Headline Indicators for Global Climate Monitoring

Blair Trewin,Kirsten Isensee,Alex Vermeulen,Anny Cazenave,Matthew D Palmer,Matthias Huss,Oksana Tarasova,Stephen Howell

doi:10.1175/bams-d-19-0196.1

Abstract

AbstractThe World Meteorological Organization has developed a set of headline indicators for global climate monitoring. These seven indicators are a subset of the existing set of essential climate variables (ECVs) established by the Global Climate Observing System and are intended to provide the most essential parameters representing the state of the climate system. These indicators include global mean surface temperature, global ocean heat content, state of ocean acidification, glacier mass balance, Arctic and Antarctic sea ice extent, global CO2 mole fraction, and global mean sea level. This paper describes how well each of these indicators are currently monitored, including the number and quality of the underlying datasets; the health of those datasets; observation systems used to estimate each indicator; the timeliness of information; and how well recent values can be linked to preindustrial conditions. These aspects vary widely between indicators. While global mean surface temperature is available in close to real time and changes from preindustrial levels can be determined with relatively low uncertainty, this is not the case for many other indicators. Some indicators (e.g., sea ice extent) are largely dependent on satellite data only available in the last 40 years, while some (e.g., ocean acidification) have limited underlying observational bases, and others (e.g., glacial mass balance) with data only available a year or more in arrears.

Highlights

The World Meteorological Organization has developed a set of headline indicators for global climate monitoring
This monitoring includes reporting on annual time scales, such as through the World Meteorological Organization’s (WMO) State of the Climate series (e.g., WMO 2019) and the State of the Climate reports published through BAMS (e.g., Blunden et al 2018), as well through the systematic Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC) (IPCC 2013, 2019a,b)
The main framework for determining key variables representing the state of the climate system has hitherto been the Global Climate Observing System (GCOS) set of essential climate variables (ECVs) (Bojinski et al 2014; Table 1), a concept which dates from the early 2000s

Summary

Introduction

The World Meteorological Organization has developed a set of headline indicators for global climate monitoring. Variable Temperature Ocean heat content Sea level Sea ice extent Glacier mass balance Ocean acidification Greenhouse gas mole fractions

Objectives

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Conclusion