Earth observation is already capable of supporting national climate action, but there are many more opportunities on the horizon, according to discussions today among leading scientists and policymakers at ESA’s Living Planet Symposium being held in Bonn, Germany.

Last year, at the United Nations COP26 climate conference in Glasgow, almost 200 countries reaffirmed the Paris Agreement goals of limiting global temperature rise to well below 2°C. Countries also stepped up their support for adaptation in response to the worsening impacts of climate change.

To support nations’ climate commitments and ambitions under the Paris Agreement, ESA is bringing together both minds and technology.

Satellites, with their global view, have long provided the evidence used to identify trends and document the state of the global climate system, says atmospheric chemistry scientist Michaela Hegglin of the University of Reading in the UK.

She has been working with ESA to draw up a roadmap for remote-sensing research in support of the Paris Agreement.

In particular, Earth observation will contribute to the Agreement’s five-yearly review cycles, known as the Global Stocktake, designed to help raise collective ambition and strengthen further climate action.

However, “it is at the national level where Earth observation can support action, for example in the reporting of emissions, monitoring carbon sources and sinks, such as forests, and providing crucial local information for the adaptation process,” Prof. Hegglin.

Emissions monitoring is the area where space-based remote-sensing is arguably the best developed capacity. With their global view, satellites can be used to detect trends in natural sources of the greenhouse gases methane and carbon dioxide in remote or hard-to-access regions of the world.

Prof. Hegglin points to the use of satellites for detecting emission hotspots from human activity as a rapidly advancing application.

“The Copernicus Sentinel-5P mission and the upcoming Copernicus Anthropogenic Carbon Dioxide Monitoring, CO2M, mission – one of six Copernicus Sentinel Expansion missions that ESA is developing on behalf of the EU – have capabilities to identify and target greenhouse-gas reduction opportunities from oil and gas fields, urban areas and high-intensity energy facilities such as power plants. The information can also be used to assess the effectiveness of related carbon reduction policies.”

The rapidly increasing capability of space-based sensing technology can help validate national reporting of greenhouse-gas emissions and inform inventories of forestry, agriculture, and other land-use changes, especially in developing countries where in-situ measurement networks provide insufficient information.

New methods that ESA is pioneering through its RECCAP-2 project and based on a technique known as inverse atmospheric modelling, can improve estimates of carbon surface fluxes between the atmosphere, land and ocean. The approach uses empirical satellite measurements of greenhouse gases.

Equipped with this independent data source, agencies could then compare this with national-scale estimates.

“The new methods pave the way for improving mitigation policy and progress reporting by individual countries to meet their pledges as part of the Paris Climate Agreement,” Prof. Hegglin notes.

These advances are particularly relevant as recent research from ESA’s RECCAP-2 project highlights significant discrepancies between models informed by satellite measurements and national inventories relating to land sink estimates and anthropogenic emissions.

In relation to adaptation, Prof. Hegglin adds, “Satellites provide a wealth of relevant geophysical variables. Although examples exist, adaptation indicators and targets are, as of yet, not clearly defined. Efforts should focus on the co-development of indicators with stakeholders and end users.”

An example is the use of high-resolution land surface temperature based on satellite data, along with canopy cover data to track the effectiveness of urban greening to mitigate the impacts of heatwaves.

“Adaptation needs are always locally-specific, hence the emphasis on co-developing applications that use satellite data with policymakers and stakeholders and to integrate other useful sources of information relating to user needs. Only then will climate services truly increase communities’ resilience at the local level,” says Prof. Hegglin.

The areas discussed at the Living Planet Symposium form elements of ESA’s proposed new climate programme, CLIMATE-SPACE.

Subject to approval at the ESA Ministerial Conference in November 2022, it aims to respond to the new requirements for Earth observation to support the UNFCCC Paris Agreement, while continuing the research and development of satellite-derived Essential Climate Variables that support the needs of the UNFCCC for systematic observations of the climate system.