高中英语同步教案：UnitGlobalwarming人教新课标选修_6

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Global warming may be twice as bad as feared

The impact of global warming could be twice as severe as the worst scenario feared by United Nations scientists, the world’s largest climate-modelling experiment has shown.

Average temperatures could rise by 11℃(20) to reach highs that would change the face of the globe, researchers who have run 60,000 computer simulations of climate change said yesterday. The conclusions suggest that forecasts by the UN’s Intergovernmental Panel on Climate Change (IPCC) may be much too conservative. In the worst case, the world would eventually heat up by almost double the maximum increase envisaged by the panel. The IPCC’s latest report predicted that temperatures will rise by between 1.4℃(2.5) and 5.8℃(10.4) by 2100.

A world 11℃warmer than it is today would be unrecognisable: while records show that the planet has been hotter than it is today for about 80 per cent of its history, there is no evidence that it has ever been more than about 7℃warmer.

Although it would take hundreds of years for the full effects to be felt, the polar ice caps eventually would melt completely, causing sea levels to rise by 70m to 100m (230ft to 330ft). Coastal and low-lying cities such as London and New York would be submerged.

As the 11℃figure is a global average, temperatures would be expected to climb even further in some regions.

David Stainforth, of the University of Oxford, the study’s chief scientist, said: “When I start to look at these figures, I get very worried about them. An 11-degree warmed world would be a dramatically different world.”

Global warming

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 new and stronger evidence that most of the warming over the last 50 years is attributable to human activities.

Human activities have altered the chemical composition of the atmosphere through the buildup 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.

Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases, such as water vapor, carbon dioxide, trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse.

Without this natural “greenhouse effect”, temperatures would be much lower than they are now, and life as known today would not be possible. Instead, thanks to greenhouse gases, the earth’s average temperature is a more hospitable 60°F.

However, problems may arise when the atmospheric concentration of greenhouse gases increases. Once, all climate changes occurred naturally. However, during the Industrial Revolution, we began altering our climate and environment through changing agricultural and industrial practices. 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.

Carbon dioxide is released to the atmosphere when solid waste, fossil fuels 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. Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of solid waste and fossil fuels.

Rising global temperatures are expected to raise sea level, and change precipitation and other local climate conditions. Changing regional climate could alter forests, crop yields, and water supplies. It could also affect human health, animals, and many types of ecosystems and deserts may expand into existing rangelands. Unless we act now, our children will inherit a hotter world, dirtier air and water, more severe floods and droughts, and more wildfires.

But solutions are in sight. We know where most heat-trapping gases come from: power plants and vehicles. And we know how to curb their emissions: modern technologies and stronger laws. By shifting the perception of global warming from abstract threat to pressing reality, and promoting online activism. By pressing businesses to use less energy and build more efficient products. And by fighting for laws that will speed these advances.

What is Clean Up Australia Day

Every year hundreds of Australians help clean up their local environment on Clean Up Australia Day. It’s easy, fun and everyone can take part.

Individuals, local groups and schools can either organise a Clean Up site, or volunteer to join an existing site.

So why not do your bit for the environment and get involved next year?

Clean Up Australia Day in 2005

Across the country over 670,000 volunteers removed more than 8,450 tonnes of rubbish from our beaches, parks, streets, bush land and waterways as part of Clean Up Australia Day, the nation’s largest community based environmental event.

Families, friends, neighbours, businesses and community groups spent the equivalent of 62,163 days, at over 7,000 sites, removing rubbish ranging from car bodies and electronic waste to