Global temperatures and atmospheric CO2 concentrations have been much higher in the deep past.
However the ice cores show that today's atmospheric CO2 methane is far higher than any time in the past 800,0000 years. The rate of global warming today is extremely high.
Atmospheric CO2 (411 ppm April 2019) is 37% higher than its 800,000 year limit (300 ppm).
Atmospheric methane (1800 ppb) is 160% or over two and a half times higher that its pre-industrial level(722 ppb).
Furthermore the rate of increase in atmospheric CO2 is unprecedented (IPCC and WMO).