrestrial herbivores as (very slow and weak) waves brought them in. The ocean would look serene and waveless and be purple due to floating bacteria. Thick bubbles of various sizes filled with poisonous H2S would belch from the sea giving the sky a green tint – thus the book’s title. The bottom line is perhaps the realization that it is mainly increased atmospheric CO2 and other greenhouse gases like methane that serve as the trigger for mass extinctions.
Next he talks about bridging all the varying scientific disciplines involved in modern climatology and paleoclimatology. For much of the book he also addresses motivations for reward and prestige among scientists and how that can affect their work.
He goes into the carbon dating work of Minze Stuiver of the Quaternary Research Institute. He dated the Greenland ice cores year-by-year dating back 200,000 years. Using mass spectrometers they were able to accurately approximate temperatures and CO2 levels. What they found is that the current climate on Earth is quite aberrant even for recent geological history. Temperature changes of up to 18 deg F over a few decades were more common in the past. Before 10,000 years ago it is thought that storms the size of the major hurricanes occurred several times a year. At about 10,000 years ago a period of unprecedented calm apparently set in. Humans settled and mastered agriculture during this new period of calm. The records of the ice cores match quite well the planetary and orbital cycles proposed by Milankvitch with those cycles being the triggers for glacial and interglacial periods. One of the unknowns that Ward emphasizes is how much CO2 and global warming would it take to alter the oceanic circulation system. Wally Broecker thinks it could slow down but is unlikely to shut down with even say 1000 PPM CO2. It may be changing now. Fresh water from melting northern ice could be a prime trigger for changing the conveyor belt. Ward goes through smaller time period climate cycles like the Dansgaard-Oeschger cycles and the cycles of floating melting ice dropping cobbles they were carrying, now called Heinrich events – seen in the ocean floor sediments. For 90% of the last 100,000 years the earth has been in an ice age so these are anomalous times indeed. Before 8000 years ago the conveyor belt is thought to have been less stable. The current stable period is a precarious stability, scientists suggest. Biodiversity strongly correlates to this stability. The implication is that the “on-off” conveyor belt tips the earth’s climate to one of two stable states: the cold one that takes up 90 % of the last 100,000 years and the warm one we are in now.
He next visits Manua Loa in Hawaii where atmospheric CO2 has been dutifully measured since the 1950’s – as part of a Canadian TV documentary about climate change. In addressing climate history of the last 8000 years Ward gives the data from William Ruddiman which shows that humans have been affecting CO2 and methane levels since the advent of agriculture, forest burning to clear land, flood for rice paddies (which is major source of methane), and livestock agriculture (another major source of methane). The CO2 range of the last 200,000 years has been between 180 and 280 PPM with most of it in the small end of the range since most times were ice age times. At the beginning of the Industrial Age CO2 levels were at 280 PPM and now they are above 400 PPM, a level unprecedented in the last 200,000 years. CO2 can also directly cause limited extinctions of certain species in the form of increases in ocean acidity and this is happening now in cases of coral bleaching. The changes in ocean pH will likely persist for thousands of years, he notes, thus changing life patterns. While there may have been times of high ocean acidity in the past he suggests that they have not been as high as they are expected to get soon for quite some time – perhaps 100 million years – since certain species were more adapted in the past to higher acidity – however, the abrupt changes now due to anthropogenic CO2 are too fast for many species to evolve adaptations. The present rate in the rise of CO2 seems to be faster than at any period in the past and global average temperatures have not been this warm since the Eocene epoch 60 million years ago which followed a mass extinction.
Next he delves into the Eocene epoch looking at fossils along the Pacific coast of North America. He notes that this hot time was a time of very high sea levels compared to today. This area was tropical during the Eocene as evidenced by abundant palm and crocodile fossils found as far north as the Arctic Circle. He explores the climatic features of the Eocene and compares them to what a 1000 PPM atmospheric CO2 level world might be like as after we humans create it. First he notes that the tropics are the source of many of the human diseases that affect us. He suggests that tropical peoples in particular have developed coping mechanisms for the heat in the form of various local drugs. I am not so sure they have the monopoly on that. He mentions widespread use of betel nut, kava root, and khat. Of course, the same could be said for alcohol and cannabis in the temperate climes. The prevalence of mosquitoes makes malaria and other diseases more likely as well. He goes through all the typical scenarios of global warming effects: melting ice, rising sea levels, changing weather patterns, submerged cities, storm surges, changes in habitat patterns, etc. He notes that the temperature rise in the Arctic has been 20 times that of other places on earth and is quite worrying to scientists. Are effects underestimated? Overestimated? No one knows for sure but some attribute a significant amount of deaths now to global warming in the form of malaria and malnutrition. He invokes the view that hurricanes will worsen in both magnitude and frequency, popular at time of publication. However, that has not occurred and may end up being a misattributed global warming affect. The increase in hurricanes from 1990-2004 may be part of a natural cycle. Heat waves are another effect that has increased. Suggestions of war and famine are speculative. Cereal grain crops may not yield well in a more tropical climate.
Next he discusses climate and the possibility of re-entering an Eocene-like epoch with famed University of Washington climate scientist David Battista. Windless tropical conditions in some temperate areas with super hurricanes pounding the equatorial tropics. The conveyor might change into a form where warm water from the tropics sinks much further south in the Atlantic which would freeze Western Europe perhaps giving the false impression to some of an impending ice age. Then when the sinking low salinity freshwater did not sink deep enough a situation of lower oxygen could develop at ocean depths resulting in the next chain in the link of mass extinctions that have occurred in the past.
He goes through some more speculative scenarios at different CO2 levels but it really is hard to know how things will play out and there are still uncertainties about that.
Great book overall by a geologist who wears the scars of his work and his craft through an adventurous but often lonely existence in far off corners of the world as well as in the academic realms.