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Global Warming: What is our understanding of it and to what extent are Humans to Blame?

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Rohit Abbi L6PC Global Warming: What is our understanding of it and to what extent are Humans to Blame? According to the National Academy of Sciences, the Earth's surface temperature has risen by about 1 degree Fahrenheit in the past century, with accelerated warming during the past two decades. There is growing evidence that most of the warming over the last 50 years is down to human activities. Human activities have altered the chemical composition of the atmosphere through the build-up of greenhouse gases - primarily carbon dioxide, methane, and nitrous oxide. The heat-trapping property of these gases is undisputed although uncertainties exist about exactly how Earth's climate responds to them. What Are Greenhouse Gases? Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occurring greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases: Carbon dioxide is released to the atmosphere when solid waste, fossil fuels (oil, natural gas, and coal), and wood and wood products are burned. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from the decomposition of organic wastes in municipal solid waste landfills, and the raising of livestock. ...read more.


Before the Industrial Revolution, human activity released very few gases into the atmosphere, but now through population growth, fossil fuel burning, and deforestation, we are affecting the mixture of gases in the atmosphere. What do we know for certain? Scientists know for certain that human activities are changing the composition of Earth's atmosphere. Increasing levels of greenhouse gases, like carbon dioxide, in the atmosphere since pre-industrial times have been well documented. There is no doubt this atmospheric build-up of carbon dioxide and other greenhouse gases is largely the result of human activities. It's well accepted by scientists that greenhouse gases trap heat in the Earth's atmosphere and tend to warm the planet. By increasing the levels of greenhouse gases in the atmosphere, human activities are strengthening Earth's natural greenhouse effect. The key greenhouse gases emitted by human activities remain in the atmosphere for periods ranging from decades to centuries. A warming trend of about 1�F has been recorded since the late 19th century. Warming has occurred in both the northern and southern hemispheres, and over the oceans. Confirmation of 20th-century global warming is further substantiated by melting glaciers, decreased snow cover in the northern hemisphere and even warming below ground. What are we unsure about? ...read more.


How fast will this warming occur? And what are the potential adverse and beneficial effects? These uncertainties will be with us for some time, perhaps decades. Global warming poses real risks. The exact nature of these risks remains uncertain. Ultimately, this is why we have to use our best judgement - guided by the current state of science - to determine what the most appropriate response to global warming should be. Are humans to blame? Many believe that human activities have accelerated global warming - but without the necessary facts, it still remains unclear. Although humans have increased the amount of greenhouse gases into the atmosphere, we are still unsure as to whether or not this has accelerated global warming. Whilst much research is conducted to finding a relationship between human activity and global warming, many multinational companies endeavour to distort information and hinder the progress in the efforts to increase profits. Only with time will we be able to distinguish whether or not humans have caused global warming - but by then it may be too late. Therefore, it would be more beneficial to the world if efforts were made now to reduce greenhouse gas emissions and curb industrial activity. However, with ever-expanding populations, third-world countries trying to develop, multinational companies increasing their industrial activities, and through many people's own ignorance and naivety, these efforts are very difficult to instil. ...read more.

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