Earth observation satellites to track climate goals under Paris agreement from above

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As extreme weather events become more intense and frequent, scientists across the world are exploring ways to control climate change. Satellites could prove critical in tracking the developments from above as countries vye to limit emissions under the Paris agreement.

The European Space Agency (ESA) is working on Paris Agreement's goals by providing technology as 200 countries reaffirmed their commitment to climate action at the United Nations COP26 climate conference in Glasgow last year.

"Satellites have been delivering evidence and documents about the global climate system for a long time," Michaela Hegglin, an atmospheric chemistry specialist at the University of Reading in the United Kingdom said. He is working with ESA to develop a research plan for remote sensing in support of the Paris Agreement.

Earth observation satellites will be used to contribute to the global stocktake, a five-year assessment cycle that aims to raise global ambition and improve future climate action. Prof. Hegglin said, "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."

Emission monitoring is the most developed application for space-based remote sensing; with it, satellites can detect trends in natural sources of greenhouse gases like methane and carbon dioxide in remote or difficult-to-reach parts of the globe, and Hegglin also refers to using satellites to detect emission hotspots from human activity as a rapidly advancing application.

The rapidly increasing capability of space-based sensing technology can help validate national reporting of greenhouse-gas emissions. (Photo: ESA)

"The Copernicus Sentinel-5P mission, as well as 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 the ability to identify and target greenhouse-gas reduction opportunities from oil and gas fields, urban areas, and high-intensity energy facilities such as power plants have capabilities to identify and target greenhouse-gas reduction opportunities The data can also be used to evaluate the efficiency of associated carbon-cutting strategies."

In underdeveloped nations where in-situ measurement networks are limited, the growing technology of space-based sensing authenticates national reporting of greenhouse gas emissions and informs inventories of forestry, agricultural, and other land-use changes.

ESA is using new methods with the help of its RECCAP-2 project to improve estimates of carbon surface fluxes between the atmosphere, land and ocean, which are based on a technique known as inverse atmospheric modelling. They will use an empirical satellite approach for measurements of greenhouse gases. Agencies could then compare this data to national-scale estimations using this independent data source.

According to the notes of Prof. Hegglin, "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." These improvements are especially important in light of recent research from ESA's RECCAP-2 project, which found considerable differences in land sink estimates and anthropogenic emissions between models informed by satellite data and national inventories.

Prof. Hegglin added, "Satellites provide a wealth of relevant geophysical variables." Efforts should focus on the co-development of indicators with stakeholders and end users. The use of high-resolution land surface temperature based on satellite data, along with canopy cover data, to track the effectiveness of urban greening in mitigating the effects of heatwaves is one example.

"Adaptation needs are always locally-specific, hence the emphasis on co-developing applications that use satellite data with policymakers and stakeholders, only then will climate services truly increase communities' resilience at the local level" says Prof. Hegglin.