Steve Koonin isn't a climate scientist an isn't qualified to give intelligent opinions on the subject. He has a history of making misleading and erroneous statements.
RealClimate: Koonin’s case for yet another review of climate science This article points out errors and flaws in Steve Koonin's 56 minute video on the need for a red team.
The climate models vary greatly in their accuracy so one cannot conclude that climate models over project future warming by 30%.
- Dr. Koonin: But if the model tells you that you got the response to the forcing wrong by 30 percent, you should use that same 30 percent factor when you project out a century.
Analysis: How well have climate models projected global warming? | Carbon Brief 2017 article
Difference in 1970-2016 mean warming rate versus observations
IPCC 1 +17%
IPCC 2 -20%
IPCC3 -14%
IPCC4 +8%
IPCC5 +16% (+9% based on a model using blended land/ocean fields)
Conclusion
Climate models published since 1973 have generally been quite skillful in projecting future warming. While some were too low and some too high, they all show outcomes reasonably close to what has actually occurred, especially when discrepancies between predicted and actual CO2 concentrations and other climate forcings are taken into account.
Models are far from perfect and will continue to be improved over time. They also show a fairly large range of future warming that
cannot easily be narrowed using just the changes in climate that we have observed.
Nevertheless, the close match between projected and observed warming since 1970 suggests that estimates of future warming may prove similarly accurate.