VOA慢速英语:如何应对气候变化？种植一万亿棵树

tropic - n. the part of the world that is near the equator where the weather is very warm

cheapest – adj. not costing a lot of money

biodiversity – n. the existence of many different kinds of plants and animals in an environment

realistic – adj. able to see things as they really are and to deal with them in a practical way

monumental – adj. very great or extreme

challenge – n. a difficult task or problem : something that is hard to do

emission – n. the act of producing or sending out something (such as energy or gas) from a source

diet – n. food and drink regularly provided or consumed

scale – n. the size or level of something especially in comparison to something else