$20-$30 trillion in damages for 2020-2022 is a reasonable estimate (taking into account hits to economic output, budgets, stock markets, some reasonable number for lives lost & human suffering). China could come up with $2-$3 trillion as reparations. $30t is likely a bit high (and $10t would be too low).
The global economy is unlikely to shrink more than 5-7% this year (call it a $4 to $6 trillion contraction). I believe the IMF and Worldbank are both around 5% contraction as their guesses. It will likely resume growth in 2021. Most of the major stock markets are being propped up and haven't suffered horribly. The big damage has been in lives lost, suffering caused (in numerous ways), and the social financial cost in budgets (blown out budgets, debt, unemployment, etc.). There will be ongoing unemployment costs for years post vaccine, which I've assumed in the $20-$30 trillion figure.
That 1/10th figure is not the problem. China could come up with $300b per year over ten years. The problem is they'll pay those reparations over their dead body, so to speak.
