If the CO2 that we emit really stays in the atmosphere for thousands of years, why did CO2 decline .43 ppm since last week?

Warmist Frustration: Atmospheric CO2 continues down — now only 399.29! | JunkScience.com

The Keeling Curve swerves: down 0.10 ppm since May 1 and 0.43 ppm since last week.