1. What are cfcs and how do they affect the environment?

Worksheet E

Expressions of certainty A scientist used the following sentences. How sure is he about each statement? There’s no doubt at all that the earth is getting warmer. It’s fairly certain that Earth will have heated up by 4 degrees. There will be many other effects. The USA and Russia could suffer from drought. Put the expressions in the correct section of the line below.

100% Sure it will happen _ _ Glaciers are definitly melting, sea levels are rising, cloud forests are dying, and wildlife is scrambling to keep pace. It has become clear that humans have caused most of the past century's warming by releasing heat-trapping gases as we power our modern lives. Called greenhouse gases, their levels are higher now than at any time in the last 800,000 years. This is going to cause additional sea-level rise. We are watching the ice sheet hit a tipping point

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50 % Sure _ This may cause drought in some parts of the world, and floods in others, as ice at the North and South poles begins to melt and sea levels rise. It is not possible to assign a specific percentage to each gas because the absorption and emission bands of the gases overlap (hence the ranges given above). Clouds also absorb and emit infrared radiation and thus affect the radiative properties of the atmosphere _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _