Global warming is worsening droughts, making sea levels rise, and fueling deadly storms. Now scientists have a new problem to add to that list: Climate change is helping rat populations thrive in U.S.

While jet streams are air patterns, the Gulf Stream is an ocean pattern that also has an impact on weather.

There’s a saying that in a big city you are never more than six feet away from a rat. It’s an urban myth but scientists are ...