@misc{Riv22c,
   author =       { Ronald L. Rivest },
   title =        { Coo-balls },
   date =         { 2022-08-06 },
   note =         { (Unpublished.) },                  
   abstract = {
 Carbon dioxide (CO2) is invisible,
  hiding the scale of our carbon dioxide pollution. 
  So we propose a thought experiment:
  \textit{Suppose CO2 generated by burning fossil fuels
  was always emitted in
   ``coo-balls'' (colored ping-pong balls)?}
  (Pun between ``coo'' and ``CO2'' intended, of course!)
  We ask, ``How many coo-balls would be emitted?''
  \begin{enumerate}
  \item 
    An average gasoline-powered car emits about one
    coo-ball every 26 cm (10 inches) of travel.
  \item
    The burning of fossil fuels produces
    about $5 \times 10^{17}$ coo-balls per year,
    enough to cover the entire surface of the earth (oceans and
    polar regions included) with a layer of tightly packed coo-balls once,
    with about
    40\% of the earth covered twice!
  \item 
    Since the beginning of the Industrial Revolution (1751),
    we have produced enough coo-balls to cover the entire surface of
    the earth (oceans and polar regions included) to a depth of
    six or seven feet!
    \end{enumerate}
}
}