In 1988, the UN and NASA said they were 99% certain that the midwest drought was caused by the greenhouse effect.
8 Jul 1988, Page 1 – Tyrone Daily Herald at Newspapers.com
The 1988 drought was the last severe midwest drought.
Climate at a Glance | National Centers for Environmental Information (NCEI)
As always, the UN and NASA have no clue what they are talking about.