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While unusual weather patterns have always come and gone, in a changing climate extreme weather events will become more frequent. And this year has already had its fair share of extremes.

But if extreme temperatures arrived in your area, would you even notice?

Often, the answer is no, according to a study published Monday in the journal Proceedings of the National Academy of Sciences. In it, researchers analyzed more than two billion Twitter messages to see how people reacted to weather events .

In fact, the study suggests, people learn to accept extreme weather as normal in as little as two years.

That might lead people to underestimate the extent of global warming, given that it has already caused extreme temperature changes. If you were born after 1976, for example, the Earth has been warmer than the 20th century average every year of your life (though local temperatures vary).