* Two-day online summit

* Summit will be opened by US President Joe Biden and Vice President Kamala Harris

* Prime Minister Scott Morrison is due to address the summit on Thursday night

* Morrison will be preceded by US Secretary of State Antony Blinken, Climate Envoy John Kerry, United Nations Secretary-General Antonio Guterres and leaders of Antigua and Barbuda, and Argentina.

* Opening session will underscore the urgent need for the world's major economies to strengthen their climate ambition to keep the goal of limiting warming to 1.5 degrees Celsius within reach

* US State Department says: "It will provide an opportunity for leaders to highlight the climate-related challenges their countries face and the efforts they are undertaking, and to announce new steps to strengthen climate ambition."

* The second session of the summit will look at investing in climate solutions, including private investment to achieve net zero by 2050. This session will involve New Zealand Prime Minister Jacinda Ardern.

* Sessions also planned on adaptation and resilience; role of states, cities and indigenous groups; impact of climate on global security; deforestation and sustainable agriculture; use of technology; and economic opportunities from climate action.

Australian Associated Press