[填空题]Climate Change
Scientists predict increasing droughts, floods and extreme weather and say there is growing evidence that human activities are to blame.
What Is Climate Change
The planet’s climate is constantly changing. The global average temperature is currently in the region of 15℃. Geological and other evidence suggests that, in the past, this average may have been as high as 27℃ and as low as 7℃.
But scientists are concerned that the natural fluctuation (波动) has been overtaken by a rapid human-induced warming that has serious implications for the stability of the climate on which much life on the planet depends.
What Is the "Greenhouse Effect"
The greenhouse effect refers to the role played by gases which effectively trap energy from the Sun in the Earth’s atmosphere. Without them, the planet would be too cold to sustain life as we know it.
The most important of these gases in the natural greenhouse effect is water vap