When the effects of climate change are too far reaching to adapt to, people sometimes face loss and damage – of property, livelihood or even their countries or their lives. In other words, when there is not enough mitigation (reduction of emissions and thereby less climate change) and when adaptation is not possible – then there can be loss and damage, due to the impacts of climate change.
A common example is the risk small island countries face when sea levels rise due to a warmer climate – as it is not possible to “adapt” to a country swallowed by the sea, the people of such countries face loss and damage.
For further reading on loss and damage, see for example the website of the International Centre for Climate Change and Development (ICCCAD). For the UNFCCC specific information on loss and damage, see their Chronology web page.