It sounds a bit like what might happen at a hat shop or maybe a
college graduation, but cap and trade is really one of the most
promising ideas for controlling the greenhouse gases that are
causing global warming. The "cap" part comes in not as a item of
clothing but rather as a limit imposed by a government on how
much of a particular greenhouse gas can be emitted by take your
pick everyone in a particular industry; everyone in all
industries, or even everyone in the country. However it's set
up, the idea is that the cap is gradually squeezed down over
time, say by a certain percentage per year. So everyone who was
putting out, say, carbon dioxide in Year 1 would have to put out
somewhat less in Year 2, and so on. This is easier for some
folks than others, though. Maybe Factory # 1 figures out a way
to capture most if its CO2 but Factory #2, making a totally
different product, just can't do that. That's where the "trade"
part comes in. Factory #1 is now putting out a lot less CO2 than
it's allowed to under t