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GLOBAL WARMING Made by: Mª Victoria Mendoza Albaladejo.4ºA
What is global warming? <ul><li>It is a term commonly used in two ways: </li></ul><ul><li>It is a phenomenon in the temperature measurements showing an increase in average temperature of Earth's atmosphere and oceans in recent decades. </li></ul><ul><li>It is a theory that predicts, based on projections based on computer simulations of future growth temperatures. </li></ul><ul><li>Sometimes the names are used climate change, which means any change in climate or anthropogenic climate change, which consider the influence of human activity. Global warming and greenhouse effect are not synonymous. The enhanced greenhouse pollution can be, according to some theories, the cause of currently observed global warming. </li></ul>
The consequences of global warming. <ul><li>The latest scientific data confirm that the Earth's climate is changing rapidly. Global temperatures rose about 1 degree Fahrenheit during the past century and are likely to increase even faster in coming decades. What is the cause? An increasingly thick layer of pollution from carbon dioxide and other greenhouse gases, mainly from power plants and automobiles, that traps heat in the atmosphere. The Intergovernmental Panel on Climate Change, a group of leading climate researchers in the world, believes there is more than 90% chance that most warming over the past 50 years has occurred due to greenhouse gas emissions heat-trapping caused by humans. Scientists say the Earth could warm more than 7.2 degrees Fahrenheit during the twenty-first century unless we reduce emissions from fossil fuels like coal and oil. This increase in average temperature will have far-reaching effects. Sea levels will rise, flooding coastal areas. Heat waves will become more frequent and more intense. Droughts and wildfires will occur more often. The disease-carrying mosquitoes will expand their range. And push species to extinction. </li></ul>
Changing weather patterns <ul><li>The result: Warmer temperatures Average temperatures will increase as the frequency of heat waves. Current warning signs • Most U.S. and is warmer in some areas up to 4 degrees Fahrenheit. In fact, all states experienced average temperatures "above normal" or "well above normal" in 2006. • The National Oceanic and Atmospheric Administration (NOAA by its initials in English) declared 2006 as the second warmest year on record in the United States, with an average annual temperature of 55 degrees Fahrenheit, 0.1 degree less than the record in 1998. • The years from 1998 to 2006 are among the 25 warmest years on record in the United States, an unprecedented event, according to NOAA . </li></ul>
<ul><li>Consequences: droughts and wildfires Warmer temperatures could also increase the likelihood of droughts. The increased evaporation during summer and autumn could exacerbate drought conditions and increase the risk of wildfires. The increased water evaporation as a result of global warming could increase the risk of wildfires. • The national drought from 1999 to 2002 was one of the three most extensive droughts in the last 40 years. • The warming may have led to increased frequency of droughts in the west has experienced over the past 30 years. • The forest fire season in 2006 set new records in both the number of reported fires and in the number of acres burned. Nearly 100,000 fires were reported and burned nearly 10 million acres, 125% more than the average in 10 years. • If the warming continues to worsen forest fire seasons, the cost could be high. The expenses of extinguishing tasks consistently have totaled more than $ 1.000 billion a year. </li></ul>
<ul><li>The result: more intense storms Warmer temperatures increase the energy of the climate system and sometimes produce heavier rainfall in some areas. Current warning signs • The national annual precipitation has increased between 5 and 10% since the beginning of the twentieth century, mainly as a result of heavy rains in some areas. • The IPCC reports that the frequency of intense rainfall has increased over the past 50 years, and it is likely that global warming induced by humans has contributed to this trend. • According to statistics from NOAA, the Northeast had their wettest summer recorded in 2006, surpassing the previous record by more than 1 inch. </li></ul>
Health effects . <ul><li>Consequence: deadly heat waves and the spread of disease Heat waves more frequent and severe may result in more deaths from the heat. These conditions may also exacerbate local air quality, already afflicting more than 80 million Americans. It is expected that global warming will also increase the potential geographical scope and virulence of tropical diseases. Current warning signs • It is estimated that in 2003, extreme heat waves claimed 35,000 lives in Europe. Only in France, 15,000 people were killed by increases in temperatures that reached 104 degrees Fahrenheit and extreme remained for two weeks. • Much of North America experienced a severe heat wave in July 2006, which contributed to the deaths of at least 225 people. • Studies have found that an increased level of carbon dioxide stimulates growth of weeds, whose pollen causes allergies and aggravate asthma. • disease-carrying mosquitoes are spreading as the climate changes allow them to survive in areas that were previously inhospitable. Mosquitoes that can carry dengue fever viruses were previously limited to elevations of 1,000 meters, but have recently appeared to 2,200 meters in the Andean Mountains of Colombia. Malaria has been detected in higher areas of Indonesia. </li></ul>
Water heating. <ul><li>The result: more dangerous and powerful hurricanes Warmer waters in the oceans adds more energy to tropical storms, making these more destructive and intense. Current warning signs • In the past 35 years the number of Category 4 and 5 storms has increased along with ocean temperature. • The 2005 hurricane season was the busiest recorded in the Atlantic, with a record 27 named storms, of which 15 became hurricanes. Seven of the hurricanes moved swiftly to become major storms, five became Category 4 hurricanes and a record four reached Category 5 strength. • Hurricane Katrina in August 2005 was the costliest and one of the deadliest in U.S. history </li></ul>
<ul><li>Consequence: melting glaciers, early snowmelt The increase in global temperatures will accelerate the melting of glaciers and ice sheets and cause earlier snowmelt in rivers and lakes. Current warning signs • At current rate of retreat, all the glaciers of Glacier National Park will be gone by year 2070. • Between January and March 2002, after existing for millennia, disbanded in the northern section of the Larsen B ice shelf in Antarctica, a section larger than Rhode Island, disintegrating at a rate that astonished scientists . Since 1995 the area of ice shelf has fallen by 40%. • According to NASA, the polar ice cap is melting at an alarming rate of 9% per decade. Arctic ice thickness has decreased 40% since the 1960s. • Arctic sea ice fell to record levels in September 2007, with nearly half a million square miles less than the previous record in September 2005, according to the National Center for Snow and Ice Data. Over the past three decades have gone more than a million square miles of perennial sea ice, an area the size of Norway, Denmark and Sweden combined. • Multiple climate models indicate that sea ice increasingly retracts as the Earth warms. Scientists Center for Atmospheric Research of the United States predict that if the current rate of global warming, the Arctic could lose all the ice in the summer of 2040. </li></ul>
<ul><li>Consequence: sea level rises It is expected that current rates of sea level rise increase as a result of thermal expansion of the oceans and melting of most mountain glaciers and the partial melting of the ice sheets in western Antarctica and Greenland. The consequences include the loss of wetlands and barrier islands along the coast, and an increased risk of flooding in coastal communities. Low areas such as the coastal region of Gulf of Mexico and estuaries like the Chesapeake Bay are particularly vulnerable. Current warning signs • The global sea level has increased from four to eight inches in the last century, a situation that seems to be accelerating. The IPCC predicts that sea levels could rise 10 to 23 inches by 2100, but in recent years sea levels have been increasing more than predicted by the IPCC. • In the 1990s, the Greenland ice mass remained stable, but the ice has diminished in recent years. This melt currently contributes about one hundredth of an inch per year to increase the sea level. • Greenland has 10% of the world's total ice mass, if it melts, sea levels could rise up to 21 feet. </li></ul>
Ecosystem disturbance <ul><li>Consequence: ecosystem change and species die It is expected that the increase in global temperatures disrupt ecosystems and cause loss of species diversity, as species die that can not adapt. The first comprehensive assessment of extinction risk from global warming found that more than one million species could be targeted for extinction by 2050 if it reduces global warming pollution. Some ecosystems, including alpine meadows in the Rocky Mountains and tropical forests and mangroves, are likely to disappear due to new local climate warming or rising sea levels along the coast. Current warning signs • A recent study of almost 2,000 species of plants and animals found a movement toward the poles at an average rate of 3.8 miles per decade. The study also found that species of the alpine area were moving vertically at a rate of 20 feet per decade in the second half of the twentieth century. • The most recent IPCC report found that approximately 20 to 30% of plant and animal species assessed so far are likely at increased risk of extinction if global average temperature rising by more than 2.7 to 4.5 degrees Fahrenheit. • Some polar bears are drowning because they have to swim longer distances to reach the floating ice chunks. The U.S. Geological Survey has predicted that two thirds of the subpopulations of polar bears in the world will become extinct by mid-century by the melting Arctic icecap. • In Washington's Olympic Mountains, sub-alpine forest has invaded the alpine meadows at higher elevations. In Bermuda and other places, mangrove forests are being lost. • In areas of California, the coastal marine species are moving northward, probably in response to warmer temperatures in the ocean and air. • During the past 25 years, some penguin populations have declined 33% in parts of Antarctica due to reductions in the winter habitat in the sea ice. • The ocean will become more acidic by carbon dioxide emissions. Due to this acidification, species with hard shells of calcium carbonate are vulnerable, such as coral reefs, which are critical to ocean ecosystems. Scientists predict that an increase of 3.6 degrees Fahrenheit in temperature exterminate 97% of coral reefs in the world. </li></ul>