Health Global warming a big issue in today’s media. If we read a news paper or watching news on TV you may read or hear about global warming , What is Global Warming? Global warming is the observed increase in the average temperature of the Earth’s atmosphere and oceans in recent decades and its projected continuation. The prevailing scientific opinion on climate change is that "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations," which leads to warming of the surface and lower atmosphere by increasing the greenhouse effect. Greenhouse gases are released by activities such as the burning of fossil fuels, land clearing, and agriculture. Other phenomena such as solar variation and volcanoes have had smaller and probably negative effects 1950. There are lots of myths about the global warming like. Myth #1: Scientists Agree the Earth is Warming Facts about this Myth It is true that the measured increase in global average temperature over the last century was about 1 degree F. But only if manmade greenhouse gas emissions .pletely stopped immediately would the temperature increase over the next century be limited to 1 degree F. Scientists estimate that the average global temperature increase for the 21st century will be anywhere from 2.5 to 10.4 degrees F, based on the current trends in greenhouse gas output. But even a rise of 2.5 to 10.4 degrees seems like it would be within tolerable limits, right? After all, outdoor temperatures swing much more than that from winter to summer. Second fact is Winters have been getting warmer? Measurements show that Earth’s climate has warmed overall over the past century, in all seasons, and in most regions. The skeptics mislead the public when they bill the winter of 20032004 as record cold in the northeastern United States. That winter was only the 33rd coldest in the region since records began in 1896. Furthermore, a single spell of cold weather in one small region is no indication of cooling of the global climate, which refers to a long-termaverage over the entire planet. Myth #2: Humans Are Causing Global Warming Facts about this myth. It is undisputed that humans are entirely responsible for the increase in atmospheric CO2 over the past few centuries. In pre-industrial times, large natural sources of CO2 were balanced by equally large natural removal processes, such as photosynthesis in plants, maintaining a stable level of CO2 in the atmosphere for thousands of years. Human-produced emissions, though smaller than natural emissions, upset this balance. Because human-produced emissions aren’t .pletely absorbed by natural processes, they accumulate in the atmosphere, increasing the concentration of CO2. There are natural sources of greenhouse gases. At times during the earth’s history, natural emissions of greenhouse gases have been critical factors in major biological calamities on the planet. For instance, during the "Permian extinction" 250 million years ago, volcanic greenhouse gases played a primary role in the catastrophic climate change that caused about 80% of the life on earth to die off. At other times, naturally released greenhouse gases have also played a role. Myth #3: The Government Must Act Now to Halt Global Warming Facts about this Myth . As we read in above paragraphs that in last 18 years we dint see any big impact of Human on global warming so most of the Scientist want to wait for more time. Some scientists followed the .mon scientific assumption that a realistic goal of global warming policy would be to stabilize the concentration of atmospheric CO2 at approximately twice preindustrial levels, or 550 parts per million by volume. Given that economic growth will continue with a con.itant rise in greenhouse gas emissions, the scientists agreed that stabilization at this level is environmentally sound as well as politically and economically feasible. They also concluded that ,Governments can cut emissions now to approximately 9 billion tons per year or wait until 2020 and cut emissions by 12 billion tons per year. Either scenario would result in the desired CO2 concentration of 550 parts per million. Delaying action until 2020 would yield an insignificant temperature rise of 0.2 degrees Celsius by 2100. Myth # 4: Human-Caused Global Warming Will Cause Cataclysmic Environmental Problems Facts about this Myth. No doubt in this myth but human are not causing the global warming as it means there are lot more natural factors which are causing these problems. Reputable scientists, including those working on the Intergovernmental Panel on Climate Change (IPCC), the United Nations .anization created to study the causes and effects of global climate warming, reject these beliefs. The level of sea water is increasing, many of scientist saying this but most of scientists feels that it is increasing for thousand of years. Periodic media reports link human-caused climate changes to more frequent tropical cyclones or more intense hurricanes. Tropical storms depend on warm ocean surface temperatures (at least 26 degrees Celsius) and an unlimited supply of moisture. Therefore, they reason, global warming leads to increased ocean surface temperatures, a greater uptake of moisture and destructive hurricanes. But recent data shows no increase in the number or severity of tropical storms, and the latest climate models suggest earlier models making such connections were simplistic and inaccurate. Since the 1940s the National Oceanographic and Meteorological Laboratory has documented a decrease in both the intensity and number of hurricanes. From 1991 through 1995, relatively few hurricanes occurred, even the unusually intense 1995 hurricane season did not reverse the downward trend. The 1996 IPCC report on climate change found a worldwide significant increase in tropical storms unlikely; some regions may experience increased activity while others will see fewer, less severe storms. Since factors other than ocean temperature such as wind speeds at various altitudes seem to play a larger role than scientists previously understood, most agree that any regional changes in hurricane activity will continue to occur against a backdrop of large yearly natural variations. About the Author: 相关的主题文章: