What a one-degree global temperature means?

Despite a majority of the world experiencing some sort of extreme weather or heat waves, the tri-state area had a relative consistency making it great for summer baseball. My dad took the picture below near Diamond Nation in New Jersey. This reminded me of something I read about global warming - wish the world with peace.

"A one-degree global change is significant because it takes a vast amount of heat to warm all of the oceans, the atmosphere, and the land masses by that much. In the past, a one- to two-degree drop was all it took to plunge the Earth into the Little Ice Age. A five-degree drop was enough to bury a large part of North America under a towering mass of ice 20,000 years ago." https://earthobservatory.nasa.gov/world-of-change/global-temperatures