Topic pages introduce the WMO's work areas. They provide accessible information, a definition, the impact and how a topic links to WMO's work. Topics are used across the website as references. Main themes Water Climate Weather Extreme weather Natural hazards Sand and dust storms Floods Heatwave Tropical cyclone Drought Sectors Health Energy Aviation Earth System domains Earth observation satellites Ocean Cryosphere Atmospheric phenomena Greenhouse gases El Niño / La Niña Challenges Socioeconomic impacts and benefits Early warning system Climate change