Achieving net-zero by the second half of the century is considered vital if global temperatures are to remain well below the two degrees rise as set out by the Paris Agreement for climate. From their vantage point in space, satellites provide a unique means of tracking progress towards achieving this balance between greenhouse gas emissions from sources and removal by sinks.

How space-based approaches can support the UN Global stocktake, starting in 2023, are the focus of technical discussions at the 2022 United Nations Climate Change Conference (COP27) currently taking place in Sharm El-Sheikh, and feature results from ESA’s trailblazing REgional Carbon Cycle Assessment and Processes project. These results come at a critical time ahead of next week’s ESA Council Meeting at Ministerial Level.

Carbon reporting

Research from the REgional Carbon Cycle Assessment and Processes project (RECCAP-2), led by Philippe Ciais of the Laboratoire des Sciences du Climat et de l’Environnement (LSCE), is informing global climate policy by constraining the carbon budget – the remaining future emissions available before the warming limits laid out in the Paris Agreement are breached.

The RECCAP-2 research team processed data models of greenhouse gases in the atmosphere, together with measurements taken on the ground and from spatial remote sensing, in order to establish a model for carbon dioxide suitable for evaluating national greenhouse gas inventories submitted by countries to the United Nations Framework Convention on Climate Change (UNFCCC).

The team modelled the data to show how the gases can move, or ‘flux’, between land and atmosphere, for example when carbon dioxide is absorbed by vegetation, released by wildfires, or transported by rivers.

This newly developed methodology is paving the way for countries to also improve checks and consistency of national greenhouse gas inventories used by the UN to assess collective action towards net zero.

Understanding the carbon cycle

Importantly, the team have used these methods to estimate emissions at a country scale enabling them to compare with national greenhouse gas inventories. In doing so, they provide the ability for countries to check, using independent observations, that they are responsibly delivering on their carbon reduction commitments under the Paris Climate Agreement.

Currently, country estimates of sector-based activity are used to compile their national greenhouse gas reports, combining activity statistics with emission factors. These estimates are periodically submitted to the UN and are used to assess collective progress as part of the UN Global Stocktake.

Clement Albergel at COP27
Clement Albergel at COP27

Results from RECCAP-2 were presented during Earth Information Day at COP27 with a video describing the results selected for the Global Stocktake Creative Space Side Event. It triggered a lot of discussions on how to best communicate scientific results towards policy makers.

RECAPP-2 is part of ESA’s Climate Change Initiative programme which is on the table for further funding at ESA’s Ministerial Council Conference taking place taking place on 22 and 23 November 2022. To support both national and global climate action, ESA’s research and development programme proposal ‘Climate–Space’ will not only continue the production of its Essential Climate Variables, but will support the UNFCCC Paris Agreement, climate modelling and tipping points.

ESA’s Director of Earth Observation Programmes, Simonetta Cheli, commented, “It is projects like RECAPP-2 that once again highlight the critical importance of satellite data while facing the climate crisis. With COP27 taking place this week and ESA’s Ministerial Council next week, we must remember Europe’s long-term goal of becoming the first net-zero continent by 2050.

Europe must continue to lead the global fight against climate change. Meeting these ambitious targets cannot be done without the use of Earth observation data. We must remind European decision-makers that this is the case.”

ESA also photos