Global_Warming

GLOBAL WARMING DINO HRISTOPOULOS SCI 207 DEPENDENCE OF MAN ON THE ENVIRONMENT JEFF KINGSBURY Global Warming is the increase of Earth's average surface temperature due to effect of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from deforestation, which trap heat that would otherwise escape from Earth. This is a type of greenhouse effect. Human beings have increased the CO2 concentration in the atmosphere by about thirty percent, which is an extremely significant increase, even on inter-glacial timescales. It is believed that human beings are responsible for this because the increase is almost perfectly correlated with increases in fossil fuel combustion, and also due other evidence, such as changes in the ratios of different carbon isotopes in atmospheric CO2 that are consistent with "anthropogenic" (human caused) emissions. The simple fact is that under "business as usual" conditions, we'll soon reach carbon dioxide concentrations that haven't been seen on Earth in the last 50 million years. Humans need top figure out what we can do to save our environment and our world! The most significant greenhouse gas is actually water vapor, not something produced directly by humankind in significant amounts. However, even slight increases in atmospheric levels of carbon dioxide (CO2) can cause a substantial increase in temperature. Why is this' There are two reasons: First, although the concentrations of these gases are not nearly as large as that of oxygen and nitrogen (the main constituents of the atmosphere), neither oxygen or nitrogen are greenhouse gases. This is because neither has more than two atoms per molecule (i.e. their molecular forms are O2 and N2, respectively), and so they lack the internal vibration modes that molecules with more than two atoms have. Both water and CO2, for example, have these "internal vibration modes", and these vibration modes can absorb and reradiate infrared radiation, which causes the greenhouse effect. Secondly, CO2 tends to remain in the atmosphere for a very long time (time scales in the hundreds of years). Water vapor, on the other hand, can easily condense or evaporate, depending on local conditions. Water vapor levels therefore tend to adjust quickly to the prevailing conditions, such that the energy flows from the Sun and re-radiation from the Earth achieve a balance. CO2 tends to remain fairly constant and therefore behave as a controlling factor, rather than a reacting factor. More CO2 means that the balance occurs at higher temperatures and water vapor levels. The science is firm that global warming is happening. Even so-called “climate skeptics” are realizing this. We have discussed many times how humans cause global warming and the main effects and causes of global warming, but with so many people still confused or unaware, when someone comes out with an excellent visual AND science-backed explanation of how human actions are causing global warming, it is a crime not to share. Science isn’t a house of cards, ready to topple if you remove one line of evidence. Instead, it’s like a jigsaw puzzle. As the body of evidence builds, we get a clearer picture of what’s driving our climate. We now have many lines of evidence all pointing to a single, consistent answer – the main driver of global warming is rising carbon dioxide levels from our fossil fuel burning. The greatest barrier to public recognition of human-made climate change is probably the natural variability of local climate. Actions to stem emissions of the gases that cause global warming are unlikely to approach what is needed until the public recognizes that human-made climate change is underway and perceives that it will have unacceptable consequences. Recent high profile heat waves, such as the one in Texas and Oklahoma in the summer of 2011, raise the question of whether these extreme events are related to the on-going global warming trend, which has been attributed with a high degree of confidence to human-made greenhouse gases. The increase of these extreme anomalies, by more than an order of magnitude, implies that we can say with a high degree of confidence that events such as the extreme summer heat in the Moscow region in 2010 and Texas in 2011 were a consequence of global warming. There are many other human-induced stresses on life… yet global warming caused by fossil fuel burning may be a unique threat because of the millennial time scale of anthropogenic carbon within surface carbon reservoirs. It has been argued that a scenario phasing out carbon emissions fast enough to stabilize climate this century, limiting further warming to a maximum of several tenths of a degree Celsius, is still possible, but it would require a rising price on carbon emissions sufficient to spur transition to a clean energy future without burning all fossil fuels. It is popular again to claim that extreme events, such as the current central US drought, are evidence of human-caused climate change. Actually, the Earth is very large, the weather is very dynamic, and extreme events will continue to occur somewhere, every year, naturally. New discoveries explain part of the warming found in traditional surface temperature datasets. This partial warming is unrelated to the accumulation of heat due to the extra greenhouse gases, but related to human development around the thermometer stations. Widely publicized consensus reports by 'thousands' of scientists are misrepresentative of climate science, containing overstated confidence in their assertions of high climate sensitivity. Climate models overestimate the response of temperature to greenhouse gas increases. Also shown was a lack of evidence to blame humans for an increase in extreme events. One cannot convict CO2 of causing any of these events, because they've happened in the past before CO2 levels rose. It is a simple fact that CO2 is plant food and the world around us evolved when levels of CO2 were five to ten times what they are today. Our green world is a consequence of atmospheric CO2. And, food for plants means food for people. The extra CO2 we are putting into the atmosphere not only invigorates the biosphere, but also enhances the yields of our food crops. This is a tremendous benefit to nature and us in my view. If high temperatures, especially when combined with high relative humidity, persist for several days (heat waves), and if nighttime temperatures do not drop, extreme heat can be a killer. Of all climate-related projections by scientists, rising temperatures are the most robust. Higher temperatures are also the most influenced by human behavior: the fewer heat-trapping emissions we release into the atmosphere, the cooler we can keep our planet. Because winter temperatures are rising faster than summer ones, cold-related deaths are likely to decline. Projected changes in temperature and precipitation under global warming are likely to lead to other effects that threaten human health and safety. For example, changing precipitation patterns and prolonged heat can create drought, which can cause forest and peat fires, putting residents and firefighters in danger. However, a warming atmosphere also holds more moisture, so the chance of extreme rainfall and flooding continues to rise in some regions with rain or snow. In many heavily populated areas, sea-level rise is more likely to put people in the path of storm surges and coastal flooding. Warmer ocean waters may spawn more intense tropical hurricanes and typhoons while ocean cycles continue to be a factor in the frequency of tropical cyclones. Scientists expect a warmer world to bring changes in "disease vectors"—the mechanisms that spread some diseases. Insects previously stopped by cold winters are already moving to higher latitudes (toward the poles). Warmer oceans and other surface waters may also mean severe cholera outbreaks and harmful bacteria in certain types of seafood. Still, changes in land use and the ability of public health systems to respond make projecting the risk of vector-borne disease particularly difficult. Warmer temperatures and higher concentrations of carbon dioxide in the atmosphere stimulate some plants to grow faster, mature earlier, or produce more potent allergens. Common allergens such as ragweed seem to respond particularly well to higher concentrations of CO2, as do pesky plants such as poison ivy. Allergy-related diseases rank among the most common and chronic illnesses that can lead to lower productivity. Regions of the world that now depend on rain-fed agriculture may require irrigation, bringing higher costs and conflict over access to water. Shifting seasonal rainfall patterns and more severe precipitation events—and related flooding—may delay planting and harvesting. Prime growing temperatures may shift to higher latitudes, where soil and nutrients may not be as suitable for producing crops, leaving lower-latitude areas less productive. Insect and plant pests may survive or even reproduce more often each year if cold winters no longer keep them in check. New pests may also invade each region as temperature and humidity conditions change. Lower-latitude pests may move to higher latitudes, for example. Shifts in the abundance and types of fish and other seafood may hurt commercial fisheries, while warmer waters may pose threats to human consumption, such as increasing the risk of infectious diseases. Extreme ocean temperatures and ocean acidification place coral reefs-—the foundations of many of the world's fisheries at risk. Two major mechanisms are causing sea level to rise. First, shrinking land ice, such as mountain glaciers and polar ice sheets, is releasing water into the oceans. Second, as ocean temperatures rise, the warmer water expands. Trapped within a basin bounded by the continents, the water has nowhere to go but up. In some parts of the world, especially low-lying river deltas, local land is sinking (known as subsidence)—making sea levels that much higher. High tides and storm surges riding on ever-higher seas are more dangerous to people and coastal infrastructure. Natural protections against damaging storm surges are increasingly threatened. Barrier islands, beaches, sand dunes, salt marshes, mangrove stands, and mud and sand flats retreat inland as sea level rises, unless there are obstructions along the retreat path. If they cannot move, these natural protections are washed over or drowned. Many shorelines have sea walls, jetties, and other artificial defenses to protect roads, buildings, and other vital coastal resources. In these areas, sea-level rise increases erosion of stranded beaches, wetlands, and engineered structures. Sea-level rise can mean that saltwater intrudes into groundwater drinking supplies, contaminates irrigation supplies, or overruns agricultural fields. Low-lying, gently sloping coastal areas are particularly vulnerable to contamination of freshwater supplies. Some 40 percent of the world's population lives within 62 miles (100 kilometers) of the ocean, putting millions of lives and billions of dollars' worth of property and infrastructure at risk. As air temperatures rises, water temperatures do also particularly in shallow stretches of rivers and surface waters of lakes. Streams and lakes may become unsuitable for cold-water fish but support species that thrive in warmer waters. Some warm-water species are already moving to waters at higher latitudes and altitudes. In a warming climate, a warmer upper layer in deep lakes slows down air exchange - a process that normally adds oxygen to the water. This, in turn, often creates large "dead zones" areas depleted of oxygen and unable to support life. Persistent dead zones can produce toxic algal blooms, foul-smelling drinking water, and massive fish kills. Earlier snowmelt, rising amounts of precipitation that falls as rain rather than snow, and more severe and frequent flooding all linked to global warming may affect the reproduction of aquatic species. Some salmon populations have declined, for example, as more intense spring floods have washed away salmon eggs laid in stream beds. When stream flow peaks earlier in the spring owing to warmer temperatures, low stream flow begins earlier in the summer and lasts longer in the fall. These changes stress aquatic plants and animals that have adapted to specific low-flow conditions. The survival rates of fish such as salmon and trout are known to diminish when water levels in rivers and streams are dangerously low, for example. That's partly because bears can snag spawning salmon more easily in very shallow water, as the salmon struggle upstream. The more intense precipitation that accompanies a warming world makes river flooding more likely. This flooding combined with sewer system overflows and other problems stemming from inadequate sanitation infrastructure can lead to disease outbreaks from water-borne bacteria. Permafrost is an essential component of many high-latitude landscapes is soil or rock that remains at or below 32° F (0° C) for at least two years. In Arctic regions, permafrost temperatures often sink to 17.6° F (-8° C) or lower. Permafrost averages 656 feet (200 meters) thick, but can be as much as 2,132 feet (650 meters) thick. Permafrost is very sensitive to direct changes in air temperature and snow cover, making it especially vulnerable to global warming. And as permafrost thaws, it can release both carbon dioxide and methane from carbon often stored in soil for thousands of years. (The type of heat-trapping gas the permafrost releases depends on moisture conditions, and whether the permafrost has contact with air.) The thawing of the permafrost can therefore worsen climate change. The thawing of permafrost in northern forests could completely alter local ecosystems. Existing thawing is already destabilizing the human infrastructure, which require frequent repair. Scientists typically measure the temperature of permafrost near the top of the "active layer," which freezes and thaws seasonally. Scientists may also drill a borehole to measure temperatures deep below ground. In other words, humans have made a huge problem and we need to figure out a way to really take care of this planet as we call Earth.