Headline Indicators for Global Climate Monitoring

Abstract The World Meteorological Organization has developed a set of headline indicators for global climate monitoring. These seven are subset the existing essential variables (ECVs) established by Global Climate Observing System and intended to provide most parameters representing state system. include mean surface temperature, ocean heat content, acidification, glacier mass balance, Arctic Antarctic sea ice extent, CO 2 mole fraction, level. This paper describes how well each these currently monitored, including number quality underlying datasets; health those observation systems used estimate indicator; timeliness information; recent values can be linked preindustrial conditions. aspects vary widely between indicators. While temperature is available in close real time changes from levels determined with relatively low uncertainty, this not case many other Some (e.g., extent) largely dependent on satellite data only last 40 years, while some acidification) have limited observational bases, others glacial balance) year or more arrears.