The top United Nations court has taken up the largest case in its history, hearing the plight of several small island nations helpless in combating the devastating impact of climate change.

The United Nations' top court will start unprecedented hearings on Monday aimed at setting legal guidelines for how countries should protect the planet against climate change and help vulnerable nations combat its devastating impact.

In the largest case in its history, the UN's highest court will hear almost 100 countries deliver testimonies on climate change. Campaigners hope it will help underline the obligations of states on global warming.