It would be beneficial to your understanding if you read the article. The title is slightly misleading.
> Even though the dataset used for the unofficial record goes back only to 1979, Kapnick said that given other data, the world is likely seeing the hottest day in “several hundred years that we’ve experienced.”
> Even though the dataset used for the unofficial record goes back only to 1979, Kapnick said that given other data, the world is likely seeing the hottest day in “several hundred years that we’ve experienced.”