Climate change presentation
Transcript: Evidence of global warming Clearing forests also releases large amounts of carbon dioxide. On top of that, plants and trees use it to grow. Worldwide deforestation means we don’t have as many trees to absorb the extra carbon dioxide.This means more of it stays in the atmosphere, trapping more heat. One of the most immediate and obvious effects of global warming is the increase in temperatures around the world. The average global temperature has increased by about 1.4 degrees Fahrenheit (0.8 degrees Celsius) over the past 100 years, according to the National Oceanic and Atmospheric Administration (NOAA). Effects of global Warming Evidence of global warming Images of global warming Images of global warming Most climate scientists agree the main cause of the current global warming trend is human expansion of the "greenhouse effect"1 — warming that results when the atmosphere traps heat radiating from Earth toward space. Certain gases in the atmosphere block heat from escaping. Since 1970, the area of snow cover in the United States has steadily decreased, according to the EPA, and the average temperature of permafrost (soil that's at or below freezing temperature) has grown warmer.One of the most dramatic effects of global warming is the reduction in Arctic sea ice: In 2012, scientists saw the smallest amount of Arctic ice cover ever recorded. Most analyses project that, within a matter of years, the Arctic Sea will be completely ice-free during the summer months. Since record keeping began in 1895, the hottest year on record for the 48 contiguous U.S. states was 2012. Worldwide, 2012 was also the 10th-warmest year on record, according to NOAA. And nine of the warmest years on record have occurred since 2000. According to NOAA, 2013 tied with 2003 as the fourth warmest year globally since 1880. Detailed measurements of atmospheric carbon dioxide (CO2) levels have been taken continuously for more than 50 years. The data show that CO2 levels have steadily increased every year. Today they are 25 percent higher than in 1957.What's more, scientists have detailed records of past CO2 levels from ice core studies, which show that CO2 levels are higher today than at any point since our distant ancestors began migrating out of Africa 800,000 years ago. Causes of global warming The heat-trapping nature of carbon dioxide and other gases was demonstrated in the mid-19th century. There is no question that increased levels of greenhouse gases must cause the earth to warm. ice cores from greenland, antarctica shows that the earth reaponds to change in the greenhouse levels. Images of global warming Images of global warming Global warming is projected to have a number of effects on the oceans. Ongoing effects include rising sea levels due to thermal expansion and melting of glaciers and ice sheets, and warming of the ocean surface, leading to increased temperature stratification. Images of global warming Effects of global Warming Effects of global Warming Declining sea ice is one of the most visible signs of global warming on our planet. Since 1979, Arctic sea ice extent in September (when the annual minimum is reached) has declined by over 30 percent, according to the National Snow and Ice Data Center. The ice extent has been declining in other seasons, when its not supposed to. Evidence of global warming Effects of global Warming Evidence of global warming Extreme weather is an effect of global warming. While experiencing some of the hottest summers on record, much of the United States also has been experiencing colder than normal winters.Changes in climate can cause the jet stream to migrate south, bringing with it cold, Arctic air. This is why some states can have a sudden cold snap or colder than normal winter, even during the long-term trend of global warming. Causes of global warming Sea-level rise has been happening even faster than scientists anticipated a few years ago. If recent projections are accurate, 2-3°F warming could bring about 3 feet of global sea-level rise by 2100, displacing approximately 56 million people in 84 developing countries around the world. Effects of global Warming Climate change presentation Greenhouse gases are released into the atmosphere in many ways, including through the burning of fossil fuels (such as coal and petroleum) and by deforestation. As some environments warm (e.g. the Arctic tundra) they also release carbon that may have been stored for thousands of years. Quite simply, it hasn't. Even global surface temperatures (which is how Spencer is likely measuring 'global warming', although they only account for about 2% of the Earth's warming), have warmed about 0.2°C over the past 15 years, according to the best available measurements. Evidence of global warming Causes of global warming