Ok, thanks, Mr. Fang. My homework here:

一项新的研究表明，极端天气正在导致墨西哥和美国之间无证人员的移入和返回，这表明随着气候变化加剧干旱、风暴和其他困难，更多的移民可能会冒着生命危险穿越边境。

 

A new research shows that extreme weather is/ was causing the to-and-fro of undocumented immigrants between Mexico and United States (Or was causing the migration and return of undocumented immigrants) , indicating that more immigrants will risk their lives to cross the borders as the weather exacerbates the drought, storms and other difficulties.