Mars has a mean surface pressure of 600 pascals, compared with Earth’s 100,000 pascals. In other words, the atmospheric pressure on Earth is about 150 times higher than Mars.
Mars has 0.95 mole fraction CO2, compared to 0.0004 on earth. The concentration of CO2 in Mars atmosphere is more than 2,000 times higher than Earth.
So lets do the math for Mars and Earth.
Mars : 600 pascals * 0.95 = 575 pascals (partial pressure of CO2)
Earth : 100,000 pascals * 0.0004 = 40 pascals (partial pressure of CO2)
The partial pressure of CO2 on Mars is 14X larger than earth, yet Earth is much warmer. Now use your brain and figure out the connotations.
Hint : It is the pressure, not the CO2 (stupid)