ReliefWeb

Introduction

The WMO Statement on the Status of the Global Climate in 2015 covers many aspects of the climate system, including atmospheric and ocean conditions, El Niño, the cryosphere, greenhouse gas concentrations, regional extremes, tropical cyclones and ozone depletion. The Statement draws on in situ and space-based observations collected through various WMO and co-sponsored programmes. It also draws on numerical objective analyses. These observations are the Essential Climate Variables that have been defined by the Global Climate Observing System.

The international datasets underpinning this assessment are maintained by advanced climate data, monitoring and research centres that collaborate with WMO. In addition, data and climate information has been collected directly from WMO Members through a special WMO survey.

The global temperature analysis combines three international datasets: the first (HadCRUT) is maintained by the Met Office Hadley Centre in collaboration with the Climatic Research Unit at the University of East Anglia (both in the United Kingdom of Great Britain and Northern Ireland); the second is kept by the National Oceanic and Atmospheric Administration National Centers for Environmental Information (United States of America); and the third is maintained by the National Aeronautics and Space Administration, Goddard Institute for Space Studies (United States). The WMO analysis also incorporates reanalysis data maintained by the European Centre for Medium-Range Weather Forecasts and by the Japanese Meteorological Agency.

Global precipitation information is provided by the Global Precipitation Climatology Centre (Germany).
The assessment of national temperature anomalies uses data collected directly from Members through a WMO survey. Data used in this publication relating to socioeconomic impacts are based on reports provided directly by Members or are taken from authoritative United Nations sources. The peer-review process involves international climate experts, regional institutions dealing with climate products and experts from the National Meteorological and Hydrological Services. In some cases, it was necessary to cross-check with national focal points in order to validate or update information available from global sources.