I have no doubt that the globe is warming. At least it has been on balance for about 400 years. Please note that the warming which started 400 years ago pre-dates the industrial Revolution, the cause of the warming, by 200 years.
This notion of causality includes the assumption that the future causes the past.
Beyond that, it's a toss up whether or not we were much cooler than we are right now about 5000 years ago. Glaciers are receding to points that are exposing 5000 year old artifacts and mummified people. It is almost a certainty that we are cooler than we were 8000 years ago. How many glaciers in North America are older than 8000 years?
In the Holocene, we have been warmer than now and cooler than now. After the temperature rise that ended the Ice Age, the temperature has vacillated within about a 2 degree range and we are smack dab in the middle of that range right now.
The rise of temperature over the last 2000 years has been about 0.7 degrees. This may strike some as an unprecedented and rapid rise in temperature, but it strikes me as astonishing stability. My living room has greater vacillations in temperature in the average winter evening.