Background - Systematic observation

The WMO supports the UNFCCC through a wide range of scientific and technical inputs, including annual GHG bulletins and State of the Global Climate statements (see resource documents). Its Members monitor the Earth's atmosphere, land and oceans, through the  WMO Integrated Global Observing System (WIGOS). A subset of WIGOS is used by GCOS for climate observations.

GCOS have identified, in their Implementation plan, a set of 54 Essential Climate Variables (ECVs) that are key for sustainable climate observations. ECV datasets provide the empirical evidence needed to understand and predict the evolution of climate, to support evidence-based decision-making on climate change and to manage associated risks.

The CEOS/CGMS WGClimate provided the Space Agency Response to the GCOS Implementation Plan at SBSTA 47 (2017). It details the continuing development of the global Architecture for Climate Monitoring from Space, including the ECV inventory providing characterisation of over 900 satellite Climate Data Records (CDRs) that directly respond to GCOS ECV requirements.

Under the Convention, there is an ongoing cycle of assessments, reports and implementation plans from the IPCC, GCOS and CEOS, supported by the WMO and guided by decisions and conclusions from the COP, SBI and SBSTA.

1995-2000 Following the IPCC Second Assessment Report (SAR 1995), COP asked SBSTA in 1997, in consultation with the IPCC, to provide an adequacy report (1998) on the global observing system on climate, which was prepared and delivered by GCOS in 1998;

After the IPCC third assessment report (TAR 2001), GCOS provided its second adequacy report (2003) to SBSTA. The COP asked GCOS to provide an implementation plan (IP 2004). The CEOS response to the IP 2004 lead to the Satellite Supplement to the implementation plan (2006).


Following the IPCC fourth assessment report (AR4 2007), GCOS provided the progress report to SBSTA 31 (2009). GCOS subsequently provided an update to the GCOS Implementation Plan (IP 2010) and an updated Satellite Supplement (2011);


Following the IPCC fifth assessment report (AR5 2013-2014), GCOS submitted the GCOS Status Report (2015) to COP 21, which incorporates updates and reviews from CEOS and a large range of other contributors and fed into the new GCOS Implementation plan (IP 2016). The CEOS/CGMS WG Climate provided the Space Agency Response to the GCOS Implementation Plan at SBSTA 47 (2017).

National Communications

At COP 5, the COP invited all Parties to provide detailed reports on systematic observation in line with reporting guidelines on global climate observing systems, as part of their national communications for Annex I Parties and on a voluntary basis for non-Annex I Parties.

At COP 11, by decision 11/CP.13 (page 45) on Reporting on global observing systems for climate, the COP adopted revised UNFCCC reporting guidelines on global climate change observing systems and decided that these guidelines be used for the preparation of detailed technical reports on systematic observation in accordance with the provisions of decisions 4/CP.5 and 5/CP.5. Annex I Parties provide these reports as part of their national communications.

At SBSTA 33, the SBSTA encouraged Parties when preparing their national communications to take into consideration the new requirements identified in the 2010 updated GCOS implementation plan, in particular the new essential climate variables (ECVs). The SBSTA noted that any future revision of relevant UNFCCC reporting guidelines, in particular those on global climate change observing systems, should take into account the new elements identified in that plan (see FCCC/SBSTA/2010/13 paragraph 44).

National Communications now need to take into account the new ECVs and other information in the 2016 GCOS Implementation plan.