The UN says natural disasters, driven by climate change, have increased five-fold over the past 40 years. Floods and heatwaves have killed more than two million people and brought about over $3.6 trillion in total losses in that time. It comes as the world continues to experience more extreme examples of global warming every year. As water levels rise, the very existence of small islands and many major coastal cities is at risk. Many experts say immediate and comprehensive action is needed to offset a global crisis like no other.