If it is just a comparison, then it is nice to state that an Adult African Elephant can usually weigh up to 6.6 tons. Just regular 6.6 tons. No millions, no billions, no hundreds. So the weight of that elephant is 0.00000012% of the total amount of carbon released through burning fossil fuels.
In all fairness to the elephant, the atmosphere is really heavy and is much more bigger than an elephant, so this isn't really a surprising answer