Political leaders and climate diplomats are going to meet in Madrid for two weeks of talks amidst a growing sense of crisis.
According to UN Secretary-General António Guterres, "the point of no return is no longer over the horizon".
Meanwhile, save the Children says that climate shocks have left millions in Africa facing hunger.
The charity says 33 million people are at emergency levels of food insecurity due to cyclones and droughts.
The world's average surface temperature is rising rapidly because human activities release greenhouse gases such as carbon dioxide (CO2). These gases trap heat in the atmosphere, much like the glass roof of a greenhouse.
This conference of the parties, or COP25, was due to be held in Chile but was cancelled by the government due to weeks of civil disturbances.