The gap in funding is very big: 100:1

Adaptation gap: poorest will be hit hardestThis is the gap for financing adaptation to climate change in developing countries.
Thus far the total funding for adaptation measures includes around $200 millions of donor funding plus few hundred $millions from the 2% levy on CDM projects. Required funds are estimated at tens of $billions per annum.

The UNFCCC 2007 project on Investment and Financial Flows to Address Climate Change highlighted both the scale of funds required and the need for innovative financing for adaptation (0.2 MB). IMERS is such an innovative proposal for international maritime transport, that puts a carbon on shipping emissions, with no burden on developing countries.
A share of net revenue raised that could be directed to adaptation alone is estimated in excess of $4bn annually.

At a time when there is a substantial mismatch between funds raised and required for adaptation the advantages and financing scale of IMERS cannot be ignored.