I just had to do the numbers...
According to
this, world burning of fossil fuels emits roughly 25 billion tons of CO2 per year, or
68 million tons per day, or
2.9 million tons per hour, or
47,500 tons per minute, or
792 tons per second.
That means our CO2 savior Dave Matthews has staved off imminent DOOM by 22.7 seconds. What a great guy.