8模块八课文原文演示教学

Unit 22 Lesson 1 Global Warming

Can we take the heat?

In the last few decades, scientists have reached consensus and reported that human beings are causing changes in the Earth's climate –something previously seen as beyond our control. They claim that in the last 50 years, gases pumped into the Earth's atmosphere by the factories and vehicles have been speeding up the process of global warming and affecting our climate. Looking ahead, scientists believe that global warming could be one of the biggest environmental problems facing the 21st century. But what exactly is global warming, why is it seen as a danger, and how is it relevant to our lives?

Global warming refers to an average increase in the Earth's temperature that, in turn, leads to climate change. Scientists found that the temperature of the Earth is controlled by greenhouse gases such as carbon dioxide which trap heat from the sun in the Earth's atmosphere. Without these naturally occurring gases, the sun's rays would bounce back into space leaving the Earth cold and impossible to live on. When the presence of these gases in the atmosphere increase, however, more heat is trapped and the Earth's temperature rises.

Over the last 100 years, the global average temperature has increased by 1°F and many experts insist that the blame for this global warming can mostly be pinned on human activities. As a result of increased industry, agriculture, the cutting down of forests, the increase in transport and the burning of fuels, nearly 6 tonnes of carbon dioxide goes into the atmosphere every year for every one of the Earth's 6 billion people. The amount of carbon dioxide in the atmosphere has risen by more than 30% in the last 250 years with half of this increase occurring since 1960. Given this data, it seems that the link between human activities and rising global temperatures is not merely a coincidence.

A temperature increase of 1ЎF may not sound like a lot, but if we continue to produce carbon dioxide and other gases in such huge quantities, we are condemning life on Earth and should expect severe consequences. Recent reports warned that global warming will cause terrible climate changes including more frequent flooding, heat waves and droughts. Serious diseases will spread and industries that rely on nature such as fishing will be badly affected. Increased temperatures will also cause the polar ice to melt, raising sea levels and flooding many islands and cities. How can we stop these disasters from happening?

Governments all over the world have a responsibility to reduce the amount of carbon dioxide which their countries are producing. If less carbon dioxide goes into the atmosphere, global warming will slow down. This is no easy task, however, and some governments, for example, the USA's federal government, express reservations about whether global warming is really caused by human activities.

Many people believe that they are simply not prepared to sacrifice the amount of money they make from industry to save the Earth. But why wait around for governments to take action? Experts advocate that each person play their part. They suggest making small changes like taking public transport, recycling, using low-flow shower heads, and buying light bulbs that use less energy. Even simple things like using recycled paper or switching off the lights when you leave a room can help. If we add up all these small changes made by everyone worldwide, they won't be such small changes. They could be the changes that save our future. After all, there's no substitute for our Earth. It's all we've got to live on.