The Rate Debate Slowing
Download 0.98 Mb.
|
- Navigate this page:
- Warming decimates biodiversity - decreases genetic variation Romm 11
- Warming ruins biodiversity – tropical habitats, reefs, and aquaculture Hannah 12
- Warming kills 80% of genetic diversity Science Daily 11
- Warming kills biodiversity Hannah 12
Impact - BiodiversityWarming kills biodiversity - leads to extinction Coyne & Hoekstra 7 - Prof Ecology @ Chicago AND Prof Biology @ Harvard (Jerry AND Hopi, "The Greatest Dying," Truthout, http://www.truthout.org/article/jerry-coyne-and-hopi-e-hoekstra-the-greatest-dying) We are relentlessly taking over the planet, laying it to waste and eliminating most of our fellow species. Moreover, we're doing it much faster than the mass extinctions that came before. Every year, up to 30,000 species disappear due to human activity alone. At this rate, we could lose half of Earth's species in this century. And, unlike with previous extinctions, there's no hope that biodiversity will ever recover, since the cause of the decimation - us - is here to stay. To scientists, this is an unparalleled calamity, far more severe than global warming, which is, after all, only one of many threats to biodiversity. Yet global warming gets far more press. Why? One reason is that, while the increase in temperature is easy to document, the decrease of species is not. Biologists don't know, for example, exactly how many species exist on Earth. Estimates range widely, from three million to more than 50 million, and that doesn't count microbes, critical (albeit invisible) components of ecosystems. We're not certain about the rate of extinction, either; how could we be, since the vast majority of species have yet to be described? We're even less sure how the loss of some species will affect the ecosystems in which they're embedded, since the intricate connection between organisms means that the loss of a single species can ramify unpredictably. But we do know some things. Tropical rainforests are disappearing at a rate of 2 percent per year. Populations of most large fish are down to only 10 percent of what they were in 1950. Many primates and all the great apes - our closest relatives - are nearly gone from the wild. And we know that extinction and global warming act synergistically. Extinction exacerbates global warming: By burning rainforests, we're not only polluting the atmosphere with carbon dioxide (a major greenhouse gas) but destroying the very plants that can remove this gas from the air. Conversely, global warming increases extinction, both directly (killing corals) and indirectly (destroying the habitats of Arctic and Antarctic animals). As extinction increases, then, so does global warming, which in turn causes more extinction - and so on, into a downward spiral of destruction. Why, exactly, should we care? Let's start with the most celebrated case: the rainforests. Their loss will worsen global warming - raising temperatures, melting icecaps, and flooding coastal cities. And, as the forest habitat shrinks, so begins the inevitable contact between organisms that have not evolved together, a scenario played out many times, and one that is never good. Dreadful diseases have successfully jumped species boundaries, with humans as prime recipients. We have gotten aids from apes, sars from civets, and Ebola from fruit bats. Additional worldwide plagues from unknown microbes are a very real possibility. But it isn't just the destruction of the rainforests that should trouble us. Healthy ecosystems the world over provide hidden services like waste disposal, nutrient cycling, soil formation, water purification, and oxygen production. Such services are best rendered by ecosystems that are diverse. Yet, through both intention and accident, humans have introduced exotic species that turn biodiversity into monoculture. Fast-growing zebra mussels, for example, have outcompeted more than 15 species of native mussels in North America's Great Lakes and have damaged harbors and water-treatment plants. Native prairies are becoming dominated by single species (often genetically homogenous) of corn or wheat. Thanks to these developments, soils will erode and become unproductive - which, along with temperature change, will diminish agricultural yields. Meanwhile,with increased pollution and runoff, as well as reduced forest cover, ecosystems will no longer be able to purify water; and a shortage of clean water spells disaster. In many ways, oceans are the most vulnerable areas of all. As overfishing eliminates major predators, while polluted and warming waters kill off phytoplankton, the intricate aquatic food web could collapse from both sides. Fish, on which so many humans depend, will be a fond memory. As phytoplankton vanish, so does the ability of the oceans to absorb carbon dioxide and produce oxygen. (Half of the oxygen we breathe is made by phytoplankton, with the rest coming from land plants.) Species extinction is also imperiling coral reefs - a major problem since these reefs have far more than recreational value: They provide tremendous amounts of food for human populations and buffer coastlines against erosion. In fact, the global value of "hidden" services provided by ecosystems - those services, like waste disposal, that aren't bought and sold in the marketplace - has been estimated to be as much as $50 trillion per year, roughly equal to the gross domestic product of all countries combined. And that doesn't include tangible goods like fish and timber. Life as we know it would be impossible if ecosystems collapsed. Yet that is where we're heading if species extinction continues at its current pace. Extinction also has a huge impact on medicine. Who really cares if, say, a worm in the remote swamps of French Guiana goes extinct? Well, those who suffer from cardiovascular disease. The recent discovery of a rare South American leech has led to the isolation of a powerful enzyme that, unlike other anticoagulants, not only prevents blood from clotting but also dissolves existing clots. And it's not just this one species of worm: Its wriggly relatives have evolved other biomedically valuable proteins, including antistatin (a potential anticancer agent), decorsin and ornatin (platelet aggregation inhibitors), and hirudin (another anticoagulant). Plants, too, are pharmaceutical gold mines. The bark of trees, for example, has given us quinine (the first cure for malaria), taxol (a drug highly effective against ovarian and breast cancer), and aspirin. More than a quarter of the medicines on our pharmacy shelves were originally derived from plants. The sap of the Madagascar periwinkle contains more than 70 useful alkaloids, including vincristine, a powerful anticancer drug that saved the life of one of our friends. Of the roughly 250,000 plant species on Earth, fewer than 5 percent have been screened for pharmaceutical properties. Who knows what life-saving drugs remain to be discovered? Given current extinction rates, it's estimated that we're losing one valuable drug every two years. Our arguments so far have tacitly assumed that species are worth saving only in proportion to their economic value and their effects on our quality of life, an attitude that is strongly ingrained, especially in Americans. That is why conservationists always base their case on an economic calculus. But we biologists know in our hearts that there are deeper and equally compelling reasons to worry about the loss of biodiversity: namely, simple morality and intellectual values that transcend pecuniary interests. What, for example, gives us the right to destroy other creatures? And what could be more thrilling than looking around us, seeing that we are surrounded by our evolutionary cousins, and realizing that we all got here by the same simple process of natural selection? To biologists, and potentially everyone else, apprehending the genetic kinship and common origin of all species is a spiritual experience - not necessarily religious, but spiritual nonetheless, for it stirs the soul. But, whether or not one is moved by such concerns, it is certain that our future is bleak if we do nothing to stem this sixth extinction. We are creating a world in which exotic diseases flourish but natural medicinal cures are lost; a world in which carbon waste accumulates while food sources dwindle; a world of sweltering heat, failing crops, and impure water. In the end, we must accept the possibility that we ourselves are not immune to extinction. Or, if we survive, perhaps only a few of us will remain, scratching out a grubby existence on a devastated planet. Global warming will seem like a secondary problem when humanity finally faces the consequences of what we have done to nature: not just another Great Dying, but perhaps the greatest dying of them all. Warming decimates biodiversity - decreases genetic variation Romm 11 — (Joe Romm, a Senior Fellow at American Progress and holds a Ph.D. in physics from MIT, 9/20/11, "Global Warming: Extinction of Biodiversity," Think Progress) If global warming continues as expected, it is estimated that almost a third of all flora and fauna species worldwide could become extinct. Scientists … discovered that the proportion of actual biodiversity loss should quite clearly be revised upwards: by 2080, more than 80% of genetic diversity within species may disappear in certain groups of organisms, according to researchers in the title story of the journal Nature Climate Change. The study is the first world-wide to quantify the loss of biological diversity on the basis of genetic diversity. That’s from the news release of a study, “Cryptic biodiversity loss linked to global climate change” (subs. req’d). The recent scientific literature continues to paint a bleak picture of what Homo sapiens ‘sapiens’ is doing to the other species on the planet. In 2007, the Intergovernmental Panel on Climate Change warned that “as global average temperature increase exceeds about 3.5°C [relative to 1980 to 1999], model projections suggest significant extinctions (40-70% of species assessed) around the globe.” That is a temperature rise over pre-industrial levels of a bit more than 4.0°C. So the 5°C rise we are facing on our current emissions path would likely put extinctions beyond the high end of that range. Last fall, the Royal Society ran a special issue on “Biological diversity in a changing world,” concluding “There are very strong indications that the current rate of species extinctions far exceeds anything in the fossil record.” I realize that the mass extinction of non-human life on this planet isn’t going to be a great driver for human action. Most people simply don’t get that the mass extinctions we are causing could directly harm our children and grandchildren as much as sea level rise. Such extinctions threaten the entire fabric of life on which we depend for food, among other things. This may be clearest in the case of marine life — see “Geological Society (8/10): Acidifying oceans spell marine biological meltdown “by end of century.” And then there’s the worst-case scenario in Nature Stunner — “Global warming blamed for 40% decline in the ocean’s phytoplankton”: “Microscopic life crucial to the marine food chain is dying out. The consequences could be catastrophic.” Life matters. Here’s more from the release: Most common models on the effects of climate change on flora and fauna concentrate on “classically” described species, in other words groups of organisms that are clearly separate from each other morphologically. Until now, however, so-called cryptic diversity has not been taken into account. It encompasses the diversity of genetic variations and deviations within described species, and can only be researched fully since the development of molecular-genetic methods. As well as the diversity of ecosystems and species, these genetic variations are a central part of global biodiversity. In a pioneering study, scientists from the Biodiversity and Climate Research Centre (BiK-F) and the Senckenberg Gesellschaft für Naturkunde have now examined the influence of global warming on genetic diversity within species. Over 80 percent of genetic variations may become extinct The distribution of nine European aquatic insect species, which still exist in the headwaters of streams in many high mountain areas in Central and Northern Europe, was modelled. They have already been widely researched, which means that the regional distribution of the inner-species diversity and the existence of morphologically cryptic, evolutionary lines are already known. If global warming does take place in the range that is predicted by the Intergovernmental Panel on Climate Change (IPCC), these creatures will be pushed back to only a few small refugia, e.g. in Scandinavia and the Alps, by 2080, according to model calculations. If Europe’s climate warms up by up to two degrees only, eight of the species examined will survive, at least in some areas; with an increase in temperature of 4 degrees, six species will probably survive in some areas by 2080. However, due to the extinction of local populations, genetic diversity will decline to a much more dramatic extent. According to the most pessimistic projections, 84 percent of all genetic variations would die out by 2080; in the “best case,” two-thirds of all genetic variations would disappear. The aquatic insects that were examined are representative for many species of mountainous regions of Central Europe. Slim chances in the long term for the emergence of new species and species survival Carsten Nowak of the Biodiversity and Climate Research Centre (BiK-F) and the Senckenberg Gesellschaft für Naturkunde, explains: “Our models of future distribution show that the “species” as such will usually survive. However, the majority of the genetic variations, which in each case exist only in certain places, will not survive. This means that self-contained evolutionary lineages in other regions such as the Carpathians, Pyrenees or the German Central Uplands will be lost. Many of these lines are currently in the process of developing into separate species, but will become extinct before this is achieved, if our model calculations are accurate.” Genetic variation within a species is also important for adaptability to changing habitats and climatic conditions. Their loss therefore also reduces the chances for species survival in the long term. New approach for conservation So the extinction of species hides an ever greater loss, in the form of the massive disappearance of genetic diversity. “The loss of biodiversity that can be expected in the course of global warming has probably been greatly underestimated in previous studies, which have only referred to species numbers,” says Steffen Pauls, Biodiversity and Climate Research Centre (BiK-F), of the findings. However, there is also an opportunity to use genetic diversity in order to make conservation and environmental protection more efficient. A topic that is subject to much discussion at present is how to deal with conservation areas under the conditions of climate change. The authors of the study urge that conservation areas should also be oriented to places where both a suitable habitat for the species and a high degree of inner-species genetic diversity can be preserved in the future. “It is high time,” says Nowak, “that we see biodiversity not only as a static accumulation of species, but rather as a variety of evolutionary lines that are in a constant state of change. The loss of one such line, irrespective of whether it is defined today as a “species” in itself, could potentially mean a massive loss in biodiversity in the future.” Warming ruins biodiversity – tropical habitats, reefs, and aquaculture Hannah 12 (Lee Hannah, senior researcher in climate change biology at Conservation International (CI), As Threats to Biodiversity Grow,Can We Save World’s Species?, http://e360.yale.edu/feature/as_threats_to_biodiversity_grow_can_we_save_worlds_species/2518/, 19 APR 2012) To date, marine systems have experienced the most extensive impacts of climate change. From coral bleaching to melting sea ice, marine systems are changing on global and regional scales. Coral bleaching occurs when water temperatures exceed regional norms, causing corals to expel symbiotic micro-organisms from their tissues, ultimately leading to morbidity or death. Bleaching has exterminated some coral species from entire ocean basins. Global extinctions may follow as temperatures continue to rise. Corals face a second threat from acidification as CO2 builds up in the atmosphere and oceans, which prevents corals and many other marine organisms, including clams and oysters, from forming their calcium carbonate shells. Overall, the evidence suggests that the world’s roughly 5 million marine species face as severe threats from climate change as their terrestrial counterparts. On land, tropical biodiversity hotspots in places such as the Amazon and the rainforests of Indonesia and Malaysia are especially at risk. All global climate models now show significant future warming in the tropics, even if more muted than warming at high latitudes. Tropical animals, insects, and plants are tightly packed along climatic gradients from lowlands to mountaintops, and these organisms are sensitive to changes in temperature and rainfall. Already, scores of amphibians in South America have disappeared as a warmer, drier climate has led to outbreaks of disease such as the chytrid fungus. At the same time, large areas of tropical forest are being cleared for timber, ranching, and farming such crops as soybeans and oil palm. While these circumstances point to likely biological extinctions in the oceans and on land, functional extinctions may be of even greater concern. Functional extinctions occur when a species’ population crashes to the point We need to protect species not only where they are, but also where they will be as the world warms. at which its functional roles within an ecosystem collapse. Functional extinction always accompanies biological extinction, but can happen before biological extinction is complete. Corals, for example, may be lost from huge areas, resulting in ecosystem conversion from coral reef to algal mat while some coral individuals still persist in isolation. Bark beetle outbreaks driven by climate change have killed tens of millions of trees from Colorado to Canada, causing functional extinctions of lodgepole pine across large areas of western North America. The repercussions of these tree losses are felt in a host of ways, from declining food for keystone species, such as bears, to increased risk of fire. Warming kills 80% of genetic diversity Science Daily 11 (Science Daily, News Agency…about Science…, Aug. 24, 2011, http://www.sciencedaily.com/releases/2011/08/110824091146.htm) If global warming continues as expected, it is estimated that almost a third of all flora and fauna species worldwide could become extinct. Scientists from the Biodiversity and Climate Research Centre (Biodiversität und Klima Forschungszentrum, BiK-F) and the SENCKENBERG Gesellschaft für Naturkunde discovered that the proportion of actual biodiversity loss should quite clearly be revised upwards: by 2080, more than 80 % of genetic diversity within species may disappear in certain groups of organisms, according to researchers in the title story of the journal Nature Climate Change. The study is the first world-wide to quantify the loss of biological diversity on the basis of genetic diversity.Most common models on the effects of climate change on flora and fauna concentrate on "classically" described species, in other words groups of organisms that are clearly separate from each other morphologically. Until now, however, so-called cryptic diversity has not been taken into account. It encompasses the diversity of genetic variations and deviations within described species, and can only be researched fully since the development of molecular-genetic methods. As well as the diversity of ecosystems and species, these genetic variations are a central part of global biodiversity. In a pioneering study, scientists from the Biodiversity and Climate Research Centre (BiK-F) and the Senckenberg Gesellschaft für Naturkunde have now examined the influence of global warming on genetic diversity within species. Over 80 percent of genetic variations may become extinct The distribution of nine European aquatic insect species, which still exist in the headwaters of streams in many high mountain areas in Central and Northern Europe, was modelled. They have already been widely researched, which means that the regional distribution of the inner-species diversity and the existence of morphologically cryptic, evolutionary lines are already known. If global warming does take place in the range that is predicted by the Intergovernmental Panel on Climate Change (IPCC), these creatures will be pushed back to only a few small refugia, e.g. in Scandinavia and the Alps, by 2080, according to model calculations. If Europe's climate warms up by up to two degrees only, eight of the species examined will survive, at least in some areas; with an increase in temperature of 4 degrees, six species will probably survive in some areas by 2080. However, due to the extinction of local populations, genetic diversity will decline to a much more dramatic extent. According to the most pessimistic projections, 84 percent of all genetic variations would die out by 2080; in the "best case," two-thirds of all genetic variations would disappear. The aquatic insects that were examined are representative for many species of mountainous regions of Central Europe. Slim chances in the long term for the emergence of new species and species survival Carsten Nowak of the Biodiversity and Climate Research Centre (BiK-F) and the Senckenberg Gesellschaft für Naturkunde, explains: "Our models of future distribution show that the "species" as such will usually survive. However, the majority of the genetic variations, which in each case exist only in certain places, will not survive. This means that self-contained evolutionary lineages in other regions such as the Carpathians, Pyrenees or the German Central Uplands will be lost. Many of these lines are currently in the process of developing into separate species, but will become extinct before this is achieved, if our model calculations are accurate." Genetic variation within a species is also important for adaptability to changing habitats and climatic conditions. Their loss therefore also reduces the chances for species survival in the long term. Warming kills biodiversity Hannah 12 (Lee Hannah, senior researcher in climate change biology at Conservation International (CI), As Threats to Biodiversity Grow,Can We Save World’s Species?, http://e360.yale.edu/feature/as_threats_to_biodiversity_grow_can_we_save_worlds_species/2518/, 19 APR 2012) With soaring human populations and rapid climate change putting unprecedented pressure on species, conservationists must look to innovative strategies — from creating migratory corridors to preserving biodiversity hotspots — if we are to prevent countless animals and plants from heading to extinction. by lee hannah Throughout much of the Pleistocene era, which began 2.5 million years ago, many of the world’s large mammals survived periods of glaciation and deglaciation by moving across a landscape devoid of humans. Then as the Pleistocene drew to a close at the end of the last Ice Age — some 20,000 to 12,000 years ago — creatures such as the wooly mammoth had to confront not only shrinking habitat caused by climate change. They also faced thousands of humans with stone-tipped weapons, a one-two punch that led to the extinction of dozens of so-called megafauna species, including the wooly mammoth, across Eurasia and North and South America. Now, with 7 billion people on the planet — heading to 10 billion — and with greenhouse gas emissions threatening more rapid temperature rises than the warming that brought the last Ice Age to an end, the many millions of living things on Earth face an unprecedented squeeze. Is a wave of extinctions possible, and if so, what can we do about it? The late climate scientist and biologist Stephen Schneider once described this confluence of events — species struggling to adapt to rapid warming in a world heavily modified by human action — as a “no-brainer for an extinction A million species could face extinction due to human encroachment and climate change. spasm.” My colleagues Barry Brook and Anthony Barnosky recently put it this way, “We are witnessing a similar collision of human impacts and climatic changes that caused so many large animal extinctions toward the end of the Pleistocene. But today, given the greater magnitude of both climate change and other human pressures, the show promises to be a wide-screen technicolor version of the (by comparison) black-and-white letterbox drama that played out the first time around.” The magnitude of the threat was first quantified in a 2004 Nature study, “Extinction Risk from Climate Change.” This paper suggested that in six diverse regions, 15 to 37 percent of species could be at risk of extinction. If those six regions were typical of the global risk, the study’s authors later calculated, more than a million terrestrial and marine species could face extinction due to human encroachment and climate change — assuming conservatively that 10 million species exist in the world. Headlines around the world trumpeted the 1 million figure. Whether that scenario will unfold is unclear. But signs of what is to come are already all around us: nearly 100 amphibian species in South America vanishing in a disease outbreak linked to climate change, large areas of western North American facing massive die-offs of trees because of warming-driven beetle outbreaks, and increasing loss of coral reefs worldwide because of human activities and coral bleaching events driven by rising ocean temperatures. Most of the world’s biologically unique areas have already lost more than 70 percent of their high-quality habitat. Directory: files files -> Answer True False 2 points Question 2 files -> Integer programming and game theory files -> 4 Integer Programming files -> Bpa vehicle Window Repair Scenario #1 task: Procure vehicle window relacement. Objective files -> Pop Warner History files -> North Carolina Inclusion Initiative Mapping Where Children with ieps are Being Served Purpose files -> Fall 2013 Spring 2014 Program Data: Standard 1 Exhibit 4d files -> Hanban – asia society confucius classrooms network 2010 request for proposal files -> Northern England’s set-jetting locations Download 0.98 Mb. Share with your friends:
|