9 Takeaways From the National Climate Reportbr By HENRY FOUNTAIN and NADJA POPOVICH AUG. 8, 2017br A scientific report on climate change obtained by , part of a regular federal climate assessment, showsbr that warming is already having a large effect on the United States.br While temperatures in the country (excluding Alaskabr and Hawaii) have increased an average of 1.2 degrees Fahrenheit since 1900, the Southwest and the Northwest, as well as the Northern Great Plains, have seen a temperature increase of 1.5 degrees or more.br How average annual temperatures have changedbr Since the first half of the 20th centurybr The report said that heat waves and droughts had reached record intensities in some parts of the country.