Several countries’ national determined contributions (NDCs) highlight climate finance as a precondition for the ambitious action needed to achieve development paths compatible with limiting global warming to 1.5°C in 2100. Many hopes have been pinned on new market mechanisms in this context, but the trade-offs demanded by carbon trading schemes continued to be hotly debated at the UNFCCC last week, not least due to their political and economic implications. Laima Eicke reports