The problem with global public goods has always been the difficulty of incentivising actors to contribute to their provision.
Critical factors for this to occur are a display of leadership by the countries that matter. And this is where it is crucial for clubs such as the G20 to step up to the plate. While it includes only a small number of countries, these are systemically important in both economic and population terms. Their importance also means that their actions have an impact on the effective provision of global public goods.